Crawlspace Insulation
Old fiberglass insulation in crawlspaces often absorbs moisture and sags, becoming useless. We replace it with waterproof alternatives that save energy.
The majority of homes in Surrey and the surrounding communities built before 2000 have fiberglass batt insulation installed between the floor joists in the crawlspace. When this insulation was new and dry, it provided reasonable thermal resistance. The problem is that fiberglass batts installed in a vented crawlspace environment in a high-rainfall climate like ours rarely stay dry. They absorb ambient moisture, sag out of their cavities, and gradually collapse onto the ground. Wet fiberglass insulation has essentially zero R-value, adds weight that can pull down on vapor barriers or staples, and provides a hospitable nesting environment for rodents.
When we replace crawlspace insulation, we evaluate the correct solution for the type of crawlspace. In an encapsulated (sealed) crawlspace, the most effective approach is rigid foam insulation installed against the stem walls rather than between the joists. This treats the crawlspace as a semi-conditioned buffer zone rather than an unconditioned exterior space, which is more accurate in the mild-but-wet Pacific Northwest climate. Closed-cell spray polyurethane foam (SPF) applied to the underside of the subfloor or to the stem walls is another high-performance option — it provides both insulation and an air barrier, and its closed-cell structure means it does not absorb moisture under any conditions.
For crawlspaces that are not being fully encapsulated, we install new unfaced fiberglass batts or mineral wool between the joists, but only after addressing the moisture conditions that destroyed the previous insulation. Installing fresh batts into a still-damp crawlspace environment means you'll be back in the same situation within a few years. Proper sequencing matters: drainage, vapor barrier, then insulation.
The thermal and energy benefits of correctly installed crawlspace insulation are tangible in the Lower Mainland climate. While our winters are mild compared to the Interior, heating systems in homes with uninsulated or poorly insulated crawlspaces work noticeably harder to maintain floor temperatures, particularly during the extended rainy season from October through March. Homeowners frequently report measurable reductions in heating costs after insulation replacement, along with improved comfort on main-floor hardwood or tile surfaces that previously felt cold underfoot.
From an EEAT standpoint, a quality insulation job should include: removal and proper disposal of all old insulation (which may harbor rodent waste and mold), inspection and treatment of any visible mold on the framing before new insulation goes in, selection of the correct R-value for the climate zone, and installation that fully covers the joist bays without compression or gaps at the edges.