In this discussion, we will address the most crucial factors to consider when inspecting a house’s crawlspace. These factors include focusing on the flooring or moisture barrier of the crawlspace, the presence of insulation, and the existence of vents.
The first aspect to examine upon entering the crawlspace is the flooring. If it consists of dirt, this is the least desirable situation and should be addressed. Dirt floors are common in older houses and are often associated with issues such as rusting pipes and rotting wood. Dirt floors do not effectively block moisture and allow humidity to infiltrate the crawlspace from the ground. When a home features dirt floors, it is strongly recommended to engage a building contractor to cover the floor with a poly vapor barrier. The edges of the barrier should be sealed with a sealant, along with any other openings through the barrier, such as around posts. Once sealed, an appropriate layer of gravel can be installed to protect the poly from damage or displacement. For those feeling ambitious, a layer of concrete can be poured over the poly instead of gravel, but these specifications should be discussed with the contractor. The primary objective is to prevent moisture from entering the building.
Regarding the ventilation, originally, crawlspaces were designed with vents to allow humidity to escape and equalize with the outdoors. However, the preferred approach has shifted towards preventing humidity from entering from the ground and avoiding vents to further minimize outdoor humidity. Coupled with insulating the exterior walls, this approach reduces heat loss.
As mentioned earlier, the main benefit of insulating the exterior walls of a crawlspace is to reduce heat loss. This results in lower heating costs, a warmer home, and more comfortable floors. Insulation also evens out the crawlspace temperature with the rest of the house, reducing condensation and related issues. When insulating, it is important for the contractor to finish with a vapor barrier to further prevent condensation and air escape. Additionally, if the home’s furnace is not located in the crawlspace, further evaluation may be needed to determine if a crawlspace heat source is necessary to prevent pipes from freezing.
When purchasing an older house, it is common to encounter dirt crawlspaces, venting, and a lack of insulation. By understanding the associated risks and solutions, potential buyers can reduce the stress involved and gain a better understanding of the amount of work required to address these issues.