Basements are typically damp and humid, which may give rise to mold infestation. This problem can be exacerbated by a lack of insulation in your basement. This is a common problem in older homes, which may have damp-proofing on the exterior walls but none on the interior. Or you may have damp-proofing on the outside and inside but no proper drainage mat.
You can always make upgrades downstairs to improve conditions, but be prepared to take a big financial hit. If your basement already has external protection, however, you may have the option of saving money by only having to deal with the basement’s internal problems.
There are different challenges when you build walls below grade. The greatest source of moisture downstairs is concrete, which is like a big sponge of porous materials that sucks up water from the wet ground. Walls above grade are designed to be dry on the exterior, something that cannot be maintained below grade because of the wet ground. The wet ground can turn the basement walls into a mold incubation chamber.
There are possible solutions to the moisture problem. They include:
- Spray polyurethane foam – SPUF, when sprayed on basement walls, provides total protection. It has a high R-value and acts as both an air and vapor barrier. The downside of this material is that it sinks after application, leaving air gaps that can compromise its effectiveness over time.
- EPS, XPS, Mineral wool – Rigid insulation panels, such as expanded polystyrene, extruded polystyrene, or mineral wool are a lot cheaper than SPUF insulation. Installing rigid insulation boards against the concrete walls improves the R-value, raises the room temperature by breaking the thermal ridge, and prevents the condensation of moist air. The stud walls also allow for easy installation of electrical wiring, drywall, and even additional insulation.
Before installing new insulation in the basement, be mindful that old insulation that was installed using insulation blowing machines must be removed first with the use of an insulation removal vacuum.