Comparing attic insulation types for Texas homes, from blown fiberglass and cellulose to batts, spray foam and radiant barriers, and which attics suit each.
Pop your head through the attic hatch in a few different Texas houses and you'll see a bit of everything. Pink batts tucked between the joists of a 1970s ranch. A gray blanket of cellulose in a 1990s two-story. Spray foam stuck to the underside of the roof deck in a newer custom home. Each of them can work well. The real question is which one suits your attic, your budget and the spot where your HVAC equipment lives.
Before you compare materials, decide where the insulation goes. Most Texas homes have a vented attic. The insulation lies on the attic floor, right above the ceiling drywall, and the attic itself stays hot. Soffit vents and ridge or roof vents let that hot air move out. This setup is simple and usually the least expensive way to reach a high R-value.
The other option is an unvented attic, where foam goes on the underside of the roof deck and the gable ends, and the vents are sealed. The attic then stays close to indoor temperature. That's a big deal in Texas, because so many homes have the air handler and ducts up there. Instead of sitting in 140-degree air, they sit in a space that might be 80 to 85. The catch is cost, and the fact that the whole attic becomes part of the house, so it has to be done carefully and to code.
Loose-fill insulation is blown in with a machine, so it fills around wires, pipes and odd framing better than anything you'd lay by hand. It's the usual choice for topping off a vented attic.
Blown fiberglass runs roughly R-2.2 to R-2.9 per inch, depending on the product. It won't absorb much water, it doesn't burn and it settles very little over time. Because each inch is rated a bit lower, you need more depth to reach a target like R-38. Expect a fairly thick layer, often well over a foot.
Cellulose is made mostly from recycled paper treated with borates for fire and pest resistance. It packs about R-3.2 to R-3.8 per inch, and because it's denser than loose fiberglass, it does a better job of slowing air movement through the layer. It settles more, so installers blow in extra depth to make up for it. It also soaks up water, which means a roof leak after a spring storm can ruin a section that would have shrugged off a drip as fiberglass.
Fiberglass and mineral wool batts come in pre-cut pieces sized to fit between framing. They're the most do-it-yourself friendly option and a common choice for walls during a remodel. In an attic, though, batts have a weakness. Every wire, junction box and piece of blocking has to be cut around neatly, and small gaps add up. Reaching R-38 or more also takes two layers, the second running crosswise over the joists.
Mineral wool costs more than fiberglass but handles heat and fire extremely well and doesn't mind moisture. For most Texas attics, batts make the most sense where a blowing machine can't reach well, like small side attics or over a finished bonus room.
Spray foam is the material you use for that unvented attic. It goes on as a liquid, expands and sticks to the roof deck, sealing air leaks and insulating in one step.
Open-cell foam is soft and spongy, runs around R-3.5 to R-3.8 per inch and is the type most often used under Texas roof decks. It lets some moisture pass through, which can help a roof deck dry if a small leak develops.
Closed-cell foam is rigid and dense, at roughly R-6 to R-7 per inch. It costs more per inch and blocks moisture. It's common in rim joists, metal buildings and spots where space is tight.
Either kind should be installed by a trained crew with the right equipment and ventilation during curing. Foam can also make roof leaks harder to spot, so plan on a good look at the roof before it goes in. Our spray foam page covers more detail.
A radiant barrier isn't insulation in the R-value sense. It's a reflective foil, usually stapled under the rafters or laminated onto roof decking, that bounces back much of the radiant heat coming off a hot roof. In a vented Texas attic, a radiant barrier plus a good layer of blown insulation on the floor is a common pairing. The foil needs an air space on its shiny side to work, and it shouldn't be laid flat on top of insulation unless it's a perforated product made for that.
For depth targets, prep steps and what an upgrade costs, see our attic insulation guide. More articles are on the insulation guides page.
The right choice depends on things you can only see from inside your attic: the framing, the ducts, the ventilation and what's up there now. Texas Energy Pros can size all of that up during a free home energy audit. Contact us to get one scheduled.
