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Joining Two Roofs With Different Heights

joining two roofs with different heights

There are many reasons to consider joining two roofs with different heights. One reason is that it can make a home look more attractive and balanced.

Another is that it may be necessary for structural support, such as in the case of an addition or second story. However, there are many things to consider before making this decision.

This post will provide you with some helpful insights on how to join two roofs together without compromising their integrity or function.

Six Steps in Joining Two Roofs With Different Heights

Step One: Assess the situation and make any necessary repairs.

If one roof is higher than another, then you will need to assess the structural integrity of your home to find out if it can support an additional weight or amount of re-roofing work before attempting to join two roofs together at different heights.

Step Two: Identify the best way to join the roof.

The pitch of your roofs will determine which type of joint is most suitable for joining them together at different heights, so this step involves assessing what materials you have on hand and how much re-roofing work needs to be done before attempting to join two roofs with a difference in height.

Step Three: Cut the rubberized asphalt membrane.

Before you can join two roofs together, then one of them will need to have a valley cut into it that is large enough for this material to be placed in between and seamed together at different angles.

Step Four: Place the rubberized asphalt membrane on top of the roof section.

After the valley has been cut, then you can place rubberized asphalt membrane on top of it and join them together.

Step Five: Place flashing over the joint.

Once all necessary re-roofing work is complete, such as fixing any leaks that may have occurred due to a lack of flashing, then you can place flashing over the rubberized asphalt membrane and seal it in with a caulk gun.

Step Six: Seal any seams or joints on your roof. Finally, after all re-roofing work is complete and your new joint has been sealed shut with flashing, then make sure to inspect areas around vents and chimneys to make sure they are all sealed as well.

By following these steps, you should be able to successfully join two roofs with different heights.

What Are Some Important Considerations When Joining Two Roofs Together?

The Type of Roof 

If you would like to join two roofs that are different heights, but the roof types are not compatible with each other (i.e., asphalt shingles on one side and metal on the other), then it may be necessary for some re-roofing work to take place first before joining them together.

The Pitch of the Roofs

A general rule is that it’s usually best to join two roofs together with a difference in height no more than three feet.

This means that if one roof has a 12-inch rise for every foot, then another can have at least an 18-inch rise for each foot. Of course this depends on the type of roof, purpose of joining them together and whether or not they are structurally sound.

In some cases it is possible to join two roofs with a greater difference in height, but there may be complications that arise from doing so.

If you’re unsure about how much your roofs can differ in rise without compromising structural integrity then consult an expert.

The Kind of Material You Are Using for the Joint

Generally speaking, the best material to use for a roof joint is rubberized asphalt membrane.

It’s flexible and malleable enough so it can be cut with tin snips and seamed together at different angles without compromising structural integrity or quality.

However, some roofs will require metal flashing if they are unable to support the weight of this type of material.

The Resources

Depending on the size of your roofs and how much re-roofing work needs to take place, it may be a good idea to hire professionals.

This is especially true if you would like things done quickly without compromising structural integrity or quality.

If you have a modest sized roof with only a few issues that need to be addressed, then it’s possible to do the work yourself.

However, this is not recommended unless you have experience dealing with roofs and are confident that your home won’t sustain any damage as a result of re-roofing or joining two roofs together at different heights.

Joining Two Roofs With Different Heights

Most Common Types of Roof Joints

Valley

A valley joint, the two overlapping sections of roofing material, is cut to form an inverted V-shaped ridge. The valleys can be placed either at the top or bottom of each section so that they overlap with one another. 

Saddle

Joining two sloping roof sections together, such as in the case of a shed or gable roof, then an inverted U-shaped valley is cut into each section.

Then, when they are placed together at right angles to one another and seamed with rubberized asphalt membrane sealant (commonly used for metal flashing), it creates a saddle joint.

Ridge

The ridge is the topmost part of a roof and is typically joined with either tiles or shingles. With a ridge that is made from metal sheeting, then rubberized asphalt can be used to create the joint.

Three Easy Steps in Installing the Gutters

Here are three easy steps in installing the gutters on a two-roof property with uneven heights.

Step One: Decide on the Gutter

Gutters come in a variety of sizes and shapes, so finding one that is compatible with your roofs can be quite difficult. When you choose which gutter to use, make sure it matches both roofs’ widths and heights before installing them side by side.

This will require some measuring beforehand! Once you have decided on a gutter, you can move onto step two.

Step Two: Mark the Gutter And Roof Spacing

You will need to mark where your gutters and roofs meet in order to properly cut through both of them at the same time. To do this, use either roofing nails or screws as physical markers so that you know exactly where to cut.

This part of the job is very tedious and time-consuming, but it can be a lot easier if you have a second pair of helping hands!

Once everything has been marked correctly, move onto step three.

Step Three: Cut Through Both Roofs At The Same Time

To do this properly, you will need a roofing saw and a hammer. The best way to do this is by cutting through both roofs from the inside out so that you can keep everything clean from debris.

Once both sides have been trimmed, you should be able to easily slide your gutter between them without any problems!

Now that your gutters are in place, all you need to do is attach them to your house and then you’ll be ready for the next rainfall!

Final Thoughts

Joining two roofs together at different heights can be done as long as there is a way to support the weight of both and structural integrity isn’t compromised in any way.

While some re-roofing may need to take place before joining them, it’s usually possible with an experienced roofer who knows what they’re doing.

Joining Two Roofs With Different Heights