How to Put Shingles on a Roof

Shingle Roof Diagram

How to calculate roofing materials

If you are interested in learning how to put shingles on a roof yourself you have found the right article. Most people do not know that they can literally save thousands of dollars by putting on a new roof themselves rather than paying a contractor to do the work. I have broken the article down into simple steps that anyone can follow. Depending on the size of your roof, you can save thousands of dollars!

Step 1: Figure out what materials and tools you will need to complete the project. If you are starting from scratch you will need to start out with the sheathing. Sheathing is what is nailed directly on top of the trusses. Most people use 1/2" OSB (Oriented Strand Board). You will need standard roofing felt. It is called 15# (pound) felt at most home improvement stores and comes in roles of 2'x50'. You will need an air compressor gun and coil roofing nails. You will need ice and water shield to prevent ice build up along the eves of the roof. You will need drip edge. Drip edge goes around the entire perimeter of the roof to allow water to safely drip off the roof. You will need cap shingles and roof vents. You will need 1/8" staples and a contractor stapler to staple the felt onto the OSB. You will need a regular hammer to hammer in nails that do not go in far enough from the air compressor. And obviously, you will need 30-40 year warranty shingles. You will also need a utility knife to cut shingles, ice and water shield, and felt. You will also need tin snips to cut the drip edge. Now that you know all of the materials you will need, please read on to learn how to calculate how much of everything you will need.

Special Tip: If you are feeling overwhelmed at this point, please don't be alarmed. If you feel like you cannot complete the project or do not have all of the tools you need, at least do yourself the favor of purchasing the materials yourself. You can save a ton of money just by supplying the contractor with the materials they need. When you hire a roofing contractor to do the job for you, they do not only charge for labor. They add additional costs onto everything. For example, a bundle of 30 year warranty shingles may only cost $25. However, the contractor may charge you $30. You can see how these costs could easily add up!

Step 2: Calculating Material Lets start off with how to calculate the amount of OSB you will need. We need to calculate the total square footage of your roof and add an additional 10 percent for waste. Let's say you have a 30' x 60' garage that you need to shingle. All you need to do is know the pitch of your trusses. The normal pitch of a truss is 4/12. This just means that for every 12 feet your trusses rise 4 feet. It is rare for a truss to be lower than 3/12 or higher than 6/12. The higher the pitch, the steeper the truss. So, let's say that we have a 4/12 pitch. All we need to do to calculate the square footage of our building is to take 30'x60' which gives us 1,800 SQ FT. The general rule is to add 5 percent of material for a 4/12 pitch. Therefor, we must take the 1,800 and multiply by 1.05. 1,800x1.05 = 1,890 SQ FT. It is always a good idea to add 10 percent onto the total amount to factor in waste. So we will take our final 1,890 and multiply by 1.10. 1,890x1.10 = 2,079 SQ FT.

Based off of the 30'x60' with a 4/12 pitch we will need this much of the following materials

OSB comes in 4'x8' sheets. There are 32 SQ FT in each piece of OSB. So we take the 2,079 SQ FT and divide it by 32 SQ FT. 2079/32 = 65 sheets of 1/2" OSB.

Drip edge typically comes in 8' (steel) and 12' (aluminum). The steel drip edge is a little bit cheaper, but aluminum will hold up better in the long run and you will need less pieces. If we have a 30x60 building this means we have to sides that are 30 feet and two sides that are 60 feet. We must add 2 extra pieces to consider waste. So 30+30+60+60+24 (2 extra 12' pieces) = 204 ft. To calculate how many pieces of drip edge we need we simply take the total length (204ft) and divide by 12' (the length of each piece of drip edge). 204/12 = 17 pieces of aluminum drip edge.

How to calculate the amount of ice and water shield needed.

Ice and water shield typically comes in 200 foot rolls. Since ice and water shield is only applied at the eaves of your roof, you will only need one roll. 60+60=120ft. We will have 200 ft. Some people use ice and water shield instead of felt for the first row. Most counties only require one row of ice and water shield, however, some require two. Be sure to check with your local inspector.

How to calculate the amount of roof felt needed.

In most home improvement stores, rolls of felt are called 15 pound roofing felt and come in 4x50 foot rolls giving us about 200 SQ FT of coverage. In order to calculate how much felt we will need we must take the total 2,079 SQ FT and divide by 200 SQ FT (1 roll of felt). 2,079/200 = 11 rolls of felt.

How to calculate the amount of shingles needed.

