Roof construction is one of the most challenging works in a house. It can be difficult to build a perfectly functional home with a good exterior. The alignment, construction, slope handling, and water leakage of the roofs can be very crucial in the case of different heights of roofs. 

If you are thinking about joining your roofs with different heights, you may go through this article.

So, let’s take a look at this discussion.

What is a roof pitch?

Before starting your process, you are required to know what a roof’s pitch is. 

It is the measurement of the steepness of the roof’s slope. It gives the idea about how steep the roof is from the pitching point to the ridge in every 12 inches depth.

Joining Two Roofs With Different Heights

Joining Two Roofs With Different Heights

Joining two roofs with different heights needs you to be always careful about the roof positioning, your calculation, and the overall idea of the situation.

Based on the pitch of the roof, joining roofs can be categorized into two sections. One for the same pitch values and the other for different pitches.


The first thing that you need is to do a thorough inspection and have an idea of the overall situation of the joining area.

Determine the point at which the two roofs will connect or tie together. To figure out how many trusses you’ll need, take meticulous measurements. 


Brace the upright and write chalk guidelines on the shingles to define the centerline of roof valleys, where they will both join to bind the two roofs together.

Removal of Obstructions 

The shingles, wall sliding, facing boards that are in the marked areas are required to be removed. And among them, one of the roofs installed trusses

Make sure to use a shingle remover or any tool of the same category to do this work and wear a pair of gloves for safety purposes.

Ridge Board placement

Add a ridge board and attach it to the first trussed roof in an overlapping manner. When the trusses have been fastened, add other roofing materials such as roofing sheets, shingle bolts, and metal drip lines to the roofing. Then, apply and trim the siding towards the end of the previous roof.

Joining the roofs

Connect the new and previous roofs. Then, cut jack rafters to join the ridge and valley boards. To finish the roof framework, brace and nail the trusses on both roofs upright.

After you’ve finished right there, you’ll need to hold the structure in place. So you can apply butyl caulk throughout the entire length of the piece.

Sealing process

Complete by mounting OSB cladding and metal flashing to the roofs and overlapping the new shingles between them.

Reasons to Join Two Roofs 

For several reasons, joining of roofs may take place. In most cases, it happens because of the home expansion. 

When a customer decides to buy a house, the budget plays a very important role. Due to some budget constraints, it is likely to buy a house that can provide you with as many facilities as possible. But not all of them.

For instance, if you want a porch, additional space, or something like that, then you can just buy a house and make it additionally. In such situations, you may need the knowledge of joining two different heights of roofs to make sure no water is leaking on your porch and to protect it from causing accidents. 

Professional Consultancy

Joining two roofs is more of a complex roofing task. If not done properly, it can cause many problems such as water leaking and damages later on.

If you are not skillful enough, it is not recommended to do it yourself. It will be better if you seek any professional help. It may reduce the cost of repairing. Repairing costs sometimes can be as much as making a new one.

As a result, hiring a roofer is still worthwhile. Initially, it might seem to be an expensive decision. However, you will realize it as the proper decision at the end of the day, especially if you do not have good roofing skills.

Final Words

Joining two roofs with different heights is similar to attaching roof techniques of the same pitch procedure. But the only change is that the rafter materials such as plywood, scrap, etc are needed to be fit in the back of the common rafter.

This section is written specially on joining roof essentials, and hopefully, this article will help you gain an idea about this roofing technique.


As a civil engineer and roofer, I love to share the experience that I have gained through the last couple of years. In the roofing industry, practical experience is a very crucial fact that can help you a lot. Hence, I want to help you with my blog.

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