Cool Roofs, Skylights and Attic VentilationBased in Cleburne, TX

The Difference

What to know before you decide.

Attic ventilation pulls outside air in low and lets hot, moist air out high. Intake comes through soffit vents under the eaves, and exhaust leaves through ridge vents, box vents or powered fans. The usual building-code guideline is one square foot of net free vent area for every 150 square feet of attic floor, or one for every 300 when intake and exhaust are balanced. Trouble tends to come from mixing exhaust types, which lets one vent draw air in through another and skip the soffits, or from insulation blown over the soffit vents so no fresh air enters at all. An overheated attic ages shingles early, and shingle manufacturers set ventilation requirements in their warranties.

Insulation is the other half of the attic. Ventilation carries heat out, and insulation slows whatever remains from reaching the rooms below. Plenty of older homes in Johnson County have a few inches of settled insulation, well short of the R-38 to R-49 range generally recommended for this climate. Blown-in fiberglass or cellulose is the usual way to add depth, with baffles at the eaves to keep the new insulation clear of the soffit vents. For a typical North Texas attic, blown-in insulation often runs roughly $1,500 to $4,000 depending on size and depth.

Skylights bring daylight into rooms that get little of it, such as a hallway or an interior kitchen. Most skylight leaks start at the flashing around the frame, and older units with failed seals fog between the panes. Replacing one means removing the old unit, checking the curb and decking around it for rot, and setting a new skylight with a flashing kit made for the roof it sits in. Low-E glass cuts the heat that comes in with the light, which counts on a south or west slope. Skylight replacement generally runs $1,500 to $4,000 in this market, and if the roof is due soon, doing both together saves a second trip through the shingles.

A sun tunnel, also called a tubular skylight, is the smaller option. A 10 or 14 inch dome on the roof feeds a reflective tube through the attic to a diffuser in the ceiling, so it fits where a framed skylight would need a shaft built. It brings a surprising amount of light into a bathroom or closet without adding much heat, and installed sun tunnels commonly run $600 to $1,500. The dome sits low on the roof and is flashed like any other penetration, so it holds up to hail and wind-driven rain the same way a well-flashed vent does.

Roof coatings have a place on homes too, mostly on low-slope sections such as a porch roof or a flat area over an addition. A reflective acrylic or silicone coating over a sound membrane or metal surface seals small leaks and cuts heat gain. Asphalt shingles are a poor fit. Most shingle manufacturers do not approve coatings, and a coated shingle roof can hold moisture, so on shingles the reflective choice is made at replacement.

These pieces work best when they are planned together, because the roof, the attic and any openings through it all affect each other. Adding attic insulation without fixing blocked soffits can trap moisture, and a new skylight on a roof with five years left means cutting into shingles twice. A free roof inspection is a sensible place to start, and financing is available for larger projects. Call (817) 558-6997 to schedule one.