How to Connect a Hip Roof to a Flat Roof

What You'll Need
Roofing nails
Polyethylene sheeting
Rigid foam insulation
EPDM roof membrane
Roof drain or gutter
Crowbar or pry bar

Connecting a hip roof to a flat roof can be done by following the steps, tools and materials provided in this how-to article on how to connect a hip roof to a flat roof. Making the connection provides you with additional roof space necessary to expand the house or build and additional room or space above. 

Step 1: Purchase Roofing Material

At a home improvement center purchase the materials needed on order to convert your hip roof into a flat roof. The materials needed for the conversion are simply a protective membrane for the roof, insulation, plywood, and roofing nails. You should ask the retailer to provide you with the best quality materials that are within the budget that you have allotted for this project.

Step 2: Remove the Hip Roof

You will need to remove the part of the old hip roof in order to accomplish the installation of the flat roof. Climb up on the roof carefully and get in position to take up the old hip roof. Use a hammer and/or pry bar to remove the old shingles and nails that hold them in place. Pull up the tar paper and all of the pieces of the roof, throwing them over the side of the house to be collected in a large trash container later on.

Once the part of the hip roof that you needed to remove has been pulled up, use the pry bar to pull up any loose nails or screws that are on the roof. Pound the loose nails in and pry up and remnant material.   

Step 3: Lay the Plywood Base and Roof Membrane

With the roof debris cleaned up, put a new plywood base on the roof on the flat surface. Use nails to secure the plywood to the new flat roof. Attach the wood membrane to the plywood, working from the bottom of the roof to the top. This will keep the roof dry and waterproof. The plywood and membrane should be secured firmly on the roof before you move forward to the next step in the connection of the hip roof to the flat roof. 

Step 4: Attach Foam Insulation

Attach the foam insulation to the plywood boards of the flat roof. The foam insulation is necessary to provide another layer of protection for the roof and keep it dry in order to resist the elements. Affix the foam insulation to the flat roof using the roofing nails to secure it in place.

Step 5: Shingle the Roof

With the tar paper laid out over the plywood and the nailer board in place, place the shingles on the flat roof. With the shingles placed on the roof you have finished the connection of the flat roof to the hip roof.