I've only dealt with large GL beams, on a temporary fitting for a half built condo in the new base village in snowmass. (long story) This page from the american wood councill is very good. https://awc.org/issues/mass-ti...
We've done a few - a private long term care facility (about $65M), recently an airport terminal expansion ($15M), and a few smaller projects in the works right now.
We like it, though it does have its challenges. For the LTC building, we had to hire a code consultant to satisfy the AHJ, since that was 6 storeys and had never been done in our region.
I did a large house with heavy timber a bunch of years ago, so older experience. One key consideration is how you are going to insulate it. Because the timber is expensive and pretty, there is a strong tendency to want to see all of it as the finished product. Which means it needs to be insulated outside the structural system itself. Which means the enclosure system is often separate from the structure (attached to it, interior or exterior, rather than integral/inside it).
My limited understanding is there are two types of MT.
One is intended to be exposed and as such is larger to accommodate the required fire ratings.
The other needs to be covered with a fire rating. This is typically a gwb assembly. As such, the hidden MT is not of finished grade - think OSB.
Using CI outside of the structure isn't something I'm too concerned about. It's something I've done quite often. Over the last decade I'd guess 90% of the buildings I've designed use a CI outside the structure.
In my mixed-use/commercial career, I never once saw a MT project pencil out when compared to literally any other system. At 8 stories and below, 5-over-3 is way cheaper. over 8 stories, steel or concrete is much more sensible. So there's that. But if a client wants to blow cash on it for some other reason, awesome. ;-) The Bullitt Center turned out very nice.
Having said that, I've always wanted to do a hybrid CLT structure (framed walls / CLT or NLT floors/roof) to get more floors in a mid-rise multi-family project with a low height limit.
Done a couple in my career, the biggest one being a 16000 sqm GFA ( 4-storey 180 metre long ). This would be a 40 plus storey if we flipped the building vertically . Everything was a challenge ; super tight deadline, transportation and a lot ( a lot ) of coordinations. One good example is that every single penetration through beams/floors needed to be coordinated/approved and then cut in the factory as there is a limit of the size that can be cut on site. Unlike a conventional RC structure , where coring is a norm.
On my 3rd Mass Timber project (100k, 30k, 200k sf). Primary reasons for using it is the perceived carbon reduction. Although... I wonder if we are kidding ourselves. Building mass timber structures that can't be disassembled and reused, typically expected to last 50 years, is basically deferring our carbon debt / kicking the can down to future generations. No?
Calling ourselves out for carbon-washing aside, the spaces inside exposed timber buildings are much warmer, comfortable feeling, and visually interesting.
Timber structure really do go up FAST.
From a "craft" point of view, it was more fun to design with timber because the structure IS the architecture. Lots of opportunities to nerd out on beautiful technical details.
There's definitely a learning curve. Wood Works is a great resource.
gwharton is right about steel. Steel and aluminum is recycled. This is because it is melted to molten state and the may be re-casted into something. Of course, there is a carbon footprint in that.
Wood can be recycled into some things but wood is not easily recycled into what it was. If a beam is recycled, it is not recycled into a same size beam or it might be glue-laminated and into another beam. However, wood that would not be usable as a beam (rotting) would not be recycled into much other than maybe paper. However, wood is renewable in that it is a made from renewable sources.
Steel comes from iron ore and mineral deposits in rock and such. It isn't really renewable. For new iron ore to exist, it would have to come from outer space or it gets bubbled up from the liquid rock levels of the earth via volcanoes. Earth doesn't really grow more dirt and rock. New earthen material comes from space rocks. Yes, we can recycle a number of these materials but it often comes with an embodied carbon and often greenhouse gases footprint.
Concrete can sometimes be recycled as well. You can crush it and use it for something else. However, a little more limited. The portland cement that binds the course aggregates is kind of limited in other applications especially once it has already cured. The sand that is already bound to the cement is not really easily reused but tiny pieces of cement and sand with aggregates can be used like crushed rock bed and potentially embedded conglomerated with new concrete and something used accordingly but in that situation, not likely for conventional structural use where rebar would be used. Most of the time, they have to do work to free the rebar from the concrete stuff so it can be melted down and recycled.
For the most part, a good 50+% of steel in new products are recycled steel. This is because we don't extract as much new iron ore to make new new as much as we have been resmelting them and then making new 'whatever' products that uses that old steel recycled. That is what happens to a lot of the old steel ships, including many of the old warships from WW I and WW II. That office table with steel legs may be made at least in part from steel from that old warship or an old building or bridge that was torn down or collapsed. Steel from WTC is probably in the recycling circulation since 2001. The final product made from that old steel may have a different carbon, nickel, etc. makeup as it goes through the recycling processes for its new use. How many times can steel be recycled? Not sure. Aluminum is known to be able to be recycled a lot but steel is not aluminum and we can't assume it bodes the same degree of recyclability. There is also other factors for why certain metals are more environmentally friendly to melt. I see many possible applications for metals just remember that while they may be recyclable they are not exactly from a 'renewable' source in the same sense as trees.
