Waterproofing a basement can be a big job or a simple one, depending on how much water is getting in. A basement that regularly has standing water requires the help of professionals. However, basements that just have a damp feel or the walls are wet without actual standing water can easily be handled by the [...]
Basement Walls - Insulating, Waterproofing, Sealing, Framing & Wall Panels
Home remodeling of any type is often all about surfaces, especially basement walls. Everywhere you look in a house, you see a surface of some type. Basement finishing is no different than any other space when it comes to the three main surfaces; the ceiling, the floor, and the walls.
What is different in basements is how those surfaces need to be treated to ensure years of worry-free enjoyment of the space. We've got sections on the site that deal with basement specific issues for each of these. One of the most popular sections of the site is basement floors.
This particular section is all about basement walls. We provide helpful information for you to consider when thinking about the new walls for basement areas of your home. Topics covered include the following:
- waterproofing basement walls
- sealing basement walls
- framing basement walls
- insulating basement walls
- basement wall panels
Basements are very different than above ground spaces in a number of ways, many of which have to do with issues related to basement ventilation and excessive moisture in basement areas. The walls are the surface most prone to damage because people often think only of waterproofing basement floors.
Waterproofing Basement Walls
One of the most common mistakes in basement finishing is to seal or waterproof the inside of the basement walls. It's a simple mistake. Homeowner's see a wet wall that they want to cover with non-waterproof material so the intuitive response is to put something waterproof on the wall first.
However, the correct action, which is sometimes not easily accomplished after construction is complete, is to seal the outside of the wall. This prevents moisture from getting into the wall itself in the first place and provides for a much drier basement.
Once water is inside the wall (usually a concrete block or poured concrete wall, both of which are porous) there is no way to get it to go back to the wet earth outside. Capillary action will draw the moisture to the dry areas of the concrete, eventually getting inside the basement and condensing on the wall surface.
The first line of defense is in keeping water away from the exterior using roof overhangs, gutter systems, and well-designed back fill slopes on the property. The next line of defense is waterproofing the wall on the outside.
Sealing Basement Walls
Basement walls should not be sealed on the interior to stop moisture that is already coming through the wall surface.
If you make the mistake of covering the inside of a basement wall with a waterproofing material such as elastomeric paint (or even regular latex paint) the water will likely form a bubble which will burst causing a huge mess or cause all of the material to peel.
One solution in this instance involves the installation of a drainage channel cut into the concrete along base of the walls. This channel acts as a small gutter along the perimeter and directs water to a drainage point such as a floor drain or sump pump.
There are sealers made for sealing basement walls such as DryLok and these claim to be strong enough to stop water coming through the wall. However, a little bit of research online (like you're doing right now) will generally lead you to an abundance of first-hand experience saying that sealers on the interior don't work! So use caution.
Framing Basement Walls
For the most part, framing in a basement is no different than other areas of your home, but there are a few key points to consider:
1. Use treated lumber against concrete. If you live in a frame house you may be used to using the same lumber for the entire framing job. This isn't advisable in basements. Any lumber touching concrete needs to be chemically treated to prevent rot and insect damage. (usually referred to as Pressure Treated lumber)
2. Consider thickness of insulation. Many basements require additional insulation to help keep the area comfortable during the winter cold season. This insulation may be very thick and wall framing must provide enough depth. This could mean switching from 2x4 (for R-11 insulation) studs to something larger, such as a 2x6 (R-19) or 2x10 (R-30).
Insulating Basement Walls
Talking of basement wall framing always brings up talk of basement insulation. Walls can be insulated with a number of materials such as:
- fiberglass bats or rolls (standard insulation)
- Sheets of foam applied directly to the concrete
- Open cell spray foam (such as Icynene)
- Closed cell spray foam (similar to the 'Great Stuff' you use to fill holes)
The type of basement wall insulation you choose depends on a number of factors such as the range of hot and cold temperatures in your area, the amount of moisture in the ground, the type of basement HVAC equipment you're going to be using, and your desired temperature in the conditioned space.
Most building departments have calculation forms that help you determine what you'll need. You can also consult with a licensed HVAC contractor or an engineer to help you.
Tip - If using spray foam insulation, be very careful to consider moisture concerns. Closed cell foam tends to trap moisture and cause unseen damage, while open cell foam doesn't do well when it gets wet. If there is any chance your outside wall will be wet, spray the foam on a framed wall a few inches away from the concrete wall. Get more details here in our section about basement wall insulation.
Basement Wall Panels
When considering walls for basement areas, a popular option is prefab basement wall panels. These are usually made similar to a thick sandwich of strong and dense foam with a finish surface on both sides. The interior surface is usually totally finished and therefore doesn't require paint or any other work before the space is ready to be occupied.
Some of these panels are strong enough to be totally self-supporting and don't require any framing or additional insulation at all. Others are thinner and are made to go on-top of framing or other structural support.
Panels are sometimes sold as part of "basement finishing systems" that provide everything needed to convert the basement to a finished area. However, and this is a big one, panels rarely look as nice as a framed wall finished with regular building materials such as drywall or plaster. Just be sure you like the look before going this route.
More Details and Ideas on Basement Walls
Hopefully this general overview has helped you better understand some of the options available to you when considering the wall aspects of a basement finishing project. We've got much more information on the site related to all aspects of your basement remodel. Use our main navigation above to look around the site for ideas and more in-depth information.