I've been trying to wrap my head around this for a while.
I'm in a hot / dry climate and I want to achieve a board formed concrete wall, exposed on the outside surface.
I can think of two ways to do this:
1) Form and pour the wall, (8" I'm thinking for now), waterproof the backside, and then put up a stick frame wall behind it on the interior to get the necessary R-value.
2) Put up the stick frame wall, and prep the sheathing to be used as one side of the formwork.
Any advice?
archanonymous
Feb 28, 16 5:39 pm
Depending on pour height, I doubt a stick-frame wall is sufficient to become formwork. I'd be particularly concerned about the base of the wall.
Whether it is more or less $$ to build formwork, pour, tear it down, and built a wall behind, or to over-build the wall and leave it is between you and the contractor.
Tyler Wallace
Feb 28, 16 5:55 pm
Thanks archanonymous.
I'm thinking now to just do the concrete on its own, then add 2" xps behind it and furr some gyp onto that.
That way the concrete guys don't have to worry about permanent framing, and the the whole assembly might be thinner.
Carrera
Feb 28, 16 10:32 pm
Have built a lot of stick framed form work…would have to be one hell of a wood wall to prevent a blowout…add to that that one trade would build the wood wall & another trade pour against it…a lot a finger pointing directed at you if it bows out.
archanonymous
Feb 28, 16 10:39 pm
Check out the process Allied Works uses for their single-lift pours without external formwork. It might inspire you somehow.
Your sill depth on the stick frame formwork wall is going to be like 18 inches because you would need something like 2 x 8 or 2 x 10 wall behind the concrete. Other option w/ rigid insulation foam would be tidy. Less expensive.
gruen
Feb 28, 16 11:12 pm
Don't reinvent the wheel. Just do a regular poured wall. Want board formed? Use styrene form liner. Comes in board formed look.
gwharton
Feb 29, 16 10:56 am
All board-form concrete is built with form liners now.
snooker-doodle-dandy
Feb 29, 16 1:19 pm
be sure to specify the right cement....so you don't get pockets in your wall because the wall is not self consolidating.
Tyler Wallace
Feb 29, 16 2:19 pm
thanks, will do. I've started looking at some form liners. So far the ones I've found have the seams between the boards going into the wall, maybe I need to see one in person, but I think I would prefer the seams to go out like it was formed with actual wood. I'll keep looking though, I don't have to make a final decision on which product for a few months.
proto
Feb 29, 16 2:47 pm
We did real board formed on a few projects at a past office...many mockups were required because the concrete guys just don't do this kind of formwork anymore. They need practice to get it down before doing the final pour. How many lifts will be required? Are cold joints ok along the wall length (or where do you do vertical joints)? The form boards need to be chosen carefully, species, cut & finish. Expect to lose some wood grain to adhesion. Decide if the projecting fins of concrete btwn boards are to be saved. Repairs are just about impossible if you get air pockets/bug holes since you can't match the grain or embedded fibers. If this is your weather wall (it is), how are you going to repair cracks? Do you need to seal the wall & what effect will this have on your finish/color? Form liners solve some of these issues, but also bring others in and require solid discussion. Even when we inspected the forms (owner, GC & architect), we still managed to miss some things.
does your owner have the ability to roll with the inherent lack of perfection that this finish will bring?
Torston
May 16, 16 4:13 pm
We've done numerous board form concrete walls. You can find our last project buried at the bottom of our website gallery at www.hansaformwork.com
300 linear feet of ten foot board form (one side) intricate window detail four men ten days complete. No honeycomb, very little defect. Up a mountain somewhere in BC.
I would advise a couple things here:
-Use real wood. Rough cut cedar from mill, explicitly ask sawyer to lower dimensional tolerances.
-We use Peri Domino for our form system. Wood face allows us to nail on board form tick tack done. Modular metal system for quick set up and strip. It is the best solution for one sided board form walls.
-Pour wall out then insulate. Spray foam insulation would be the superior product here.
-If you need some consultation feel free to shoot us an email found on our website. We love arch. conc. formwork!
go do it
May 17, 16 2:46 am
Torston,
Impressive work indeed. The board formed house looks interesting can you post anymore pictures of it? Through the window of one of the pictures I can see a smooth wall surface maybe the backside of a wall? Do you guys use plywood on the inside and boards on the outside? Also where you have waterproofed at grade level there looks to be a brick ledge maybe not for brick but for another veneer wainscotting, is that the intention? If not what are the plans to finish at grade?
Your smooth walls are very nice also and from what I can read in the article is that you use plywood so what are your forming / pouring / stripping strategies to get such nice work? From the pictures I can't see any hand troweling marks do you line the forms with plexiglass or some other smooth material?
Shoot out some more pics!!
Torston
May 17, 16 11:04 pm
Go to it
Just put a couple pics up on our google+ page just from that project (google Hansa Formwork). You will get a good idea how it was all formed. The brickledge you speak of is not, it is simply where we ended the boardform as it would have been below grade and not seen anyways.
Fair faced is made drastically easier using the right formwork manufacturer. We use Peri for everything we do, we own Domino (that's the yellow/red forms you see on our website) and have good experience with all their systems right up to ACS which we have built for them. With that said we used Peri Vario for all our formwork and just a regular Matte B formply for finish. Typically most architects want the finply most Peri Formwork is faced with, but these guys wanted a softer finish.
