I have been looking around here the last couple of days and I have been impressed with the knowledge here. I am looking at building my home on my property (40+ acres) in South Eastern, NC (Zone 3). Eventually, I am looking to be entirely off-grid but initially I am looking to make an efficient home economically, both short-term and long-term.

We are looking at a 400 sf bottom floor with an additional 200 sf loft. Everything will be square, with no crazy corners or anything extra. Just a simple, efficient home. I was initially planning on doing a pier and beam foundation and stick built, my father-in-law is a carpenter and we could build a house of this size pretty quickly so we would save money on labor costs, with a shed style roof to accommodate the loft.

So then I started looking at passive solar and needing thermal mass, etc. Then I found information about SIPs, ICF, etc. So my plan is in flux to meet my goals.

1) Best initial cost in connection with #2

2) Long term economical energy cost

3) As efficient as I can make it (heating will be a small stove, wood/gas/electric). Cooling in the summer will be one of the biggest factors, it doesn't get incredibly cold in the winter.

4) 600 sf total, 400 sf bottom floor with 200 sf loft. I want to stay small, but I am open to options for most economical way to build (larger bottom floor, smaller loft, etc. although I think having a smaller bottom floor saves money on foundation costs.)

Any guidance, information, thoughts, concerns, anyone has would be greatly appreciated.

There are hundreds or thousands of people across the country doing the same thing as you. There are lots of ideas and methods out there, - which you'll hear of soon - but it's relatively easy to build a home which would be comfortable and easy to heat & cool with one small mini split - which runs on electricity - so you can get to net zero & self reliance soon. I recommend getting one of Joe Lsiburek's building guide's (https://buildingscience.com/book-categories/builders-guides) which will help sort out confusion over vapor barriers and hundreds of other topics. His company has open archives of studies and papers on every part of building - good resource.

Thank you very much Bob. I have been doing a ton of reading and will continue to do so. I look forward to any assistance that anyone here provides.

There are a variety of ways to get where you want to go. No one construction method is best for all climates. We built ICF in upstate SC, and are blown away by the performance. I also considered SIP's and conventional stick, but for one old man, working alone, ICF was the easiest. Other things to consider are strength if your area is prone to high wind (hurricanes?), sound control, and insect damage. ICF makes for a very quiet house. As for termites, there is evidence that they will tunnel considerable distances (undetected) through foam. I think that ICF would be better protected than stick frame, though. Unless there is no wood at all in the home, termites can get in. I once bought an antique trumpet that had active dry wood termites in the wooden case!

Obviously, I'm sold on ICF, but it is more expensive. I did all of my own stacking and prep, and hired an experienced ICF contractor to fill the forms with concrete. In the total cost of a house, the shell isn't all that much of the cost. Plumbing, electric, HVAC, kitchens and baths are all expensive, and the more of this you can do, the more you will save.

Thank you very much jdebree. I guess ICF is one of the methods I am most unfamiliar with but that sounds very interesting. We are planning on keeping it very simple with regards to electrical, plumbing, HVAC, kitchens and baths... so that will probably work to our favor.

1) Electrical will be a few outlets and lighting in addition to our washer/dryer, refrigerator, and maybe a few other appliances.
2) Plumbing; I still have to discuss this with the permit people, but I am looking to do a composting toilet and a grey water retention system. The plumbing would be for a single bathroom sink/shower and washer in the bathroom and our sink in the kitchen.
3) HVAC will be something without ducts.
4) For kitchens and bath, one of each and as simple as we can make them.

General question, if we are looking at 600 sf total (20x30 interior, actual foundation to account for whatever wall thickness I will need); what are the cost comparisons of a single story vs single story with a loft among the various building methods? Looking at ICF, SIP or stick built; if we stay with the same design philosophy of simple & efficient which one would be more cost effective to build and heat/cool?

Our preference was to have everything on one floor, but then we are older (60's) and looking toward the day when one or both of us won't be able to manage stairs. In a southern climate, a loft will tend to be hot unless very well insulated, and even then, heat rises, so when the main floor is comfortable, the loft will be warm. I also don't know what you would use for HVAC in such a small space. Our house is about 1300 square feet inside, and a single 12K mini-split keeps the whole house comfortable year-round. We have a second 9K unit in the master bedroom, but only use it in the very coldest weather (single digits). A 600 sq ft well-insulated structure is going to be a very small HVAC load. Mini-splits shine in this case because they handle being 'oversized' better than most systems.

One more thing about ICF, especially in moderate climates is that it performs well above it's rated R-value during spring and fall. I guess it's the thermal mass. We've had a very mild fall, and have yet to turn our heat on this season. The coldest morning we've had this fall was 22 F., and it was 65 F. in the house. On Thanksgiving, we had 10 people in the house, and the temperature shot up 10 degrees inside because of all of the body heat plus running the oven. We had to open the windows! Our walk-out basement is also ICF, and the coldest it gets in the winter is 60 F., and the warmest it gets in the summer is 78 F. Minis are incredibly efficient. In the summer, A/C only adds about $20/month to the power bill. Last winter, we had three nights in single digits, but the heat only added about $40 to the power bill.

Thanks again, jdebree. I found some old threads of yours where you were struggling with the additional cost of ICF and different numbers that you were throwing around. Did you look back at your costs to see how they compared?

No, once I decided to go ICF, I never looked back. I've also never added up what the entire house cost. I should be able to; I kept good records, but I'm a little afraid to!

JBjunior, check out the "tiny house" thread over in the SIP forum that's going on right now. Maybe it's a little smaller of a house than you're thinking about, but the exciting part is the helical pile foundation. Talk about cost efficient!

Thanks Jelly, I checked it out and it is very interesting. It is a little smaller than what I am looking for but it would be interesting to know the cost.

Good Guidelines Giving Bob I and jdebree. Great!!!!!

Helical piles are a good option if you have unstable soil, but I believe that a frost protected shallow foundation beats it in cost efficiency - and it has a low soil loading (but more than pilings down to something solid).

Posted By JBjunior on 30 Dec 2015 04:38 PM
General question, if we are looking at 600 sf total (20x30 interior, actual foundation to account for whatever wall thickness I will need); what are the cost comparisons of a single story vs single story with a loft among the various building methods? Looking at ICF, SIP or stick built; if we stay with the same design philosophy of simple & efficient which one would be more cost effective to build and heat/cool?

In general single story is going to be more efficient and less expensive to build. Your loft is going to most likely require a cathedral type ceiling which can limit the available area that you have to place insulation. Not to mention making access to place that insulation a little more difficult. A loft/2nd story in ICF is probably going to require an additional pour day as you typically build those 1 floor at a time and build the floor diaphragm to support the poured wall before you go any higher

Jdebree makes a good point. How long you planning on living in this house? You going to still feel like doing stairs in 15-20 years? Are you even going to have that choice? Our original plans were similar to yours. the older we got and the more we thought about it, the more the plans morphed into a single level over a daylight basement. Garage is in the basement, but there is room to put one on the up hill side at the same level as the main floor at a later date...

Thanks for the additional information. I plan to have this house forever. In 15-20 years, I could still be using stairs in my late 40s early 50s. I think I have decided on a single story, for many reasons.

I have always partial to a Ranch-on-slab, especially since the radiant floor is built-in.

I have always partial to a Ranch-on-slab, especially since the radiant floor is built-in.

Yep, footing and floor in one pour with a good clean work surface to stack ICF(with one more pour to reach the roofline), or stand up SIP's or stick build the frame. Just don't skip on the sub-slab and perimeter insulation