Crawl Spaces - Insulation, Vapor Barriers, and Ventilation

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Video Transcript

Crawl space- Insulation, Vapor, Barriers and Ventilation
By: Home AdditionPlus.com

Hi, I am Mark Donavan from HomeAddtionPlus.com and today I am going to talk to you about how to keep crawl spaces dry and warm.

The first thing about keeping a crawl space warm is to insulate the ceiling rafters or the floor joists between the base and you want to put in at least an R19 or 6-inch type insulation in between the floor joists and you can hold the installation up with this metal rods that just easily poke into the floor joists and keep the insulation secure up against the floor of the room above us.

Also, when installing insulation in crawl space, you want to make sure that you put the insulation in the knee walls. Again, these are 6-inch studs so there is R19 insulation in the knee walls. You also want to make sure the insulation goes right up against the base between the four joists.

Now that we have talked about keeping your crawl space warm, the next major topic is how to keep it dry. With all basements or crawl spaces, they tend to be high in humidity and that is because moisture wicks in from the ground up into the airspace. And what you need to do to prevent that is put a vapor barrier on the ground before you pour concrete floors or before you put a crush stone material in the crawl space.

So what we have done here is we have installed a polyethylene or plastic vapor barrier between the ground in the crawl space in the gravel that we placed over top. Polyethylene prevents the moisture from the ground wicking up and forming as a vapor, humidity vapor in the crawl space area. We then put a couple of inches of crush stone on top so that we do not damage the polyethylene plastic when we are walking or crawling around in this space.

So you definitely want to make sure you put polyethylene onto the floor of the basement prior to putting gravel or even if you are deciding the pour concrete flooring.

The last thing you need to think about when doing a crawl space is ventilation. Here we have about 16-inch by 8-inch high screen of the ventilation system. We have a couple of them installed in this particular space, which is approximately 20 x 16. And what we have this for is to help eliminate the high moisture levels that can still occur even with the moisture barrier, the polyethylene plastic that we have installed in the floor of the crawl space.

There is some debate on whether or not it is a good idea to have ventilation or not. Some argue that in the hot summer, we have hot humidity, that it is negative to have a ventilation like this installed because the warm, moist, hot air comes in. It condenses on the pipes maybe in the crawl space and cause water to form, which then can lead to mold and mildew. So some people say shut off or block up the ventilation systems during the summer months and then open it up in the fall time.

My view is I would rather not have to worry about closing them and opening them on a regular basis, so I leave them open all year long. And I wrap the pipes and interior pipes that I have with an insulation material that helps prevent the condensation that could form by the high humidity.

So there you have it. Those are the three main issues that you need to think about with crawl spaceâ€”ventilation, insulation and the vapor barrier.

If you have any other home improvement questions, visit us at Home AdditinPlus.com today.