# How to Estimate Building Room Additions

Building a room addition is an easier task than constructing an entire house, but calculating how much material is needed is the same no matter what size the building is. Following a few simple steps makes calculating studs, sheath and hardware a much simpler process. Contractors use ratios and mathematics to properly calculate building supplies. This ensures that only the correct amount of material is purchased. If you are planning on building a room addition, and you need an accurate material list, read through the following steps to learn how it is done.

## Step 1

Measure how many linear feet of walls you will construct. Multiply that number by three and add 10 percent for waste. This provides you with the linear footage needed for all of your top and bottom plates for every wall.

## Step 2

Take the number of linear feet of walls and figure one stud for every linear foot. Add 10 percent for waste. This estimate covers the amount of studs needed if they are placed 16 inches on center. This also allows for all of the fire blocking.

## Step 3

Figure out the full width of the room to calculate how many ceiling joist is needed. Measure the length of the ceiling joist and the opposite measurement of the room. You will need one ceiling joist per linear foot. For example, If your ceiling is 12 feet long and 10 feet wide, you will need 10 12-foot-long joists.

## Step 4

Purchase a 50-lb. box of 16-penny common nails, and a 50-lb. box of 8-penny common nails. Do not purchase sinkers. Common nails are full width and full length. If you use sinkers, you will only have to top them off with common nails anyway.

## Step 5

Use 1/2-inch struc-1 4-ply sheer (minimum of 8 feet for the walls). You will need one sheet per linear foot. Calculate the linear feet of the walls and divide by 4. This will give you the proper estimate of sheer material needed for your room addition.

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