Spray Foam vs Fiberglass Insulation

For most Oklahoma homes and buildings, yes. The key difference is that spray foam air-seals and insulates in one step, while fiberglass batts are air-permeable — they slow heat but don’t stop the air leakage that drives most energy waste. Fiberglass also can sag, settle, and lose performance when compressed or damp. Spray foam holds its performance for the life of the building. Fiberglass’s main advantage is lower upfront cost. We’ll give you an honest assessment for your specific project during a free estimate.

Fiberglass works by trapping still air, so anything that disturbs that air or compresses the batt reduces its effectiveness. Over the years batts can sag and settle, leaving uninsulated voids, and air can wash through and around them at gaps and penetrations. If a batt gets damp, it loses performance until it dries. Spray foam doesn’t have these failure modes — it bonds to the surface and stays put.

No. Fiberglass is air-permeable — air passes through it freely. That’s why a fiberglass batt and spray foam can show similar numbers on paper but perform very differently in a real house. Spray foam acts as both the insulation and the air barrier in one material, sealing the gaps around wires, plumbing, and framing that fiberglass leaves open.

Yes — fiberglass typically costs less upfront, and that’s its main advantage. Spray foam is a higher initial investment. The trade-off is long-term: spray foam’s air sealing and stable performance usually deliver larger, more durable energy savings over the life of the building. Every project is different, so the right call depends on your goals and budget — that’s exactly what a free estimate is for.

It depends on the application. When we foam the underside of a roof deck, existing blown-in or ceiling insulation generally has to be removed first — leaving it in place can create a moisture gap between the old insulation and the new foam, which can lead to mold. In other situations the approach differs. We’ll inspect what you have and recommend the right approach during your free on-site estimate.

Spray foam, especially closed cell. Closed cell foam is a vapor barrier at sufficient thickness and controls the condensation that causes mold in the first place; foam itself is not a food source for mold. Fiberglass, on the other hand, absorbs and holds water — damp batts lose performance and can contribute to mold problems. For crawl spaces, metal buildings, and other moisture-prone areas, this difference is a big reason homeowners choose spray foam.