Am in process of working with designer for this last house, I’m 74 single but in good shape! Located in western NC House will be 1400 sq ft single story 2 bed built with SIP’s and very energy concious as well as carbon neutral focussed. Question has come up as to which foundation approach to use. Lot is flat so minimal prep is needed. Designer is discouraging use of ICF’s for perimeter or foundation walls – says provide opportunity for termite tunneling. Does not want to route ducting, electric chases etc through slab. Budget will not allow radient heating (and I do want A/C). Budget is tight (as usual!)
So, what are the pro’s and con’s I’m facing with either approach? All I can think of is how foot friendly is concrete? How difficult/expensive is putting wood floor on top of concrete? I do know of some of the concerns about crawl spaces and preference to condition them etc. What else do I need to take into account for either approach? TIA
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either will require insulation to be efficient.
I spent a long time in Vegas, where nearly everything was slab on grade. Done right it works well enough. I'd recommend that if you are truly trying to be enrgy efficient, you should install, 4-inches of foam, over a high quality vapor barrier, over clean, free draining sand. Plumbing is typically installed in trenches below the slab with sand bedding. With PEX water lines, there is minimal potential for leakage. Wood floors are a little harder to install. Engineered wood, floating floors work pretty well though.
One thing to consider with the crawl space is that you won't be bale to get down there your self for too many more years to work on anything.
Look into using a SIP floor system if you do go with a crawl space. And, be sure to check the cost difference to add a full basement. I'm working on a building now, that if I had been given longer to review the plans during design would have a basement. The footings are at 9-foot below finish floor, so it wouldn't have cost much more to have done a full basement.
If you do a crawl, make sure it's high enough. I think code is 18" in most areas, but that's often ignored, and 2 feet is better -- more if you can swing it.
But pay attention to drainage. You don't want the crawl filling up with water because it was dug low to meet the clearance requirement.
One very important consideration at 74 (or even 54) is that a slab can be built near to the ground, with no steps to get into the house. As a result (and with some careful attention to things like wide bathroom doors and wide halls) you may be able to stay in the house longer than with a more conventional setup.
slab on grade vs crawlspace
My choice would be crawlspace. Height 4' clear, run all ductwork under the floor, including the furnace unit. Easy access for servicing plumbing lines, electrical lines, phone lines, cable, etc.
At 74 you probably got rid of all your "stuff" ; it still leaves you room for golfclubs (seldom used), electric train sets and all things you can exchange seasonally.
ICFs have a solid concrete connection to the footing, I cannot see termites tunnelling under the walls, concrete floor (3") seals it also. Of course you would use 10 -12" compacted gravel, 6mil poly, 3" rigid 2' inside perimeter. Insulate at least the inside of the crawlspace walls (if not using ICF), have one heatduct open in the wintertime.
Crawlspace will allow you to "play around" with flooring. I am thinking threshold free showers, clean-outs. etc.
I just have an aversity to hacking up concrete floors if I wanted to change/remodel something
Just for the fun I am tinkering around with a similar home that has no hallways
PS if you cannot go down with the crawlspace, maybe berm it. There have been some very spectacular designs made with this design. But it all depends on the surrounding land/developement
I'd guess that a crawl might be more expensive. Concrete may cost less If you do a monolithic pour and if your frost depth is shallow. It can also depend somewhat on your floor finish, too. The concrete is harder for walking on (my wife commented on our new house concrete floor).
Concrete slab means putting ducts in the ceiling, not much different than in the floor. You COULD do ducts under slab. You have flooring options w/ slab ... acide etched stain finish w/ any pattern/design you like, tile, carpet and wood. Personally I like the acid etch approach since it doesn't really use much more materials than the concrete itself. Wood seems a bit involved. Maybe do some comparisons of the cost.
Energy wise, not sure if there is much difference. Do I assume you have a big cooling load and moderate heating needs? If the heating load is moderate, you might insulate your perimeter and leave it out under the slab. With the crawl, I might tend to seal the crawl for heating and insulate the perimeter (however, I'm not really familiar w/ the climate there).
that's my 2 cents
I strongly recommend ducts in the floor, if you have forced air and live somewhere where heating is pretty important. We have ducts under our basement floor (well, it's a "split entry", so the lower level is only about 4 feet down), and even though we've had water problems from time to time I still very much like having the ducts at floor level along the outside wall. (With a ground-level slab and plastic (vs Transite) pipe for the ducts the water problems would be eliminated.)
There are various pads that can go under floor coverings to cushion the concrete, but I suspect that the "hardness" of concrete is more psychological than real.
