How to Build a Roof Frame

Building a Roof Frame can be simple if its for your dog house or shed. However, building a roof for a house is a lot more complex. What we will cover in this article is just the basics to building a roof frame.

Things You'll Need

• tape measure, hummer, chalk line, saw, level, measuring square, framing square

Instructions

1. To keep it simple in this example we will build a 10'X 10' two gable roof with a 12-pitch, how a 12 pitch works is for every 12" of run there is 12" of rise. Like with any building project pre planning and a good material list can save you a lot of time and money. So if this is your first roof project spend a little extra time double checking your plans / material takeoffs.

2. Pick out the two walls that will be your gable walls, normally they are the front and back walls. Take the width of the wall our example is 10' and subtract the width of the ridge board. (The ridge is the board at the very peek of your roof that all the rafters attach to, normal ridge boards are 2x8 to 2x12) we are using 2x10 so subtract 1-1/2" from 10' [9'10-1/2] then divide it by 2, 9'10-1/2/2=[4'11-1/4] That number is the run and rise of the roof, off the center of the gable walls the ridge needs to be braced up level off the center measurement and the ridge needs to measure to your rise number [4'11-1/4] from the top of the wall to the top of the ridge.

3. Getting the rafter numbers, since most people don't know the math to calculate everything needed to get the right rafter measurement. There is a simple solution take a measuring square and place it on the wall plate flush to the outside of the wall. Next you want to take the rafter measurement 3-1/2" up from the back side of the wall plate, that is called the "heel height". From the 3-1/2" mark on the measuring square to the ridge is the first rafter measurement but must be taking from both sides and it also must have the same measurement on both sides.

4. Laying out the roof rafters, there is two measurements needed we got the 1st one above the 2nd one is from the heel height [measurement] to the tail of the rafter where it meets the overhang / the fascia boards. A 12" overhang on a 12-pitch roof would be nailed 8-1/2" down from the top of the wall or measured from where the top of your heel height measurement ends up our heel height was 3-1/2" and thats how we got 8-1/2" down from the top of the wall. (that mark is also to the top of the overhang / 2x6 / fascia boards) The easiest way to get this measurement is to pre-build your overhangs on the walls then brace them off level. To build a quick overhang chalk a line across the wall to the bottom measurement of the overhang adding 5-1/2" for the 2x6 fascia. Nail in a 2x4 to the line, run 2x4 blocks about every 2 feet down the 2x4, (remember to subtract 3" off the overhang measurement [12"]-[3"]=[8-1/2"] for the 2x4 blocks) last nail in the 2x6 to the 2x4 blocks so that the bottom of the 2x6 is nailed in flush to the 2x4s. Set the measuring square back on the wall after the overhang is brased and leveled in the same place as it was when you pulled the first rafter measurement at the 3-1/2" mark. From that mark pull the tape measure across to the outside edge of the 2x6 fascia, holding the tape measure in place run a measuring square up the inside of the 2x6 to the tape measure, from measuring square to measuring square (or tip to tip) is your rafter tail measurement. Now you have two measurements and 3 marks to make on the rafter board. 1st is where you pull the measurement from, 2nd is to the heel height, 3rd is to the tip of the rafter tail. See How To make rafters if needed.

5. Laying out the roof rafters, this layout goes on the non-gable walls and is normally ran on 16" centers but can be ran 24" on center. If you built a overhang on the gables (normal is 6") you would pull from what would be the outside of the gables overhang and the first measurement needed for 16" centers is 15-1/4" (24"centers would be 23-1/4") that measurement is to the rafter then GO,(or to the other side of the line) From that mark you would make marks down the wall every 16" making a line then putting a X on the other side of the line, (X marks the spot for your rafters) if pulling from the left you would mark to the right and if pulling from the right mark to the left of your measurement. However this layout comes out on the wall it should be the same on both sides of the ridge so that all the rafters are running square.

6. Last frame in the roof, add in all the rafters to the layout marks and add in 2x4s 16" on center to stud in the gables on the gable walls, best way to do this is to level up off the studs below if you can and mark the rafter where the stud runs level then pull your measurement. Finish by sheeting the roof and gables with 1/2" OSB roof sheeting. Nail with 8-D nails.

Resources

• Get a material list made online