I’m building a house and looking at cost-cutting measures. One such measure would be to opt for putting part/most of the foundation on a slab vs. over a full basement. (This is in NY’s Hudson Valley, on a level lot, btw.)
Now, I know the arguments for a full basement–esp. that it’s cheap square footage. But the dang things add literally thousands of dollars to construction, and could mean the difference between me having, say, radiant floor heat (which I really want), or a basement (which I don’t want that much). Plus, the damn things ALWAYS leak. My sister’s 100-y.o. basement leaks, my parents’ 40-y.o. basement leaks, and my brother’s 3-month-old basement leaks.
But … all I ever hear about slabs is that they’re terrible. They’re damp, they crack, they make it impossible to get to stuff underneath (plumbing) in case there’s a problem… but this is all re: slabs made 40+ years ago, without modern moisture barrier recommendations, etc.
Does anyone here have a newly built house on a slab? Pros and cons? Am I just asking for trouble if I don’t sink the money into a full basement?
Why do you have to have a slab? Can you not pour footings, and then block up a foundation from that? That way, you still have access under the house for plumbing/electrical/burying bodies etc. We don’t hardly even have basements here in the south, and that’s the way I’ve seen 'em all done down here.
For what it’s worth, I’d spring for the basement. I used to manage an exterminating company, and getting rid of termites in a slab house is a way big pain in the ass. Reinfestations are also common in slab houses, as the moisture and hidden cracks that develop in the foundations make a happy ground for the little bastards. Also, I think its better to have a basement just so you can see and deal with plumbing problems, etc., (like you mentioned). Another advantage is the bonus storage space.
Mrs. Consigliori and I own a house with a basement. It leaks from time to time if we have a big rain, but it never floods. The water drains away very well, and we don’t have a problem with excessive moisture in the subflooring.
FYI, another commonly used term for “slab-on-grade” is “floating slab”. Would you want your house floating on anything? Differential settlement of the slab can, and will, cause cracking and possibly other structural problems over the long term. Depending on your location, freeze-thaw cycles can also greatly contribute to cracking. I work with a number of engineers who design floating slab garages and patios all the time but wince even at the thought of using one for a house.
If you don’t want a basement, you might consider putting the house up on caissons, although there might not be that much cost savings this way.
slab-on-grade houses are the norm for new housing construction where I live (north of LA, no freeze-thaw cycles). I imagine that at least one thing in favor of a house floating on the ground is that it will help the house stay upright in the event that the earth it’s floating on starts jumping around (where a basement could cave in).
If anyone pours a basement it should have a weeping tile and a sump pump. It shouldn’t ever leak unless the ground is saturated and you’ve got a nasty crack.
Our 22 year old house’s basement only leaked when the window wells were allowed to get full of debris and we had major spill over. We fixed that problem and haven’t had a lick of trouble since. Secret is, a good setup dry well under the basement, and a sump pump that pumps the water away from the house. I don’t know how many houses I’ve seen where the sump pump outlet is the wall of the house.
*Ours pumps out to a small pond in the back yard and to the road. The pump itself is a turbine, and is major overkill, but that is my fathers way of doing things.
Never cut cost on structural elements of a house. Cut cost on fixtures and other insignificant things that can be changed. Get 2X6 exterior walls with as much insulation as you can. These kinds of things pay for them selves in terms of livability and longevity. Leave the drywall out if you have to until you can afford to put it up.
Actually, I have seen several shows that put radiant floor heat in bathrooms, etc on houses with a basement. Yea, it’s nice, but it’s not really economical for heating a whole house either, especially if you ever want carpet. If you have a basement, that’s something you can always add later.
As stated in other posts, a properly constructed basement will not leak. You could get a dry basement in a swamp if you really wanted to.
They still have those problems with slabs, especially if you skimp on them. If you’re trying to save a buck and go with the minimums, chances are you’ll still have these problems with a new slab.
You’re asking for everything to be more difficult. You can’t run plumbing to a new fixture as easy. All the electrical and phone, etc needs to be routed through the attic. Much more difficult than running it through a basement. If I have a leak in my plumbing, I have to pay for someone to jackhammer through my slab to get to it, or dig under it. That’s thousands compared to about $20 worth of parts and I can fix it myself with a basement. I can add just about anything I want to any room (outlets, cable, etc) without crawling in my attic. With a basement, you have a built in wiring closet. You also have a lot of storage. I’m moving from Texas to PA next summer and you can be sure I will not buy a house unless it has a near full basement.
