Today, we’re going to be going over how to install butyl tape and also vapor barrier. Here’s your sill plate. Here’s the block. Most of the time, the sill plate is the only pressure-treated piece of wood in the crawl space. What you want to do is look at the termite gap because that is a significant factor in the crawl space. You’ve got to install the vapor barrier or the plastic or the vapor retarder three inches below the sill plate to leave a gap. Mr or Mrs termite person can come in and look around to make sure no termite tunnels are coming from behind the vapor barrier up into the sill plate, which eventually leads into the house. What I’m going to show you is how to install a vapor barrier or a vapor retarder. That you don’t have so that you do have that three-inch gap.
One Inch Butyl Tape
Here’s our one-inch butyl tape, and here is our two-inch butyl tape. We’re going to do a demonstration for both. So before actually getting started, what you have to do is prepare the cinder block for the butyl tape. You want to take your little scrub brush, and you want to knock off all the loose pieces so that you are getting good adhesion. Even if this is brand new cinder blocks, it’s still going to need some things knocked off of it. Now you can go crazy if you want to and get it super clean, but knock the loose stuff off to allow the butyl tape to adhere better.
The next thing you want to do is measure your three-inch line. Remember, it’s three inches from here. We’re going to measure our three inches and then use our chalk line to ensure that we stay just below that three inches with the butyl tape. It can be lower than three inches, and it just cannot be higher. It’s okay to go slower, but you can’t go any higher. It would help if you left a three-inch gap here. We’re going to stretch this across.
Keep in mind that if you do the chalk line first and decide to do this, you’re going to remove your chalk line. So make sure you do the chalk line after you brush off the concrete. I’d hate for you to brush off or do the chalk line and then have to go brush off all that concrete. And then you got to do the chalk line over all over again.
There’s Adhesive On Both Sides
You have to be careful because this is adhesive on one side, and then you take the tape off on the other. I’m going to show you how to do this. You have to make sure that you get it just below the seal and play with the adhesive still on, which cannot be easy to do with one hand. Let me go ahead and show you how this is done. You want to take that, and you get it, you get it on there, and then you take your little roller, Get all the air bubbles out. Now the nice thing about the two-inch is that it has two sides of the tape. So if you want, you can pre-cut it, see there’s tape on both sides. So if you’re going to pre-cut it, you can do that.
That is a nice feature of the two-sided tape. You can even lay it down, and you can drop it; you can do whatever you need to do. It even has a way to put it back. So that is pretty cool that you can do that. So here we are. We have our two-inch. You can see the difference in size here. The nice thing about it is, is I can kind of mess around with it, and I haven’t lost my adhesion.
Put The Tape Just Below The Line
You want it just below the line. Butyl tape is some sticky, sticky stuff. Both of them are very sticky. Get the air bubbles out. One of the great things about using butyl tape, no matter if it’s one inch or two inches, is that if you’re trying to accomplish the crawl space’s encapsulation on your own, this gives you a great way to have some extra help. It’ll hold the plastic up for you while you put in the Christmas tree fasteners, or maybe you want to use a Ramset or a Hilti nail or something like that. I wanted to show you how the butyl tape is applied. We’ve got the three-inch gap. So we’re going to peel this off and put some vapor barrier on it.
You want to make sure you have the three-inch gap. This gap will give you a bit, and you just run your finger along with it. It’s being held up totally by itself now. Then you go through. If you want to give it a little bit more compression, you can do this. I wanted to show you a picture of right here because this is a crawl space where all used was the butyl tape to hold up the plastic vapor barrier. This vapor barrier also has reinforcement in it. And this crawlspace, many homeowners ask to go out and put in a dehumidifier.
Use A Six Mil Barrier
It’s a six-mil reinforced vapor barrier, and I encourage people to use a Christmas tree fastener. They sell these by the 100 and by the five hundred, And it tells you a drill quarter-inch hole. These Christmas tree fasteners go right in through the vapor barrier. You got a lot more forgiveness on this side because it’s a more significant surface area. Now we’re going to drill, pre-drill our holes, and put the Christmas tree fasteners. When you start to drill the holes, you want to make sure you have a hammer drill and put a Christmas tree fastener. You should put them about every 16 inches.