Crawl Space Encapsulation

crawl-space-encapsulationIf you have air quality issues in your home, then it’s very possible that the root of the problem may lie in your crawl space or basement.

As much as 50% of a buildings air can flow up from the crawl space, so it’s essential to keep this space as dry and clean as you possibly can, or your homes air could suffer. This can result in a whole host of problems from mold, damp and mildew. The solution to this problem is creating a barrier in your crawl space and utilising a dehumidifier, combined with insulation this relatively cheap process can help improve the air quality and energy efficiency of your home.

In this guide we’ll take you through all of the frequently asked questions, the requirements, and step by step DIY instructions to encapsulate your crawl space on a budget.

What is Crawl Space Encapsulation?

polyethylene sheetIn simple terms encapsulation means exactly what you might have guessed – sealing your crawl space in order to mitigate indoor moisture problems. This can either be done professionally or relatively easily as a DIY project; the materials are cheap and easy to access. A polyethylene sheet is typically utilised as the barrier between the inside of your home and the crawl space; typically, this is installed to all dimensions of the crawl space, the foundation, the walls and even the ceiling.

The barrier formed between your living space and the moisture that rises from the crawl space is most affective when all proportions of the crawl space are sealed.

After you have made an effective barrier, the next step generally involves using an air conditioning system to ensure the humidity of your property is well maintained.

Perhaps the most cost effective combination incorporates the polyethylene barrier and a regular dehumidifier to help control the water vapour levels of the crawl space.

When Should You Consider Encapsulating your Crawl Space?

If you are suffering from the effects of excess moisture levels in your home, then encapsulating your crawl space can be an effective way to help tackle the issue head on. Common signs that you home may be affected by excess water vapour include the following:

  • Condensation on the windows
  • Mold and damp problems
  • A musty smell in your crawl space
  • Increased cooling expenses

Advantages of Encapsulation include:

  • Improved air quality in your home
  • Helps prevent mold and damp
  • Reduces risk of common pests taking home in your crawl space
  • Increased energy efficiency

How to Encapsulate your Crawl Space?

There re a few things to consider before proceeding with the process of sealing up your crawl space, for instance do you plan on doing it yourself? Should you do a simple seal or a comprehensive one?

Sealing Vs. Complete Encapsulation – This may be confusing to some but there is a slight difference between sealing your crawl space and encapsulating your crawl space. Sealing typically means only applying a layer of polyethylene over the foundation or earth and approximately 6 inches of the foundation walls.

Encapsulation, on the other hand, refers to sealing all areas of the crawl space – the floor, walls and the ceiling. If you have this done by a reputable company, then they usually also install insulation as well as the lining, which will help increase the energy efficiency of your home.

Can you Do-It-Yourself?

If you decide to go with a reputable company, they will usually assess your crawl space and completely encapsulate it, which is probably the most common choice. In some cases, it’s not appropriate to encapsulate a crawl space, and it’s always possible that excessive moisture levels in the home can be caused by some other issue. Therefore, it can be worth having a professional take a look for you.

Regardless, many people make the decision to do it themselves as there’s no arguing that it’s often cheaper. The materials required to encapsulate your basement area are relatively easy to obtain online, but it may be best to buy them locally since the amount of polyethylene you require may bump up the shipping fees considerably.

If you have the budget, then we would advise getting it done professionally, since there is always something you can overlook with a lack of experience and know-how. Regardless of the choice you make, keep in mind the information below so you can ensure yourself or the company you hire are doing a good job.

Before you begin Encapsulating: Preparation is essential  

Prior to starting the sealing process it’s essential to thoroughly investigate all areas of the crawl space. What you should be looking for is any pools of water or substantial moisture issues on the walls; these should be dealt with before encapsulation occurs as otherwise issues can result.

Also check for any pest problems such as ants and termites, as these can be exuberated by installing a physical barrier between them and the home. Pest control companies can also place certain restrictions on properties and dictate how much crawl space can be covered, therefore, it’s always worth consulting with a local company.

Another important consideration is any pipe work of heating equipment that may rely on a drafting. Could sealing the space lead to any potential concerns?

Encapsulating your crawl space means analysing it before hand to ensure you are taking into account all potential problems that could arise. This can be difficult and for that reason many choose to hire the professionals.

Encapsulating Your Crawl Space: Step by Step:

Step 1: Assess the Space

  • If you’re going to be encapsulating your crawl space you need to measure all dimensions so you know how much material you need to line all areas. Therefore, get accurate measurements of the walls, floor space and ceiling.
  • Once you have done that, you need to give it a good clean, this doesn’t mean making it perfect and free from dust, but you do need to remove any sharp objects such as nails and rocks that could possibly puncture the lining in the future.
  • Finally cut the barrier material i.e. polyethylene sheeting to size for the walls, floor and ceiling and place them next to the corresponding wall. Bear in mind that each section ought to be slightly larger than the actual wall as you will be overlapping them to ensure all areas are completely sealed.

Step 2: The Installation Process

Installing the moisture barrier is by far the most important part in the encapsulation process. To begin you or the contractor will place double-sided sealing tape at all of the points the polyethylene will be placed, i.e. at all corners of the walls and below the floor joists. Next you will lay the barrier material, ensuring it is smooth and creates a constant seal throughout the space. You will probably need to cut the material to size around certain areas such as pipe work, but remember to seal any breaks in the sheeting with additional sealing tape.

This is going to be a two man job, as one of you will need to steady one side of the sheeting as one of you holds the other end. It’s also going to be difficult to navigate around pipe work and other barriers alone, so make sure you’ve got an extra set of hands if you intend on doing it yourself.

The best place to start laying the material is the walls; once you’ve made sure these are attached lay down the flooring and ensuring the material covering the floor and walls overlap. A few inches of overlap should be adequate.

Step 3: Insulate the Hatch Door

Often overlooked but equally as important as sealing the walls, you need to make sure the access door to your crawl space is insulated. The easiest way to do this is by using simple pieces of foam board insulation also termed polyisocyanurate (Thermax from Dow).

Step 4: Controlling the Humidity Levels in your Home

Once your crawl space or basement is adequately sealed and encapsulated you need to help control the humidity levels in your home. The ideal humnidity level in your crawl space should be below 50%, which is difficult to achieve. There are other methods to do this, but by far the cheapest and easiest method is to utilise a dehumidifier in your crawl space. These work by turning moisture in the air into water.

This will help maintain the moisture levels in your home at a consistent rate, helping to keep your walls are free and prevent any mold growth or mildew. The best model for this in our view is the Santa Fe Advance dehumidifier manufactured by Thermastor.

If you don’t fancy going down into your crawl space every time you want to adjust the humidity levels, which is common in different seasons, then you should consider a dehumidifier with a remote control option.

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