Guidelines for Putting a Steel Roof on a Gabled House

Steel Roof

• A steel roof is made from thin gauge panels that are affixed directly to the roof. The panels act as a roof covering and have no structural value. Compared to some other roof coverings, such as asphalt or wood shingles, a steel roof is simpler to install and is virtually maintenance-free. Ribs are pressed into the steel to add strength to the panels and provide a convenient overlap point when installing adjoining panels. Many different colors are available in baked-on finishes that last many years without fading.

Shingle Roof Preparation

• A gable roof that has an existing asphalt shingle covering requires a few preparations before a steel roof can be installed. In many localities, building codes permit the installation of two layers of roofing. Installing new asphalt roof shingles over an existing asphalt shingle roof may save time and money, but all roof coverings need to be removed before a new roof -- whether it be shingles or steel -- can be installed. If your roof has only one layer of asphalt shingles, a steel roof can be installed without tearing off the shingles. The steel panels cannot be placed directly over asphalt shingles. The coarse texture of asphalt shingles can be abrasive to the underside of a steel roof. In this instance, 1-by-4-inch lumber strips should be nailed over the shingles on 2-foot centers the entire length of the roof. The steel is affixed to the strips, keeping it off the shingles.

New Roof Preparation

• A new roof or a roof where the shingles have already been torn off and removed make things easier when installing steel panels. A layer of roofing paper stapled over the roof sheathing is all that is needed. The steel panels can be affixed directly to the roofing paper.

Steel Roof Fasteners

• Special screws are used to affixed steel roofs. Every time the steel panels are pierced with a fastener, there is the potential for a leak. For this reason, steel roof retaining screws have a rubber gasket just under the head of the screw. The trick to driving in these screws is to tighten the screw just enough so that the gasket makes contact with the steel surface. Over-tightening the screw can compress the rubber gasket too much, and under-tightening may not force the gasket against the steel. In either case, you may have a leak. A solution to this dilemma is to use a power drill to drive the screws that has an adjustable clutch. When the clutch is adjusted to the correct torque, the drill will stop applying power once a certain tightness has been achieved.

Trim

• A steel ridge cap is used to cover the ridge at the top of a gabled roof where the two sides meet at the top of the slope. Rubber gaskets with a self-adhesive backing are applied over the ridges of the steel panels before the cap is applied, making for a water-tight seal once the trim is secured. The ridge cap -- as well as trim for the gable ends and the eaves -- are attached to the steel panels using the same type of screws with rubber gaskets.