"new new" --- I meant "new steel". (ie. fresh newly made steel vs recycled).
Dec 7, 24 2:31 pm ·
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pj_heavy
Respectability is one of the aspects when it come to carbon footprint a product/material generates to the atmosphere . Cradle to Gate / Life cycle data would , in my view , provide more comprehensive info when choosing the material and system.
Can you elaborate more on what you mean by "respectability" and what you are trying to convey. I think it is partly an issue of the comments seemed to cut off part of your thought somewhere like an incomplete last sentence.
Structural steel manufactured in an electric arc furnace, which is most of the plants in the US, typically includes over 90% recycled content. Steel manufactured in an old-school basic oxygen furnace uses a much lower recycled content, and also is a much larger carbon emitter--the process is much more wasteful and once the furnaces start, they essentially never stop running.
Part of why I said 50+%. I don't have exact data on those old school furnaces so I felt 50+% is probably a good baseline as there is less old school steel production being used in the U.S. as it used to be as well as major reduction in iron ore extraction in some mode of calculation when there is a lot of recycling of steel from all kinds of stuff. I agree with Wood Guy.
I like the natural light and warmth of the mass timber system. However, my observations are based on visually checking out a few buildings while driving around and the vast information and pictures available. In my own relatively amateur ways it reminds me the laser cut cardboard models students make. Its applicability is perfect for L.A.
Our firm is manufacturing a micro-home where a laminated wood structural diaphragm is fabricated on large factory floor layout tables with high pressure plates that bond the glued layers into a floor/foundation plate cassette assembly - this plate is one piece and doesn't us independent components such as floor joists, edge (band) members, or mechanical connections - cross bracing sections are designed in as required and the voids are insulated as required by code.
Do people actually this stuff? It’s nothing more than an expensive trailer with nicer finishes.
Dec 9, 24 7:45 am ·
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BluecornGroup
do they want Boxabl's, S2A's, or tiny houses? - huge market for transportable & expanding homes with level HC floor plans - think forest fires and floods - much interest from the Navajo Nation's housing authority and a Houston 120 unit micro-home subdivision developer - sorry you don't like the concept ...
I find the expensive nomadic house concept thing very strange. Seems odd that there is a market for fashionable park-model type trailers.
Dec 9, 24 11:24 am ·
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BluecornGroup
These are not "nomadic" housing units but that can be an applicable descriptive term (sort of romantic) - these homes are based on traditional floor plans and because many potential buyers are senior citizens they can be totally HC-accessible including the use of 1:12 deck ramps - perhaps you are aware many homeowners can't get fire insurance and many policyholders are being dropped due to the real risks - these are not "trailers" for mobile home parks with those negative connotations - I prefer a "MicroHome" classification - I design custom homes and these homes are about one-third the cost per SF with the same level of quality, cutting edge architectural design, and engineering creativity including grid-free packages ...
Dec 9, 24 1:28 pm ·
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Almosthip
"cutting edge architectural design" How are these units cutting edge? I would like to learn more about your cutting edge architectural designs that are "based on traditional floor plans"? Is than not an oxymoron
?
Dec 9, 24 5:57 pm ·
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BluecornGroup
you're right - not cutting edge design - you guys are the expert architects ...
Cutting edge doesn't have to be about floor plans. All floor plan typologies for residential dwellings have already been devised in some form or another by 1970. Taking in variations that emerged from the rambling floor plans of the mid-20th century ranch style and related homes which are themselves a general modification of traditional domestic floor plans that have been explored globally before the 20th century. You aren't going to find new floor plan typology. Use defined how the plans are laid out. We have explored just about every permutation of plan typology between vernacular and high style residential architecture. Room layout and arrangements are all been explored. It is just how we design the space and how it feel, and variations in room shapes and so forth, the construction technologies used, and so on. What you won't find much new is in how rooms are arranged in relation to one another. There is like how many 'rooms' or function areas in a home? You have 1-4 or 5 bedrooms, a living room & dining room (or a combined room... great room), 1-4 bathrooms, a kitchen (maybe a pantry room or it is integrated, and possibly a laundry room. You may have an attached or detached garage or car port or parking space. Now, newer possible ideas is exploration of integrating transition between indoor and outdoor spaces and such with on-site outdoor 'rooms' and how they integrate to the associated indoor room. You may explore options like interior divisions whether they be walls, stem walls, series of posts or other matters of demarcation of boundaries of spatial areas for a particular function. These are where to explore not so much the few dozen floor plan types and a myriad of variations of those types.
I don't see a major revolutionary paradigm change in domesticity that much that effects floor plans. Technology doesn't really change the plan type. It might be some changes in our interior design and built-in furnishing but it really doesn't equate to a very different plan type than what already existed by 1970 going back 25,000 years. We already have an idea of the plan typologies for all those are.
Dec 9, 24 9:04 pm ·
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pj_heavy
@almost …cringeworthy words ; Award winning, cutting edge , boutique, renowned … the list goes on
Blue, sometimes. certain words have been overly used for weird, esoteric, and so idiosyncratic to the designer that it has nearly no practical value, and effectively garbage. All things that has no place in anything remotely in the realm of manufactured homes and mobile homes. Also the words being overly used, it doesn't hold meaning and the general public would say, I heard that one before. You aren't building space ships and space houses are ya? No, not really.
