Metal Roofing Frequently Asked Questions

Question:  What are the advantages of metal over other types of roofing?

Answer:  Prefinished metal roofing is offered in a broad palette of attractive colors with long-life coatings that do not support the growth of moss, mildew or fungus. Metal panels are lightweight, yet strong enough to withstand severe weather—snow easily slides off the roof. Finally, metal roofing lasts longer, conserves energy, and requires virtually no maintenance.

Question:  Can I install metal panels directly over my old, worn-out shingles?

Answer:  Since metal weighs only 1/3 as much as shingles, you can often attach metal panels without tearing off your existing shingle roof. This eliminates the cost and problems of disposing of the old shingles. The best way to do this is to attach 1" x 4" or 2" x 4" furring strips at 24" o/c parallel to the eave and ridge. Check local codes to determine if tearing off shingles is required in your area.

Question:  How do I attach metal panels?

Answer:  You may use either screws or nails—both color matched to the color of your roof. Screw fasteners are preferred over nails for superior pullout resistance and weathertightness. Screw fasteners are designed to go into the flat part of the panel. Nails MUST GO in the high rib of the panel. Fasteners are typically spaced 24" o/c.

Question:  Can I add insulation under the metal panels?

Answer:  Yes. Among the types of insulation that can be used are fan-fold foam insulation or foil-faced plastic bubble insulation. You can save utility costs by making your roof more energy efficient.

Question:  Is metal roofing noisy when it rains?

Answer:  No more noisier than the soothing patter that you hear now. The metal roof panels are installed over felt paper and plywood on the outside, with a layer of sound-deadening insulation and your drywall ceiling on the inside. These materials help deaden the sound.

Question:  How long will a metal roof last?

Answer:  This could very well by the last roof you will ever put on your home, barn, shed or hobby shop—with life expectancies that can easily exceed 30 years. Corrosion resistant substrates and long-life finishes ensure long-term performance, minimal maintenance and life-cycle cost savings.

Question:  Are any special tools required?

Answer:  Metal roofing and siding can be easily installed using standard hand tools such as a screw gun, hammer, metal snips, caulk gun, pliers, chalk line and tape measure. Cutting metal panels is best accomplished with an electric metal shear; however, panels may be easily cut with a circular saw with a metal-cutting abrasive blade.

Question:  What is the best material to use along the ocean?

Answer:  The salt spray from the ocean is very corrosive to most steel panels; therefore, the best solution would be to use a painted aluminum panel in these areas.

Question:  Do I need a rubber membrane underlayment under metal roofing panels?

Answer:  A rubber membrane underlayment is always a good idea as an additional barrier against water infiltration. You should always use one under a valley condition or any other detail that is likely to be difficult to seal. A rubber underlayment is also recommended at the eave and up to at least 24" past the exterior wall in a northern climate to help prevent water from entering the roof due to ice damming. It should also be used on very low slopes and when the metal panels are not sealed at their side laps.

Question:  Why does your installation manual show the metal wall panels held so high above the ground? Can't I run the panels all the way down to the ground?

Answer:  We show the panels held up above the ground level to make sure the bottom of the panels are not in constant contact with moisture, which would accelerate corrosion. To avoid contact with moisture, the panels should not be in constant contact with the ground or vegetation.

Question:  Will a metal roof make my house or building more susceptible to a lightning strike?

Answer:  No. A metal roof will not make a building more susceptible to a lightning strike. Lightning will tend to strike the highest object in a given area, regardless of what that object is made of. A metal roof can actually be beneficial in the event of a lightning strike due to being a non-combustible material.

Question:  Can I use a lead pencil to mark on my metal panels?

Answer:  No. Standard lead pencils, or those made with graphite, will accelerate the corrosion of the metal near the mark. You can use masking tape and mark on the tape to prevent corrosion -- plus, masking tape is easier to see.