Crawl space insulation

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Polish hammer

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I have a 1300 square foot ranch home that sits on a poured concrete floor and poured wall... I can't seem to find much information on crawl spaces with concrete floors.. there currently is zero insulation down there stays dry I do run a dehumidifier year round because I'm not down there ever. Walls are 4 feet tall so what do I do insulate the walls or the floor joists? All the outside vents are closed off and it is always cooler down there.
 
Sprayed polyurethane foam (also called structural foam) is the way to go down there. Highest insulation value, and it seals the whole works up pretty air tight... so, you would probably want to leave one cold air return and one heat vent open to the space during the winter. Otherwise, the humidity down there would rise to unacceptable levels that even your dehumidifier probably couldn't keep up with. It would be well insulated, though, so your net heating bill would likely be lower than before, in spite of pumping some heat into the space. Uninsulated, it's probably sinking more heat out of the house than it would take to heat it a little with insulation.
 
Unfaced insulation on the floor of the house then foam board under that to create a vapor barrier. It's code where I work to have one heat and one return in the crawl space. Do i agree with that not always. Some ventelation is good but being 4 feet deep it should be below the frost line so some heat and return may help keep it a steady temp and humidity level.

Depends if you are trying to keep heat in the crawl space or out of the crawl space.
 
That's true we are at 42 inches here but Alaska may be more. Most of my stuff is less than 42 inches and been good so far. That's y I say do you want to keep the heat in the crawl space or out. If your frost line is over 4 feet you better keep the heat out and in the house.
 
Our frost line isn't 4 feet I believe 3' I'm close to Lake Michigan so we usually don't even see much over 2 feet.. As far as heat in or out of space I don't really have a preference just thought insulation somewhere down there would be beneficial for the upstairs of the house
 
Where I'm at the frost depth is 60" and we don't bother with a crawlspace at that depth, we just build a basement and insulate it on the outside of the foundation. In your case I would get a closed cell spray foam and fill the joist cavities, 6" should be great plenty and help keep the toes warm.
 
Do you have plumbing and ductwork in the crawlspace? I'm guessing so. We just did a remodel, rebuild and used thick foam board insulation on the inside crawlspace wall. Then I stuffed R38 in the ends of the joist bays on the sill plate. That way the whole thing stays warm. It's what was required by the building codes here also. The foam board goes up quickly, and the batts on the sill plate are quick too. I was racing against the clock before the inspector arrived when I insulated the crawlspace. I was able to cut and throw batts of insulation through a hole in the subfloor, push them along the floor while crawling, and stuff them into the joist bays in under 45 minutes. The space had 2 24' sides and one 36' side with joists 16" on center.

If you do it yourself look for sales on insulation. I saved a lot using the 11% rebate at a big box store. There was also a big sale on insulation at the time too.
 
That' was my original thought but then I wasn't sure if doing under the floor would be the best I already did the sills but then stopped
Because I the whole vapor barrier and or moisture thing had me nervous to ask first... Yes there is plumbing and duct down there
 
I'm definitely not an expect, and it gets colder where you are than it does here. I would think insulate the crawlspace walls to keep the plumbing warm. Also, any heat lost from the duct work will just go to the insulated crawlspace. The foam board should also act like a vapor barrier on the wall.
 
You should treat it like a basement since it is below the frost line. Insulate the walls and end joists. Keep some heat and return down there and you should be good. Heating that space will help keep your floors warmer and your house more of an even temp.
 
I am amazed to be a part of such helpful community. I'm new the town and was in search of professional plumbing services and a colleague of mine suggested me drain repair service NJ I want to know how other home honors perform their drain cleaning. Any suggestions will be greatly appreciated.
 
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