I hate to say it but I've never done a board formed concrete wall. Truth be told; I've not done much exposed cast in place insulated concrete panels.
I know, I'm worthless. ;)
I'm trying to come up with a detail for an insulated board formed concrete wall. I've included a sketch of what I'm thinking so far. Be gentle, it's just a sketch and has a lot that still needs to be figured out.
If anyone has any advice or resources regarding insulated board formed concrete walls I'd appreciate it.
don't be ashamed, I haven't either - but I think 7 1/2" is not a preferred number for thickness, I've only seen whole numbers in 2" increments, 4",6",8".....And I believe the form boards are completely up to the desired outcome, make it beautiful!
Nov 12, 24 12:51 pm ·
·
OddArchitect
Yeah - I figured as much. I'll be coordinating with structural about the slab thicknesses. I'm most concerned about the wall ties. I don't want them to be obtrusive and rust after they've been broken off.
Nov 12, 24 2:01 pm ·
·
Wood Guy
7 5/8" are common in some markets. My builder friends in Kansas City say that's what they use there. I've only seen even-number increments here in New England.
You can get fiberglass snap ties. Just be careful if the walls are tall; my brother had a 30' monopour fireplace blow out in an almost-finished house once and it wasn't pretty.
Nov 12, 24 2:09 pm ·
·
OddArchitect
That's my concern WG. The walls are 30'-0" tall. Not my design.
Define 'obtrusive'? Easy enough to spec. stainless ties w/ silicone. Or pony up to properly finish the hole.
Nov 12, 24 3:09 pm ·
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JLC-1
30' tall? I hope some framed bracing somewhere?
Nov 12, 24 3:22 pm ·
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Kowski
Resident structural engineer here, 1/2" increments are usually doable in my experience, it all comes down to the inherent tolerance of concrete construction & the quality of your local concrete subs. 1/2" is the smallest tolerance that can be hit reliably, 1/4" is very difficult to hit consistently and 1/8" is close to impossible. You might spec 1/8" but you won't get 1/8". Your structural engineer should know the right increment, and they'll want input on that thickness so they can design for strength. Good luck!
Nov 13, 24 9:29 am ·
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Non Sequitur
Unrelated to the wall question but I have a client at the moment who is adamant about the dimensions of a concrete pour. Since we're evolved beings, we use the metric system but the formwork guys used archaic inchies and feeties. No big deal, numbers are close enough because a hard conversion gives us just under 3.5mm O/A delta. Apparently that's a concern? Dude, your wall is 125' feet long. 1/16" error in either direction is the least of your worries.
Nov 13, 24 9:59 am ·
·
OddArchitect
Appleseed
wrote:
Define 'obtrusive'? Easy enough to spec. stainless ties w/ silicone. Or pony up to properly finish the hole.
Obtrusive as is easily seen and looks like ::bleh::. I was planning on using plastic coated stainless steel wall ties. The issue is the height of the wall makes them rather large. When they're broken off it's easy to damage the finish. It's easy for the proper hole finish to not match. I've seen it a lot.
Nov 13, 24 10:33 am ·
·
OddArchitect
JLC-1 wrote:
"30' tall? I hope some framed bracing somewhere? "
Oh yeah. There will need to be a lot of that. This project just finished SD and I wasn't involved in it so I'm still coordinating things.
We have GC sometimes recommend some sort of version of this sandwich poured concrete assembly and we always say no but that's because they are trying to cut corners around our foundation insulation min requirements. Don't think I've ever done a wall like this that was not precast or tilt-up and installed as panels.
OA... what is the goal here? Concrete finish both sides with minimal insulation? That 75mm rigid is not giving you much.
btw, 7.5" (190mm) is a common foundation thickness in my area. Actually, they will form to whatever I tell them but we have loads of issues with trades lining up forms. Hopefully you're looking at a haphazard array of boards as a finish?
Nov 12, 24 2:59 pm ·
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OddArchitect
The idea here is to have a board formed wall on both sides for aesthetics that is insulated. Without violating privacy here is the design concept. Again, not my design.