If you decide on the slab foundation make sure that you get a “post tension” foundation. Here in central Texas we have very expansive clay “gumbo” soil which expands when wet and contracts when dry. In some areas this can result in the soil rising and falling as much as a foot. A post tension foundation is made with steel cables running through it which are placed under thousands of pounds of tension which compresses the slab and makes it much more rigid than a simple poured slab. So even though sidewalks and driveways may end of going every which way, the foundation itself stays intact.
I am buying a house in columbia county NY right across the river from you. It is a modular design on a slab - 5 years old. The house is elevated on posts over the slab about 3-4 ft so there is plenty of room to run wires, venting and plumbing - but you have to crawl through it.
The concrete posts connect to a metal frame of the house that connects to the wooden structure. The home inspector said this design would be very difficult for insects to get in. We are not sure weather it’s a floating slab or one with posts.
Since this is a vacation house I am not too concerned with storage space. The walls are 2x6 and the house is very well insulated. If it were my only house I think I would look for one with a basement because of the storage issue and to make it easier to run wires and such.
I’m an architect in Illinois, with absolutely nothing to add. Well, maybe a little.
What everyone else has said is exactly right. A properly sealed basement will not leak, and a sump pump becomes an accessory, not a necessity. Companies like WR Grace, 3M and Sarnafil make below grade waterproofing products that work well. At the very least, you should consider a crawl space, which would minimize your excavation costs but come with all the advantages Dilbert mentioned.
Are you building the house yourself, or have you hired a contractor to build it for you? Do you have an architect involved? The reason I ask is, it might be worth your while to get an architect to specify a waterproofing system for you. Typical “waterproofing” measures (mopping with tar, sticking rigid insulation on) don’t work in the long term, as you have noted. Proper waterproofing involves a membrane, a perforated draintile, and granular backfill.
I’m not trying to blow your budget or drum up business, but this is an area that cutting corners will cause you some major grief in the not to distant future. Paying someone a few hundred bucks now will save you thousands in the future.
Wow something I know about. I make my living handling construction defect claims. I have lots involving foundations. Basements and slabs both settle, crack and contribute to water problems. There is no performance difference between properly constructed foundations. It’s just that certain building techniques and styles are better suited to different areas of the country.
In the frozen north basements are more prevalent because it drops the load bearing portions of the foundation below the frost line. It is highly unlikely that you could build a true floating slab in NY State. Building departments will require footers of some type to bring the load bearing elements below the freeze thaw level. If you have to pour 24"-36" deep footers anyway, the cost savings may not be that great.
The two key contributors to basement leaks are:
*A lack of gutters. Every house every where should have gutters that discharge more than 10’ from the house
*Poor grading. The final grading of every lot should channel surface water away from the home by sloping gently away from the foundation.
Personally I’d vote for the basement. It sounds like this might be your best bet. You described the lot as not being level. This means that if you are going to construct a slab foundation, you will need to create a building pad that elevates the foundation above the path of ground water, which will run down the hill when it rains. Compaction of this pad and the soil under it are of paramount importance.
A crawl space type of construction would also be more favorable. However, the crawl space will act as a collection area for the surface and ground water. You will need to make sure that best practices by the general contractor to remove water from the crawlspace. I’d suggest a number of linked sump pits and pumps.
I’m sure someone has already told you this, but if your trying to save money do as much of the finish work as you can. Paint, wall paper, tile even lay carpeting in order to cut this out of the construction costs and to prevent the General contractor from charging the usual 20% of over head and profit.
Already planning to do that–all the tiling, all the painting, most of the trim, the cabinetry, and maybe even some of the drywall (mainly b/c we prob. won’t finish the spare bedroom yet). The floors are going to be polished concrete, so no carpeting costs there.
Thanks for all the advice folks. Looks like I’ll have to dig down deep, as it were.
etc. We don’t hardly even have basements here in the south, and that’s the way I’ve seen 'em all done down here.