Attic air sealing in Simi Valley CA - a sealed attic floor before insulation goes in

Most calls start with a bedroom upstairs that stays hot all afternoon, a room over the garage that never feels right, or a new owner of an older house who wants to know what's above the ceiling. Sealing comes before attic insulation, because new insulation laid over open gaps just has a draft blowing through it. The price moves with the size of the attic, how many openings run through the floor, how much old insulation we have to pull back to reach them and how much headroom we have to work in. The schedule mostly depends on what I find on the first look, since some problems have to be fixed before anyone seals anything. I walk the attic with you and put the scope in writing, so you see what your job involves before it starts.

I start in the attic with a flashlight before anything gets sealed. I'm looking for roof leaks, old wiring and fans venting into the attic, because sealing over any of those only hides the problem, so I'll tell you about them and they get handled first. Then our crew pulls back the old insulation where we need to reach the gaps and checks it, because insulation that's been soaked or is full of droppings comes out instead of going back down. We seal around pipes, wires, duct boots, the hatch and the tops of interior walls, using caulk for small cracks, spray foam for bigger gaps and rigid board for wide openings. Around a furnace or water heater flue we use fire-rated material and keep the space it needs from anything that can burn. We keep the eave and ridge vents clear the whole time, because those openings are meant to stay open, and an attic that can't breathe ends up with moisture in the framing. I look over the work before we finish.

Sealing is usually half of a bigger attic job. In an older house with thin or settled coverage, retrofit insulation brings it back up once the gaps are closed. Spray foam insulation seals air while it insulates, but it costs more, so for most attics I'd rather seal the gaps and top up loose fill, unless your ductwork runs through the attic.

The city's Building and Safety Division handles permit submittals and inspections in Simi Valley, and whether sealing on its own needs a permit is something I'd confirm with them rather than guess, so their front counter at (805) 583-6723 is the place to ask. If your job does need one, we file it with the city and meet the inspector on site.

A lot of the houses here are older, with can lights in the upstairs ceilings and summer heat that builds up fast under the roof, so open gaps in the attic floor tend to show up as a hot bedroom by late afternoon. Older can lights that aren't rated to touch insulation can be covered from the attic with fire-rated boxes, though swapping them for newer airtight fixtures rated for insulation contact is the better fix, and that changes what goes on the estimate. We see the same kinds of houses on jobs in Moorpark and Thousand Oaks. We're based in Simi Valley and work across the cities around it in Ventura County and the nearby parts of Los Angeles County, so if you're not sure we cover yours, just ask.