General price per square foot of home additions?

It’s years off, but I’m wondering if there’s a rule of thumb/avg price per square foot of home additions.

It’d be cinderblock exterior, fully wired, sloped roof(shingle), drywall finished inside, poured concrete floor, central florida.
2 rooms, about 15x15 each, and one small bathroom.

Here in the metro Jackson, Miss. area you’d better be prepared to pay $75 per sq foot and up. A friend of mine (insisting upon the “best”) paid close to $100.

Hubby and I are remodeling his house, and doing most of the work ourselves. We might get out for about $25 per sq. foot. That’s with a lot of elbow grease, mind you.

Since you are pouring a concrete floor, you might consider stained concrete. We found the cost to be very competitive - we did that ourselves for about 70 cents a square foot. We’re also looking at a “loose lay” vinyl floor (no glue required) that runs about a dollar (for the living/dining area).

If you’re so inclined, and have the time and patience, doing your own drywall can cost you less for one reason - a lot of guys putting it up get real sloppy with the mudding-in. Then it takes them more times to go back and sand/re-mud. With extra care you can get away with going back twice - instead of paying them to go back four times.

Also you can do your own painting. We’ve used Wal-Mart paint at $8 a gallon, and to me it looks just as good as that expensive $25 a gallon kind.

I’d say $75 sq foot is on the low end. For adding on square footage to the house, you’re going to pay as much as you’d pay for building a new house of the same square footage. So if a house of your style and 1500 sq ft would sell for, say, $150,000 plus lot, then that’s a price of $100/sq ft.

A big variable will be the quality of the finishing. Custom houses with some upscale finishes (3" baseboards, rounded corners on drywall, an arch here or there, higher quality lighting) can easily go for $120-$200 sq ft.

We are developing our basement right now, which is a lot cheaper than adding new space. The quotes we got ranged from $45 - $75 per square foot.

Your best bet is to call some local contractors. If you get guys who will do the whole thing themselves, you’ll get the most accurate picture - they have the sq. ft. prices worked out as a science.

Barring that, you can always try to find a bookstore that carries the Means books which are the standard in the construction industry. They’re relatively obnoxious to use though: take the measurements of each individual item, multiply by city factors and add them up.

If you’re planning to have a contractor do it, just get the bids, they should be provided for free and they’ll be able to tell you if there are any costs you’re not counting on (tree removal, gradings/compaction etc.) that could make a huge difference.

This is almost worthy of a new thread, but I thought I’d hijack this one.

In my area (and I assume the whole USA), basements aren’t counted towards livable space. I imagine this is code or a law, and I’ve heard one possible reason, which I’ll get to below.

Our newly acquired ranch style home has a completely finished basement. There’s even a complete bathroom, a bedroom, running water, and is the size of the rest of the house. But the house is “only” xxx feet, with 1.5 baths and 3 bedrooms, ‘cos nothing downstairs “counts” – yeah, I knew this and didn’t care; it’s a nice friggin’ basement and it’ll be nice to host parties rather than crash them all the time.

So, what I’ve been told but haven’t investigated yet is that it’s a fire-code issue. There’s typically only one entrance to a basement here, and if it’s blocked by fire, you’re going to have an aweful death.

So… if I were to spend a smallish sum to install a new stairway in one of the spare bedrooms (opposite end of house where existing stairwell is) – or even add an outside entrance (expensive, but maybe worth it), have I suddenly built up thousands of dollars in equity because I now have another bedroom, double the square footage, and another complete bathroom? That is, do these become “legally recognized” parts of the house, rather than just a finished basement? It’s not a walkout, if that would make a difference.

According to the real estate agents here, it still won’t count unless it’s a full walk-out basement. Best way to make your home worth more is to turn that .5 bath into a full bath.

And just to add to the general discussion, when a drunk driver decided visit one of our bedrooms at 3:30 a.m., the cost of rebuilding the 5’ x 9’ section that he took out (no foundation or roof damage) was $11,000. Granted, building is a lot cheaper than re-building, but labor costs can get real big, real fast.

Generally, living space that is below grade is not counted in formal square footage specifications. Walk-outs, I’m not sure about, but I’ll bet it differs in different jurisdictions. We have a full walk-out which is being developed to the same spec as the rest of the house. We even have in-floor radiant heat and 9 foot ceilings - it’ll actually be nicer than the upstairs. But it still doesn’t count as square footage in MLS listings. People can and do add it all together as ‘living space’. So you’ll see ads like this: “2600 square foot 2-story home with developed basement giving almost 4,000 square feet of living space.”

My guess is that the reason we don’t count basements is so that people can compare apples to apples. When I see an ad for a 2,500 square foot 2-story home, I can picture its size pretty well, and know what type of house I’ll be looking at. If that 2,500 square feet turns out to be 1,500 plus a developed basement, it puts that house in a wholly different class of housing. So for a searchable database like an MLS system, you want to maintain consistency.

Nonetheless, developing a basement (if it’s done right) adds significant value to a house. Usually not as much as it cost to develop, but often close. In our case, with a walkout basement with floor to ceiling windows across the entire back, developing the basement should raise the value of the house almost enough to pay back the development.