Roof Replacement in Thornton, CO

A re-roof in Thornton is a tear-off. The city's mid-roof check expects the old covering gone entirely, so plan on a tear-off, not a second layer over the first (the roof inspection page covers each city visit). HomeGuide prices tear-off at $1 to $3 a square foot. What goes back is set by the 2024 International Residential Code: asphalt shingles must be nailed to wood structural panels or solid lumber, with galvanized, stainless, aluminum or copper roofing nails that have at least a 12-gage shank and a 3/8-inch head and reach 3/4 inch into the deck. Chalk lines snapped on the bare sheathing keep those nails in the shingle maker's nailing zone.

Spaced boards with gaps between them are legal under wood shakes, which the code lets roofers fasten to 1x4 boards. Shingles can't go on them. The code wants panels or solid lumber under asphalt, and Thornton's Roofing Standards send roofers to the shingle maker's instructions for the maximum sheathing spacing. A shake-to-shingle conversion therefore means sheathing the whole roof with plywood or OSB, either over the boards or after pulling them. On ordinary decks the issue is soft spots: delaminated plywood, rot along the eaves, OSB swollen where a pipe boot leaked for years. HomeGuide puts new decking at $2 to $5 a square foot, and nothing new can be laid until the city has inspected it.

Thornton's Roofing Standards decide how much of a hail-damaged roof comes off. Once the job needs a permit, every slope that has damaged shingles on it is replaced in its entirety, and partial replacement on a single slope is not allowed. If hail cracked shingles on the two west-facing planes only, those two planes get redone completely and the rest can stay. The new and old shingles may meet only at a ridge, a hip or an open valley, so a roofer can't stop a row short of the peak. The insurance side of a hail job (deductibles, adjuster, supplements) is on the hail damage roof repair page.

Going from asphalt to steel, tile or synthetic slate changes more than the look. The same ridge-hip-valley rule applies, so a house can carry shingles on the main roof and metal roofing on a porch only where the two coverings meet at one of those lines. Slope matters next: the code lets standing seam go down to 1/4:12, while asphalt needs at least 2:12, which is why a shallow porch roof often gets the metal. Weight is the third check. HomeGuide notes that a heavier covering such as tile or slate can mean adding trusses, so ask for the framing to be looked at before you commit to concrete tile.

Under the shingles sits underlayment that has to carry an ASTM label: D226 felt, D4869, D6757, the self-adhering D1970 membrane, or D8257 synthetic. Roofs pitched between 2:12 and 4:12 need two layers. Valley lining goes in before any shingle. An open valley lined with metal must be at least 24 inches wide, for example 26-gage G90 galvanized steel, and a closed valley can use a 36-inch strip of smooth roll roofing or self-adhering membrane. Along walls, step flashing at least 4 inches by 4 inches turns water back onto the roof. Drip edge is a separate city requirement covered on soffit and fascia repair, and Thornton's position on ice and water shield is on attic ventilation.