Again, we will use the same square footage we calculated for the OSB and Felt (2,079 SQ FT). Contractors and most home improvement stores will ask you, "How many squares of shingles do you need?". If you know nothing about roofing, a square of shingles typically equals 3 bundles of shingles. A square of shingles simply means 100 SQ FT worth of shingles. On rare occasions, it can take 4 bundles to equal a square. If it makes it easier, you can look at each bundle of shingles as 33.3 SQ FT of coverage. I will show you two ways to calculate this. If we have 2,079 SQ FT we need to cover we need to figure out how many square this is. To do this, we simply divide by 100. 2,079/100 = 21 square. To figure out how many bundles we need we must multiply by 3 or 4 bundles depending on how many it takes to make 1 square. I would say 98% of the time it only takes 3 bundles to a square. 21x3 = 63 bundles of shingles. The other way to calculate this is to throw the whole "square" concept right out of the window. Just look at each bundle of shingles as 33.3 SQ FT of coverage. 2,079 SQ FT/33.3 SQ FT = 63 bundles of shingles. PHEW! It's easier than it looks!

Next, we need to calculate how many coil nails we will need. Coil nails are used in your air pressure gun to nail on the shingles. Typically a 1/4" coil roofing nail is best. For every 1,500 SQ FT of roof you have, 1 box of coil roofing nails will be needed. We will need 2 boxes for our example.

How to figure out how many roof vents you will need.

The best type of roof vent is called a shingle over roof vent. It comes in a 20' roll that goes right over the peak of your roof. You then shingle over top of the vent. We would need 3 rolls of this for our example project. 60ft/20ft = 3 rolls. Some people prefer the older style roof vents that are usually about 2ftx2ft and go near the peak of the roof on each side of the building. These types of vents are to be places about every 10ft on each side of the peak. We have 60ft of peak so we would need 6 vents on each side. This gives us a total of 12 vents. *NOTE: You do not not both of these vents. You either need the roll out vent that goes directly on top of the peak, or the older style 2x2 roof vents.

How to calculate the amount of cap shingles needed

Cap shingles are shingles that go directly on top of the roof vent or over the peak of the roof. Cap shingles can be purchased pre-cut from most home improvement stores. However, they are usually overprices. Cap shingles can be cut out of regular 3-tab shingles. Every bundle of 3 tab shingles will give you at least 30ft of cap. For our example we would need either 2 bundles of pre-cut cap shingles or 3 bundles of 3-tab shingles to cover the 60ft peak.

Now that we know exactly how many materials we need, let's take a look at how to put shingles on a roof!

Step 1: Nail on the OSB. This will be much faster if you have 2-3 people. 2 to position the OSB and 1 to nail. If you do not have a nail gun, this will be a very time consuming process. A 2 1/2inch galvanized nail will do. You will need something called plywood clips to keep the OSB tight along the perimeter of your roof.

Step 2: Apply the drip edge. Use your 1/4" coil nails and nail on the drip edge over the entire perimeter of the roof. You want the shingles to lay over top of the drip edge.

Step 3: Staple on the felt. Simply roll out the felt. Have one person roll the felt and the other staple. If you have a hammer stapler this will be a very quick process. Just hammer staple a decent quantity of staples to hold the felt on to the roof. Be sure that the staples are tight to the felt. If the staple does not go in all the way, be sure to hammer it in. If it is left sticking up, it puts the shingles at risk of developing a leak.

Step 4: Staple on the ice and water shield. This process will go just like the felt did. Simply roll it out and staple. You can cut the ice and water shield and felt with a utility knife.

Step 5: Cut off the roof felt and ice and water shield that is hanging over the eaves of the roof. You want to have a nice clean and prepared surface ready for the shingles. Grab a broom and sweep off the roof to make sure there are no stray nails or staples before applying the shingles.

Step 6: Applying the shingles. It seems like a long journey, but we've finally made it to the shingles. Go one row at a time with the shingles. There are other methods that some contractors find faster, however, if you are new you need the rows of shingles to be straight. You apply each row of shingles exactly halfway over the existing rows. In other words, the overlap is exactly half the height of the shingle. Place 4 coil nails on each shingle. Make sure there is one nail near each end of the shingle and 2 evenly spaced in the middle. Butt the shingles next to each other as close as you can. You DO NOT overlap shingles that are placed next to each other. ONLY overlap the row the goes on top of the shingles.

Step 7: Before you get to the top of the roof. Nail on the roll out roof vent. A 6D Galvanized 2 and 1/2 inch nail will work. There are usually pre-cut holes in the roof vent for you to hammer the nails through and into the roof. After you have applied the roof vent, place the cap shingles over top of the roof vent.

Step 8: Clean up all of the waste from the cut shingles and make sure nothing is left on the roof.

Step 9: Enjoy your great new roof and the amount of money you just saved!

A project like the example in this article would cost about $4,500 to complete if you purchased the materials yourself and had minimal labor costs other than time. If you were to hire this done, it would cost at least $10,000. The question is, is it worth saving $5,500 to do it yourself? On a project like this you could save at least $1,000 just by purchasing the materials yourself. Even if you don't think you are capable of completing the job, you could at least save money on materials. It's a win-win either way!

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