Top 8 Most Efficient Ways on How to Add a Porch Roof to the Existing House & More 2023

Add a Porch Roof to the Existing House

If you want to add a porch roof to the existing house, it’s not as difficult as you might think. There are several different types of roofs that can be added to your home, each of which has its own advantages and disadvantages.

Most of us don’t think much about our roofs, but they play a crucial role in keeping your home safe and healthy. The roof can be an eyesore if it’s not well maintained, but it can also save you from potential damages and disasters. If you want to add a new porch roof to your existing house roof, there are certain factors that you should keep in mind before you start building.

How much does it cost to add a porch roof to an existing house?

Adding a porch roof to an existing house can cost anywhere from $2,000 to $10,000 depending on the size and complexity of the project. The cost will also depend on the type of roof that is chosen and whether or not permits are required.

Should I hire someone else or do it myself?

It is always a good idea to hire someone else to do a task that you are not confident in doing yourself. This is because there is a higher chance of making mistakes when doing something by yourself.

On the other hand, if you are confident in what you are doing and believe that you can complete the task on your own, then by all means go ahead and do it yourself. There are many online resources that can help you with the process of starting and running your business.

Most Common Ways to Attach A Patio Roof to An Existing roof or new roof

There are different ways to attach a patio roof to an existing house. Here is the most common way to attach a porch roof and decking.

The first step in attaching a porch roof is to remove the old asphalt shingles or roofing material. Next, you will need to drill holes into the porch roof joists and fasten 2x4s between them at intervals of 16 inches. Then, screw through the plywood sheathing and porch roof decking into these joist holes.

Make sure that all screws are secure before continuing to attach the roofing material using fascia board or metal lath. Finally, paint or seal your new patio roof with a topcoat of polyurethane to protect it from the elements.

Prepare the new roofing material

Before you start your roofing project, it is important that you have all the necessary tools and materials ready. This includes the new roofing material that you will be using. You can either choose to hire a professional roofer or do it yourself depending on your skills and experience.

When choosing which type of material to use for your new roof, there are a few things that you should take into account:

-The weight of the new roof

– The heavier the rooftop structure, the more difficult it will be to move during and after the roofing project.

-The type of roofing material

– The different types of roofing materials have different weights and fibers, which can affect how easily they will integrate with the existing structure.

-The weather conditions in your area

– Certain types of roofing materials are better suited for certain climates, which you should take into account when making your decision.

Below are some things to keep in mind when choosing a new roof:

-Choose a material that is compatible with the existing porch structure and overall building style.

-Be sure to factor in weight and transportation when choosing a roofing material.

-Select the right type of roofing material for your area’s weather conditions.

-Be sure to get professional roofing estimates before starting the project.

1. Check Your Local Building Codes

Before you start the construction process to add a porch roof to the existing house, it is important for you to check your local building codes. In most cities and towns, there are some specific requirements for adding a roof extension to an existing house main roof.

For example, in some places, you are required to use roofing material that is fire retardant. You may also need to get a building permit from the local authorities.

These are a set of regulations that you must follow in order to build, repair, or remodel your house, for those who are not familiar with them.

The local building codes in an area are typically different from the ones that are employed in another. The primary purpose, on the other hand, is similar. It’s to make certain that the construction meets the local community standards, including health and safety standards, in addition to other standards.

Before beginning your project, most local building codes also require you to obtain some building permits from the local building code office. They also need to see your plan as well so that they can determine whether or not the current building or renovated home parts match the community standards. As a result, from the beginning, you should give it.

Building Permit

You can also sketch a plan before starting the project, which is helpful for you. We can do so because you will learn not only the design of the porch roof addition but also the design from it.

There are two things you must seriously consider when you are creating the plan. The size of the roof addition and the function of the protected area are both factors.

This will be valuable in deciding the design of the current roof when you show up with it. It will also know about the detailed measurements of each material, allowing you to more thoroughly provide everything requested.

2. The House and The Existing Roof are both worth Evaluating

existing House roof

After you check the local building codes, it is time to evaluate your house and existing roof.

For this, there are two things you must consider seriously. Those are the space available for the new porch roof addition and the area of the existing roof.

A roof addition of this size must be evaluated on the overall square footage of the house. It is not simply a matter of adding another room!

There are non-standard roofing materials that can cause problems if installed improperly, either through an improper framing plan or shoddy installation. For example, metal flashing can contact your siding and create unwanted damage. So you must make sure to have a professional evaluate the existing roof to match any new construction before starting anything!

Of course, what we said here is that you should only evaluate the area where you will add the new roof addition. This step is very crucial for you to know, but many people skim it anyway, and that is not a thing that we wish you to see.

