Rod Martin's Complete Basement Systems Q&A

Can I turn my crawl space into a basement?

The short answer is, yes. It is indeed something you can do, if you really want a basement. However, as foundation, basement, and crawl space experts, we couldn’t recommend against this modification enough. Here’s a few reasons why. First of all, digging out a crawl space is no small weekend DIY job. These types of jobs tend to take quite a while to get done, and if you don’t know what you’re doing, it can lead to serious consequences for your foundation and the rest of your home. During the project, your home needs to be temporarily propped up on stilts, which, if not done properly, can lead to a dramatic failure in your foundation wall. Then comes the issues with pouring an extension onto your foundation. To extend your foundation wall for an entire basement, you’ll need to pour an additional 4-6 feet of concrete all around the home. The problem arises in the seam between the old and new foundation walls. It is very difficult, if not impossible, to fully seal the seam between these walls. This seam is a perfect spot for water intrusion, especially if you were having water issues before. Finally, a full crawl space dig out is not a cheap project. To give you an idea, to dig out a 400 square foot crawl space could cost anywhere between $30,000 and $60,000, all for an additional 400 square feet of storage space. While having a basement could definitely increase your home’s value (depending on the market), there is very little chance you’ll see a return on your investment. In other words, it’s expensive, and it won’t raise the value of your home nearly as much as the project costs.

Do crawl spaces have soil vapor barriers?

Unless previously disclosed or seen when you bought your home, your crawlspace doesn’t usually have a vapor barrier installed. More often than not, most crawlspaces have a dirt floor, which are usually damp and full of pests and debris. Many come with a tarp or some sort of liner across the bottom, which usually renders ineffective at preventing crawlspace moisture if your crawlspace isn’t fully encapsulated from top to bottom. Some homeowners may try to install some sort of vapor barrier themselves, but most are usually not installed properly and can still house pests, water, mold and debris commonly found in crawlspaces.

Do I need a vapor barrier in my crawl space?

Yes. Without a vapor barrier in your crawlspace, the moisture in the soil, circulating humid air and any other water infiltration can seep into your crawlspace. The moisture makes a perfect space to harbor mold, mildew and pests, ruin insulation and wood, and deteriorate any other organic material in your crawlspace. A properly installed vapor barrier can completely eliminate moisture from coming up through the floors, vents and walls, ensuring that your crawlspace stays clean, healthy and dry.

Will the bad smell in my crawlspace go away if I encapsulate it?

Absolutely! the source of the foul smell is most likely a combination of must, mold and pests due to moisture being trapped inside the crawlspace. When a proper encapsulation is done, mold and mildew and pests are removed, and shouldn’t continue to be in your crawlspace once moisture is eliminated.