How To Build A Porch Roof (13 Steps From The Pros)

Roofed porches can be pleasant places to relax, and they provide coverage around the entrances of your home from some harsh weather conditions.

But some homes may need a new porch roof or not have one. Similar to building a roof over a deck, installing a porch roof is a task for people skilled and ready to tackle a large project, but it can be rewarding to build your own.

If you’ve wondered how to build a porch roof, here’s a helpful guide to help you plan the process. It will cover the materials needed, cost of the project, a step-by-step guide, and a FAQ to answer all your questions.

Cost of Building a Porch Roof

The cost of building a porch roof depends mostly on getting the best materials and what they cost in the current market. Some people may also need to invest in good power tools before starting the project.

Small items like screws and washers shouldn’t cost much, especially if you already have some lying around. Concrete and support like gravel can also be inexpensive in the quantities needed.

You can cost these products out at local hardware stores, but they tend to be less than ten dollars a bag.

One of the materials that will cost the most is lumber. The wooden frames needed for the project can vary in price with the current market rate of lumber.

Expect to pay over a hundred dollars for the wood for this project alone.

Shingles can also be an unexpected part of building a porch roof that can add to the cost. Typically the prices at stores can average over 30 dollars. Trying to match the shingling to your house may factor into the cost.

If you need to purchase power tools is the final major spending factor. Some may not need to worry about this, but having quality tools ensures the job is quick and safe.

What You’ll Need

Here’s a quick look at everything you’ll need. Gathering the necessities can be smooth. When figuring out how to build a porch roof, it’s crucial to be well-prepared with your materials.

Equipment and Tools

First is a list of equipment and tools. Most perform this job with power tools, so please ensure you’re comfortable operating the equipment and know basic safety procedures.

Here’s all the equipment necessary to build a porch roof:

• Cordless drill
• Ratchet wrench set
• Circular saw
• Post hole digger
• Speed square
• Hammer
• Ladder
• At least 15 lag screws and washers

One important note about the tools, like the cordless drill, is to remember that you’ll be performing some tasks above the ground. Having portable power tools and someone to help handle switching items can be beneficial.

Speed squares are handy measuring tools that can guide you when determining the angles for the project.

Materials

Now is a quick list of the materials necessary when planning how to build a porch roof. As mentioned, lumber can be the most expensive part of the process. Choosing quality lumber at least five inches thick for posts and beams is crucial.

Your measurements can alter the exact wood you’ll need. When you determine the rise and run of the project in the next step, you can decide on the wood necessary.

Usually, you can expect to have a few measurements like:

• 2-by-4 pieces of wood
• 2-by-8 pieces of wood
• 4-by-4 pieces of wood
• 2-by-6 pieces of wood

Generally, you’ll also need these materials:

• 1/2 inch plywood sheathing
• Shingles or roofing felt
• Drip edge
• Fascia boards
• Nails and screws
• Heavy duty bolts

Depending on local codes and personal choice, it may also help to set the supports of your porch into the ground. If that’s necessary, you’ll need these extra items:

• Bags of gravel
• Quick-set concrete

13 Steps To Building A Porch Roof

You’ve got the materials and cost down, so here’s the step-by-step guide to prepare you for how to build a porch roof. Take these as general guidelines to help you plan your project.

1. Verify Local Building Requirements and Codes

Although you may be excited to jump in, it’s essential to take your time to check in with local building codes before even beginning construction.

Building codes can be complicated, but they offer guidance to protect yourself, your family, and the property. Violations can lead to complications that leave people vulnerable to lawsuits or insurance not covering issues.

You can find local building codes online or by visiting state code offices. Sometimes, it’s also possible to find copies of code books in libraries.

Keep in mind your state-specific building codes that can help prevent local damage types like intense freezing, flooding, or other environmental risks. 

2. Pull Building Permits

Usually, you’ll need to submit a building permit, which can take up to thirty days to be approved. Most areas require building permits for structures attached to homes.

