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Foundation sill plate question

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http://boards.diynetwork.com/eve/forums/a/tpc/f/6221916776/m/5013913077

May 05, 2013, 08:59 AM
mikem201
Foundation sill plate question
Hi guys,

I have some quick questions. When you have your 8" thick foundation wall should you install your sill plate recessed in a bit to account for sheathing and an space for the sheathing to rest on? Or should the sill plate be flush with the outside of the foundation wall? Same with rigid foam do you set the sill back to account for the rigid foam as well?
May 05, 2013, 11:15 AM
redoverfarm
Generally poured walls are 7-1/2" not the actual 8". At least that was the case with mine. The sill is usually Pressure treated and the same width 2X8(1-1/2' X 7-1/4) and is flush to the outside of the wall. Any siding material overhangs the foundation. The siding material should not rest on the ground though. If installing a termite shield it should be a material that will not react with the chemicals in the Pressure treated to cause corrosion of the termite shield. Copper is the ideal material but for me it was cost prohibitive. As a solution I installed the aluminum termite shield and then used # 30 felt which provided a barrier between the two. In addition there should be a foam sill material installed between the concrete and the sill plate or concrete and the termite shield to sill up any imprefections in the wall.
May 05, 2013, 02:52 PM
mikem201
quote:
Originally posted by redoverfarm:
Generally poured walls are 7-1/2" not the actual 8". At least that was the case with mine. The sill is usually Pressure treated and the same width 2X8(1-1/2' X 7-1/4) and is flush to the outside of the wall. Any siding material overhangs the foundation. The siding material should not rest on the ground though. If installing a termite shield it should be a material that will not react with the chemicals in the Pressure treated to cause corrosion of the termite shield. Copper is the ideal material but for me it was cost prohibitive. As a solution I installed the aluminum termite shield and then used # 30 felt which provided a barrier between the two. In addition there should be a foam sill material installed between the concrete and the sill plate or concrete and the termite shield to sill up any imprefections in the wall.


I guess my whole thing is when you leave the sill plate flush with the edge of the foundation wall and and install sheathing, wrap, rigid foam and siding and you look up from under all of this what covers it all? Its not going to down to below grade or anything where you back fill it obviously.
May 05, 2013, 05:42 PM
redoverfarm
I guess you could improvise and put a freeze board or other trim to cover the bottom. You want your sill plate to evenly distribute the weight load on the wall. If you off set the sill then it would not be doing that. In addition you want any moisture to weep out over the wall and not land on the wall and possibly run under sill plate.

This message has been edited. Last edited by: redoverfarm,
May 19, 2013, 07:08 PM
briteboy
I put the sill plate flush with foundation. But I recess the floor joists enough to accomodate the rim board, sheathing, etc.

Exterior materials like brick, stone need an air space between itself and the sheathing anyway.

Siding needs to overlap the foundation wall (even if it's just a little) to prevent moisture from directly hitting the sill plate.

I use PT sheathing 2' above sill plate (at least). If it's a pony wall below grade, I use PT sheathing all the way up until above grade.

Hope this helps.
May 19, 2013, 07:17 PM
GardenSprite
Briteboy, you had no way of knowing but Mikem is a troll and has been extremely rude to the posters here.

Before you respond to any more of his manipulative queries, you might want to read this thread, all the way to the end.

Venting Issue, Plumbing Section,
http://boards.diynetwork.com/e...1013504/m/2613934077

Just a word to the wise.