Nov 12, 24 3:04 pm ·
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Non Sequitur
Like this? I pass by this one every day. It was done with tilt-up poured concrete panel sandwiches.
Cast in place insulated board formed concrete panel.
A good amount of structural engineering will probably be needed to accomplish this.
Due to the 30’-0” heights of the panels we will probably need additional steel structure to support the panels.
We’ll need to speak with structural about how this works as it will probably be two concrete walls tied together with insulation between.
Precast concrete panels.
This is literally what precast panels are for.
I’m unsure about how to finish the outside corner of the boxes or if that is even possible with precast panels.
Tilt up concrete panels
Cannot finish the ‘back’ side of the panel.
Would need to use a veneered stone product to mimic board formed concrete on the interior.
Board formed concrete with metal stud wall.
We would do a board formed concrete wall on the exterior and frame metal stud walls with insulation on the interior.
A veneered stone products would be used in the interior stud wall to mimic board formed concrete.
Composite siding.
Use a Resysta type product to produce a board pattern similar to board formed concrete.
Nov 12, 24 3:52 pm ·
·
Non Sequitur
You can finish both sides of tilt-up if you press something into the top after pour. That's how the example in my pic was done. But you're probably looking at a precast panel system if you want better control. I'm balls deep in precast panels and will see my first full wall erected next month. I'm expecting finished corners... fingers crossed.
Partner with an experienced sub! Import one if necessary...it's that important.
Make sure there is money in the construction budget for multiple concrete mockups. Some of those need to be before issuing CDs because you need to see the effects of the specified processes & materials with time to adjust based on what you learn.
Review board layup prior to closing forms for pouring.
List specific mockup details you want to see in place: cold joints, lift joints, pattern repeat transitions, actual wood grain from multiple species, board separation for fins, fin frequency/hgt, max acceptable bug hole sizes, outside corners, inside corners, etc, etc...
and in the mockup spec language, make time for testing multiple repair methods too, not just first-time forming of walls. Any repairs will be a bitch & you may decide repairs won't be acceptable at all. What happens if you get a crack later? Etc...
It takes a lot of effort to even do a "passable" job. Doing a "nice" job is ridiculously pedantic cuz the GC gets a single shot at the installation. You can't just wing it; it needs to be thoughtful and purposeful. The architect/gc relationship needs to be strong, and the owner needs to be all in for the effort.
You'd better have your criteria itemized for what constitutes a failure up front. When a wall comes out less than awesome, the owner and gc can see it in the way the architect looks at the new wall instantly. It's no fun trying to goose the build team into a redo if they think they hit your rubric for a good wall.
Good luck
(I wouldn't do it again -- I'd almost just prefer a rough sawn wood wall...)
Thanks for the advice. I'm you've raised many of the concerns I have. Glad (and sad) to see I'm not crazy.
Nov 12, 24 4:11 pm ·
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OddArchitect
proto - any advice on how to define what is acceptable and defective work in this situation?
Nov 13, 24 12:49 pm ·
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proto
Use your design mockups to set your parameters.
One way might be to make a list of the typical repairs on a new concrete wall. Then reverse-engineer the parameters for when an identified repair condition has a threshold. What are you willing to put up with? Then itemize those in numbers and words. Example: Crack size thresholds. Crack length thresholds. Crack position/orientation thresholds. Crack hierarchy of issues to threshold of repair/rejection. Then repair hierarchy of processes. Etc. Do it for finishes, mixes, wood formwork, timeline of form-pulling for ideal embedment of just the right amount of wood fibers...etc
OA, insulated core sandwich panel are not uncommon in EU. You might want to look into Schöck Isolink for an anchor/connector between insulation and the walls in between. This product has very low thermal conductivity and would never rust . For the board - form look, we have used Reckli formliners many times / they have wide range of standard pattern and you can also do customisation. The downside of these system is perhaps cost and availability of manufacturers available in N America? ( i have zero clue)
G’luck
Nov 13, 24 7:21 am ·
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OddArchitect
Thanks. Using European products is not going to fly for this public works project. Materials need to be locally available (within 1,000 miles).
