A recent article in my local newspaper titled “Building a better basement” explains the difference of using traditional stick framing and drywall with panel systems for basement remodeling projects. So, naturally red flags went up for me when I saw the title. Primarily because what we have done in the past that we thought were the right things to do, are really not and are causing lots of problems today. Especially the four letter word “mold”. I think back to when my father finished our home when I was younger putting up the sheet of plastic (vapor barrier) before applying the paneling to the insulated stick framing, not to mention the rotten wood I found when tearing down finished basement walls in my own home. If you are wondering what I may be afraid of, check out a couple of studies on insulating existing basements I posted last year. (Building Science Sunday: Basement Insulation)
I want to take a little time and explain some of these systems mentioned in the article a little further and make a couple of suggestions. Now the good thing is that all the companies mentioned in the article all agree that the basement has to address any moisture issues if any first. Because if you have water problems in your basement, it doesn’t matter how mold resistant a product says it is. If the material does not get a chance to dry and is not exposed to sunlight, mold can grow on almost any surface. So lets talk about some of these systems.
Acoustical panel systems are by far my least favorite of the systems. These semi rigid fiberglass panel systems were originally designed to be acoustical panels to reduce reverberation in large spaces such as gymnasiums and movies theaters. And as in their product name, they are panel systems, and there is no hiding that. So aesthetically it does not cut it for me. However, due to their nature, they do have an insulation quality to them, but like fiberglass batt insulation, it insulates by trapping air within the produce to slow the heat transfer. However, they do nothing to stop moisture migration. This is a good and bad thing at the same time. Because in even dry basements, there is still small amounts of moisture vapor moving through your wall, and if you read the article posted above, you will now know that you want your basement walls to be able to dry to the interior, which this product will allow. However, if there is large amounts of moisture movement, it could possibly condense within the product, getting it wet and potentially causing mold growth. Therefore it would be wise to leave a small air gap behind the system to allow a free flow of air to help dry the system out if it does happen to get wet.
Rigid foam panel systems I believe to be a much better solution. The foam panels will typically have a higher insulating value per inch and help to prevent future moisture problems much better than the acoustical panels systems. However you want the foam panels to be applied directly to the foundation wall. You do not want the 1″ gap between the basement wall and wall system as some of the installers recommend to run plumbing or electrical wiring. This air gap leaves a place for the moisture moving through your basement walls a place to condense, especially since the temperature of the basement wall will now be colder because of the new insulated wall system. It is a better idea to cut in a chase into the foam behind the finish to run this equipment. The foam panels will still allow your basement walls to dry to the interior, however I would be leery of a vinyl wall covering. In the commercial building sector, especially in hotels, vinyl wall covering has been known to cause severe mold problems unless there are micro perforations. However just like the acoustical wall systems, they are a panel system, and it is hard to hide that fact.
Conventional framing and drywall finishing is perfect for the DIY’er and an option that will help to seamlessly blend a new lower living level with the rest of the home. However there are some things to consider when framing up against a basement wall. You want to apply a 1-2 inch rigid foam panel directly to the basement wall before framing any new wood or metal walls. This foam layer provides the necessary thermal barrier as well as moisture control that is provided by the rigid foam panel systems. The additional framing can be used to run all your utilities such as plumbing and electrical wiring and gives you the structural members to hang a TV and any other miscellaneous items as well as space for additional insulation. However it is wise to apply a capillary break below your new framed walls in the basement as I mentioned in one of my earlier posts about a sill sealer that helps prevent any moisture from the basement floor to migrate into the framing. And as mentioned in the article, basements are inherently moist areas. That is why I recommend a paperless drywall product that using a fiberglass mesh facing instead of paper, removing the food for mold and increasing the durability. I used this product in my own home as well as modified the wall system by using 2×3 framing members and holding them an inch away from the wall and filling the cavity with an expanding spray foam insulation. I will explain my choices in a future post.
Now the article referenced at the beginning of the post mentions installing carpet, which I would not recommend installing directly to the concrete floor (especially a carpet pad). Older homes never installed a vapor barrier below the basement floor, which obviously allows moisture to move through the floor into the carpet. Most local hardware stores now sell a sub floor product that is a 2′x2′ sheet of plywood with a plastic coating and feet underneath that leaves a small air gap allowing any water to run to the floor drains below the floor without ruining the surface. In this case, you can install any type of floor material, including wood. However if you don’t want to have the additional expense of the sub floor system, then I always recommend a solid flooring material such as tile or linoleum.
Well I hope I did not overwhelm you, but at least educated you a little more about what may be going on behind your walls.
Joshua has a degree in architecture and is a LEED Accredited Professional that has worked in the design and construction industry for over 10 years, focusing his efforts on energy efficiency and building science. He has organized multiple events in Ohio to give young designers the opportunity to learn about “green” home design and produce actual projects. He was also a key player in Ohio’s first LEED for Homes Platinum project. Joshua is also a certified Building Analyst through the Building Performance Institute and performs home energy audits, assisting home owners in reducing their energy usage.
