The point is, hot-dipped galvanized nails will do the job for 99% of the houses out there. I'd only specify stainless roofing nails if I lived at or close to the ocean. Hot-dipped galvanized nails can last well over 100 years in non-oceanic climates.he point is, hot-dipped galvanized nails will do the job for 99% of the houses out there. I'd only specify stainless roofing nails if I lived at or close to the ocean. Hot-dipped galvanized nails can last well over 100 years in non-oceanic climates.
Costs more to build out. As you said, there are all kinds of other factors, but the same square footage in two stories will cost less to build than in one. Most homes with traditional foundations can sustain a second floor addition without additional support.
1 Contractor costs for a more extensive project (such as 500 square feet of new floor space with two bedrooms and a bathroom) can run $50-$250 or more a square foot, or $25,000-$125,000, and costs can go as high as $300-$500 a square foot for complex and luxurious projects. If you're adding weight to your foundation, you may need a report from a structural engineer at a cost of $300-$800 or more, to see if your existing foundation needs to be reinforced or repaired. 2  You'll probably need a set of plans for your bedroom addition. 3  Your builder might be able to supply them.