Figuring Lumber Amounts for Homebuilding

Getting the right amount of lumber for your homebuilding project can be very important. Ordering to much lumber can add unnecessary costs to your project. Not ordering enough lumber or missing a component can bring your project to a screeching halt.

When I do a lumber takeoff, I do it in the order that it would be built. I start with the sill plates followed by the floor joists, tongue and groove plywood, and wall lumber (studs, plates, sheathing). If its a two story home, the next item would be the second floor floor joists followed by the second story walls (interior and exterior), then the ceiling joists, rafters and roof sheathing. If the house is a ranch, you would go from walls to ceiling joist, rafters and roof sheathing. That's the bulk of your lumber list but there are other incidentals that need to be added to your list. These items include:

Stair material (if carpenter built)
Soffit and fascia (plywood and 1x, 2x etc.)
Construction adhesive
Housewrap (Tyvek, Typar)
Nails (8d, 16d coated sinkers, cap nails)
Bridging (for floor joists)
Header material (2x12's, 2x10's, whatever is spec'd)

There are three methods that I use to figure a lumber list when building a new home. The first one that I use is for figuring my wall studs. I figure the total lineal feet of wall for the exterior walls. If its 150' then I order 150 studs. I do the same for the interior walls and for the second floor walls if there is one. This takes care of cripples for doors and windows and extra studs it takes to frame inside and outside corners. I always add 10% for wall bracing. Also, by getting the lineal feet of wall you have just figured what is needed for top and bottom plates. Take that lineal footage total times 3 and you have the total feet of plate you need for your walls.

To figure the amount of floor joists needed, I use a different method. If the length of a building is 32', I take that length times 4 and divide it by 3 and add 1. The total amount of joists needed in this example is 25 pieces. I use this same method to figure ceiling joists and rafters.

Sheet goods like plywood and foam sheathing are figured by using the square footage formula
length x width /32 = number of pieces of plywood.

There may be other ways to figure these things, but these simple methods always worked for me.

Mike Merisko (c) 2006
www.sawkerfs.com