Feedback on my ICF double stud wall detail
Last Post 23 Oct 2014 03:49 PM by tomk358. 31 Replies.
Printer Friendly
Sort:
PrevPrev NextNext
You are not authorized to post a reply.
Page 2 of 2 << < 12
Author Messages
Dana1User is Offline
Senior Member
Senior Member
Send Private Message
Posts:6991

--
14 Oct 2014 02:47 PM
EPDM is both water proof to liquid water and a powerful vapor barrier. It's not a problem to "...trap and direct moisture against your foundation..." since concrete is not harmed by water. (There are 2000 year old concrete foundations still functioning fully submerged in the Mediteranean, after all.) The EPDM is there to protect moisture-suceptible materials (such as wood foundation sills) from any moisture wicking up through the concrete, or entering the house through the slab as water vapor.

Some of the best most air-tight sill gaskets out there are made from EPDM: http://www.conservationtechnology.com/building_gaskets.html

The flatter the top of the concrete, the easier it is to get a good air seal with EPDM sill gaskets, but they are WAY more mechanically compliant and moisture proof than the cheap foamies, and are usually pretty air tight without the need for more goop/foam. (Of course a blower door test & remediation on the whole shell is still a good idea, and you can foam/goop seal any leaks that might still be there.)

greentreeUser is Offline
Advanced Member
Advanced Member
Send Private Message
Posts:587

--
14 Oct 2014 04:54 PM
"Its not a problem to trap and direct water towards your foundation", thats some great advice.
Might as well forget the drain tile, backfill with clay and forget the waterproofing cause its only concrete, its been around for centuries.
Tens of thousands of damp basements across the country have given basements a bad rap because of that line of thought. We have to live and occupy the other side of that wall.
Dana1User is Offline
Senior Member
Senior Member
Send Private Message
Posts:6991

--
14 Oct 2014 04:57 PM
Show me the place in the drawing where his use of EPDM is a problem.
greentreeUser is Offline
Advanced Member
Advanced Member
Send Private Message
Posts:587

--
14 Oct 2014 05:03 PM
Im not talking about his EPDM, Im talking about your comment.

And I think I made a clear distinction between gasket and sheet. I'm questioning sheet epdm and advocating gasket under the mudsill.
tomfrischUser is Offline
New Member
New Member
Send Private Message
Posts:12

--
14 Oct 2014 06:10 PM
I think the confusion is on my part- I didn't make a distinction between EPDM sheet and gasket. Here is a new updated detail that should explain better.

-Moved the OSB shear to the outside of the bearing wall. This will make it harder to attach the gussets, but easier to air seal, and then the drywall doesn't need to be air sealed at all. Is that a crazy idea?
-Changed the outside truss 2x4 to a 2x2. Will that be a problem?
-Changed the roxul to XPS.
-Changed to a FPSF monolithic slab/footing.
-Added the distinction for EPDM gasket and sheet.
-Added a radon pipe.
-Added a fabric layer to assist in the blown insulation- sounds like its much easier to blow through fabric screen than drywall.
-I switched to engineered siding for the weight and strength. Looks like about $500 extra in material cost between the 2 from what I can tell in my situation.

Finally, as far as drain tile, sump, and bleeders- since the below grade section of wall would just be for one corner of the property, and the rest would be slab on grade, I think I can get away without all that stuff. The city inspector didn't seem to have a problem with it on first glance, but I will be sure to talk to them more specifically about it.javascript:amaf_insertHTML('');amaf_toggleInline(4909,28787,0);
greentreeUser is Offline
Advanced Member
Advanced Member
Send Private Message
Posts:587

--
14 Oct 2014 06:45 PM

Tom,
Pretty cool seeing your wall evolve in this thread.
tomfrischUser is Offline
New Member
New Member
Send Private Message
Posts:12

--
14 Oct 2014 06:52 PM
It's pretty cool having all these folks help me evolve it!
tomk358User is Offline
New Member
New Member
Send Private Message
Posts:18

--
22 Oct 2014 08:08 PM
Well, my ICF double stud wall has turned to a monolithic slab on grade with Riversongish truss...so it goes as they say.

Here's the latest revision of my wall, foundation and roof details. Thought I'd share it with everyone, to see what other problems I've caused for myself. As usual, thanks for your support and feedback.



I'm curious if ya'll think I still need perimiter drain tile when the top of the slab is 8" above grade. Seems kinda silly, unless it's there to keep the XPS and EPS from drowning?
jonrUser is Offline
Senior Member
Senior Member
Send Private Message
Posts:5341

--
23 Oct 2014 11:38 AM
I don't think you need to drain around an above grade slab. I can't make out where grade is in your last drawing - I'd check what code allows (as I recall, some say the thickened part has to extend 12" below grade, which adds up to 20").
tomk358User is Offline
New Member
New Member
Send Private Message
Posts:18

--
23 Oct 2014 12:55 PM
jonr- yeah, my drawing is getting a little crowded with information. The grade is marked with the heavier dotted line and labeled 5% grade, which is confusing now that I look at it. The plans inspector here in Portland Oregon told me I can do 18" to the bottom of the foam for a FPSF and that satisfies him, but I won't know for certain till I officially submit my plans to the permitting folks.
jonrUser is Offline
Senior Member
Senior Member
Send Private Message
Posts:5341

--
23 Oct 2014 03:46 PM
I expect that your 18" is based on your local frost depth. Most FPSF's use horizontal wings of foam, which should reduce this (and save some concrete). 18 (below grade) - 4 (foam) + 8 (above grade) = 22" thick concrete. But maybe that is the right thickness structurally.
tomk358User is Offline
New Member
New Member
Send Private Message
Posts:18

--
23 Oct 2014 03:49 PM
I'll have to ask them about that, he said 18" no matter wings or not, but maybe I wasn't asking the question in the right way.
You are not authorized to post a reply.
Page 2 of 2 << < 12


Active Forums 4.1
Membership Membership: Latest New User Latest: hudson2000 New Today New Today: 0 New Yesterday New Yesterday: 2 User Count Overall: 34707
People Online People Online: Visitors Visitors: 112 Members Members: 0 Total Total: 112
Copyright 2011 by BuildCentral, Inc.   Terms Of Use  Privacy Statement