Best resource for doing Formwork the right way: www.Peri.de
hbpeter
Feb 6, 21 7:27 pm
Torston
I concur with go to it, your board formed walls look great. We are doing a project consisting of 3'H x 40'L built with horizontal laid 2x6 doug fir which we have face burnt and brushed to enhance the grain then coated with lacquer. this will be our first SCC pour so I'm in need of input. Our concrete supplier has specified 3000psi SCC with a 27" spread, how tight do the forms need to be between the boards and the form tie holes to mitigate excess leakage? Our plan is to use Cresset voc Platinum as the release, can you recommend a better choice in releases? Lastly, does the SCC mix seem right according to your experience?
I've been trying to wrap my head around this for a while.
I'm in a hot / dry climate and I want to achieve a board formed concrete wall, exposed on the outside surface.
I can think of two ways to do this:
1) Form and pour the wall, (8" I'm thinking for now), waterproof the backside, and then put up a stick frame wall behind it on the interior to get the necessary R-value.
2) Put up the stick frame wall, and prep the sheathing to be used as one side of the formwork.
Any advice?
Depending on pour height, I doubt a stick-frame wall is sufficient to become formwork. I'd be particularly concerned about the base of the wall.
Whether it is more or less $$ to build formwork, pour, tear it down, and built a wall behind, or to over-build the wall and leave it is between you and the contractor.
Thanks archanonymous.
I'm thinking now to just do the concrete on its own, then add 2" xps behind it and furr some gyp onto that.
That way the concrete guys don't have to worry about permanent framing, and the the whole assembly might be thinner.
Have built a lot of stick framed form work…would have to be one hell of a wood wall to prevent a blowout…add to that that one trade would build the wood wall & another trade pour against it…a lot a finger pointing directed at you if it bows out.
Check out the process Allied Works uses for their single-lift pours without external formwork. It might inspire you somehow.
Your sill depth on the stick frame formwork wall is going to be like 18 inches because you would need something like 2 x 8 or 2 x 10 wall behind the concrete. Other option w/ rigid insulation foam would be tidy. Less expensive.
Don't reinvent the wheel. Just do a regular poured wall. Want board formed? Use styrene form liner. Comes in board formed look.
All board-form concrete is built with form liners now.
be sure to specify the right cement....so you don't get pockets in your wall because the wall is not self consolidating.
thanks, will do. I've started looking at some form liners. So far the ones I've found have the seams between the boards going into the wall, maybe I need to see one in person, but I think I would prefer the seams to go out like it was formed with actual wood. I'll keep looking though, I don't have to make a final decision on which product for a few months.
We did real board formed on a few projects at a past office...many mockups were required because the concrete guys just don't do this kind of formwork anymore. They need practice to get it down before doing the final pour. How many lifts will be required? Are cold joints ok along the wall length (or where do you do vertical joints)? The form boards need to be chosen carefully, species, cut & finish. Expect to lose some wood grain to adhesion. Decide if the projecting fins of concrete btwn boards are to be saved. Repairs are just about impossible if you get air pockets/bug holes since you can't match the grain or embedded fibers. If this is your weather wall (it is), how are you going to repair cracks? Do you need to seal the wall & what effect will this have on your finish/color? Form liners solve some of these issues, but also bring others in and require solid discussion. Even when we inspected the forms (owner, GC & architect), we still managed to miss some things.
does your owner have the ability to roll with the inherent lack of perfection that this finish will bring?
We've done numerous board form concrete walls. You can find our last project buried at the bottom of our website gallery at www.hansaformwork.com
300 linear feet of ten foot board form (one side) intricate window detail four men ten days complete. No honeycomb, very little defect. Up a mountain somewhere in BC.
I would advise a couple things here:
-Use real wood. Rough cut cedar from mill, explicitly ask sawyer to lower dimensional tolerances.
-We use Peri Domino for our form system. Wood face allows us to nail on board form tick tack done. Modular metal system for quick set up and strip. It is the best solution for one sided board form walls.
-Pour wall out then insulate. Spray foam insulation would be the superior product here.
-If you need some consultation feel free to shoot us an email found on our website. We love arch. conc. formwork!
Torston,
Impressive work indeed. The board formed house looks interesting can you post anymore pictures of it? Through the window of one of the pictures I can see a smooth wall surface maybe the backside of a wall? Do you guys use plywood on the inside and boards on the outside? Also where you have waterproofed at grade level there looks to be a brick ledge maybe not for brick but for another veneer wainscotting, is that the intention? If not what are the plans to finish at grade?
Your smooth walls are very nice also and from what I can read in the article is that you use plywood so what are your forming / pouring / stripping strategies to get such nice work? From the pictures I can't see any hand troweling marks do you line the forms with plexiglass or some other smooth material?
Shoot out some more pics!!
Go to it
Just put a couple pics up on our google+ page just from that project (google Hansa Formwork). You will get a good idea how it was all formed. The brickledge you speak of is not, it is simply where we ended the boardform as it would have been below grade and not seen anyways.
Fair faced is made drastically easier using the right formwork manufacturer. We use Peri for everything we do, we own Domino (that's the yellow/red forms you see on our website) and have good experience with all their systems right up to ACS which we have built for them. With that said we used Peri Vario for all our formwork and just a regular Matte B formply for finish. Typically most architects want the finply most Peri Formwork is faced with, but these guys wanted a softer finish.
Best resource for doing Formwork the right way: www.Peri.de
Torston
I concur with go to it, your board formed walls look great. We are doing a project consisting of 3'H x 40'L built with horizontal laid 2x6 doug fir which we have face burnt and brushed to enhance the grain then coated with lacquer. this will be our first SCC pour so I'm in need of input. Our concrete supplier has specified 3000psi SCC with a 27" spread, how tight do the forms need to be between the boards and the form tie holes to mitigate excess leakage? Our plan is to use Cresset voc Platinum as the release, can you recommend a better choice in releases? Lastly, does the SCC mix seem right according to your experience?