How to Replace a Roof on a Modular Home With a Tin Roof

Tack a layer of tar paper or synthetic underlayment over the existing roof. There is no need to attempt to remove the modular home's original shingle roof — most metal roof systems can be installed over the old one, saving you extra work and potential damage to your home.

Snap chalk lines along the length of the roof from top to bottom, every 10 feet. This aids you in correctly aligning the tin sheets when installing them. Measure to ensure the lines are at a perfect right angle to the eave.

Install the eave trim, screwing it to the roof on both the front and the top every 2 feet. Glue foam inside closure strips to the top to seal the gap with the roofing panels when you install them. Install valley trim, if necessary, the same way, with rows of screws and a closure strip along both edges.

Position the first tin panel in place on the downwind side of the roof, aligned with the gable edge and overhanging the eave by 1 inch. Secure it in place, driving a screw on either side of each rib every 2 feet. Add the next panel just above the first, overlapping it by 6 inches, and continue to the ridge, cutting the final panel to size so it will fit.

Stick a strip of butyl tape to the inside edge rib of the first panel and lay the first panel of the next column just upwind of it, overlapping their edge ribs. The tape will seal the panels against the elements. Install this column of panels the same way as you did the first, securing side-by-side panels with tape all the way up. Continue adding panels upwind until the entire roof is covered.

Apply a strip of butyl tape to the outer rib of one gable-edge panel. Install the gable trim over this strip of tape, driving screws every 2 feet through the top and side of the trim. Do the same for all gables.

Glue an outside closure strip to the upper edge of all ridge-line panels and install the ridge trim, screwing it in place every 18 inches along both edges.