Set the shingled roof pieces on the facade of the cabin and check that the roof will sit flat on the top of the Gatorfoam peak. If there are shingles or battens on the facade that prevent the roof from sitting properly on the facade, trim them off.
Take the two pieces of your roof and lay them shingle side down on a work surface, with the roof top surfaces together (as if you had flattened out an actual roof) Cut a piece of kraft paper the same size as your two roof pieces together (7 inches by 18 inches) and glue it to the bottom of both roof pieces so that the roof will hinge in the middle. Run a brayer or rolling pin over the paper to make sure it sticks evenly to the underside of the roof. Trim away any excess paper, you just want to cover both undersides of the roof and enable the roof pieces to hinge at the top. Set this aside to dry.
When the roof assembly is dry, set it in place on top of your cabin facade so that it rests on the front porch posts. If it fits correctly, apply glue to the top of the support posts, and the roof slope of the cabin facade, and glue the roof firmly in place.
When the roof is dry you can cut more twigs to form the decorative cross members which will help support the roof.To finish the cap on the shingle roof, lay a final row of shingles on the roof cap once it has dried in place. Make sure the final row of shingles is set back 1/2 inch from the row below, and is trimmed to end at the peak of the roof. Overlap alternating cap shingles from either side as you go across the capping row.
Finish any raw edges with wood ageing solution.