Estimating construction materials starts with the primary count of lumber framing, often referred to as framing takeoff. Lumber takeoff is a metric used by contractors and architects to estimate the amount of wood needed for a job. The technique uses a formula that considers the outside dimensions of a structure, as well as its location on site.
The formula is based on the square footage of the framing members (i.e., studs and headers) multiplied by the number of layers in each member.
The first step in estimating your framing takeoff is analyzing a set of construction plans or drawings. These plans will give you the exact dimensions of each wall and the number of layers that are required for the project.
How to do a lumber takeoff?
Estimating construction materials begin with a fundamental framework count, commonly referred to as a framing takeoff. A wall framing estimate involves estimating studs (usually 2×4 or 2×6), headers for door and window openings (2×12 is easiest), and horizontal plates for the top and bottom of the wall (the plates utilize the same wood as the studs). Additionally, in your framing takeoff calculation, you may want to calculate the number of sheets of sheathing needed for the outside of the wall.
Start your lumber takeoff with a plan or sketch
To calculate your framing takeoff, the first step is to start from a set of building blueprints or plans. Alternatively, if you don’t have a plan, create a sketch showing wall sizes, door openings, window openings, and wall studs. You should note the spacing between wall studs and the points of intersection with other walls.
Find out the number of studs
These can be calculated by using simple calculations. You first have to measure the wall length in feet and then multiply it by 0.75. Next, you need to add three studs for 90-degree corners or 4 studs for 45-degree corners. Any opening that is less than 1.5 meters wide requires 2 studs, while any opening that is more than 1.5 meters wide requires 1 stud. Once these calculations have been made, a 15% wastage factor must be taken into account for all the quantities.
Estimate the header materials
Standard-sized door and window headers are usually constructed using two pieces of 2×12 lumber positioned over a piece of 1/2-inch-thick plywood that is cut to match the headers’ size. It is the total thickness of the header that is 3 1/2 in to correspond with the width, or depth, of a 2×4 wall frame.
In order to calculate the amount of framing for each door and window opening, you should utilize the overall width for the opening plus 7 inches.
Find out the number of supporting plates
Now you need to calculate the supporting plates for the walls. You should think about single bottom plates or double top plates for load-bearing walls. It would be helpful if you multiply the wall length by 3 to find out the overall length of the plate. It is best to allow a wastage factor of 5-10% for the plates.
Calculating the sheathing
Finally, the last thing to do is to calculate the sheathing. To calculate the area of the sheathing, you need to multiply the length by the height of the wall and then subtract the opening area. Then you divide by 32 and complete to the nearest whole number. The resulting figure will be the sum of the number of sheets required for one wall face.
Now you have an idea of how to do a lumber takeoff. For accurate and cost-effective construction takeoffs contact Bidding Professionals today!
