gallonsquare feet. Other websites say a gallon will cover 400-450 square feet of smooth surface. If you've got a rough textured surface or surfaces which need 2 coats of paint, a gallon will cover about 200 square feet. The above answer may be a general rule of thumb.
Highly rated roofing contractors tell us that asphalt is the most affordable roofing option, followed by wood, tile, metal, and slate. Materials for a metal roof can cost up to $350 to $1,500 per 100 square feet. Angie's List members recently reported paying an average of $12,236 for a metal roof installation.
Metal Roof Cost. Typical costs: Installing interlocking steel shingles starts around $3-$7.50 a square foot (for labor and materials), or about $5,100-$16,500 for professional installation on a one-story ranch-style house with a gently sloping roof of 1,700-2,100 square feet.