How To Add A Porch Roof To Existing House Structures (DIY Step-By-Step w/ Videos)

Do you have an existing patio slab or some other surface in your front or backyard that is in desperate need of a cover?

Do you find yourself wishing you could spend some time outdoors when the weather gets hot and sunny?

Would you like a space that’s cool and shady enough for you to do just that?

In this article, we’ll walk you through all the steps you’ll need to take to learn how to add a porch roof to existing house structures. We’ll help you understand which types of materials you need as well as just what’s involved in the whole process.

Keep in mind that this isn’t a job for woodworking beginners. You should at least have some intermediate skills working with wood and other DIY materials before you start on a project like this one. It’s better if you have more than intermediate skills, but this can be a fun challenge for those who are looking to learn more about carpentry, too.

Read through the directions below and see for yourself if you feel like this is a task you can tackle. Let’s get started learning how to install that new porch roof right away!

Materials Needed

building a porch roof diy
  • Two 6x6 lumber posts
  • Two anchor bases with accompanying washers, nuts, and bolts (often sold in kits)
  • Materials for header board and rafters
  • 1x6 lumber boards
  • Ledger board
  • Steel joist hangers and steel nails
  • Aluminum flashing
  • Lag screws
  • 2x6 lumber
  • Fascia board
  • Power drill and masonry drill bit
  • Circular saw
  • Tape measure
  • Hammer and nails
  • Paint or finish as necessary


  • 1
    Bear in mind that this article is going to assume you already have a concrete slab-style patio or front porch area. If not, you will need to look up information on how to lay one of these slabs before you get started.
  • Keep in mind, too, that you will need to get the appropriate permits for this DIY job before you get started, whether your roof is going in the back or on the front of your home. You may also need to get permission from your HOA, depending on where you live.
  • 2
    First, use a tape measure to figure out the height of the wall you’re going to be attaching the porch roof to. Also, measure to determine the precise center of the wall, and mark the center.
  • 3
    Mark the location of your support posts. If you have a small patio, you will likely only need two of these on the corners of your patio slab opposite the house you’re building off of.
  • 4
    Using your power drill with a masonry bit attachment to drill 1/2-inch holes for your anchor bolts. These will be used to secure both of your poles.
  • 5
    Install the anchor bolt and secure it with a washer and nut. Tighten firmly with a wrench.
  • 6
    Use a circular saw to cut the end of the your post beams so that they are both flat and of even length.
  • 7
    Set the first post into the first anchor base. Drill pilot holes into the wooden post and then use a hammer and nails to nail the anchor base to the post.
  • 8
    Repeat the process on the other post.
  • 9
    Now it’s time to make the header board for your rafters. For this task, you’ll need to move to the side of your house where you’re attaching the new roof. Use lag screws to secure the header board to the existing wood of your home.
  • Note: Your header board will need to be a piece of lumber cut to the correct length for your patio and the correct width for the side of your home. This will differ depending on your specific setup.
  • 10
    Add aluminum flashing behind the header board to prevent water damage.
  • 11
    Paint or finish the wood you’re using for your header board and attach the joist hangers before attaching the rafters to the board. You should attach them about every 12” or so. Be sure they are spaced evenly.
  • 12
    Cut the rafters if needed to the correct length for your patio space. Paint the rafters before hanging.
  • 13
    Secure the rafters into the joists and ensure they are level.
  • 14
    Nail or screw fascia board to the end of the rafters to finish the job.
  • 15
    From here, you’ll need to determine what you want to cover the space with. You may choose to use plastic sheeting, a sun shade, corrugated metal, or more wood, depending on your preferences. Each of these will be installed differently.
  • For plastic sheeting, one of the most popular options, you can simply screw the plastic to the top of the rafters using a power drill.


As you can see, there are quite a few steps involved when you’re looking to install a roof to a pre-existing patio slab. When you’re going to install the roof to an existing home, the steps become even more complicated. This may not be a job to undertake if you’ve never tried any woodworking or carpentry projects on your own before, and even if you have help, you will need to be sure someone working on this project has some experience in similar tasks.

With that said, however, bear in mind that it may cost quite a lot more to have the roof installed professionally than it would to put it up on your own. With that said, of course, there are always hidden costs in putting up a roof (or handling any other DIY project around the home) on your own, too. For example, there’s always the chance you could end up doing more damage than you expect, especially if you don’t have a lot of previous experience. If you do any damage to the side of your home in the process of installing your patio roof, then you’re going to wind up being out a lot more money than you would have been if you’d hired a professional to tackle it instead.

When trying to decide whether or not to take care of this job on your own, it’s a good idea to weigh all your options. Figure out if you feel like you can really handle the tasks involved, and if you feel uncertain about any of it, there’s no harm in saving up some extra funds to pay for a pro job instead.