Building permits can cost some extra money. Occasionally, you may also need to spend time consulting with an engineer or architect to meet codes.

To submit a building permit, you have to have a proper porch roof plan that local offices will approve. 

Patiently waiting through this process keeps you safe and can be an opportunity to gather materials.

3. Determine Rise and Run

Here’s one of the most crucial steps for planning how to build a porch roof. Determining the rise and run is fundamental to your building plans and can impact roofing and rafter length.

Rise and run is a basic math formula that helps calculate the angle or pitch of your roof. Generally, people try to match their porch roof to the pitch of their house when possible.

Many roof rise and run calculators are available online to help with this step.

You need two basic measurements to find your house’s rise and run. The rise is the height from the ceiling joist to the roof ridge, measured in inches. Run is the length measured in feet from the house outwards to where the porch will end.

Divide your rise by your run to find the pitch of your roof.

4. Remove Siding For Rafter Plate

Now that you know the rise and run of your porch roof, you should know where the rafter plate will need to attach to your house. To do so, you may have to remove the house siding.

Mark out the location of the rafter plate with chalk. It must be at least three inches lower than any windows to avoid building materials from blocking them.

Remove any house siding and material in the way so that you can secure the rafter place to wall supports and studs.

You don’t have to remove anything if your house is brick or you’re attaching the porch to brick. Marking the location for the rafter plate can still be helpful for proper planning.

5. Install the Rafter Plate and Hangers 

Take time installing the rafter plate and hangers to set up your project skillfully. Secure the rafter plate, usually a load-bearing beam, to the house with lag screws.

Depending on the method of building, you may choose a different way to secure the rafter plate. Occasionally, I-beams or trusses can require alternative fastening.

Generally, after attaching the rafter plate, you can add hangers. You can space these about 16 inches apart when screwing them in, and each end of the roof should have one.

6. Position and Install the Support Posts 

Next is positioning and installing the necessary support posts. Figure out where to place the posts by starting opposite the rafter plate.

Usually, you should position the posts between six and ten feet apart. Odd numbers of columns tend to be more pleasing to the eye.

Make sure you consider if your porch has steps before placing the posts. Local building codes may also require a set number of supports before you finish your design.

Place the columns up with anchors and check that it’s leveled. If you have freezing risks, you may have to dig a hole and fill it with gravel to secure the post with concrete in the ground.

Brace each post as you continue placing them, and keep all your columns in line with the house and floor.

7. Install the Header Beam

Install the header beam with screws or nails. Usually, you can construct your header out of 2×6 or 2×8 planks. Insert a piece of 1/2-inch thick plywood between the boards and nail them together to add extra substance.

You can set the header by toenailing, drilling angled holes, and securing it to the top of your support posts.

It can be helpful to determine the load that will be on the headers and beams of your structure when planning how to build a porch roof. Bulk up your header so it can handle the weight.

8. Cut and Install Rafters

You’ve set up the supports, so you can now cut and install your rafters. Each will connect to the rafter hangers and the top of the header beam against the rafter board.

Before installation, you have to cut the rafters. Use the carpentry techniques of “tails” and “bird mouths,” which help keep the structure flush.

Measuring out these cuts is when the speed square can help quicken the process. This specialty tool keeps the measurements accurate and will help the rafter fit in place.

If you’re new to building porch roofs, practicing your cuts on spare wood may help you figure out the fit before you use your primary lumber.

9. Install Roof Sheathing

Roof sheathing is a simple step to add the foundation to your porch roof.  

You can nail sheathing plywood to the rafters. These flat boards will provide the base for your roofing materials. Usually, you can use 1/2-inch thick plywood to get the job done.

Choosing proper roof sheathing and fasteners can help protect your roof from damage and give you a stable base for maintenance.

It can be especially crucial if you live in an area affected by coastal storms because roof sheathing failure and loss are common structural issues during hurricanes.