Not much more to add, except:
Radiant heat tubing is not too costly to install into a slab. You don't have to use it right away, but it will be there.
If you are working with a designer, why do you feel you have to ask questions here? Maybe you don't have the right designer. Maybe you don't need one at all.
Slabs are awfully hard. My past two shops have been slabs on grade. Great work surfaces but hard to stand on for all day. Something to consider depending on what your standing/sitting ratio is in the house.
Your attitude at 74 is great. I'm about to nudge into 63 and am facing a major remodel. But it was not even ten years since the last one and I know my energy has diminished. In ten years I'm not sure I'd want to tackle another big job. I admire you.
But somehow people love tile in the kitchen.
I don't love tile in the kitchen. It is hard, unforgiving, and cold. Add to that trying to keep grout lines clean is a pain in the kiester. Tearing out the tile and replacing with vinyl is high on my list of improvements for this home.
go for the slab!
I just finished a slab-on-grade, SIPS home at the NC coast, and firmly believe that a slab is the only way to go. Definitely I put radiant floor heating in (solar panels too to warm the water, NC is generous offsetting the coast with tax credits), beautiful way to warm the toes and air near us humans. Plus crawlspaces are nasty/ skinny/ moldy/ gross places full of spiders. ICK! Use our state resource, Advanced Energy, in Raleigh to locate subcontractors, knowledge trained professionals and state of the art techniques. Good Luck! - Catherine
crocs!
that's what crocs are made for, little pillows on the feet. Concrete allows nice designs and colors (Kemiko stains), no allergens, easy clean-up, radiant floor heating; difficult to keep subcontractors thinking 'this IS the finished floor', we went through a lot of red rosin paper to protect it, but mainly that was just a visual reminder that this IS the finished floor. - Catherine
Basement
I'm pushing 70, and would always go basement unless you have a high water table (even though near zero percent of builders here on the left coast will do a basement)
Mom is 89, she still loves here basement, esp in summer when you can hang out there and not need to run the AC. (central IL) .
Slab-on-grade gets my vote, too.
Insulation can be 4" foam that is installed horizontally around the floor perimeter, extending only 4' inside, assuming you don't install radiant floor heat.
HVAC ducts and equipment should be inside the conditioned envelope, not in the attic. Trusses can be designed to create a path for ducts or you can furr down the hallways to hide them and use high sidewall registers in the rooms.
Proper hvac design and register selection will give good air throw and mixing that will eliminate worries about having floor registers for the heating season, and will be better in the cooling season.
Stained concrete floors are durable, attractive and cheap. So are area rugs.
No worries about crawlspace moisture, crawlspace vents or crawlspace critters or mold.
Keep plumbing centralized, if possible.
True, you can't have a wine cellar under the house, so just buy a free-standing climate-controlled one instead.
Live it up--you're only 74.
Gee, you don't expect much.... super insulated, 'green,' net zero- AND cheap AND simle. Let's back up and get back to building houses, rather than chanting buzzwords.
The idea that a slab can be laid with minimal digging is simple ignorance. You need to dig deep for the foorings, and you need drainaige under the slab. Slabs are also very intolerant of tree roots growing under them. Let's start again, from the beginning.
Termites? Site prep and treatment should be the first thing done. Properly done, the entire footprint ought to be protected.
Having a crawl space gives you an additional level in which to run your ducts, pipes, and wires. This sure helps with later repairs and alterations. Putting in the piers ought to be no harder than prepping for a slab. As an added plus, a crawl space allows for a COMPLETE termite inspection.
With termites an issue, I'd want all the wood (has to be wood since you're on a budget) treated -including cut ends- as it's built. Not just at ground level .... the critters can build 4-ft. tubes up to access wood, and some types fly.
Otherwise, minimise termite food. Hardiplank siding, sprayed foam insulation, paperless drywall. Termites burrowing through foam? Sure, they can do that ... but I shudder at all the homes in termite country with decorative brick (or stone) veneer faces. That space between the veneer and the walls is a perfect, and un-inspectable, highway for termites.
It's not just the hardness of a concrete floor that causes discomfort- it's the way it suck heat right out of your feet. By contrast, there's no reason a modern wood floor (TJI's and 1-1/8" subfloor plywood) can't be squeak-free.
If you want to save, keep things simple. Open design. Formica counters and vinyl flooring. A simple gable roof with passive venting. Smaller appliances. I weary of projects where inadequate wiring and plumbing are demanded, because all the money went for 'just the right' marble and appliances that cost more than my truck.