Homebuilding Information and Planning - Figuring Lumber Amounts for Homebuilding

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.