I have a question about “furring out” the sill plate in my home. My foundation is on masonry (cinder) blocks. The blocks are about 10″ wide. The sill plate that sits flat atop the blocks is a 2×8. Technically it is only 7.5″ wide. That gives me roughly 2.5″ of exposed block on the interior side. One of the the sill plate edges lines up to the edge on the exterior wall. The blocks have 3-4 channels in the center. These channels allow air (albeit very slowly) to leak into the house. Over the course of the whole foundation, a lot of air is getting in. I would like to seal these holes up permanently and the version of sealing that I am going to do is just to block the air from getting in. I am also planning on spray foaming the rimjoist but before I do that, I want to fur out the sill plate to be flush with the interior edge of the foundation block. The existing sill plate sits on a gasket of some sort. Could be fiberglass but I don’t know for sure. Home was built in ’64. My idea was to add in pressure treated wood ripped down to roughly 2.5″ wide and then nail it up to the sill plate (maybe screw it but I will probably add an adhesive too). Under the pressure treated wood, I would place that blue sill plate material foam stuff so that I keep the wood off of the blocks directly, even though it is in the interior of the house. This is where it gets a little fuzzy. Can anybody provide guidance if I am going astray here and making too much work for myself? I can post a pic if that would help. I would just butt up the PT wood to the sill plate, apply caulk, screw or nail in place. After I am done, I would then run a bead of caulk from the “new” sill plate edge bottom to the foundation to seal that gap. This new sill plate fur out is not load bearing in anyway.
Thanks
dennis
Replies
unless you anticipate a need to nail something to this in the future, it would be better and easier to use 1-1/2" blue foam ripped and use spray foam top glue it into place
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unless you anticipate a need to nail something to this in the future, it would be better and easier to use 1-1/2" blue foam ripped and use spray foam top glue it into place
Blue Foam Ripped...by The Beach Boys, right? Fur out!
somebody is spending too much time in Californica;)
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I grew up here, mostly, so it was in my blood before I moved east. It's an interesting combination of influences, the laid back SoCal attitude and the NY in-your-face approach.
But even as pleasant as life can be here, with the nearly ideal year-round weather (at 10AM local it's 61 degrees with an expected high of 71), I'm looking forward to being in the country again, with a real NE spring, summer and fall.
These channels allow air (albeit very slowly) to leak into the house. Over the course of the whole foundation, a lot of air is getting in. I would like to seal these holes up permanently and the version of sealing that I am going to do is just to block the air from getting in.
I somehow doubt that "air" is "leaking" up thease channels. Many channels may be blocked as a matter of course alternation, and just where is this "air" coming from? The block are sitting on top of a solid concrete footing buried way below grade.
Maybe the old sill sealer is leaking and that is the draft you are feeling? The top course should have been filled solid with mortar as a proper building method.
In that case Piffin's advice would be right on. Your way should work as well although it will expend more labor.
Maybe the old sill sealer is leaking and that is the draft you are feeling? The top course should have been filled solid with mortar as a proper building method.The holes are not filled at all. I do not know how far down they go but you can definitely put your hand (well, technically a smaller hand) into the block holes. unless you anticipate a need to nail something to this in the future, it would be better and easier to use 1-1/2" blue foam ripped and use spray foam top glue it into placedoesn't putting blue/pink XPS board cause a problem because it does not have a thermal barrier? my basement is not finished at the moment and I am not sure if/when it will be. but i do like this idea a lot.
The holes are not filled at all
Makes me wonder what the sill is fastened to.
Unless the sill is just concrete-nailed to the mortar joists or some such odd practice.Occupational hazard of my occupation not being around (sorry Bubba)
doesn't putting blue/pink XPS board cause a problem because it does not have a thermal barrier?>>>>>>>>>>>>>>>>>>
??????????????
The foam is the thermal break.
Not what I meant to say. Does not leaving blue foam board exposed w/o drywall over it cause a code problem? I thought the material was not fire rated. The code problem would come into play either with selling the house or if the house caught on fire. I don't think the insurance co would be forgiving if they found evidence of something like that done. Not planning on moving of a house fire anytime soon but just bringing it up.dennis
We had a discussion about similar the other day. I believe it was here.
