Siding & Exterior Diagrams
4 diagrams · 1 calculators
Lap-siding exposure and overlap, even coursing, wall-area takeoffs, and the full weather-resistive wall assembly for fiber-cement and engineered-wood siding.
Calculators in this category
Siding & Exterior · 4 diagrams
- Siding & Exterior
Lap siding exposure vs. board width vs. overlap — why an 8¼-inch board covers only 7 inches
A lap board hides part of itself: the overlap is covered by the course above, so an 8¼″ board shows only 7″. Exposure (width − overlap) is what drives how much siding you buy — not the board width.
- Siding & Exterior
Even coursing for lap siding — avoiding the sliver top row under the soffit
Running every board at max exposure leaves an ugly sliver under the soffit. Even coursing shrinks the reveal just enough (108″ ÷ 16 = 6¾″) so all courses are equal and the top one lands clean at the eave.
- Siding & Exterior
Gross vs. net wall area for siding — subtracting windows and doors, then adding waste
Size a siding order by net area, not the whole wall: subtract the windows and doors from the gross wall, then add 10–15% for cuts and coursing.
- Siding & Exterior
Lap siding wall assembly — sheathing, house wrap, starter strip, flashing, and ground clearance
What goes on behind lap siding, bottom to top: sheathing, lapped house wrap, a starter strip that sets the first course angle, the nailed courses, and base flashing — with the siding held at least 6″ above finish grade.