The prime goal of the evaluation remains to demonstrate whether or not the existing roof can be modified with the current addition. It’s also helpful to know whether or not the existing roof is safe for the extension.

The one thing you must focus on in this step is whether or not you can erect the new roof for the porch without causing any damage right after the project is finished or in the future. A fresh roof is a heavy one. You must take certain that the structure, as well as the house, can be dealt with care.

As a result, everything must be reliable and strong. It also implies that you must ensure that no parts of the house or the roof are crumbling or soft. If by any chance, when doing the evaluation, you discover some worrying or even damaged parts, it would be healthier to repair them first before starting the project.

You can also check whether or not some things later can make the process to add a porch roof to the existing house one harder to complete in this evaluating step. Phone wires, power cables, or nearby trees and branches are among the items that can be used.

3. Check the Porch Level

Now, if you already know whether or not the porch can be modified with the new roof addition, you can move on to this step. This is where we recommend that you check the porch level so that you will know whether or not there are any obstacles in the way of the roofing project.

To do this, you need to measure the height of both porch and roof, as well as make sure that there is enough clearance for your equipment. You also have to take into account any steps or railings on either side of the porch. By doing all these things, it will be much easier for you to start building your new roofing structure without having any problems later on.

4. Building the Supporting Posts

After the porch level is checked, you can now start building the supporting posts. To be able to do this step, you must first determine the dimensions where you will place the supporting posts.

After you have determined the dimensions of your roofing posts, you can now start to dig the holes where they will be placed. Make sure that all sides of the post are covered with enough soil so that it will not show when the post is finished. After digging and filling in each hole, make sure to tamp down the soil around each post before putting in your roofing material.

If we go into details The current addition structure allows reinforcing posts, which are critical. These are the ones that will take up the new roof, which also means they function as the design’s underpinnings.

There are two types of support that you can use in this project, as we already informed you at the beginning of this article. The first is single posts, and the second is support columns. However, we will only discuss the supporting posts that are generally simpler to work on.

The top thing to do is demonstrate where you wish to place them if your choice goes to plain posts rather than columns, based on some consideration. You can stake the ground by busing a stake in each location once you choose it. This is for informing you of the correct locations to drill holes for installing the posts.

The next thing to go is to drill a hole to position the post once each location has been corrected. following that, you can place a post in each of the holes and then use a concrete mix to settle it.

You can design a temporary brace for each of them in order to ensure that all of them can remain in place while the concrete is drying.

5. Attaching the Valley Board

patio attached

Depending on the size of the new addition that you need to make the porch area, attach a valley board by attaching it down on the existing roof. One thing that you need to get here is that a different design will require a different number of boards.

When the fresh roof you choose is in hip style, for example, you will require more. You will only need to attach a valley board to the existing roof if you choose the shed design, which is commonly easier to make.

This element’s function is as a concrete nailing surface that you’ll later utilize to install the new porch cover’s rafters. The ancient roof of the house is utilized to erect this part.

Another thing you need to know in this case to add a porch roof to the existing house is that you get two options: strip the shingles of the existing roof or leave it. There remain either one of the options that are best to choose. However, if you need to spare time, you can simply let the old shingles in the same place without putting anything on them.

The next thing you must perform after adding the valley board is wiping roofing cement on the pinned part of the board, as well as along the edges. It’s supposed to restrict possible leaks, right?

You need to realize that roofing cement is different from the standard concrete mix if you are not familiar with it. This can be described as an adhesive and patching material created for use only on the roof.

Roofing cement holds a few functions. One of them is for stopping leaks that can damage or reduce the benefit of valley boards, which is none other than the material we need for adding a new roof extension to the existing one.

6. Attaching the Top Plate

If you have chosen the hip roof style, then you need to attach a top plate to the roof of your house. This will serve as a solid surface that is used for attaching rafters.

To do this, use nails and screws to fix the roofing shingles. Make sure that you use the proper tools for this, as otherwise, you can damage your roof and patio.

The next thing you must do is attach the top plate once you have the valley board connected properly on the existing roof. The main goal of doing this is to connect all of the support posts. It will also help them later secure to the roof.

You must weigh the dimensions of the roof addition in addition to the posts that you have previously manufactured in this step. This action will aid you in verifying the rafters’ sizes.

All of the posts will be joined by the top plate. If you only need two supports in the design, the other top plate will be added to the valley board that you had previously prepared.

7. Attaching the Rafter

attaching the rafters

The next step has to lock the rafters. These are none other than the wooden element that slopes down from the roof’s ridge or hip to the top. Because the construction we create is a porch cover, in this case, one end of the rafters will be nailed down to the valley board.