Houses for other worlds like mars or I should say, cities with biosphere and such durable even in martian dust storms that can move rocks and you don't want that to break the glass of your snow ball so you need a laminate system with a thick outer layer of ballistic polycarbonate then several thinner layers of glass and polycarbonate and a medium to thick layer of inner side polycarbonate panels that may be forms into something like hexagons and maybe a few pentagon shaped panels that forms the dome structure that has a frame system and the stuff is sealed, panel by panel to like space ship level. Since it is impossible to get the whole planet terraformed into a habitable planet in one go. We need to get water distribution and other stuff to mars to seed the planet and for it do that. That takes likely a 1000 years to do... maybe more.
As you can see, cutting edge isn't so cutting edge unless it is in a very breaking edge of science in this kind of level pushing the boundary of human existence beyond this solar system. What we deal with is more higher end of technology that is becoming more approachable financially. CLT is an evolution of glulam, for example. It evolved from that where it is like, if we do enough layers of boards glued in a stack we can go from glue-laminated beams to walls. We already were seeing glulam beams on the order of 4-6 ft. depth of beams up to 60+ ft long. So why not another 2 to 8 feet more and have a wall? Then the idea came about that this can also be floor plates. Eliminating the need for floor joists. CLTs do have an R-value. You count the R-value per inch of the material. If it is thick enough, it can reach the R-value needed per code but it would be ridiculously thick.
So, an option could be to do it on the outside in in some layered system. With floors, you may need to do something like furring strips to install the insulation and then a subfloor sheet and then your finish flooring which in cases may be preferred to follow the decor feel of the warm wood feel of the CLTs or compliment it. Exterior walls can have a layered system. In any case using CLTs, like trusses and glulam, and even conventional SIPs requires some kind of crane to lift and move it into place. They are generally too heavy for moving around manually without such equipment. This means you may need area to operate. This can be an issue in existing neighborhoods for residential projects with overhead telephone and power lines / cabletv-internet to contend width. This is part of the challenge of bringing such into say a undeveloped lot or a lot where a house once stood and is now vacant or something like that.
In some cases, I have considered something like SIPs with CLTs and options around that for a project but being more hybrid. CLTs can make for some f---ing nice shear walls. I like the idea of something like SIPs where I could have a relatively continuous insulation which makes for a nice even heat loss (albeit at the reduce rate for R-13+ level (depending on thickness) (up to potentially R-21+) and when looking at the wall through thermal imaging would not have all the stripes where the studs are where the heat loss is higher because the studs have a lower R-value per inch than the insulation between studs. Big thing is CLTs are not something easily afforded by modest budget clients unless you are talking a 100-200 sq.ft. home. (10ft. x 20ft.) or something about that size. It would be very high $/sq.ft. but affordable on a total budget but then people want square footage. They don't want to feel like they are raising a whole family in a panel van. Now, seriously, that can bring a creepy vibe to that. We want people to have homes.
Personally, to contribute to better housing, I would encourage states to also allow building designers to build SFRs with attached ADUs and such. Oregon's law is something that needs some tweaking and a limited scale of MFRs as well as townhouses up to 3 stories. Any such engineering in those where required would involve engineers. I know some states allows building designers to work on some MFRs. An SFR with an ADU is typically treated as two-family residential (ie. same as a duplex apartment) by the architectural licensing boards. I think some cases, we need to update the language of the exemptions so we can do more to contribute along this line. That is my position, albeit a tangent beyond this topic. Enough on that. In any cases, mass timber can have some interesting opportunities in residential, for sure.
There's a company near me building CLT homes and other buildings off-site: https://www.opalbuild.us/. They were formerly called GO Logic and were pioneers in the high-design, high-performance category in the US. I talked with the co-CEO just a few weeks ago and he said business is booming.
Thx, Wood Guy - "3D BIM modeling enables seamless communication across procurement, manufacturing, and construction of panelized building shells and high-value volumetric modular building elements." - there are a multitude of businesses such as Opel - Northstar is more along the lines of https://www.s2amodular.com/adu/ however we only manufacture with light gauge steel with mass timber build (floor/foundation plate) platforms - jtk
Dec 10, 24 11:28 am ·
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Wood Guy
I was responding to the OP; I didn't read many responses. My business, and Opal's, are based on reducing embodied carbon to the greatest degree reasonably possible, so steel framing is the last thing we would choose. But I'm glad it's working for you. I don't keep close track of what different prefab companies are doing but I wasn't aware of any of them using CLT to the extent they are.
You do know that almost 100% of the steel produced in the USA is recycled and is the most recycled material - in the last 50 years or so we have cut down half of the world's forest (mostly clear-cutting old growth timber) - I have a much different way of looking at environmental issues and standards such as LEED - our company uses steel because it is 10x stronger, fireproof, insect-proof, recycled, durable, and lightweight ...
