Introduction: Crawlspace Encapsulation
Crawlspaces are a menace. They're dark, dirty, and humid. Bugs like to live in there. They're vented to the outside air in the summer (and in the winter if you neglect to close your vents) which can be very humid and this defeats the purpose of venting. Mold loves a dark humid environment with plenty of wood to eat. Today, with the help of my
lackey friend Sunkicked, I'm going to show you how to put an end to this menace under our feet.
If you've never heard of crawlspace encapsulation a quick internet search will enlighten you... quickly. The basic principle is to completely cover the ground of the crawlspace with a heavy vapor barrier and even run it up the walls to block any moisture that might come in through the concrete blocks.
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Why?
I was in my crawlspace insulating pipes when I noticed mold on some of the floor joists. Being someone that watches Holmes on Holmes and Holmes Inspection I was immediate scared sh*tless. If you haven't watched one of those shows you can't begin to imagine how much they drill the fear of mold into you. You'll have nightmares. Moldy nightmares. Night mares about mold is what I'm trying to say. So I called a professional cleaning company to come out and have a look. They said it wasn't worth my money to pay them to clean it and that I could deal with it with a little cleaner and a sponge... and a proper mask.
I wanted to make sure there were no future problems and that's when I first read about encapsulation. I didn't know what it might cost though. To give you some idea why I chose to do it myself:
After a woman I work with heard about this she had someone come and do it for her and paid $8,000.
I paid about $300 to do this 30' x 25' space. That's a savings of nearly 97%. Boo. Ya.
I think I made the right choice.
Step 2: Needful Things
Vapor barrier. What the heck kind of vapor barrier? Definitely not that wussy 6 mil plastic you can get from the nearest home improvement store. What the encapsulation pros use is a thick vinyl material. I'm sure that to buy that material new would be exceedingly expensive and reduce your savings. That's why I got used billboard tarps from Billboardtarps.com (actually I think I bought them through Amazon.com, but they were from these people).
This stuff is tough. They are three ply 15 -17 mil vinyl, tear resistant, mildew resistant, waterproof. They are made to last years outdoors exposed to UV and winds, so just imagine how long it will last in the dark under your house. Hell, people use these for pond liners!
And they have cool stuff printed on one side of them. Check out the pictures.
I estimated that I'd use 2 of the 14' x 48' models. They come in many different sizes.
Step 3: More Needful Things (How Awful Would That Movie Have Been?)
Other than that you'll need the usual stuff.
- A Drill --- one capable of drilling into concrete with a concrete bit
- Silicone caulk
- Sharp utility knife
- Tap Con or any other brand of Masonry screws ---- usually they're blue and come with an appropriate sized drill bit
- Furring strips --- enough to go completely around the perimeter of your crawlspace; you can pre-drill these every 2 feet to save from doing it in the crawlspace
- Extention cords
- Knee pads
- Dutch courage
Step 4: Doing It
My crawlspace is only accessible from inside the house so it helped to unfold the tarps on the lawn and then refold them to make it easier unrolling them in the crawlspace. Do this to best suit your needs. We folded the 14' side in half and then rolled the tarp up from the 48' end. We then folded this bundle in half making a 7' bundle to carry into the crawlspace. Once inside it was easy to unfold it and roll it out.
If you're up for doing a lot of cutting and going back and forth you can carefully measure your crawlspace, work out a little diagram, and cut it piece by piece.
* Use the drill to make holes in the concrete. Hold up the furring strips and use them as a template for your drilling.
* Apply a bead of silicone along the top of your concrete blocks, this will be a watertight gasket that will keep the humidity rising out of the Earth down under the barrier.
* Arrange the tarps so that once they are screwed in place behind the furring strips they will drape down the wall and onto the ground.
* Spread everything out evenly and cut away excess in as big of pieces as possible. These pieces we ended up using in patching holes where needed.
* You'll want to overlap any cuts by at least 1 foot. In many instances I ended up with 2 feet. You can use HH-66 to seal the joints, but I chose not to. I know that the water line running into the house has been in the ground since the early '60's and that the huge old cast iron drain will need to be replaced so I didn't want to have to cut and patch later. You can use housewrap tape if you wish, but my overlaps were so big that I didn't bother with either.
Step 5: Done
Yeah, done. Like it was so easy and took no time to do. Right. Actually, it wasn't all that bad. I'm very lucky that I have such a spacious crawlspace as well as a
lackey friend who will work for cheap booze and a hamburger. If it it were shorter and required lots of belly crawling I'd definitely recommend going the route of careful measuring and cutting. As it was I think me and my helper in orange worked about 3 or 4 hours one day and then I finished up the rest in 2 or 3 hours the next day. Not bad, but keep in mind that it was only about a 30 by 25 space.
Was it worth it?
Oh heck yeah. I was amazed at how warm it kept it in the winter. I put a thermometer with a high and low memory down there during some of our coldest days that winter single digits and low teens) and the temperature never got below 54 degrees. As an experiment I didn't reopened the vents for a year and haven't noticed any new growth of mold. If that trend continues then after this summer I may seal the vents permanently. I've done other work in the crawlspace and it's completely no problem at all to go in there. So clean and bright. Many times I've gone in there in pajamas because I've remembered a tool or something I'd left behind on the last trip in.
If you have moisture issues, it's definitely worth it. If you think you might have to hide from a massive government plot to kidnap you and experiment on your DNA, it's definitely worth it. If you live in an apartment you probably don't have a crawlspace. So who's house are you in? You're weird.