Question 1

How do you waterproof a metal roof?

Accepted Answer

The short version of how to waterproof metal roofing: clean the roof, tighten or replace loose and rusted fasteners, seal the seams and flashing with butyl tape or metal roof sealant, prime any rust, then apply two or three thin coats of a liquid waterproof coating over the whole surface.

Question 2

What is the best sealant for a metal roof?

Accepted Answer

Butyl tape and polyurethane or silicone-based metal roof sealants work best on seams, laps, and flashing because they stay flexible as the panels expand and contract. For full coverage, an elastomeric acrylic or silicone coating is the usual choice.

Question 3

Can you waterproof a metal roof with holes?

Accepted Answer

Yes, but the holes must be patched first. Small holes get sealant and seam tape, larger ones get a metal patch bedded in sealant, and rusted-through panels should be replaced. Coating over an open hole will not hold.

Question 4

How long does a metal roof coating last?

Accepted Answer

A quality coating system lasts about 10 to 20 years depending on the product and the prep work. Acrylic usually needs recoating around the 10 year mark, while silicone tends to last longer.

Question 5

How much does it cost to waterproof a metal roof?

Accepted Answer

Professional coating runs about $1.50 to $4.00 per square foot installed, with a full elastomeric restoration closer to $2.00 to $5.00. Rust, roof pitch, and access move the price the most.

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