Nov 13, 24 10:40 am ·
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pj_heavy
Those stainless steel wall ties you've drawn wouldn't fly in high spec build ( thermal bridging ) ... anywho
Nov 13, 24 10:03 pm ·
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OddArchitect
Oh the wall ties in the 'sketch' aren't finalized. I'm looking at several thermally broken wall tie options.
Nov 14, 24 9:56 am ·
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pj_heavy
“you’re welcome’” …..
Nov 14, 24 3:59 pm ·
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OddArchitect
????????
I still won't be using the product you've been promoting. It's not available in this part of the US.
As I said in the OP - it's just a sketch. The wall ties aren't chosen yet. I've narrowed it down to three thermally broken wall ties that are available in the US. Now I just have to see if they will be strong enough to work with concrete walls this high.
Nov 14, 24 4:07 pm ·
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pj_heavy
no worries Chad. All good
Nov 14, 24 5:58 pm ·
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pj_heavy
btw , The two products are global brands and available in the US. We used this system in the projects 10,000 miles away from where it’s been made in Germany.
Nov 14, 24 6:02 pm ·
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pj_heavy
already regret posting this/ i’m out.
Nov 14, 24 6:04 pm ·
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OddArchitect
I appreciate the recommendation!
I knew about the product before you mentioned it. It's a European made product and the nearest supplier to the project is more than 1,000 miles away, hence why we cannot use it. I'm going to be recommending to the owner that they revise their material limitations but I have to be realistic. :(
Never done board formed, only plywood, but all in Japan, where it is not so hard to find skilled trades. Ando quality is above average, but not unusual.
Board formed concrete used to be more common in Japan, but without the insulation, because that is not prioritized. THIS building (google map) across from H + DeM Prada in Tokyo looks nice and the ties are not noticeable. Maki's house is similarly handsome. As long as they are finished properly with mortar the ties should not be an issue. Maybe in USA it is harder to do that?
The double wall approach is what Ando uses in cold climates. Apart from the concrete issues, the coping detail seems out of place, especially for the design you have shown. It looks like the intent is to have no coping and to mimic the joints on the slope?
fwiw, Ando usually uses no special coping, only a hand-troweled concrete top that slopes inwards. It looks sharp, with the trade off being that the walls of his early buildings are kind of black and stained (huge shock when I first visited his work in the late 90s), and they need to be cleaned after a few years. More recently he uses a coating that works better to repel dirt etc, and that seems to help. With board formed walls I would be sure to do the same. Lots of places for grime to accumulate.
Coping details? I assume you mean the parapet cap? Don't worry about that - it' won't be done that way. There will be a standing seam metal roof over the concrete walls. That was just shown there so other team members wouldn't freak out about the top of the wall being 'open'.
After so many years, I finally got to see the Salk Inst recently and, with a board formed experience from work under my belt, the visit was an absolute wonder..!
Going to Japan might blow my mind!
yes the parapet cap is what i meant. I thought it was coping in English? Good to know.
The Salk is beautiful. I saw it a few years ago when it was being renovated, but even in that less than ideal state it was clearly a masterpiece. Ando concrete is technically a lot cleaner and sharper, but I like the Salk. It feels warm somehow. Something I have never felt with Ando's work.
But if you are into concrete definitely visit Japan. There is a lot of amazing works worth seeing. Including this one most recently (https://www.spoon-tamago.com/keisuke-oka-arimaston-building/). It's a crazy hand made building filled with invention, a bit like Gaudi. If you think board-formed concrete is pushing the limits, this guy is so far beyond the avant-garde he feels retro.