The code allows foam to be used to insulate the box so I don't see where that would be a problem.
I did not think that you could leave rigid foam exposed but you can leave spray foam exposed. See area below figure 3 below:http://www.buildingscience.com/documents/information-sheets/4-air-barriers/info-408-critical-seal-spray-foam-at-rim-joistDo you have a link for saying that rigid foam exposed is ok? the material does have written on it that it must be covered.
What is the difference?
The pink/blue rigid insulation has written on it that it needs a fire barrier/break. I take that to mean it needs drywall over it. If you did not have the drywall over it, you would leave the material exposed and I assume violate a building code. Now in and of itself, if you don't invite in an inspector or otherwise tattle on yourself, who cares. But if you have a fire, you might not have enough time to get out or the insurance company will be difficult if they find out. Or try to sell a home with a code violation, and you will have to go back and fix the problem. I want to do it right the first time.A lot of the the spray stuff comes fire rated. That means it just has a certain amount of time before it lights up. I would like to go the rigid foam route because it is cheaper but I also want to do the job right. Not trying to be antagonistic here I just want to know what I can/can't do.
I believe that the code citation is an exception that is acceptable. I don't have it, but remember reading it.
You must live in a state with high degree of code involement to worry so much.
I do live in NYS, particularly western NY. If there is a law or a way to keep you from being free, we have it. After all, it takes a special place to get 3 billion in debt. I don't know if the codes here are that strict. I have been trying to find that out but it has been harder than you think. I just need to find the right person. I can contact the local building code guy but sometimes easier said than done. Thanks for responding.
Walk into the Building Dept at ~8:30 am and ask to speak to an inspector. They are usually available at this time prior to leaving for the day on inspections, and often will answer any questions you might have.
"I am the master of my fate, I am the captain of my soul." Invictus, by Henley.
I also live in upstate NY. Utica. Upstate does not really get to involved in the codes issues, with minor exceptions.
What city??
I am in Rochester.
had a feeling.
depends what code is in your locality. some places only require s r cover if this is living space, not a problem in crawlspace.
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This is for the basement and crawlspace. The basement is not finished and not sure if and when I will get to it. If somebody wants to bailout my basement, I am ready to go : - )Nothing is going on in the basement but the furnace is down there as well as the dryer.
If it needs a bailout I'd advise against finishing it.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
By bailout, I mean a capital injection. Nothing like a water problem or such. Sarcasm was very high there : - )
Generally, if something CAN be read in a way to mean something entirely different from the poster's intent, I'll read it that way, just out of general cussedness. (But I usually understand the original intent as well -- it's just that the English language is so much fun to play with.)
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
then there is your free word association game coupled with you adult attention deficit disrober
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Dunno -- the right person disrobing gets my attention pretty well.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
Don't tell me - tell him or her
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grew up south of you in Wyoming county
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the foam IS a thermal barrier, as well as a vapour barrier.Re the previous comment on where is the air coming fm - I understand that air circulation thru the block cores via thermal siphon is causing cold draft into the inner space.
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I understand that the air leakage in e.g. a brick wall is a lot more than many people think. Most people presume they don't leak any air, but they do. I presume it is through the small gaps in e.g. mortar/grout that allows a masonry wall to 'leak air'. Personally, though I've no experience or detailed knowledge of this science.
I'd stuff newspaper down in the cores (as a backer) and then spray foam them. You only need about 2" of foam in each hole, so don't stuff the newspaper down too deep. Slice any lumps off the foam flush with the top of the block after it sets.
Then apply a cut-in-half piece of sill seal and sister your ripped 2x to the sill on top of that.
You might want to consider making your "sister" thick enough to allow you to then apply 1/2" or 3/4" foam to the walls and cover the whole thing with drywall.
I had actually started stuffing fiberglass insulation in the holes. Intended to foam those in with great stuff. There are a lot of holes so it will take some time. Plus factor in the cleanup at the rim joist. It is not an easy job, just labor intensive.