Cost difference in above grade sq ft vs below grade?

kelhuckApril 17, 2012

Hi all! Looking for some real life experiences here. We're planning to build an energy efficient (ICF) 2 story farmhouse. It is 3600 sq ft above grade, and will have an unfinished basement. Now that our plans have been finalized, we're starting to rethink everything. (Doh!) We have a nice site for a walkout basement, so I think the best use of our space and $ is to basically chop the second story off and put it in the basement. Sq footage would be about the same. I'm wondering how much we would really be saving-if anything at all- by doing this. Does anyone have real life experiences or knowledge with regard to a similar situation? Please help me think thru this!


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I don't have too much to say about relative cost. It's a tradeoff between increase in concrete cost vs. framing if above ground. You have different exteriors, too. Above ground needs siding, below ground needs waterproofing and insulation.

On the subject of waterproofing, if you do go below ground for either a crawl space or full height walls for a basement, I strongly advocate waterproofing the buried walls, not just "dampproofing" them. Waterproofing can be a either a heavier (60 mil) spray applied goop or peel/stick membrane. Then, too, you need to have the footing drains and sub-slab drains done properly and daylighted downslope. There are plenty of sites, such as, with lots of good information of this stuff.

We've been in our new house coming on a year now. It, too, is two levels with walkout on the lower level. It is framed construction on poured concrete walls, not ICF, but most of my comments don't have anything to do with this. We are in NH and have cold winters, too. I specified 4" of foam insulation under the lower level slab, as well as 2" of foam on both inside and outside of the foundation walls. ICF has the walls covered by definition. The downstairs level of our house if full-height framing all the way across the front and halfway up the slope on one side, a pony wall for half the other side, and full-height concrete on the rest of the uphill perimeter. The back (uphill) 30% of the lower level is the utility/storage space.

We first tried to have the slab polished and acid stained. Perhaps the sub who tried it was incompetent, or as he claimed there was something about the surface that prevented him from getting a good result. He switched to an epoxy application to salvage something, but he didn't get that right, and the appearance was not good for finished floor surface. However, between the insulation and vapor barrier under the slab and the epoxy coating above it, that slab is rather tight to any moisture penetration. We wound up with commercial carpeting over the main living area downstairs and laminate flooring in the bedrooms (3) down there (two more BR upstairs). We like the result. I hope this helps.

    Bookmark   April 17, 2012 at 7:48PM
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If you were going to have a basement anyway, then wouldn't you be saving the entire cost of the 2nd floor?

When we built, it was roughly $40k for the basement including slab, walls and waterproofing. The walls were poured. Framing was $65k and brick + siding was $50k. Some of the framing was interior walls, some was the walkout wall and some was the roof - none of that would be saved. I suspect $40k is about right for the 2nd floor cost - so really no difference if you are comparing building a 2 story on a slab vs ranch with walkout basement.

Now - there are less windows in a basement. If you are doing vinyl, then above grade in my example is actually cheaper. But this was for 2x4 walls with batts, not ICF.

Lastly - if you are talking energy efficiency, you can't beat below grade. You also spend a lot of money on ICF that doesn't necessarily pay off in terms of energy efficiency.

    Bookmark   April 17, 2012 at 9:04PM
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Let me just apologize up front- I know what I'm trying to ask, but I can't always get the words I type to form what I'm thinking, if that makes any sense! :) IRL, I'm a much better listener!

@david- "If you were going to have a basement anyway, then wouldn't you be saving the entire cost of the 2nd floor?" That's exactly what it SEEMS to me, but I wanted to make sure I'm not missing something important/obvious. The worst thing I can think of is maybe a lower appraisal? And obviously, less storage space, but that doesn't bother me too much.

Let me clarify: Design A basement would be completely underground, except for a couple of egress windows, and unfinished (bedrooms on 2nd floor). Design B would be walk out on one side and would be about 80% finished (bedrooms located here).

So then I think, if I'm only going to save $xx, is it worth it? Having the bedrooms on the 2nd floor vs the basement means more: siding (Hardie), electric, HVAC runs (and tonnage), ICF block/cement, taxes/insurance(?). All are pretty good chunks of money, but is losing the wide open basement space worth it?

I'm just trying to decide if it's a significant savings. If so, I'll probably go back to the drawing board (literally) and pay for another set of plans. If it's not that big of a difference, I might just stick with what I have.

Would like to hear opinions from anyone who's had to make the same decision, or (like david_cary) knows the approx cost breakdowns.

@dickRNH- thanks for the reminder about the waterproofing- need to add that to my "ask potential builders" list. Glad to hear that you're enjoying the space in the basement. Sometimes I worry that it will be sub-par living space, but experiences like yours prove that it doesn't have to be!

    Bookmark   April 17, 2012 at 10:24PM
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I think you also need to consider the exterior "look" of the home when making your decision. We also built a new farmhouse. If you want a true traditional farmhouse appearance, this is much easier to achieve with a two story.

We ended up with a much larger house than originally planned because I wanted to maintain a traditional farmhouse look and still have the master on the main floor. This caused our footprint to increase in size and make the second floor larger than necessary.

In all the 3d modeling that we did, I could not find a way to have the traditional exterior that I wanted without having that second story. If a ranch or similar exterior is ok with you, this might not be an issue!

    Bookmark   April 17, 2012 at 10:36PM
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don't minimize the appraisal issue. Below grade space doesn't "count". If you have all of the bedrooms down there, then you technically would have a zero bedroom house. You would need at least two bedrooms on the main floor above grade just to get a permit and satisfy the bank. And, a 2 bedroom home 1500 square foot ranch with 1500 square foot basement won't appraise like a 3000 square foot two story 4 or 5 bedroom one will. No how many "real" bedrooms you have when you count basement rooms, they don't count. That means a lot more out of pocket expense when it comes to construction cost as the bank would only be lending on a 2 bedroom ranch home, not a two story 5 bedroom home.