That's certainty the 'look' we're going after. Writing the spec and creating the details to get that 'look' seems to be rather complicated and expensive. Around $70 per SF of board formed concrete. :s
Haven't read thru all the comments but there are insulated sandwich systems. basically they are based on specialized wall ties to keep the "plies" dimensionally consistent. Board forming will add another layer of complexity in that the formwork itself will need to be well engineered, including bracing. That said you can always use standard forms with your boards applied to the inside. The fastening of the boards and the dimensions of the wall ties obviously all need to be worked out. Let find some time and look thru the files for an old project - I have a system somewhere around here. The other thing I will had - depending on your engineer - it is highly likely that the outer and inner wythes will not be equal thickness. Often the outer wythe is considered for the weather face, while the inner wythe would be the primary structure - but again this depends.
Was going to suggest this as well. Precast can be done with boards, or board forms, depending on what you're going for. The nice thing is, less expensive and better quality control BUT it takes a ton more coordination.
I was also going to suggest precast. The co-ordination isn't much more. Once the foundation and structure are in place you will need an accurate survey before precast fab happens. And of course a crane so it may add to the $$ but likely shorten the timeframe. Hard to say without knowing the scope.
Nov 21, 24 12:34 am ·
·
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Insulated Board Formed Concrete
I hate to say it but I've never done a board formed concrete wall. Truth be told; I've not done much exposed cast in place insulated concrete panels.
I know, I'm worthless. ;)
I'm trying to come up with a detail for an insulated board formed concrete wall. I've included a sketch of what I'm thinking so far. Be gentle, it's just a sketch and has a lot that still needs to be figured out.
If anyone has any advice or resources regarding insulated board formed concrete walls I'd appreciate it.
Thanks!
don't be ashamed, I haven't either - but I think 7 1/2" is not a preferred number for thickness, I've only seen whole numbers in 2" increments, 4",6",8".....And I believe the form boards are completely up to the desired outcome, make it beautiful!
Yeah - I figured as much. I'll be coordinating with structural about the slab thicknesses. I'm most concerned about the wall ties. I don't want them to be obtrusive and rust after they've been broken off.
7 5/8" are common in some markets. My builder friends in Kansas City say that's what they use there. I've only seen even-number increments here in New England.
You can get fiberglass snap ties. Just be careful if the walls are tall; my brother had a 30' monopour fireplace blow out in an almost-finished house once and it wasn't pretty.
That's my concern WG. The walls are 30'-0" tall. Not my design.
Define 'obtrusive'? Easy enough to spec. stainless ties w/ silicone. Or pony up to properly finish the hole.
30' tall? I hope some framed bracing somewhere?
Resident structural engineer here, 1/2" increments are usually doable in my experience, it all comes down to the inherent tolerance of concrete construction & the quality of your local concrete subs. 1/2" is the smallest tolerance that can be hit reliably, 1/4" is very difficult to hit consistently and 1/8" is close to impossible. You might spec 1/8" but you won't get 1/8". Your structural engineer should know the right increment, and they'll want input on that thickness so they can design for strength. Good luck!
Unrelated to the wall question but I have a client at the moment who is adamant about the dimensions of a concrete pour. Since we're evolved beings, we use the metric system but the formwork guys used archaic inchies and feeties. No big deal, numbers are close enough because a hard conversion gives us just under 3.5mm O/A delta. Apparently that's a concern? Dude, your wall is 125' feet long. 1/16" error in either direction is the least of your worries.
Appleseed wrote:
Define 'obtrusive'? Easy enough to spec. stainless ties w/ silicone. Or pony up to properly finish the hole.
Obtrusive as is easily seen and looks like ::bleh::. I was planning on using plastic coated stainless steel wall ties. The issue is the height of the wall makes them rather large. When they're broken off it's easy to damage the finish. It's easy for the proper hole finish to not match. I've seen it a lot.
JLC-1 wrote:
"30' tall? I hope some framed bracing somewhere? "
Oh yeah. There will need to be a lot of that. This project just finished SD and I wasn't involved in it so I'm still coordinating things.
We have GC sometimes recommend some sort of version of this sandwich poured concrete assembly and we always say no but that's because they are trying to cut corners around our foundation insulation min requirements. Don't think I've ever done a wall like this that was not precast or tilt-up and installed as panels.
