Hi,

I plan to build a house around 1600-1800 sq ft in the not-so-distant future.  I've pretty much convinced myself to go with a cement/EPS ICF like Perform Wall for the walls and SIPS with standing seam galvalume for the roof.  This will be on a slab foundation in Texas.  I've read that traditionally building up is cheaper than building out, but that is probably based on using stick framing, cheap shingle roof, (maybe full basement), etc.  I'd like to get an idea of how different house styles compare using the materials above.

The house will be a pretty simple shape regardless of which style I end up choosing: fairly simple roof, no random bumpouts, etc.  I would like a fairly open first floor (read big spans), so that may have some bearing on the type/existance of a second.  I'd like a porch big enough to use as a living area either under the main roof, or under a shed roof off of the main structure, depending on the design of the whole thing.  Oh, and no garage (maybe a carport).  The options I've considered are:

1 story ranch:  Simple rectangular shape with low pitched gabled roof.

1.5 story cottage/bungalow:  Basic rectangle with a fairly high pitched gabled roof.  Bedroom in each gable end, and a bath and living area in the middle with a shed dormer on each side.  Everything else downstairs.

2 story:  Partial or full 2nd story.  Same rooms upstairs as 1.5 story.  Again, fairly simple roof.

Before I saw the light, I was thinking the 1.5 story with 2x6 framing was the way to go.  What I'm worried about is thinking something like that will be efficient, but in reality it ends up being more complicated and expensive than it's worth.  Can those of you with more knowledge than me shed some light on how these compare cost- and complexity-wise?  Any insight would be greatly appreciated.

Thanks,
    - Ian.

the simpler the house the less it will cost. no surprise there. if i have lot size i always opt for 1 story especially for only 1800 sq ft. at my age i dont like steps anymore and the wife wants every thing on one floor.
a 2/6 house will be the cheapest way to go and will work fine. you have to look at sips and icf as an upgrade and no they will not have a return on investment in a reasonable timeframe. it is somewhat like autos. i drive an avalanche. Cadillac makes a vehicle called an Escalade ext. they are both basiclly the same vehicle. the cadillac costs $24000 more. they will both do a basic job. is it worth it? i dont know but they sell a lot of them so somone feels it is worth it.

I know it will be more expensive than stick, and I'm fine with that.  I'm really curious about whether the building up vs. out holds for the building systems I want to use.  For example, suppose there is a 1 story house and 2 story house that both have a square foot print, same living space, same roof shape, etc.  Given that the 2 story will have less foundation and roof, but added floor and stairs, will one be significantly less expensive to build than the other, enough to justify going with that shape?  Or is it in the noise, and should we just design what we want?  We plan to live there for the forseable future, so if it is 2 story, the master bedroom will be downstairs.

    - Ian.

We have been doing basically the same research. This is not gospel, but what we have heard, read or learned:

• 2x6 (24 OC) seem much more affordable than ICF, especially with crews that have not built many ICFs (2x6 is using foam sheathing).
• Frame homes can be built much tighter now, if the attention is paid to energy efficient building approaches.
• Building up (only 2 stories) will save compared to building out based on foundation used, but it will probably not be significant.
• Slab over basement is a good cost saving especially in rocky terrain (Mountain West).
• Basic rectangles, no bump outs, basic gabel roof, common available materials, etc...

Good luck.

storm brings up some good value points, but every site needs to be looked at for it's own issues.

I have said in the past, if I didn't build with ICFs, I would build with 2x4 walls and one of the sprayed Ivynene type insulation products. Rather than use 2x6s to have more room for more of an inferior and often incorrectly installed product, why not buy a better insulation product? This type of construction would be more similar to a SIP system, but the intent is the same....stop infiltration and exfiltration. This should fall somewhere in between typical framed construction and ICFs. Just another value point a client can chose!

I'm not an expert, but I believe all things considered, a two story home is less expensive to heat/cool than the same sq footage of a single family home. 

Hi Ian:

The choice of whether you should go for one story or two storys will depend on a number of factors, the primary factors being your own preference in terms of convenience, style, your site conditions, your neighborhood, ... and so on.

Then the cost of building, and energy savings, ... should be secondary factors.