Blown-In Insulation in Dallas, TX: Fiberglass or Cellulose, How Deep, and How It Goes In

Blown-in insulation is loose fiberglass or cellulose blown through a hose onto the attic floor until the whole floor sits at one even depth. We install both materials, in existing homes, and always across the whole attic.

Most questions about blown-in come down to four things: which material suits the attic, how deep it should go, what needs doing before the blowing starts, and what you should have in writing at the end. If you are still working out whether the attic needs anything at all, attic insulation in Dallas is the place to start.

Dimensional Contracting works out of Arlington and has been in business since 2003. Dallas and the rest of Dallas County are inside the area we cover. The attic evaluation is free.

Fiberglass loose fill is light, so it puts little weight on the ceiling below, and it settles only a little once it is down. It needs more depth than cellulose to reach the same R-value, so a fiberglass attic looks deeper for the same result.

Cellulose is made mostly from recycled paper treated with a fire retardant. It is denser, so it reaches a given R-value in less depth, and it packs in around wiring and framing. It settles more than fiberglass after it goes in, which is why it is blown deeper at first.

Insulation is rated in R-value, not inches, and the depth that gives you an R-value depends on the material. ENERGY STAR recommends R-49 for an attic with no insulation and adding about R-38 where three or four inches are already down. It gives the same figures for climate zones 2 and 3. Every bag of loose fill carries the manufacturer’s chart that turns an R-value into a depth for that product. It lists the thickness when it goes in and the minimum settled thickness, which is the depth the product needs to give its listed R-value once it has settled. The estimate should name the material, the R-value and the depth.

Federal rules say what an installer has to put in writing for loose fill (16 CFR 460.17): the area covered, the thickness when it was installed, the minimum settled thickness, the R-value and the number of bags used, dated and signed. Keep it with the house papers. Depth markers standing in the insulation are worth asking for too, because they let you check the depth from the hatch years later.

A few things are easier before loose fill goes down than after. Gaps in the ceiling around pipes, wiring and the top plates are worth sealing first, and we seal them with foam sealant and caulk. Attic air sealing shows where they usually are. Soffit vents have to stay clear so the attic can still draw air in, and recessed lights that are not rated for contact with insulation need room left around them.

Dry, clean insulation can stay and be added to. Insulation that is wet or soiled comes out first, because new material blown over it hides the problem and fixes nothing. Packed-down insulation is not automatically a removal job. We check the condition across the floor before recommending either.

Spray foam and radiant barrier. We insulate whole attics with blown-in fiberglass and cellulose, and we do not patch one corner of an attic on its own.