Building a Saddle Roof: Everything You Need to Know

Photo of a house with a saddle roof.

Roofing is one of those skills that can be daunting to anyone who isn’t a professional. The best type of roof for a DIY roofing project is a saddle roof. This is because they are relatively simple to construct without the need for detailed plans or special tools, so as long as you understand the basics and can do some easy math.

What is a Roof Saddle?

A saddle roof is a simple structure that is designed to divert water from areas of a roof where water tends to collect or leak. They are generally built around the tall side of a chimney or in spots where the roof transitions from one area to another. Typically the saddle is the same pitch as the surrounding area. Often they’re covered with shingles matching the rest of the roof or with metal flashing.

Saddle Roof Picture

If you aren’t quite sure what a saddle roof looks like, the picture below gives you an idea of just how beautiful they can be.

How to Build a Roof Saddle

Before you get your power tools out and start cutting, you will want to take some measurements. You’ll need to determine the pitch, line length, its span, and the run and rise of your roof. The span is the horizontal distance from one side of your house to the other. The run will be exactly half the distance of the span. The rise is the length of the center of the span to the top of your roof line. You’ll measure the line length from one of the supporting wall lines to the center of your roof at the top of the highest part.

This might sound confusing, but when you draw out your measurements, you’ll see that it is merely a triangle with some legs.


Now that you have all of those numbers figured out you will need to decide on the desired pitch of your saddle roof. The pitch is the angle from the roof ridge to the wall plate. Although pitch can vary, the most common for a saddle roof is 1/3 or 1/4. Having the right pitch is essential as it affects how rain and snow will fall off your roof. If the pitch is too high, it could cause snow, ice or water to collect on the roof and eventually cause damage to your shingles that could result in leakage.

Start cutting

Once you have determined the pitch, line length, span, run and rise of your roof, the next step is to lay out your wood and start marking your cuts. There are three types of cuts used when creating the beams that will be used to construct your saddle roof. The plumb cut is where the top of the beam will connect to the ridge plate; position the bird’s mouth on top of the ridge plate and the tail cut will create the edge for the building eaves.

Get out the Power Tools

The most common method of laying out the beams is to use a 2-foot framing square. You will want to hold the framing square so that the face of the square is up (you will see the manufacturer’s name). Then lay the square on the end of the board. When you measure from the blade to the tongue, it should be 14-7/15 inches, multiply that by the run of the building and add 12-inches to get a final figure for the overhang.

Check the beams

You should then look at your beams and check for any kind of curves on the board. Making your pattern on a straight board is important so that the saddle does not end up sagging over time. Lay out your beam and position the square at the end of the board, making sure that the tongue is on your left. Then position the square so that the 8-inch is on the outside and the 12 inch is on the top edge of the board.

Mark the line of the tongue to get the plumb cut for your roof ridge. Measure that line to figure out the line length of the beam. Move the square along the board two more times marking the additional plumb cuts. The middle mark will be the bird’s mouth which is where the beam will sit against the wall plate.

Attaching the beams

Take another beam and duplicate the measurements from the beam you were just working on. You will then take a circular saw and start cutting out the bird’s mouth and along the tongue. This will allow you to make the frame. You will want to make braces for the frame which will be the height of the boards plus the rise. Align the plumb cuts with the braces and the bird’s mouth with the roof and nail into place.

Once you have your boards installed, make sure to add any supports such as center supports or collar ties that might be required by your city code. After you add the supports, you will use vertical studs to attach everything to the wall studs securely.

How to Shingle a Roof Saddle

Now that you have your roof saddle built and attached you will want to apply shingles. It is important to have another person around when applying shingles in case there is an accident. Before attaching the shingles, you will want to apply the drip edge. The drip edge is a metal strip that goes along the eaves of your roof to prevent water from getting under any shingles and causing wood rot. Every 10 inches you will apply a one-inch roofing nail. Then install the water and ice shield to any vent holes, chimneys, eaves and ridge areas.

Roofing felt paper

Next, you will add the roofing felt paper to the entire roof. This acts as a backup to make sure that the wood used to build does not come into contact with any water. Roofing felt comes in large rolls which makes installing it very easy to do. Roll it out in straight rows on the roof, with 3/4″ overhang around the edges. After you completely cover the roof, you will want to cut out holes for vents and then install them.

Installing the shingles

Now it is time to start installing the shingles. Starting at one edge of the roof you will want to add one shingle. Measure up the eave from the end of the shingle to the roof. You will then use that mark to place a chalk line to the other side of the roof lengthwise. Repeat this until you reach the top of the roof. This is time-consuming but very important to ensure that your shingles are straight and your roof has proper coverage.

Going back to the original shingle you put down and place a nail at the end of each shingle, most shingles should have a nail guide on them which shows you where they should go. Move down the roof and continuing adding shingles making sure to place them right up against each other. When you get to the second row, you will want to cut three inches off the shingle and apply them in a stair pattern. The third row will require you to cut off 6″ and so on until you reach the top of your roof.

Roof Cap

The last step of building a saddle roof is the roof cap. After you add all of the shingles, you will have to apply the roof cap. The roof cap goes along the peak of the roof and is a crucial step. The cap helps keep elements from getting under the shingles below and prevents leaks. You can buy a pre-made roof cap if you prefer. Or you can create one yourself by bending a shingle to fit the shape of the roof’s peak. To apply, you will add a nail to each side of the peak, five inches from the highest point. Once the peak has been covered, apply roofing cement to cover the nails at each end of your roof.

A saddle roof might be relatively simple to build as a DIY project, but they don’t look it. Now that your new saddle roof is complete, you can admire its beauty, and take pride in the job that you did.


Photo by Rowan Heuvel on Unsplash


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