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Crawlspace Encapsulation

Updated: Oct 28, 2023

I’m sure we have all seen the advertisements from companies pushing for the crawlspace to be encapsulated. What is encapsulation and what does it do for your home? Encapsulation basically is a process where the crawlspace of a home is cleaned out, then covered from the ground up to the floor joists / girders with plastic sheeting to protect it from moisture which can cause mold, mildew, wood decay as well as attract termites and other pests. Does this actually work to protect the wood from these things? If the process is done correctly, yes it does, but there is more to it. Should every home be encapsulated? Before that question can be answered let’s take a deeper look into things and then you can decide.

Crawlspaces are known for moisture issues, which then causes most of the other issues in it. Where is this moisture coming from? How is it penetrating into the crawlspace? Is the soil damp or dry? Are there puddles of water? If so, are they spread out over the entire crawlspace or just around the edges at the foundation? If puddles are present, are they around the entire foundation, or just one area? If there aren’t puddles, is the perimeter at the foundation muddy or wet? Is the entire crawlspace damp / muddy / puddled or are there dry areas? All of these questions, and others should be answered before deciding on what needs to be done to protect the crawlspace. The answers will help direct how the issue(s) should be addressed.

Water/moisture can enter into the crawlspace a couple ways. One is coming up through the soil. Rainwater for example can wick its way under the home and come out of the soil in the crawlspace causing elevated moisture levels. The other is directly through or under the foundation or foundation wall. The crawlspace walls are not normally sealed as you would find a basement wall. This allows water to penetrate through the porous brick/block. Depending on circumstances, it can go under the foundation footing too. This method of entry can also damage the foundation. Water is the number one cause of foundation issues. Resolving the water issue can save you from costly foundation repairs.

The companies which install the encapsulation tend to first install a French drain system in the crawlspace linked to a sump pump to remove any water after it penetrates the crawlspace. Once this is installed, the plastic sheeting is installed. This is not just a loose layer of plastic like a vapor barrier. They wrap (encapsulate) everything coming out of the ground (piers, columns) and seal it to the brick/block before it reaches the wood to prevent moisture reaching and damaging these areas. It does make for a very clean, nice-looking crawlspace. Does this mean the moisture/water problem is fixed? That depends on the answers to the questions above. If the moisture/water was found to be penetrating through/under the foundation wall, then IMO it isn’t fixed. This process does nothing to address the cause of the problem. It only reacts to the moisture penetrating the crawlspace. It’s like placing a pot under a leaking pipe to catch the water instead of fixing the actual leak. The moisture may not be reaching the wood, but it is still getting in, hidden and can possibly still cause damage to the foundation.

If moisture is wicking into the crawlspace through the soil, which can cause soil in the crawlspace to be damp then their process of encapsulation is a good method to prevent any issues from occurring related to that type of moisture penetration. Yes, even dry, dusty crawlspaces can have an issue with mold / mildew due to moisture wicking through the soil. It is hard to believe, but I have been coughing on dust from the soil and still find mold/mildew present. Mold/mildew is proof of elevated moisture levels.

If you don't have the issue of water coming through or under your foundation, there is one downside, at least in my opinion it is. Once the encapsulation process is complete, it blocks being able to view the foundation walls to see if there are any cracks or other issues present. Which I feel would be important to know.

Back to the question, Should you get your home’s crawlspace encapsulated? The honest answer is it is truly your choice, even if you have moisture related issues. Encapsulation does provide protection for the wood in this area from the moisture related issues, is much cleaner, but if there are issues present with water penetrating through the foundation, it doesn't fix that issue, it treats it after it comes in and covers it with plastic. IMO repairs to prevent the water penetration should be performed first, then if desired, have it encapsulated. One other thing to help you decide. How much does it cost? I have seen quotes ranging from $25,000 to $35,000 for an average size home, and that was pre-covid pricing. The cost today could be far greater knowing the high inflation we have been experiencing.

Things to think about: Water penetrating through the foundation wall can come from different things. The first thing is the gutters. Most homes have the downspouts ending directly at the side of the home. This dumps all the water it collects where you don’t want it. We recommend having it extended a minimum of 5 feet from the home. The grading of your yard could be contributing. Does the yard slope towards your home, or does it slope away? The grading of your yard should have it sloped away to guide the water away from the foundation. Clogged gutters can be another issue causing water to fall directly at the foundation. There are just a few things that can be contributing or causing issues with water in the crawlspace.

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