OA... what is the goal here? Concrete finish both sides with minimal insulation? That 75mm rigid is not giving you much.
btw, 7.5" (190mm) is a common foundation thickness in my area. Actually, they will form to whatever I tell them but we have loads of issues with trades lining up forms. Hopefully you're looking at a haphazard array of boards as a finish?
The idea here is to have a board formed wall on both sides for aesthetics that is insulated. Without violating privacy here is the design concept. Again, not my design.
Like this? I pass by this one every day. It was done with tilt-up poured concrete panel sandwiches.
That's what I'm thinking.
I'm looking at multiple options.
Cast in place insulated board formed concrete panel.
Precast concrete panels.
Tilt up concrete panels
Board formed concrete with metal stud wall.
Composite siding.
You can finish both sides of tilt-up if you press something into the top after pour. That's how the example in my pic was done. But you're probably looking at a precast panel system if you want better control. I'm balls deep in precast panels and will see my first full wall erected next month. I'm expecting finished corners... fingers crossed.
I was thinking about the stamped look on the 'back' side.
Partner with an experienced sub! Import one if necessary...it's that important.
Make sure there is money in the construction budget for multiple concrete mockups. Some of those need to be before issuing CDs because you need to see the effects of the specified processes & materials with time to adjust based on what you learn.
Review board layup prior to closing forms for pouring.
List specific mockup details you want to see in place: cold joints, lift joints, pattern repeat transitions, actual wood grain from multiple species, board separation for fins, fin frequency/hgt, max acceptable bug hole sizes, outside corners, inside corners, etc, etc...
and in the mockup spec language, make time for testing multiple repair methods too, not just first-time forming of walls. Any repairs will be a bitch & you may decide repairs won't be acceptable at all. What happens if you get a crack later? Etc...
It takes a lot of effort to even do a "passable" job. Doing a "nice" job is ridiculously pedantic cuz the GC gets a single shot at the installation. You can't just wing it; it needs to be thoughtful and purposeful. The architect/gc relationship needs to be strong, and the owner needs to be all in for the effort.
You'd better have your criteria itemized for what constitutes a failure up front. When a wall comes out less than awesome, the owner and gc can see it in the way the architect looks at the new wall instantly. It's no fun trying to goose the build team into a redo if they think they hit your rubric for a good wall.
Good luck
(I wouldn't do it again -- I'd almost just prefer a rough sawn wood wall...)
Thanks for the advice. I'm you've raised many of the concerns I have. Glad (and sad) to see I'm not crazy.
proto - any advice on how to define what is acceptable and defective work in this situation?
Use your design mockups to set your parameters.
One way might be to make a list of the typical repairs on a new concrete wall. Then reverse-engineer the parameters for when an identified repair condition has a threshold. What are you willing to put up with? Then itemize those in numbers and words. Example: Crack size thresholds. Crack length thresholds. Crack position/orientation thresholds. Crack hierarchy of issues to threshold of repair/rejection. Then repair hierarchy of processes. Etc. Do it for finishes, mixes, wood formwork, timeline of form-pulling for ideal embedment of just the right amount of wood fibers...etc
Thanks proto!
[deleted]
OA, insulated core sandwich panel are not uncommon in EU. You might want to look into Schöck Isolink for an anchor/connector between insulation and the walls in between. This product has very low thermal conductivity and would never rust . For the board - form look, we have used Reckli formliners many times / they have wide range of standard pattern and you can also do customisation. The downside of these system is perhaps cost and availability of manufacturers available in N America? ( i have zero clue)
G’luck
Thanks. Using European products is not going to fly for this public works project. Materials need to be locally available (within 1,000 miles).
Those stainless steel wall ties you've drawn wouldn't fly in high spec build ( thermal bridging ) ... anywho
Oh the wall ties in the 'sketch' aren't finalized. I'm looking at several thermally broken wall tie options.
“you’re welcome’” …..
????????
I still won't be using the product you've been promoting. It's not available in this part of the US.
As I said in the OP - it's just a sketch. The wall ties aren't chosen yet. I've narrowed it down to three thermally broken wall ties that are available in the US. Now I just have to see if they will be strong enough to work with concrete walls this high.
no worries Chad. All good
btw , The two products are global brands and available in the US. We used this system in the projects 10,000 miles away from where it’s been made in Germany.
already regret posting this/ i’m out.
