Expert: Nazim Nice - 5/14/2009

Question
QUESTION: Hi Nazim,
I've designed a 1350sf single story home to be built in southern NJ. I would
like it built in poured concrete, steel beams, industrial designed windows. It
could possibly have a partial berm on one or 2 sides. A large cost savings
would be in its rawness. House will maintain the natural aesthetic of the
materials, ie the rusted steel, marked concrete, plywood, exposed
utilities/electrical, plumbing, no drywall. Clerestory windows. Totally solar
and as green as possible. Wood or bamboo floor, some concrete. Questions:
Approx what might I expect to pay for this type of structure per sf? How
would it be insulated if to retain and appreciate the rough exterior and
interior concrete? Should I find an architect before I purchase the property?
Thanks.

ANSWER: Hi Nancy,

I applaud you for wanting to design & build something different than the typical home!

For costs, you should probably start discussing your vision with several contractors in your area, and then asking them what they think it will cost.  My guess would be in the range of $150-$250/sf.  That's a broad range, but you may find that your 'unconventional' approach costs more simply because contractors may not be familiar with this type of design.  Also, sometimes this 'exposed' construction costs more because all the exposed items need to look better than if they were hidden behind a wall. So again, I would start looking for a contractor sooner rather than later.  And interview several and find one that you feel you can work with.  Then as the architect you hire is designing the project, the contractor can be involved, suggest ways to reduce costs or add other input to the design, and estimate the construction cost of the project.

Insulating concrete if you want it exposed on the inside and outside is tough.  There are ways, especially in tilt-up concrete to sandwich insulation between two layers of concrete.  The general concept of tilt up construction is to pour the concrete wall flat on the ground.  Then install a layer of insulation, and pour another layer of concrete. Then when it's all set, the wall is tilted up vertically into place.  I'm simplifying things here, and you'd want to work with a structural engineer and experienced contractor, but this is the general idea of how to get an insulated concrete wall without the insulation showing.  If you berm the house, part of the concrete wall could be insulated below the earth so the insulation wouldn't show.  Other than that, in Seattle we have a way to meet energy code by leaving those walls uninsulated, but adding additional insulation elsewhere, so the net result is a house that is equally as energy efficient as the 'generic' standard requirements.  You may find N.J. has a similar code, but I would caution that you may end up with an uncomfortable house.  Uninsulated concrete will be like a cold radiator in a N.J. winter!  

Regarding when to hire an architect. I would suggest as soon as possible. Having an architect while looking for the land is a good idea because he/she can help you evaluate the site for things you may not think of, and things that are specific to your area.  For example, they should have knowledge of local zoning codes and setbacks which may take you a long time to figure out on your own.  Each site will need to be evaluated for ability to connect to utilities: sewer, well, septic, power, gas, phone, cable, internet etc. You may also look for an architect with some small commercial as well as residential experience. It sounds like your house may be a little bit of both types of construction.

So I would find a good architect, look for a site, and start looking for contractors.  Your architect will likely know some good contractors.

We have an article on our website on how to choose an architect that may help:
http://www.motion-space.com/seattle-architects.htm

Hope this helps.  Good luck with your project!

Nazim Nice
Principal / Architect
http://www.motion-space.com
--
Looking to remodel a basement: http://www.motion-space.com/seattle-basement-remodel.htm

Looking to add a second story: http://www.motion-space.com/seattle-second-story-additions.htm

See more of our work: http://www.motion-space.com/seattle-architects-projects.htm

Green Design Resources: http://www.motion-space.com/seattle-architects-green-design.htm

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---------- FOLLOW-UP ----------

QUESTION: Would it make more sense to use insulated concrete block rather than poured
concrete for what I described?

ANSWER: Hi Nancy,

It may be easier to construct.

Here are some options:
http://www.durisolbuild.com/default.html

I have used Durisol blocks before and they are a very sustainable product.  You can get optional inserts with insulation. The blocks are made of wood products.  They are stacked and filled with concrete.  You still have to put an interior and exterior finish on though, so you won't get your raw concrete look.

Here are some other options that include block and poured concrete options:
http://www.cement.org/homes/ch_buildsys.asp
http://www.thermomass.com/construction/pouredinplace.htm

It looks like there are new methods to include insulation in a poured wall.  This may be the way to go, or an insulated concrete block, so you get your raw aesthetic and don't have to put an interior or exterior finish on.

Nazim Nice
Principal / Architect
http://www.motion-space.com
--
Looking to remodel a basement: http://www.motion-space.com/seattle-basement-remodel.htm

Looking to add a second story: http://www.motion-space.com/seattle-second-story-additions.htm

See more of our work: http://www.motion-space.com/seattle-architects-projects.htm

Green Design Resources: http://www.motion-space.com/seattle-architects-green-design.htm

See our newest product: http:/store.lumenid.com





---------- FOLLOW-UP ----------

QUESTION: Thanks again, Nazim.
If I outsulate the house and adjoin a berm rising about 3/4 to the top do you
think that would provide adequate insulation? Would a heated floor throughout
the house provide sufficient heat to offset the insulation issue? Would both
solutions be practical? Thanks.

Answer
Hi Nancy,

My guess would be 'no' it wouldn't provide enough insulation.  The part of the concrete exposed would likely transfer the cold down much of the wall on the inside, so you would have a lot of thermal bridging. It may result in an uncomfortable space.

If you haven't already, be sure you or your architect looks at what is permitted by the energy code in your area. What you are discussing may not even be permitted.  

A heated floor is probably a good idea if you want the minimal look, but won't you still need A/C in N.J?  A/C is most often accomplished by an air based system. If you install heated floors (which would be wonderful if they are concrete), then you'll likely have to put in a separate system for the A/C.  If the house is small, you might be able to get away with some smaller zoned A/C units that are not whole house, but would serve the main rooms with units that hang on the wall and a small heat pump outside. As far as the heated floors offsetting heat loss, the spacing of the water tubing in the slab can be decreased so that more heat is output in areas where there is more heat loss.  

Nazim Nice
Principal / Architect
http://www.motion-space.com
--
Looking to remodel a basement: http://www.motion-space.com/seattle-basement-remodel.htm

Looking to add a second story: http://www.motion-space.com/seattle-second-story-additions.htm

See more of our work: http://www.motion-space.com/seattle-architects-projects.htm

Green Design Resources: http://www.motion-space.com/seattle-architects-green-design.htm

See our newest product: http:/store.lumenid.com