Dec 10, 24 7:36 pm ·
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Non Sequitur
^Steel is not fireproof. Also, wood literally grows on trees so it is the most renewable resource out there.
Dec 10, 24 7:40 pm ·
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Wood Guy
Bluecorngroup, I have spent a ton of time over the last 15 years getting to this point in my understanding of things like embodied carbon emissions; you aren't going to convince me that steel is a good material to use, other than situations where nothing else will reasonably work.
As I responded to Rick above, "Structural steel manufactured in an electric arc furnace, which is most of the plants in the US, typically includes over 90% recycled content. Steel manufactured in an old-school basic oxygen furnace uses a much lower recycled content, and also is a much larger carbon emitter--the process is much more wasteful and once the furnaces start, they essentially never stop running."
Fortunately most steel plants in the US are EAF, not BOF, but if you're importing steel from China, your recycled content is likely 0-25%.
I also know a fair amount about forestry and I do lament the local older-growth forests we lost 1-2 centuries ago, but plantation-grown timber is still far better when it comes to important things like carbon emissions and pollution in general than steel. Almost all of the wood used on my projects comes from within 200 miles of me, including Advantech and Zip sheathing. I avoid using wood from elsewhere as much as possible, especially rainforest lumber.
I wonder if you realize that insulating between steel studs is a complete waste of insulation? Steel studs are designed to be nearly perfect heat radiators, efficiently moving heat from warm to cold. At least framing lumber is R-1.2/in.
For what it's worth, I have similar arguments for concrete and foam insulation. I use all three when they're the only material that will work. But I actually care about the future of humanity so I don't use them when a lower-impact material will work just as well, or better.
My basis on 50+ % is a guess on the general mixture of steel with high recycled percentages, very low and various levels in between so it is a guess without digging through hard data and recollection from various papers out there over the years. I can't give exact numbers on that because it is particularly difficult to figure that out without needing some serious research grant money to fund such research. So it's a guestimate.
While steel will generally melt, they don't burn quite in the same manner as wood. It's a technical splitting hair on flammability and such but steel also doesn't begin to melt until it reaches a certain temperature which is higher than wood (generally). So while not "fireproof" (nothing really is), it has certain fire resistance but other materials would be better for so-called "fireproofing". Using concrete or lots of gypsum plaster material. The best material (performance wise per volume) we had for so called fireproofing was asbestos but it also comes with its own problems and health hazard issues. It became illegal to use. So we have to use other materials and methods. Stone and concrete, while it doesn't burn like wood (in the same manner per se.. and is more in common to steel because steel comes from earthen material like concrete and stone (namely from metallic ores such as iron) so they have certain similarity. However, stone and concrete can have explosive properties so there is hazards when concrete or stone gets really hot and hazards related to that. So you try to minimize fuel sources that would sustain a fire long enough to get the materials to these temperature zones. So they extinguish themselves out. Fire doesn't sustain well on earthen materials like dirt, rock, concrete, or steel. So as a fuel it is very possible fires extinguishes themselves out if you have limit fuel to consume and spread. So you have options. In some ways, I like using natural stone masonry because it's most just cutting the rocks and such so embodied carbon footprint due to human processes is reduced. However, they are not renewable per se in the same sense and rate like wood. So use of both are great options. For stone masonry, if I had a choice, I would apply Incan techniques of stone masonry or borrow from it for making stones that naturally interlock and when assembled naturally stay assembled. These performed astronomically well in the most powerful earthquake we ever recorded... without even needing rebar. I can still see the use of pinning and locking any wood structure on it. Trapezoidal wall cross-sections and the likes for examples. Keep the superstructure from sliding around and all that would be important to performing in extreme earthquake forces but other factors as well.
As a general rule of thumb, the more human processes are involved ("artificiality") the more environmental cost (often carbon and GHG footprint) and so to make it into a product, the product is likely to be less sustainable and more hazard to the economy. This is because the processes have a cost factor and I am not talking about money. These implications should be considered in design and construction process. You'll be weighing options and have to reach your conclusions for the project. The best thing for the planet, environmentally, is less humans or humans returning to living like they did before the ice age and pre-civilizations. We know that's not going to be winning any popularity contests.
Dec 10, 24 10:42 pm ·
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BluecornGroup
Richard, you would make a great college instructor - much of what we are discussing is in the academic arena where everything is boiled down to a classification level (silver,gold, etc.) based on a point rating system (LEED) and I've paid for this training - this is the American way-of-late - everything now fits in its little quantitative box where you pay dearly for an assessment - I live in the Native world where homes were built of adobe bricks, pine vigas, and latillas - in the Pueblo tribal way their traditional homes have a spirit of their own and when they are no longer used they are allowed to die and melt back to their mother (the mother earth of all of us) - these are things that are never explained in a college classroom ...
Dec 11, 24 12:15 am ·
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Mass Timber Experiences
Anyone here ever worked on projects doing mass timber?
If you're able to share what type of project was it?
What are your thoughts on working with mass timber?