I appreciate the recommendation!
I knew about the product before you mentioned it. It's a European made product and the nearest supplier to the project is more than 1,000 miles away, hence why we cannot use it. I'm going to be recommending to the owner that they revise their material limitations but I have to be realistic. :(
What proto said.
Never done board formed, only plywood, but all in Japan, where it is not so hard to find skilled trades. Ando quality is above average, but not unusual.
Board formed concrete used to be more common in Japan, but without the insulation, because that is not prioritized. THIS building (google map) across from H + DeM Prada in Tokyo looks nice and the ties are not noticeable. Maki's house is similarly handsome. As long as they are finished properly with mortar the ties should not be an issue. Maybe in USA it is harder to do that?
The double wall approach is what Ando uses in cold climates. Apart from the concrete issues, the coping detail seems out of place, especially for the design you have shown. It looks like the intent is to have no coping and to mimic the joints on the slope?
fwiw, Ando usually uses no special coping, only a hand-troweled concrete top that slopes inwards. It looks sharp, with the trade off being that the walls of his early buildings are kind of black and stained (huge shock when I first visited his work in the late 90s), and they need to be cleaned after a few years. More recently he uses a coating that works better to repel dirt etc, and that seems to help. With board formed walls I would be sure to do the same. Lots of places for grime to accumulate.
Thanks for the advice. I really appreciate it!
Coping details? I assume you mean the parapet cap? Don't worry about that - it' won't be done that way. There will be a standing seam metal roof over the concrete walls. That was just shown there so other team members wouldn't freak out about the top of the wall being 'open'.
After so many years, I finally got to see the Salk Inst recently and, with a board formed experience from work under my belt, the visit was an absolute wonder..! Going to Japan might blow my mind!
yes the parapet cap is what i meant. I thought it was coping in English? Good to know.
The Salk is beautiful. I saw it a few years ago when it was being renovated, but even in that less than ideal state it was clearly a masterpiece. Ando concrete is technically a lot cleaner and sharper, but I like the Salk. It feels warm somehow. Something I have never felt with Ando's work.
But if you are into concrete definitely visit Japan. There is a lot of amazing works worth seeing. Including this one most recently (https://www.spoon-tamago.com/keisuke-oka-arimaston-building/). It's a crazy hand made building filled with invention, a bit like Gaudi. If you think board-formed concrete is pushing the limits, this guy is so far beyond the avant-garde he feels retro.
[coping def works]
It's all good Will! Thanks for all the insight!
This house:
AM House is a Vietnamese holiday home surrounded by tropical gardens
From this list:
Eight minimalist bedrooms lined with exposed concrete surfaces
Would seem to have the "look" your after.
That's certainty the 'look' we're going after. Writing the spec and creating the details to get that 'look' seems to be rather complicated and expensive. Around $70 per SF of board formed concrete. :s
Haven't read thru all the comments but there are insulated sandwich systems. basically they are based on specialized wall ties to keep the "plies" dimensionally consistent. Board forming will add another layer of complexity in that the formwork itself will need to be well engineered, including bracing. That said you can always use standard forms with your boards applied to the inside. The fastening of the boards and the dimensions of the wall ties obviously all need to be worked out. Let find some time and look thru the files for an old project - I have a system somewhere around here. The other thing I will had - depending on your engineer - it is highly likely that the outer and inner wythes will not be equal thickness. Often the outer wythe is considered for the weather face, while the inner wythe would be the primary structure - but again this depends.
Was going to suggest this as well. Precast can be done with boards, or board forms, depending on what you're going for. The nice thing is, less expensive and better quality control BUT it takes a ton more coordination.
I was also going to suggest precast. The co-ordination isn't much more. Once the foundation and structure are in place you will need an accurate survey before precast fab happens. And of course a crane so it may add to the $$ but likely shorten the timeframe. Hard to say without knowing the scope.
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