How to Estimate a Siding Replacement Job | Reddit & LinkedIn

A siding estimate has five cost buckets: siding material, trim and accessories, house wrap and flashing, tear-off and disposal, and labor. The field siding is the obvious number, but trim, corners, and the wrap-and-flashing layer are where accuracy lives, because they drive both material and the hours it takes to detail the job.

Price each wall and each major detail as its own line. A two-story house with lots of gables and windows is far more labor per square than a simple single-story box, and a line-item estimate keeps that complexity visible instead of buried in a lump sum.

Measure each wall in square feet, subtract large openings like garage doors and picture windows, and convert to squares, where one square equals 100 square feet. Add a waste factor that depends on the material and the cut complexity, since fiber cement and lap siding on a cut-up elevation waste more than flat vinyl on a plain wall.

Keep small openings in the measurement, because you still trim and flash around them. Document the per-wall numbers in the estimate so a later change in scope is easy to reprice fairly.

The biggest unknown in a siding job is what sits behind the old material. Once you tear off, you can find rotted sheathing, missing or failed house wrap, and bad flashing around windows. None of that is visible when you bid, so it is the classic source of change orders and disputes.

Handle it honestly up front. Price a clear unit rate for sheathing replacement per sheet and note that wrap and flashing will be renewed. That turns a tear-off surprise into a pre-agreed line instead of an argument on the scaffold.

Siding and exterior markup for a small contractor commonly runs 20% to 35% on top of direct cost, but your overhead and target profit set the real number. Remember markup is not margin: a 30% markup is about a 23% margin, so price from the margin you need to keep.

Tall and complex elevations need scaffolding and slow the crew, so let the labor line reflect real access conditions. A documented, line-item estimate with a sheathing contingency defends your price against a low bidder who has not accounted for what is behind the siding.

The fastest path to a signed estimate is to draft against your own templates. ContractShield lets you photograph each elevation, say or type the wall measurements and material, and get an AI draft of siding, trim, wrap, flashing, and labor in about 25 minutes total. You approve each line, and every line shows where its price came from.

Once the client accepts online, milestone payments, a deposit, a dry-in draw, and a final payment, are built in, with automatic reminders and collections on any past-due balance.