I've only dealt with large GL beams, on a temporary fitting for a half built condo in the new base village in snowmass. (long story) This page from the american wood councill is very good. https://awc.org/issues/mass-ti...
We've done a few - a private long term care facility (about $65M), recently an airport terminal expansion ($15M), and a few smaller projects in the works right now.
We like it, though it does have its challenges. For the LTC building, we had to hire a code consultant to satisfy the AHJ, since that was 6 storeys and had never been done in our region.
I did a large house with heavy timber a bunch of years ago, so older experience. One key consideration is how you are going to insulate it. Because the timber is expensive and pretty, there is a strong tendency to want to see all of it as the finished product. Which means it needs to be insulated outside the structural system itself. Which means the enclosure system is often separate from the structure (attached to it, interior or exterior, rather than integral/inside it).
My limited understanding is there are two types of MT.
One is intended to be exposed and as such is larger to accommodate the required fire ratings.
The other needs to be covered with a fire rating. This is typically a gwb assembly. As such, the hidden MT is not of finished grade - think OSB.
Using CI outside of the structure isn't something I'm too concerned about. It's something I've done quite often. Over the last decade I'd guess 90% of the buildings I've designed use a CI outside the structure.
In my mixed-use/commercial career, I never once saw a MT project pencil out when compared to literally any other system. At 8 stories and below, 5-over-3 is way cheaper. over 8 stories, steel or concrete is much more sensible. So there's that. But if a client wants to blow cash on it for some other reason, awesome. ;-) The Bullitt Center turned out very nice.
Having said that, I've always wanted to do a hybrid CLT structure (framed walls / CLT or NLT floors/roof) to get more floors in a mid-rise multi-family project with a low height limit.
It would be nice! Like you we've looked at CLT / MT for several projects but they are never economical.
Done a couple in my career, the biggest one being a 16000 sqm GFA ( 4-storey 180 metre long ). This would be a 40 plus storey if we flipped the building vertically . Everything was a challenge ; super tight deadline, transportation and a lot ( a lot ) of coordinations. One good example is that every single penetration through beams/floors needed to be coordinated/approved and then cut in the factory as there is a limit of the size that can be cut on site. Unlike a conventional RC structure , where coring is a norm.
Will chime in later on.
we also used a robot to nail down the floor s at some area! very fun.
On my 3rd Mass Timber project (100k, 30k, 200k sf). Primary reasons for using it is the perceived carbon reduction. Although... I wonder if we are kidding ourselves. Building mass timber structures that can't be disassembled and reused, typically expected to last 50 years, is basically deferring our carbon debt / kicking the can down to future generations. No?
Calling ourselves out for carbon-washing aside, the spaces inside exposed timber buildings are much warmer, comfortable feeling, and visually interesting.
Timber structure really do go up FAST.
From a "craft" point of view, it was more fun to design with timber because the structure IS the architecture. Lots of opportunities to nerd out on beautiful technical details.
There's definitely a learning curve. Wood Works is a great resource.
Your point about the recycle-ability is taken, but it's not like steel or concrete is recycled, either. Given those choices, I'll take mass timber.
Steel is one of the few things (in construction or elsewhere) which does actually get recycled consistently.
gwharton is right about steel. Steel and aluminum is recycled. This is because it is melted to molten state and the may be re-casted into something. Of course, there is a carbon footprint in that.
Wood can be recycled into some things but wood is not easily recycled into what it was. If a beam is recycled, it is not recycled into a same size beam or it might be glue-laminated and into another beam. However, wood that would not be usable as a beam (rotting) would not be recycled into much other than maybe paper. However, wood is renewable in that it is a made from renewable sources.
Steel comes from iron ore and mineral deposits in rock and such. It isn't really renewable. For new iron ore to exist, it would have to come from outer space or it gets bubbled up from the liquid rock levels of the earth via volcanoes. Earth doesn't really grow more dirt and rock. New earthen material comes from space rocks. Yes, we can recycle a number of these materials but it often comes with an embodied carbon and often greenhouse gases footprint.
Concrete can sometimes be recycled as well. You can crush it and use it for something else. However, a little more limited. The portland cement that binds the course aggregates is kind of limited in other applications especially once it has already cured. The sand that is already bound to the cement is not really easily reused but tiny pieces of cement and sand with aggregates can be used like crushed rock bed and potentially embedded conglomerated with new concrete and something used accordingly but in that situation, not likely for conventional structural use where rebar would be used. Most of the time, they have to do work to free the rebar from the concrete stuff so it can be melted down and recycled.
For the most part, a good 50+% of steel in new products are recycled steel. This is because we don't extract as much new iron ore to make new new as much as we have been resmelting them and then making new 'whatever' products that uses that old steel recycled. That is what happens to a lot of the old steel ships, including many of the old warships from WW I and WW II. That office table with steel legs may be made at least in part from steel from that old warship or an old building or bridge that was torn down or collapsed. Steel from WTC is probably in the recycling circulation since 2001. The final product made from that old steel may have a different carbon, nickel, etc. makeup as it goes through the recycling processes for its new use. How many times can steel be recycled? Not sure. Aluminum is known to be able to be recycled a lot but steel is not aluminum and we can't assume it bodes the same degree of recyclability. There is also other factors for why certain metals are more environmentally friendly to melt. I see many possible applications for metals just remember that while they may be recyclable they are not exactly from a 'renewable' source in the same sense as trees.
