Crawl space insulation

[Karlton]

Thanks for taking the time to help a newbie out. I have a small crawl space under my kitchen and in the winter, the kitchen gets very cold. I am considering insulating this crawl space and would like to obtain your thoughts on this situation.


Crawl space facts

• 10’ x 20’
• Unvented
• Dirt floor, but a previous owner had put wood boards down in an attempt to level the floor - wood has deteriorated and is harboring silverfish
• Plumbing in crawl space
• House is in Laramie, WY – very cold winters, low humidity year round
• We have only lived here a year and have not seen moisture

Based on what I have read I was going to

• Use Borax to eradicate the silverfish
• Remove all of the old wood
• Put a layer of 6 mil plastic on the floor
• Insulate the perimeter walls of crawl space where it does not interfere with plumbing

Thanks very much for your feedback.

[pushkins]

Yes you are correct to remove all the wood, a simple pest killer (like defender etc...) would probably take care of the silver fish and other pests, I'm surprised you didn't mention any termites, that's the ideal home for them as well. Most definitely add the 6mil vapor barrier over the dirt floor
As for the insulation issue that becomes another issue, the only insulation code "clearly" allows for crawlspace walls is hard foam sheet, BUT it cannot be installed in an area that would allow fumes or smoke (should it ever catch fire for whatever reason) to move into living areas of the house, I mention this because you obviously have good access to this area but didn't mention if it was from a crawlspace door to the exterior of the home or via a basement access etc...

If it were me I'd skip the crawlspace wall insulation and install faced insulation up into the floor joists (paper facing heated area), this protects your plumbing at the same time. Min. R19 but if you have 2x10's or 2x12' as floor joists you can get R30 in without a problem.

[Karlton]

Thanks very much. The crawl space door opens to the basement. I didn't consider the code involved with wall insulation. I'll get back in there and examine the floor joists.