We live in masachusetts and are planning on building an new house. Our green architect strongly favors a concrete slab and being from the northeast where every house has a full basement we are a little uneasy. Anyone have any opinions on slabs in the northeast?

There are several factors to consider. First and foremost is the lay of the land. The only place I would normally recommend a slab would be on a lot that was flat level. If your lot has any slope at all, then look at an elevated floor system, either a crawl space or basement. If all the homes near you have basements, then go for the basement, unless your lot has specific issues that would rule out the basement.
Your architect should be designing a home that fits into the area where it is being built. The type of foundation should be site specific and geography specific. If the site calls for a basement and you build a slab, the costs will be basically the same, and you lose the advantages of having the basement. Geographically speaking, if all the other homes in your neighborhood have basements and yours is on a slab, you could take a huge hit on the appraisal.
BTW, I personally don't think that slab on grade is necessarily a 'green' thing.

Wes,

Very good advice.  I do not think that building green rules out basements.  In many cases, basements can save energy provided the walls are insulated.

I don't believe that slab on grade with FPSF is nearly as expensive as a full insulated basement. I'd ask an appraiser about the effect of a basement vs more utility space above grade.

jonr,
I have no doubt that, given a flat site, the slab on grade with FPSF would be a wiser choice. However, if you have to spend multiple thousands of dollars backfilling and preparing your site, would that money not be more wisely spent on a basement that can take advantage of the unlevel natural site?

Sure, if you have to remove a lot of soil anyway, might be best to have some underground or partially underground space.

Wow. Thank you very much for the input. I guess I should give a little more information. First off we are at the very beginning stages. We have the land which is outside of worcester mass and it was given to us by family so we really have no plans to ever sell. The lot is fairly flat so it appears that there should be little in terms of backfilling. All the houses in the area as far as we know have basements, as just about all houses in new england. Our architect, who we spent the day with and visited the site, but we have not signed on with as of yet, examined the site and said it was fairly flat and a slab would work. However, he does not like basements that do not open up and have lots of natural light as he believes they are often damp, dark and wasted space. He thinks the money should be spent upstairs adding more space for storage. He mentioned that the hot water heater and furnace would fit in a small 5X8 room, so a basement is of no use. The slab would then be ideal for the thermal mass. However if we did do a full basement he would incorporate the thermal mass in the flooring by pouring a layer of concrete anyway and we would place our wood floor or tile over it. He believes its more cost effective to have a slab vs full basement. We have reservations about this, partly because we can not imagine not having a basement in new england, however do not want to spend money on something that is nothing more than a storage space. We will have an attached garage with storage above and soon after the house is built another smaller garage with an attic to store stuff.

Your further explaination does help clear up your situation.
Your architect and I agree on the basement issue. With level ground, a basement would not be as attractive, as one on a slope, so it could be daylighted. I personnally like basements, when they can be opened up and used for something other than storage. But I am not a fan of fully inground basements, as they too often become a negative space, rather than a positive use space.
If you are just at the beginning of the design process, take a closer look at your architect's ideas, and consult with others, real estate agents and appraisers, etc., before making a final decisison.
Breaking away from the 'tried and true' is a hard thing to do, in life as well as in construction.

A basement designed and built correctly does not have to be "damp, dark and wasted space".  If I were building on a flat lot in the South where basements are not that popular, then I would skip the basement.  But if I were building the same house in New England where almost everyone has a basement, then I would have a basement.  The rooms in the basement can be used for a lot of things besides storage.  The design really makes the difference in how the rooms can be used. 

How deep does a regular foundation have to be in your climate?  I doubt that the depth would exceed 7'.  One way to allow more light into the basement is to allow some space all around the house for windows between the top of the ground and the main floor.  In other words, do not dig the hole too deep.  Just deep enough so the footer will not heave.  

Avoid using concrete block for the basement walls.  Too porous and limited in strength.  I have seen too many block walls have trouble with leaking and/or leaning in.

If you do decide to have a slab instead of a basement, then consider using an elevated slab above the ground.  The top of the floor slab should be at least 12" above the existing ground so that proper drainage can be obtained around the house.  Too many times I have seen builders remove the top soil and then build in a saucer.  A saucer may work well for coffee but not well for a house.

With your climate in mind, I would encourage you to superinsulate your home.

The slab vs basement question is not an easy one and depends on expected usage patterns.