There are trade-offs... keep that in mind.
Agreed, Structural steel in the US are easily with 90+% recycled content. Crushed concrete could become aggregates or coarse fill...
"new new" --- I meant "new steel". (ie. fresh newly made steel vs recycled).
Respectability is one of the aspects when it come to carbon footprint a product/material generates to the atmosphere . Cradle to Gate / Life cycle data would , in my view , provide more comprehensive info when choosing the material and system.
Can you elaborate more on what you mean by "respectability" and what you are trying to convey. I think it is partly an issue of the comments seemed to cut off part of your thought somewhere like an incomplete last sentence.
* Recyclability
Structural steel manufactured in an electric arc furnace, which is most of the plants in the US, typically includes over 90% recycled content. Steel manufactured in an old-school basic oxygen furnace uses a much lower recycled content, and also is a much larger carbon emitter--the process is much more wasteful and once the furnaces start, they essentially never stop running.
Part of why I said 50+%. I don't have exact data on those old school furnaces so I felt 50+% is probably a good baseline as there is less old school steel production being used in the U.S. as it used to be as well as major reduction in iron ore extraction in some mode of calculation when there is a lot of recycling of steel from all kinds of stuff. I agree with Wood Guy.
I like the natural light and warmth of the mass timber system. However, my observations are based on visually checking out a few buildings while driving around and the vast information and pictures available. In my own relatively amateur ways it reminds me the laser cut cardboard models students make. Its applicability is perfect for L.A.
Our firm is manufacturing a micro-home where a laminated wood structural diaphragm is fabricated on large factory floor layout tables with high pressure plates that bond the glued layers into a floor/foundation plate cassette assembly - this plate is one piece and doesn't us independent components such as floor joists, edge (band) members, or mechanical connections - cross bracing sections are designed in as required and the voids are insulated as required by code.
www.NorthstarMicroHomes.com
Do people actually this stuff? It’s nothing more than an expensive trailer with nicer finishes.
do they want Boxabl's, S2A's, or tiny houses? - huge market for transportable & expanding homes with level HC floor plans - think forest fires and floods - much interest from the Navajo Nation's housing authority and a Houston 120 unit micro-home subdivision developer - sorry you don't like the concept ...
I find the expensive nomadic house concept thing very strange. Seems odd that there is a market for fashionable park-model type trailers.
These are not "nomadic" housing units but that can be an applicable descriptive term (sort of romantic) - these homes are based on traditional floor plans and because many potential buyers are senior citizens they can be totally HC-accessible including the use of 1:12 deck ramps - perhaps you are aware many homeowners can't get fire insurance and many policyholders are being dropped due to the real risks - these are not "trailers" for mobile home parks with those negative connotations - I prefer a "MicroHome" classification - I design custom homes and these homes are about one-third the cost per SF with the same level of quality, cutting edge architectural design, and engineering creativity including grid-free packages ...
"cutting edge architectural design" How are these units cutting edge? I would like to learn more about your cutting edge architectural designs that are "based on traditional floor plans"? Is than not an oxymoron ?
you're right - not cutting edge design - you guys are the expert architects ...
Cutting edge doesn't have to be about floor plans. All floor plan typologies for residential dwellings have already been devised in some form or another by 1970. Taking in variations that emerged from the rambling floor plans of the mid-20th century ranch style and related homes which are themselves a general modification of traditional domestic floor plans that have been explored globally before the 20th century. You aren't going to find new floor plan typology. Use defined how the plans are laid out. We have explored just about every permutation of plan typology between vernacular and high style residential architecture. Room layout and arrangements are all been explored. It is just how we design the space and how it feel, and variations in room shapes and so forth, the construction technologies used, and so on. What you won't find much new is in how rooms are arranged in relation to one another. There is like how many 'rooms' or function areas in a home? You have 1-4 or 5 bedrooms, a living room & dining room (or a combined room... great room), 1-4 bathrooms, a kitchen (maybe a pantry room or it is integrated, and possibly a laundry room. You may have an attached or detached garage or car port or parking space. Now, newer possible ideas is exploration of integrating transition between indoor and outdoor spaces and such with on-site outdoor 'rooms' and how they integrate to the associated indoor room. You may explore options like interior divisions whether they be walls, stem walls, series of posts or other matters of demarcation of boundaries of spatial areas for a particular function. These are where to explore not so much the few dozen floor plan types and a myriad of variations of those types.
I don't see a major revolutionary paradigm change in domesticity that much that effects floor plans. Technology doesn't really change the plan type. It might be some changes in our interior design and built-in furnishing but it really doesn't equate to a very different plan type than what already existed by 1970 going back 25,000 years. We already have an idea of the plan typologies for all those are.
