lumberjill
New Member
Posts:6
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| 07 Feb 2012 12:04 AM |
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What could cause a large gap to appear between the rim board or sill and the top of the ICF walls. |
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ICFHybrid
Veteran Member
Posts:3039
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| 07 Feb 2012 02:05 AM |
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What are the dimensions of the "large gap"?
Did the large gap appear;
a) before the pour?
b) during the pour?
c) after the pour?
d) after the concrete set? |
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Chris Johnson
Advanced Member
Posts:878
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| 07 Feb 2012 07:40 AM |
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picture would help |
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| Chris Johnson - Pro ICF<br>North of 49 |
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lumberjill
New Member
Posts:6
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| 08 Feb 2012 11:54 AM |
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 Concrete has set, Roof installed October, Insulated ceiling over Christmas, gap appeared just the last 2 weeks |
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JakeG
New Member
Posts:55
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| 08 Feb 2012 02:41 PM |
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How often is the sill plate connected down to the concrete? (to code?) With proper fasteners?
What type of trusses are they?
Could they have pulled up due to drying of any sort?
No additional roof load in the past short while?
Any part of the sill cantilevered or spanning two different base materials? (i.e. transition from concrete to wood at any point?)
Just thinking out loud....can't say I've ever seen this. |
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Dana1
Senior Member
Posts:6991
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| 08 Feb 2012 02:53 PM |
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Without a good capillary break between the concrete and sill I can believe quite a bit moisture related warp & wow of the sill plank could occur, particuarly if it's isn't mechanically secured to the concrete with fasteners. The concrete is still sourcing moisture to the wood from below, but the drier air of winter is pulling moisture out the top. It's hard to tell much of anything from a single snapshot. |
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JakeG
New Member
Posts:55
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| 08 Feb 2012 03:19 PM |
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Capillary break is code here in Ontario.
Can't have wood touching concrete.
Also, mechanical fasteners, and specific type of fasteners/spacing, are code as well.
Not saying that people haven't "cut corners"...
If the sill is in direct contact with the concrete below, you will get problems eventually (probably sooner rather than later!)
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Chris Johnson
Advanced Member
Posts:878
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| 09 Feb 2012 02:18 PM |
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I'd hazard to say you got moisture in the wood and 2x is famous for warping.
Not the best answer...but I think you are going to have to live with it, short of taking the roof off it's not coming out easy.
When you drywall...no screws into the top and you made need crown molding in the future if it moves around |
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| Chris Johnson - Pro ICF<br>North of 49 |
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Lbear
Veteran Member
Posts:2740
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| 10 Feb 2012 11:56 AM |
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Posted By JakeG on 08 Feb 2012 03:19 PM
Capillary break is code here in Ontario.
Can't have wood touching concrete.
Also, mechanical fasteners, and specific type of fasteners/spacing, are code as well.
Not saying that people haven't "cut corners"...
If the sill is in direct contact with the concrete below, you will get problems eventually (probably sooner rather than later!)
How do you install a capillary break? Isn't it normal practice in the ICF industry to just install treated wood directly onto the concrete ICF wall? |
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dmaceld
Veteran Member
Posts:1465
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| 10 Feb 2012 12:09 PM |
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Posted By Lbear on 10 Feb 2012 11:56 AM
How do you install a capillary break?
Isn't it normal practice in the ICF industry to just install treated wood directly onto the concrete ICF wall?
"Directly onto" guarantees an air gap between the concrete and sill plate. I used the plain ol' blue sill foam on my wall. Fills the gap and provides a break. However, most any 2x will warp and cup. My 2 x 10s and 2 x 12s were cupped before they ever hit the work site. Bolting them down to the wall helped flatten them. Don't use treated if you can figure out how to get by with untreated. The crookedness of untreated 2x's is multiplied 3 to 10 times in treated. Nothing like paying premium money for inferior product!  |
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| Even a retired engineer can build a house successfully w/ GBT help! |
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Lbear
Veteran Member
Posts:2740
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| 10 Feb 2012 03:43 PM |
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Posted By dmaceld on 10 Feb 2012 12:09 PM
"Directly onto" guarantees an air gap between the concrete and sill plate. I used the plain ol' blue sill foam on my wall. Fills the gap and provides a break. However, most any 2x will warp and cup. My 2 x 10s and 2 x 12s were cupped before they ever hit the work site. Bolting them down to the wall helped flatten them.
Don't use treated if you can figure out how to get by with untreated. The crookedness of untreated 2x's is multiplied 3 to 10 times in treated. Nothing like paying premium money for inferior product!
What about using a Glulam piece of wood? That is why I am not keen on using 2x, it is prone to warp and even split, especially when running screws into if for a SIP roof. That is why I would prefer a 4x, much more meat there and provides a better nailing/screwing board. A nice 4x10 or 4x12 would work better. Some even recommended steel sill plates??? |
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Dana1
Senior Member
Posts:6991
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| 10 Feb 2012 03:51 PM |
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Or just metal capillary breaks. (Copper flashing extending over the foam on both sides is worth it in termite prone areas.)
