How to Build a Porch Roof Addition

pieces of fresh lumber
  • 20-40 hours
  • Advanced
  • 3,500-7,000
What You'll Need
1/2 inch sheet of plywood
Roofing cement
Roofing shingles
Supporting posts
Pen or Pencil
Metal brackets

If you have an open porch, then building a porch-roof addition can make the space even more useful. You will be able to use the new space to store dirty shoes and boots, along with other things you want to leave outside but keep undamaged from rain. As long as you have the right tools, building this addition is simple.

Step 1 – Evaluating

It’s important to make sure that you can build the structure without causing any harm to your house. Ensure that your porch and home can cope with the extra weight of a roof, as it needs to be strong and stable. Make sure there are no weak or rotting spots.

Also take a look for anything that could make attaching the roof difficult, including power cables, nearby trees, and phone wires.

Step 2 - Drawing up Plans

It's always a good idea to spend time planning the design of your porch roof before starting. Make sure that the plans are accurate and go into enough detail. The exact size of your roof addition will depend on what you want and what you will be using your new, covered space for.

Step 3 – Making Sure Your Porch is Level

You will now need to make sure that the porch is level. If it’s not perfectly level, you will need to correct this before working on the roof.

Step 4 – Installing Supporting Posts

Now, consider where you will locate the support posts, marking the position of these on the ground using a stake, so that you know where to dig. Once you are happy with the location, dig the holes for the posts. Then, put the posts into the hole and concrete them into place. While they’re drying, you should temporarily brace them.

Step 5 – Attaching the Top Plate

Now, you need to attach the top plate, sized to the dimensions of your new, roofed space to the support posts. This will connect all of the posts together and create a box.

Step 6 – Attaching the Rafters

Once you have done this, you will then be able to fit the rafters. Rafters can be cut to length from lumber and then fitted so that they are snug and accurate. Either make a birds-mouth cut in the rafters, or use metal brackets to connect them. Make sure everything is perfectly level.

Step 7 – Covering the Roof

Next, cover the roof using a 1/2 inch sheet of plywood. Ensure the wood hangs slightly over the edge of the roof to help with run-off. Finally, cover the roof with shingles, and nail them into the plywood sheet and rafter.