@almost …cringeworthy words ; Award winning, cutting edge , boutique, renowned … the list goes on
not to mention "arrogant" - why would "award winning" be on this list? - or "renowned"? - or "cutting edge"? - does "creative" make your list? ...
@Blue… go to HdM website and see if you can find those words i mentioned. They are not humble people in real life but … look at their works.
OK - I get your point ...
Blue, sometimes. certain words have been overly used for weird, esoteric, and so idiosyncratic to the designer that it has nearly no practical value, and effectively garbage. All things that has no place in anything remotely in the realm of manufactured homes and mobile homes. Also the words being overly used, it doesn't hold meaning and the general public would say, I heard that one before. You aren't building space ships and space houses are ya? No, not really.
Houses for other worlds like mars or I should say, cities with biosphere and such durable even in martian dust storms that can move rocks and you don't want that to break the glass of your snow ball so you need a laminate system with a thick outer layer of ballistic polycarbonate then several thinner layers of glass and polycarbonate and a medium to thick layer of inner side polycarbonate panels that may be forms into something like hexagons and maybe a few pentagon shaped panels that forms the dome structure that has a frame system and the stuff is sealed, panel by panel to like space ship level. Since it is impossible to get the whole planet terraformed into a habitable planet in one go. We need to get water distribution and other stuff to mars to seed the planet and for it do that. That takes likely a 1000 years to do... maybe more.
As you can see, cutting edge isn't so cutting edge unless it is in a very breaking edge of science in this kind of level pushing the boundary of human existence beyond this solar system. What we deal with is more higher end of technology that is becoming more approachable financially. CLT is an evolution of glulam, for example. It evolved from that where it is like, if we do enough layers of boards glued in a stack we can go from glue-laminated beams to walls. We already were seeing glulam beams on the order of 4-6 ft. depth of beams up to 60+ ft long. So why not another 2 to 8 feet more and have a wall? Then the idea came about that this can also be floor plates. Eliminating the need for floor joists. CLTs do have an R-value. You count the R-value per inch of the material. If it is thick enough, it can reach the R-value needed per code but it would be ridiculously thick.
So, an option could be to do it on the outside in in some layered system. With floors, you may need to do something like furring strips to install the insulation and then a subfloor sheet and then your finish flooring which in cases may be preferred to follow the decor feel of the warm wood feel of the CLTs or compliment it. Exterior walls can have a layered system. In any case using CLTs, like trusses and glulam, and even conventional SIPs requires some kind of crane to lift and move it into place. They are generally too heavy for moving around manually without such equipment. This means you may need area to operate. This can be an issue in existing neighborhoods for residential projects with overhead telephone and power lines / cabletv-internet to contend width. This is part of the challenge of bringing such into say a undeveloped lot or a lot where a house once stood and is now vacant or something like that.
In some cases, I have considered something like SIPs with CLTs and options around that for a project but being more hybrid. CLTs can make for some f---ing nice shear walls. I like the idea of something like SIPs where I could have a relatively continuous insulation which makes for a nice even heat loss (albeit at the reduce rate for R-13+ level (depending on thickness) (up to potentially R-21+) and when looking at the wall through thermal imaging would not have all the stripes where the studs are where the heat loss is higher because the studs have a lower R-value per inch than the insulation between studs. Big thing is CLTs are not something easily afforded by modest budget clients unless you are talking a 100-200 sq.ft. home. (10ft. x 20ft.) or something about that size. It would be very high $/sq.ft. but affordable on a total budget but then people want square footage. They don't want to feel like they are raising a whole family in a panel van. Now, seriously, that can bring a creepy vibe to that. We want people to have homes.
Personally, to contribute to better housing, I would encourage states to also allow building designers to build SFRs with attached ADUs and such. Oregon's law is something that needs some tweaking and a limited scale of MFRs as well as townhouses up to 3 stories. Any such engineering in those where required would involve engineers. I know some states allows building designers to work on some MFRs. An SFR with an ADU is typically treated as two-family residential (ie. same as a duplex apartment) by the architectural licensing boards. I think some cases, we need to update the language of the exemptions so we can do more to contribute along this line. That is my position, albeit a tangent beyond this topic. Enough on that. In any cases, mass timber can have some interesting opportunities in residential, for sure.
There's a company near me building CLT homes and other buildings off-site: https://www.opalbuild.us/. They were formerly called GO Logic and were pioneers in the high-design, high-performance category in the US. I talked with the co-CEO just a few weeks ago and he said business is booming.
Thx, Wood Guy - "3D BIM modeling enables seamless communication across procurement, manufacturing, and construction of panelized building shells and high-value volumetric modular building elements." - there are a multitude of businesses such as Opel - Northstar is more along the lines of https://www.s2amodular.com/adu/ however we only manufacture with light gauge steel with mass timber build (floor/foundation plate) platforms - jtk
I was responding to the OP; I didn't read many responses. My business, and Opal's, are based on reducing embodied carbon to the greatest degree reasonably possible, so steel framing is the last thing we would choose. But I'm glad it's working for you. I don't keep close track of what different prefab companies are doing but I wasn't aware of any of them using CLT to the extent they are.