If you do have a basement, IMHO it should be within the thermal envelope of the house, and have insulated walls and slab ( although there is admittedly some debate about the usefulness of basement underslab insulation).
A properly constructed basement can be a warm, well insulated dry place and can be used for far more then storage. If the space is used wisely it is worthwhile. If the alternative to a basement is a second structure that will perform the same function as a basement ie storage and workshop space, It is probably less costly to add a basement then a same sized garage.
IF the basement is poorly built and sole purpose is to store crap that you don’t need anyway, it is a bad investment.

Cheers,
Eric

You say that lot is "fairly flat". I'm not sure what that means. If you have enough slope to get an exposed basement or could even do large window wells to accomodate larger "normal" sized windows, it might be something to consider. I don't buy into the "dark, damp spaces" argument. I know many people with finished basements that are warm, dry, and comfortable - regardless of whether they have daylight windows.

The thing that holds the most appeal for me with a basement is that you have options for expanding your living space relatively cheaply. In our area, a typical cost to build a new house is around $100/sq ft (very round numbers, not including the land that you're building on). A basement finish can average $25-$30/ft. Finishing 1000 sq ft may cost you $25,000 but that's going to be a lot cheaper than adding an addition, or buying/building a bigger house.

But that's assuming you already have the basement. Add the cost of getting the basement in the first place and then compare to the *incremental* cost of getting more space by adding an aboveground floor (ie, less than $100/sq ft). You can also leave above ground space unfinished.

Thank you everyone for your information I appreciate it.

Add egress windows and this space can be living space not just storage. It will be the most energy efficient part of your build, regardless of construction method used above ground.

Posted By jonr on 19 Jul 2010 08:11 PM
But that's assuming you already have the basement. Add the cost of getting the basement in the first place and then compare to the *incremental* cost of getting more space by adding an aboveground floor (ie, less than $100/sq ft). You can also leave above ground space unfinished.

I can only speak for my own experience, but when we built, our excavation/concrete bill was around $20,000 (for a 2000 sq ft ranch).   That included the footings, foundation walls, flatwork for the basement, garage, and driveway.  If you build on a slab, you still need footings, the slab, garage floor, and driveway.  The total bill was $20,000 and the only difference I can see between building on slab and having a basement is the basement walls.  I can't imagine that portion could have been more than $5000 or so.  For that amount of money it seems like a no-brainer to at least have the option of storage & potential to finish space down the road.

But you can build those same basement walls above ground and save the digging - especially with a FPSF. The saved digging cost (plus footing drains, waterproofing and backfill) can offset much of the cost of siding (desirable above ground, not needed below ground). If you ever do finish it, it will add far more value if it is above ground. Maybe it helps to call it a fully exposed basement.

I think the first question you need to answer is what you would use a basement for. If you have a good use for one, then go for it, otherwise it is much less expensive to use a frost protected shallow foundation (FPSF) which does not need footings etc only a thickened perimeter depending on climate.

I am in the process of building a house on an FPSF in the Fingerlakes of NY (very similar to your Woostah climate), but I had specific reasons for wanting one vs a basement. One of the reasons is not wanting to have to use electric to run a sump pump to keep the basement dry. Instead my ground floor is my at level basement, stick built and all set up to be finished (plumbed and wired) if we ever decide we need it as living space.

-Rosalinda

considering you live in/near worcester and are going to have to dig 5 feet + for your footings (frost level is >42"), why not dig a bit more, go for a full basement foundation? i'm sure you're not planning on selling, but what about future generations? not having a basement WILL hurt resale. even if it's just a spot to store your crap.

if you do go for a slab, take a look at an alaska slab. we just built a garage in the adirondacks in ny utilizing an alaska slab. it's a very cool way to do a monolithic pour.

Isn't an Alaskan slab the same as an FPSF? In Worchester MA you look as if you are about the same as where I am, under 1500 air freezing index days - so you need a 12 inch perimeter footing with 2 ft of vertical R4.5 min foam vertical around the perimeter, and no horizontal foam.

NYS code is right out of the FPSF guide, so I imagine MA is the same
www.toolbase.org/PDF/DesignGuides/revisedFPSFguide.pdf

-Rosalinda

You should look at the insulated slabs they use for passives homes in Europe. Here are some links. http://www.plasticsportal.net/wa/plasticsEU~en_GB/portal/show/common/plasticsportal_news/2005/05_532 http://www.isoquick.de/ http://www.100khouse.com/2009/06/11/passive-project-foundation-slab-insulation/