Or very low permeance membrane capillary breaks.
Most foamy sill gaskets are barely a capillary break, have fairly high vapor permeance, very crummy at air-sealing to boot. They're way better than nothing, but not a much of a total solution. |
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lumberjill
New Member
Posts:6
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| 13 Feb 2012 06:07 PM |
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We just had the building inspector look at the gap, and he thinks it's just a matter of the sill board bowing due to being moist on one side (concrete side) and dry on the other, he suggested cutting wood and glueing into the gap and installing hurricane brackets attached to the roof truss and to the sill plate. We are in Alberta, has anyone heard of this and is it a common occurence |
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Chris Johnson
Advanced Member
Posts:878
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| 13 Feb 2012 06:25 PM |
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Yes it is common when lumber sits on concrete, even take a 2x4 and lay it on a concrete slab, it will start looking like a hockey stick in no time.
The biggest thing I see, it appears by the picture you used a 2x10 or 2x12 plate, anchor bolts are spread 4-6' apart so there is lots of room for the wood to twist as it did.
Chances are the wood is still snug to the concrete section and the worst of it is on the edges, maybe I can't see it correctly, so I am not sure where you would be installing this cut and glued wood, perhaps you can elaborate or send a sketch |
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| Chris Johnson - Pro ICF<br>North of 49 |
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lumberjill
New Member
Posts:6
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| 13 Feb 2012 06:32 PM |
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He described it like putting in a shim and he did mention it seemed to be bowing on the inside edge, he said you could wait and see if it may come back down, but he said the nails from the trusses which go in at an anlgle may not sink back down with the sill plate.
What about these hurricane plates, what do they do; prevent it from bowing any more or keep the roof from being raised? |
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dmaceld
Veteran Member
Posts:1465
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| 13 Feb 2012 06:49 PM |
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Posted By lumberjill on 13 Feb 2012 06:32 PM
What about these hurricane plates, what do they do; prevent it from bowing any more or keep the roof from being raised?
Your answer. http://www.strongtie.com/ftp/catalogs/c-2011/C-2011-p173-p176.pdf |
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| Even a retired engineer can build a house successfully w/ GBT help! |
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Lbear
Veteran Member
Posts:2740
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| 13 Feb 2012 07:13 PM |
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Are Glulam beams any better than treated wood when they sit on concrete?
There MUST be a better alternative to the green lumber sitting on top of a concrete wall.
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Chris Johnson
Advanced Member
Posts:878
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| 13 Feb 2012 08:51 PM |
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LBear, where are you located?
I ask because when I was in California we used 3x PT for top plates
If you hand select your 3x you can pick the flat straight ones, we also had anchor bolts @ 24" o.c. max, so that too helped prevent warping.
Lumberjill, you may see some flattening in due time, but it will never go back to being perfectly flat, I think you just live with it. |
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| Chris Johnson - Pro ICF<br>North of 49 |
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Alton
Veteran Member
Posts:2164
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| 13 Feb 2012 08:52 PM |
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The Glulam beams that I have watched being made in a factory consist of untreated, kiln dried, finger-jointed yellow pine. Very strong and can contain camber so its own weight and total load will not make the beam sag below level. (Most home owners do not like to see a sag in the ceiling regardless how safe it is.) Untreated wood can absorb water from concrete which can hasten it demise. Some framers will install a piece of galvanized sheet metal under a beam or roof truss to keep them from touching concrete. If steel is used between the wood and concrete, just be sure that the steel has at least a G90 coating if the building is in a salt-air environment such as the coast. |
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Residential Designer &
Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period .
334 826-3979 |
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Lbear
Veteran Member
Posts:2740
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| 13 Feb 2012 09:39 PM |
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Posted By Alton on 13 Feb 2012 08:52 PM
The Glulam beams that I have watched being made in a factory consist of untreated, kiln dried, finger-jointed yellow pine. Very strong and can contain camber so its own weight and total load will not make the beam sag below level. (Most home owners do not like to see a sag in the ceiling regardless how safe it is.) Untreated wood can absorb water from concrete which can hasten it demise. Some framers will install a piece of galvanized sheet metal under a beam or roof truss to keep them from touching concrete. If steel is used between the wood and concrete, just be sure that the steel has at least a G90 coating if the building is in a salt-air environment such as the coast.
I just found out that they make TREATED Glulam beams. I wonder if a treated 4x12 Glulam beam would be the better choice, depending on cost.
Posted By Chris Johnson on 13 Feb 2012 08:51 PM
LBear, where are you located?
I ask because when I was in California we used 3x PT for top plates
If you hand select your 3x you can pick the flat straight ones, we also
had anchor bolts @ 24" o.c. max, so that too helped prevent warping.
I am in Arizona. The problem out here is that getting kiln dried is difficult. Might as well pay for the treated Glulam and have them shipped over. The interior of the home will incorporate a lot of wood. I really like the way interior wood softens a homes space. |
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