Expert: Richard Taylor, AIA - 9/21/2008

Question
Hi Richard!
My wife found a property in a neighborhood she is particularly fond of but the house is trashed. Additionally, the additions that have been done over the years look like they were done with no thought to aesthetics or function. Our question is is it unreasonable to tear down the house and reuse the existing foundation? Does the cost of saving on the foundation outweigh the cost of having an architect redesign the house using the existing foundation? We like the idea of keeping as much material out of our local landfill as possible. Also, do you know the national average (or local in Salt Lake City) of cost per SQ FT to build? Any thoughts?

Answer
Hello Sean, thanks for your question!

"Unreasonable" is in the eye of the beholder, but what you're proposing is certainly worth considering.

It would take a cost analysis to determine whether you'd save money by demolishing everything but the foundation, but if it's in poor shape, it very likely might be feasible.

One of the first questions you need to explore it whether the foundation itself is worth keeping; is it structurally sound; is it waterproof (or can it be waterproofed); is it tall enough for the basement you want; will the size and shape of it permit the kind of house design you want above?

I've done two projects like this recently; both houses were demolished, including both foundations.  One was impossible to reuse because it was too small, the other was the right size but wasn't structurally sound (and was too short).

Unless the foundation is in very good shape and is otherwise suitable for the house you want to build on it, my "off the cuff" answer is that by the time you've demolished the rest of the house, it probably doesn't make sense to keep the foundation.

When you demo the house, keeping the building materials out of the landfill is a good idea, but you may be able to demo the house AND be environmentally sensitive.  Here's what I've done - call Habitat for Humanity and have them strip the interior; they'll usually take cabinets, appliances, plywood, doors, hardware, and anything else they can resell in their store (if they have one in your area).  St. Vincent de Paul societies will also sometimes take building materials off your hands.

Then call your local fire department and offer the shell of the house for a training burn.  We did this a few years ago in a small town and it was a big success.  The local FD gets little experience in house fires so they were grateful for the training opportunity.  When they finished, the amount of material going to the landfill was greatly reduced.

Plus, the owners got a nice tax break - the burn is considered a charitible donation.

Costs for homebuilding are wildly different across the country; are wildly different from one part of the state to another; and are wildly different for various types of house designs - there's no meaningful "average" cost to build.  In my area I've seen $120 psf and $300 psf.  In Arizona I've seen $1200 psf.

If you want to get in the right ballpark for cost, visit new home projects in your area and ask.  When you visit "spec" homes, be sure to subtract the cost of the lot.  Talk to builders and Architects in your area, maybe even call a few real estate agents.  That should get you enough information to know about what to expect.

Hope this helps,

Richard Taylor, AIA
www.rtastudio.com
www.rtaplans.com