Expert: Richard Taylor, AIA - 7/14/2003

Question
Hello:

We are in the very early stages of buying a piece of property and having a home built for us. We are intrigued by many of the principles discussed in the well known book “The Not So Big House” written by Sarah Susanka. In trying to come up with initial design/layout/function ideas a number of basic questions regarding cost have arisen. I will not ask “How much does it cost to build a house” but can you enlighten us as to a few relative costs:

1) How does the addition of a basement(unfinished), crawl space, or slab on grade impact the per square foot cost of a house. I know which one is more practical, all other things being equal, but which is most expensive and by how much. I recognize that the choice impacts many other aspects of the design etc. but if we ignore those for the moment. Let us assume a single-storey 2000 square foot home on a level, non-rocky plot of land. We live in Southern Ontario, Canada and require footings at a minimum depth of four feet.

2) How does the decision to build a bungalow impact the construction cost (not land costs), i.e., how much more does a 2000 sq. ft. bungalow cost compared to a 2000 sq. ft. two-storey home cost, or vice-versa. A bungalow has more roofing members etc. but a two-storey has in increase in the load bearing members etc.

Any and all input you can provide would be greatly appreciated.

Thank you

Matthew

Answer
Matthew:

Thanks for you question!

I appreciate the information up front - I get a lot of "how much does it cost..." questions without any qualifications!

Generally, a basement is more expensive than a crawl space, by somewhere around 20% or so depending upon the layout of the house and a few other minor factors.  But it is very cheap space and you can't come back later and add it on! With a footing depth of 4 feet required, you've almost dug the basement anyway.

A crawl space is not much more expensive than a slab, but then you introduce a host of other factors that will impact the cost and practicality, especially in your climate.  Heating and cooling, electrical, slab-edge insulation, etc. will kill any advantage of the slab.  Florida is a great place for slab construction. Ontario isn't.

Regarding the Bungalow, I think you're asking about the relative costs of single-story ("ranch") homes vs. two-story homes.  For the same square footage, the 2-story will be significanly less expensive.  I'd expect it to be a good 20% to 40% less.  For a 2000 sf house, the cost of any of the additional bearing members you mention would be negligible.

Unfortunately, it's difficult to quantify this sort of thing.  As a reader of Sarah Susanka, you know that good design must balance cost, quality, and quantity.  The layout of the house design will impact all three of these.  It's conceivable that when all factors are taken into account up front, some of what I've said above would be wrong.  The key is to thoroughly examine the entire problem and then begin creating solutions that address the whole problem without any assumptions about basement vs. crawl, ranch vs. 2-story.  That's the real essence of custom design.

If you assume you can only afford a 2-story home on a crawl, you'll limit the chances of discovering a unique solution and end up at the mercy of "square foot costing."

We're currently working on a small home on a sloped lot with a limited budget.  The owner can't afford the space she needs if we add second floor bedrooms, but neither can she afford a ranch plan.  The solution takes advantage of the slope and puts the extra bedrooms in the basement - which has a full "walk-out" and great views.  We're building the basement anyway, so it's very cheap space.  That also allowed her to have some areas of volume ceiling on the first floor, something not possible in a two-story plan.

Start with a detailed definition of the problem, not with a preconceived solution and you'll make a better house.

Hope this helps!

Richard Taylor, AIA
Richard Taylor Architects, LLC
www.rtaylorarchitects.com