The other end will match the support post’s top plate, which joins the two together. There remain two options available in this case. The first is to make metal brackets to adhere the rafters to the top plate. The next is to employ the birdsmouth joint technique, which is excellent for light-frame construction, such as the construction of the porch cover discussed in this article.

8. Plywood and Shingles are used to cover the Roof

We’ve arrived at the final step of the process to add a porch roof to the existing house, which is about to be the roof. There have two sub-steps here for you to learn.

The top is for sheathing to protect all of the roof frame’s surface. You should use plywood with a thickness of 12-inch in this case.

The reason we suggest you choose plywood for the roof sheathing is that it has a better ability to keep water for a lengthy time. This material, in addition, is extremely tough when applied as a roof coating.

The next step you must take here is to reinforce the sheathed roof with shingles by attaching these materials down to the plywood sheathing and rafters. We suggest you choose something with the same appearance as your existing roof in this case. The reason is easy: a coordinated look.

What’s More, you can do?

There’s a lot you can do after completing the porch roofing project. For example, if rain is an issue for you or your home, consider installing roof flashing to prolong the life of your protection system. In addition, take into account any picturesque details that might be present on your property before starting construction – these features may need special consideration while building your porch roofing.

Also, you can do these of the following:

1. Let The Air Flow, avoid The Splash Of The Rain

The primary goal of installing a patio roof remains to cover you from the rain and sunlight’s glare. Unfortunately, you may need to stop the airflow at times.

You must place the patio sheeting over the top of the roof about 300 millimeters so that it can perform shield from the rain without blocking the airflow, to restrict the rain’s splash but let the airflow.

It’s your best bet, especially if you don’t own a fully-covered patio that gets a lot of airflows.

2. Make Your Patio Roof A Little Bit Higher Than Usual

If you want to go high, then you can use this method. This method is suitable for roofs that are at least 2 feet higher than the eaves of the house.

To do this, you will have to attach a rafter from the roof to the patio roof joists at approximately a 45-degree angle and then secure the rafter with building code-approved screws.

3. Neat and Tidy Look

Extra height is desired to create a sleek and tidy appearance, while eaves, fascia, and gutter are removed, and rafters are cut back.

On top of the wall, install FHS columns. Following that, lock and reinforce the patio to the rafters. The beam must be raised to the desired height.

You’ll need a custom box gutter on the house and a custom barge on top.

It will support you in ensuring that everything is watertight. To finish the job, you may also need some sort of slicing beneath.

Some Styles You can go with

1. Japanese Style Patio Roof

The image of Japanese houses is conjured up by this patio roof. The opened beams that overhang a tiny bit are supported by the wooden posts.

The latticework lets natural light come through, allowing you to be partially protected. The Japanese style of this patio is emphasized by the lanterns dangling over the green couches.

Some bamboos are grown next to and in front of the patio in order to give it look like a Japanese traditional house.

The latticework does not completely block natural light in order to let it flow through the patio roof.

The rain is so heavy that the roof cannot save you.

2. Modern Patio Roof

The patio roof is made of metal, and it is supported by posts. The latticework covers the beams that overhang a little bit.

It is attached to the wall so that you can open or close it. The eaves are not that high, so the roof is not too shingled. It does not have any lanterns or bamboo plants.

The modern patio roof may be one of the best roofs for you because it has a lot of different designs that you can choose from.

3. Spanish Patio Roof with Eaves Open

This patio roof style is more traditional than others and it features two eaves that are open like a porch door.

Wood en posts support the roof, and the beams overhang a little bit.

Latticework covers the beams and is attached to the walls below so that they can be opened or closed.

There are no lanterns hanging from the eaves, but there may be some in other parts of your patio roof such as on brackets near each post.

This style of patio roof is perfect if you want something vintage-looking with traditional features.

4. Outdoor Pergola Style

This patio roof looks like a pergola. This is the reason why it is called an outdoor pergola style.

This design gives a nice touch to your house and also creates a beautiful view from your patio. It complements the style of most houses.

The roof is made from metal, and it features open eaves that run the length of the patio roof.

Posts support the roof, and beams overhang a little bit.

Latticework covers the beams and is attached to the walls below so that they can be opened or closed.


If you are looking for a patio roof that is different from the others, then the Spanish patio roof with open eaves may be perfect for you. It features traditional features and looks great on your patio.

The step-by-step tutorial that we provided here to add a porch roof to the existing house is only available. You have to learn that a new roof for protecting a porch area is available. Of course, each of them employs a unique set of techniques and possibly involves a different level of difficulty.

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