# Crawl Space/Foam Insulation DIY



## Windows on Wash (Aug 30, 2011)

You are straddling both options in your current crawl space arrangement. It needs to be either insulated to the outside wall and treated as conditioned or insulated under the floor.

If the ground is not showing much moisture, you can likely get away with a conditioned crawl.

http://www.buildingscience.com/docu...s/crawlspace-insulation?searchterm=crawlspace


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## cbaur88 (Jan 25, 2011)

Windows on Wash said:


> You are straddling both options in your current crawl space arrangement. It needs to be either insulated to the outside wall and treated as conditioned or insulated under the floor.


Without a doubt it needs to be insulated under the floor. Even though the vents are covered cold air is still getting in making the crawl space extremely cold.


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## Windows on Wash (Aug 30, 2011)

Did you read the link that I sent you?

When you treat the crawlspace as "conditioned" you are going to seal up and insulate the exterior walls and supply some amount of conditioned air to the space.

You either insulate the crawlspace ceiling.....or.....the outside walls.

Not both.


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## cbaur88 (Jan 25, 2011)

Windows on Wash said:


> Did you read the link that I sent you?
> 
> When you treat the crawlspace as "conditioned" you are going to seal up and insulate the exterior walls and supply some amount of conditioned air to the space.
> 
> ...


Yes the link was read and I completely and utterly understand you either insulate the walls or the ceiling. The house was built with vents around the foundation of the crawlspace so one assumes it was meant to be unconditioned which is why I would re-insulate the ceiling properly and reverse the batts or use foam. The previous owner appears to have done a no no by insulating everything vents, ceiling, walls, etc....


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## Windows on Wash (Aug 30, 2011)

Crawl spaces are almost unilaterally built as vented, however, this does not mean that is the best approach. 

Most customers will get far better efficiency and comfort by converting their crawl space into a conditioned crawl.

We convert vented crawls into conditioned crawls all the time.


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## cbaur88 (Jan 25, 2011)

Thanks Windows on Wash, that's very interesting to know. With that said I really am not sure which direction to head towards then. My main goal is to prevent the living space above the crawlspace from getting cold and drafty as it is now. I am not sure what you would call my crawlspace as of right now. As previously mentioned it's got vents but they are blocked. The wall of most of the foundation is insulated as well as the ceiling. Which direction to go is or what exactly to do I am at a loss right now.


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## Gary in WA (Mar 11, 2009)

Some reading to help you decide: http://www.advancedenergy.org/buildings/knowledge_library/crawl_spaces/pdfs/Closed Crawl Spaces.pdf

As per Code if you go with conditioned (requires air supply ducting in crawl); http://www2.iccsafe.org/cs/committeeArea/pdf_file/RE_06_64_07.pdf

Cover the exposed dirt with plastic, notice the vents mentioned as WW said: http://dirt-crawl-spaces.com/crawlspace-dirt.html

Some new ideas/science, with more links at the bottom: http://www.buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces/

Gary


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## CrawlSpaceMoist (Nov 24, 2011)

Yeah, you've got a couple of decisions to make.
The cheapest route is to go back to a vented crawl - remove the insulation from the vents and walls and fix it in the joists. Make sure you've got a poly down on the floor from wall-to-wall.
The better answer, especially for cold, drafty floors, would be to truly seal this crawl. Remove the crappy insulation from the vents and seal them with a rigid insulation cut down to size and caulked in place. Take the insulation off the walls and either afix an about R10.6 rigid insulation or a wrapped fiberglass (if you can find some). Go around your sill band and caulk, if nothing else where you can see light from outside. 
Most state codes require either joist or wall insulation, but don't specifically prevent both being in place, a quick call to your code enforcement division will clarify. Also, codes require a sealed crawl space be conditioned. There are many ways, but either with a dehumidifier or using hvac air are the 2 most common. Oh, and don't forget that poly on the floor!


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## cbaur88 (Jan 25, 2011)

CrawlSpaceMoist said:


> Yeah, you've got a couple of decisions to make.
> The cheapest route is to go back to a vented crawl - remove the insulation from the vents and walls and fix it in the joists. Make sure you've got a poly down on the floor from wall-to-wall.
> The better answer, especially for cold, drafty floors, would be to truly seal this crawl. Remove the crappy insulation from the vents and seal them with a rigid insulation cut down to size and caulked in place. Take the insulation off the walls and either afix an about R10.6 rigid insulation or a wrapped fiberglass (if you can find some). Go around your sill band and caulk, if nothing else where you can see light from outside.
> Most state codes require either joist or wall insulation, but don't specifically prevent both being in place, a quick call to your code enforcement division will clarify. Also, codes require a sealed crawl space be conditioned. There are many ways, but either with a dehumidifier or using hvac air are the 2 most common. Oh, and don't forget that poly on the floor!


Great excellent advice CSM, I really appreciate it. I'll take a peak at my twps website to see if I can find any codes for when I one day sell my house.


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