You do know that almost 100% of the steel produced in the USA is recycled and is the most recycled material - in the last 50 years or so we have cut down half of the world's forest (mostly clear-cutting old growth timber) - I have a much different way of looking at environmental issues and standards such as LEED - our company uses steel because it is 10x stronger, fireproof, insect-proof, recycled, durable, and lightweight ...
^Steel is not fireproof. Also, wood literally grows on trees so it is the most renewable resource out there.
Bluecorngroup, I have spent a ton of time over the last 15 years getting to this point in my understanding of things like embodied carbon emissions; you aren't going to convince me that steel is a good material to use, other than situations where nothing else will reasonably work.
As I responded to Rick above, "Structural steel manufactured in an electric arc furnace, which is most of the plants in the US, typically includes over 90% recycled content. Steel manufactured in an old-school basic oxygen furnace uses a much lower recycled content, and also is a much larger carbon emitter--the process is much more wasteful and once the furnaces start, they essentially never stop running."
Fortunately most steel plants in the US are EAF, not BOF, but if you're importing steel from China, your recycled content is likely 0-25%.
I also know a fair amount about forestry and I do lament the local older-growth forests we lost 1-2 centuries ago, but plantation-grown timber is still far better when it comes to important things like carbon emissions and pollution in general than steel. Almost all of the wood used on my projects comes from within 200 miles of me, including Advantech and Zip sheathing. I avoid using wood from elsewhere as much as possible, especially rainforest lumber.
I wonder if you realize that insulating between steel studs is a complete waste of insulation? Steel studs are designed to be nearly perfect heat radiators, efficiently moving heat from warm to cold. At least framing lumber is R-1.2/in.
For what it's worth, I have similar arguments for concrete and foam insulation. I use all three when they're the only material that will work. But I actually care about the future of humanity so I don't use them when a lower-impact material will work just as well, or better.
My research and experience tells a much different story but we won't argue it here ...
Going with WG's side here Blue.
My basis on 50+ % is a guess on the general mixture of steel with high recycled percentages, very low and various levels in between so it is a guess without digging through hard data and recollection from various papers out there over the years. I can't give exact numbers on that because it is particularly difficult to figure that out without needing some serious research grant money to fund such research. So it's a guestimate.
There is recyclability and there is renewability. These are two different measures to factor and consider in sustainability.
While steel will generally melt, they don't burn quite in the same manner as wood. It's a technical splitting hair on flammability and such but steel also doesn't begin to melt until it reaches a certain temperature which is higher than wood (generally). So while not "fireproof" (nothing really is), it has certain fire resistance but other materials would be better for so-called "fireproofing". Using concrete or lots of gypsum plaster material. The best material (performance wise per volume) we had for so called fireproofing was asbestos but it also comes with its own problems and health hazard issues. It became illegal to use. So we have to use other materials and methods. Stone and concrete, while it doesn't burn like wood (in the same manner per se.. and is more in common to steel because steel comes from earthen material like concrete and stone (namely from metallic ores such as iron) so they have certain similarity. However, stone and concrete can have explosive properties so there is hazards when concrete or stone gets really hot and hazards related to that. So you try to minimize fuel sources that would sustain a fire long enough to get the materials to these temperature zones. So they extinguish themselves out. Fire doesn't sustain well on earthen materials like dirt, rock, concrete, or steel. So as a fuel it is very possible fires extinguishes themselves out if you have limit fuel to consume and spread. So you have options. In some ways, I like using natural stone masonry because it's most just cutting the rocks and such so embodied carbon footprint due to human processes is reduced. However, they are not renewable per se in the same sense and rate like wood. So use of both are great options. For stone masonry, if I had a choice, I would apply Incan techniques of stone masonry or borrow from it for making stones that naturally interlock and when assembled naturally stay assembled. These performed astronomically well in the most powerful earthquake we ever recorded... without even needing rebar. I can still see the use of pinning and locking any wood structure on it. Trapezoidal wall cross-sections and the likes for examples. Keep the superstructure from sliding around and all that would be important to performing in extreme earthquake forces but other factors as well.
As a general rule of thumb, the more human processes are involved ("artificiality") the more environmental cost (often carbon and GHG footprint) and so to make it into a product, the product is likely to be less sustainable and more hazard to the economy. This is because the processes have a cost factor and I am not talking about money. These implications should be considered in design and construction process. You'll be weighing options and have to reach your conclusions for the project. The best thing for the planet, environmentally, is less humans or humans returning to living like they did before the ice age and pre-civilizations. We know that's not going to be winning any popularity contests.
Richard, you would make a great college instructor - much of what we are discussing is in the academic arena where everything is boiled down to a classification level (silver,gold, etc.) based on a point rating system (LEED) and I've paid for this training - this is the American way-of-late - everything now fits in its little quantitative box where you pay dearly for an assessment - I live in the Native world where homes were built of adobe bricks, pine vigas, and latillas - in the Pueblo tribal way their traditional homes have a spirit of their own and when they are no longer used they are allowed to die and melt back to their mother (the mother earth of all of us) - these are things that are never explained in a college classroom ...
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