10. Install Roof Shingles

Nailing down roof shingles is the next step. 

Before installing the shingles, it’s best practice to lay down roofing paper and a drip edge. Both components help keep moisture away from your home and protect the wood of your roof.

When you install shingles, begin at the bottom and nail in the rows upward. Attach the roofing components to the sheathing.

11. Install Fascia Boards

Fascia board installation is another step that helps prevent moisture and mold issues. You can nail fascia boards to the rafter tails and can be between the house and porch if necessary.

These vinyl coverings help support the roof and offer a place to install the gutters. Water and moisture wick off the material instead of seeping into any exposed wood.

Nail the fascia board into place when it’s level with the edges of the rafters. It can help to use caulk or putty to seal edges and nail holes from extra moisture, but this step isn’t necessary.

12. Install Gutters

Gutter installation can be an optional step for your plans on how to build a porch roof. It may be worth adding if your area has a lot of rain and tree coverage.

Luckily, gutters are a quick addition. You can screw fascia brackets into the rafter tails. Measure and cut your gutters before installing them into the brackets.

Complete the gutters by placing end caps and cutting out the downspout holes. Add your downspout, and enjoy a porch roof with its gutter.

Usually, you can find gutters that match your home. If you like, you can attach the gutters by purchasing a connector. Remove the end caps and place the connector where your porch meets the corner of your house.

13. Reinstall the Siding

Finally, you can reinstall some siding to your house.

If you cut out any extra around where the porch connects, it’s time to cover up the work area and put the finishing touches on your porch roof.

You may also need to install some siding onto the porch roof. This final step helps wrap up the job, and you can be proud of your work completing this task to improve aesthetics.

Vinyl siding is the most common, and try keeping it spaced well. The material can expand and contract in extreme heat or cold, so it’s important to leave gaps. Also, avoid hammering nails too tightly to allow contraction.

Frequently Asked Questions

• Should I use treated lumber for a porch roof?

  Generally, it can be a good idea to try and use treated lumber on a porch roof. There’s some debate about using treated lumber, but this wood can avoid water and insect damage.

  Lumber is treated either by chemicals or pressure. Understanding how to select treated lumber by reading the tags for information on preservatives can help you avoid unnecessary additions.

  Pesticides can kill termites, but it doesn’t eliminate pest risks. Carpenter ants can still seek out the wood, and termites may spread to other non-treated areas. Use extra caution when using chemically treated lumber.

  Still, it’s usually a good idea to use treated lumber on areas encountering a lot of moisture, like roofing.

• How much overhang should a porch roof have?

  Porch overhangs can depend on your intentions for your porch, but they are usually at least 12 inches away from all sides of the roof.

  Extended overhangs that reach up to two feet are typical for people who want more shade or protection from the elements.

  You may even choose to have an overhang shorter than 12 inches if your area is regularly dry. Choose a length appropriate for your needs and keep it uniform across the roof’s edge.

• What holds up a porch roof?

  Frieze beams and header beams help hold up a porch roof. These structural components take the weight and distribute it to the posts.

  Each post also helps add support, especially ones anchored into the ground. Keeping up with local building codes will ensure your porch roof is supported.

• What kind of plywood should you use for a porch roof?

  CDX plywood is the usual choice for roof sheathing. This plywood has a particular type of glue that handles rain and moisture well.

  Typically, it’s best to use plywood at least a 1/2 inch thick. It’s essential to pick good plywood to create the base of your roof when you need to stand on it for maintenance.

Final Thoughts

Figuring out how to build a porch roof can seem intimidating, but various resources can guide you through each step. Start by familiarizing yourself with building codes, and you’ll be guaranteed to create a safe and comfortable porch.

It’s an advanced project, but this information can help clear up the fine details. Now you can confidently choose out your materials and plan the build.

Stay safe while building a porch roof, and prepare to enjoy your new addition to your home.