Almost every residential roof has a piece that isn't steep-slope — a porch, an addition, a patio cover, a flat-roofed garage — and it's the part most likely to be under-scoped, mis-coded, or written as "included" when it isn't. This guide gives roofers the working rules for residential low-slope: what the IRC requires below 2:12 and 4:12, which systems belong where (rolled roofing, modified bitumen, self-adhered, TPO), the line items that disappear on these sections, how to handle attached patio covers and carports, and why these small areas deserve their own macro.

Metal roofing keeps taking residential market share — and 2026's steel and aluminum tariffs have made it the most expensive category to misprice. This guide gives roofers the working playbook for metal: how standing seam and steel shingle systems differ in the field and in the estimate, the Xactimate line items that go missing on metal scopes, why "repair vs. replace" is a bigger fight on metal than on asphalt, how to protect margins when panel prices move between bid and install, and how to build a metal macro library that doesn't forget the trim.

Most roofers don't lose money on big, dramatic estimating errors — they bleed it through the same small Xactimate mistakes repeated on every claim. From wrong price lists and lowball waste factors to forgotten steep charges and the infamous felt-suffix mix-up, this guide breaks down the nine most expensive Xactimate mistakes roofers make, what each one costs, and the system that prevents all of them at once.