Every framing work starts by estimating the lumber required for the job. Essentially the majority of the wood needed will be 2 x 4 and 2 x 12. Other than that you will need sheeting or siding material. A good estimating rule for stud counting is one stud per lineal foot. This fast estimating method will only work for door and window trimmers, intersecting wall channels and corner drywall backing. Headers, posts and hardware are measured and counted individually. 2 x 4 inch material will account for most of the lumber. You can use fabricated trusses for the roof, and 2 x 12 inch material for headers for doors and windows.
1. Framing Estimate: Draw the Layout
Start by doing a sketch of the building to be framed including the roof. It is important to identify the location of doors and windows and any other vent opening. Having the right dimensions or working with standard measurements will provide additional savings at a later stage as waste material will be minimized.
2. Framing Estimate: Mark the Layout
Write down each measurement in inches and use a marker to keep track of what framing areas have already been added. This take-off process will be ideal to determine the logical sequence you will be using when framing the building. Make separate lists for every plank of different widths and every stud, strip or timber you will need.
3. Framing Estimate: Studs
For each wall, you will need to add three times the length of the wall; two of them to be used as top plates and the third one will be the bottom plate. To determine how many studs you will need, divide the length of the wall by 16, as studs are placed every 16 inches. Remember to add four studs for each corner. Bottom sill plates are made from pressure treated lumber. Be specific when ordering pressure treated lumber.
4. Framing Estimate: Headers
Now let’s determine how many headers will be needed when framing. When the door being used is wider than six feet, you need to add three pieces for each side of the door. When the door opening is less than six feet, only two pieces of wood are needed. Write down two pieces of 2 x 12 that will be used for the headed of each door. These headers will be equal to the size of the opening plus seven inched when the door is less than six feet. One ½ x 12 inch plywood piece is also needed to match the width of each header.
5. Framing Estimate: Trussess
Let’s start framing the roof. Determine the slopes side of the building. Divide that measurement by 16 and then add 2. This number will be the total amount of wood trusses required for the roof. These two trusses will be at the start and the end of the wall. To calculate the fascia, measure the length of each slope side, add double the overhang measurement on each end of the roof.
6. Framing Estimate: Sheeting
The final framing estimating step will be to determine how much sheeting we need. Start by measuring the height of each wall. Multiple that number times the length of the wall and then divide by 32. For every wall opening, multiply the height times the width and divide it by 12, and add all opening together. Subtract the openings’ from the total area of the wall. Round up to the nearest whole and repeat for each wall. Once you have all walls measured, add all those numbers to determine the total number of sheets needed. Example: a 20' long wall that is 8' high with one 4'by 5' window would figure like this, 20'x8'= 160sqft ; 4'x5'=20sqft. Then 160 subtract 20 divide by 32, 160-20/32=4.37 So it would take 5 sheets of 4'x8' OSB sheeting to cover the total area of a wall 20'x8'.