What’ are your thoughts on the best way to insulate a crawl space. I’m skeptical that foaming in insulation and sealing my crawl space is the way to go. High initial cost, possible need for dehumidifier, potential for serious damage with flooding. Lots of different thoughts on what’s best but would like to hear from locals living in a flood zone.
Any which way you go, whether foam or plastic, the need for dehumidification or conditioning will be essential once sealed. If you go with the foam route, talk with your pest/termite control people and insurance to make sure you don’t void your coverage. Good luck.
Fishing Nerd
“skilled labor isn’t cheap, cheap labor isn’t skilled”
My neighbor had his crawlspace encapsulated. It looks fantastic and stays at a constant temperature year round. Not sure what it cost but it dang sure wasn’t cheap.
“Apathy is the Glove into Which Evil Slips It’s Hand”, but really, who cares?
I’m a crawlspace contractor and would be happy to answer any questions you may have. Give me a ring at 843-323-6976
or just insulate R-19 in the joists and put down a good vapor barrier and open the crawl space vents
Pioneer 197SF
I did a bunch or digging around on this topic. There are a lot of different thoughts/methods and many articles to read through.
All said and done…
IMHO, crawlspace encapsulation is for new construction. The home should be designed around it.
Again, IMHO, a good vapor barrier and open vents is the best way to handle existing homes. If you have standing water, look at perimeter drains and a sump.
More important is getting water away from the house. My last home I installed gutters and dug 150ft of drain pipe to pull all the down spout water away from the foundation.
My current 6mil plastic is about dead. I have been looking at 12 or 20mil plastic vapor barrier with the hopes it lasts more than a few years. The higher quality material should allow for over lapped taped seams, full coverage, and still allow your termite company access to inspect/treat.
ding ding - correct
get some thick black plastic for the vapor barrier, it will last forever
Pioneer 197SF
I see a lot of crawlspaces in my line of work and will tell you from my experience, an encapsulated crawlspace is usually the way to go. It’s just too humid in the summer month around here to use the outside air to ventilate your crawlspace. It really just all depends on your crawlspace though. Do you have duct work in the crawlspace? If so encapsulate. Your ducts work will perform better in more of an interior type space rather then an exterior type space. Is your foundation wall a continuous block foundation wall with a few vents or a series of piers with louvers? Continuous block wall foundations tend to hold a lot more moisture because of the lack of air flow.
As for the insulation, you do not need floor insulation. Floor insulation has very little to no affect on the heating and cooling systems. Often insulation does more harm then good. Please do not spray foam your floor!!! Spray foam is great for walls and attics, but not a floor system. You need to be able to see your floor from time to time to check on things.
Remove the floor insulation all together, install a thick ground vapor barrier at least 10mil plastic, block the foundation vents with rigid foam that can be easily knocked out in the event of a flood or install smart vents to appease your flood insurance and install a dehumidifier to condition the existing air. In doing so you will create more of an interior type crawlspace rather than an exterior type space. I’ve seen this type of system work every time. Your crawlspace may have some different conditions, so have someone who knows what they’re doing look at it.
Feel free to post some pictures and I can give you better idea of how to go about things.
This picture is from an recently house I looked at. This is the type of crawlspace that would benefit from an encapsulation. The fungi growing on the wood is destroying the floor system.
I encapsulated my crawlspace a couple of years ago. My joist went from 23% moisture down to 14% during the summer months. I was able to get fairly inexpensive plastic from https://billboardtarps.com/, you can buy used billboard at 13-16oz thickness for 14-16 cents per sq ft.