Q. ­ Posted by Pete:
An old drywaller gave me this formula for estimating the number of 4x12 sheets needed on a job: Take your floor square footage, multiply by 3.5, then divide that by 48. Anyone tried this? How accurate is it? Any other formulas?

A.Posted by Larry:

My rocker uses 3.7 per sq. ft., but buys a variety of sizes to minimize waste.

Posted by Alan:

If your man can hang at that ratio, he must be buying the rock himself. I use 4-4.5 per sq. ft., to get a quick and dirty budget number, but in my region (D.C. area), hangers are often piece-workers. I have seen crews doing a simple two-bedroom apartment have an immense pile of scrap left over (they very likely cut up whole sheets just to get paid for hanging them). But I’ve also seen crews hang a chopped up attic addition, with vaulted ceilings, and have no more scrap left over than you could haul out in a single trash can.

Posted by Mike:

The 4-4.5 formula works for me also, but I’m always thinking about how to use even larger sheets to be more efficient.