    Bookmark   April 17, 2012 at 11:28PM
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Yeah - the appraisal is a big issue. It is possible that this is not true in every locale but people here have said it over and over.

Okay - so your walkout will be cheaper to build. Back to my example, the added cost would just be the back wall - with Hardie, you might be at $10k so savings of $30k. You might also save on HVAC that is not figured in that. At some point, this savings is minimal - since you would probably want a unit to cover the basement and you can only go so small. If you are building a very efficient structure, you might already be down to 2 tons per floor.

If I guess that ICF was double the cost of a 2x4 wall, then the savings might be closer to $45k (in my area).

    Bookmark   April 18, 2012 at 6:15AM
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Everyone makes good points on slab versus basement. We built a house for a customer that was originally 4,800 sq/ft on a slab design. Before construction began they realized that they needed more room for mechanical's and storage. The plan called for areas on the 1st and 2nd floor for boilers, electric panels, and water distribution. When they realized how much was needed for ducting, air-handlers, electric panels,and water system they found it was going to alter their open floor-plan. Because of floor area ratio to their lot size that could be used they ended up with a finished 7'6" cellar. After construction was finished they said that without the basement they would not have had the same house. In the cellar are 3 air handlers, distribution and 4 sub-panels, smart-room for electronic switching and video distribution, water supply system, 2nd laundry, and plenty of storage. Without this area a lot of 1st floor area would have been sacrificed. They have an attached garage, but wanted that for cars and not storage. The cost involved was definitely more than a slab. If it is in your budget a basement allows for more flexibility in usung the 1st and 2nd floors. As others mentioned you have to adhere
to codes as to what is allowed below grade with concerns to fire egress and amount of window are versus living space.

    Bookmark   April 18, 2012 at 7:24AM
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Talk with your lender about whether or not you can count basement bedrooms from a loan appraisal perspective. Talk with a realtor about whether or not you can count the basement bedrooms when listing the house (I think that you can).

As far as cost to finish, you will save some on the exterior finish for the portion of the basement that is surrounded by dirt. However, you might have increased costs in the other areas with a walkout depending on door/window costs. You will still have to frame out the basement walls to finish them, so you might not save that much versus framing a 2 story with an unfinished, non walkout basement.

When we built, the added cost for an unfinished walkout basement was about $15,000 more than a non-walkout.

If you plan on finishing out some of the basement later than at build time, make certain that you let the builder know so that he can consolidate as much of the mechanicals into one area as possible. We have gas and electric coming in one room, sump in another and water heater/HVAC in a third area. All of these were shown as unfinished when we built, but it limits what we can do if we want to finish out any additional space later.

    Bookmark   April 18, 2012 at 9:44AM
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live wire oak - Maybe in your area bedrooms in walk out basements don't count as bedrooms, but they do here. We have two bedrooms at grade and two in the basement and the bank considers it a four bedroom house.

    Bookmark   April 18, 2012 at 8:15PM
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We are thinking along the same lines as you. We are getting ready to price out our build and have been looking at a builder. Last Saturday we went through 2 ICF houses and had gone through another finished one 2 months ago. The one we saw awhile ago had 3 bedrooms upstairs, the master on the main floor and a mother-in-law apartment in the basement. He also kept mechanical, his safe room, and gym in the basement. It was all ICF--all 3 levels. All levels were air tight and felt equalized in temperature. One of the houses we saw Saturday had 2 bedrooms in the lower level and one on the main level. My thought was, "Oh, they have 2 bedrooms in the basement." The second one was ICF on 2 floors with a 5' crawl space. It seemed a waste of space to me.

For a bedroom in a basement, my builder said that you need a 3' x 4'6" window. He also said that a full basement house appraises for more money than the 2-level one, but that in NC banks can allow for bedrooms in the basement.

I also agree with the poster who said you'd lose your farmhouse look. It would probably look more like a split level home. We want ours to be handicap accessible since it will be our retirement home. And with the window requirements, we want to walk in at level with no steps.

BTW, are you going ICF for all floors? We are just getting our plans firmed up and getting ready for costs but we may be in the same boat as you in a month or so.

    Bookmark   April 20, 2012 at 10:09PM
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Thanks, everyone, for your replies! I apologize- I've been super busy lately and haven't had the time to reply until now.

I agree that changing the look from my original, utmost, desire- the farmhouse look- is a decision that needs to be weighed carefully. I definitely don't want to become unhappy with our exterior down the road. However, I have always liked the look of the Cedar Ridge by Don Gardner, and I think I could make that exterior look right with my first floor and still be happy. Do you think it would look ok as a farmhouse?

A preliminary rendering of our design, for a comparison:

Originally we wanted approx 2500sq ft house. Because of my requirements for the 1st floor, the house ballooned to 3600 sq ft, split nearly evenly. Now I'm worried, because of the increased sq footage, that we won't be able to afford the upgrades- nice kitchen, central vac, nice deck, etc. I also would like to make sure I can still take my kids on vacations and live a decent life. I don't want to invest all my money in a structure just because I'm drawn to certain look. I'm trying to find that balance between what I WANT and what I NEED.

I definitely need to reserve room in the basement for all my equipment. We'll have a Waterfurnace and all the pipes for radiant heat, water softener, water heater, etc, etc. Can't forget to include that in my planning! Thanks for the reminder, @kymike1!

I need to call my mortgage guy and just talk this over with him.

@stillwaters- we want to do ICF from the basement, up to the roof. We'll spray foam the roof. We also want our first floor to be handicap friendly. We haven't received any actual quotes back yet, but with everything else that we've had quoted so far, we've been UNpleasantly that's what we're expecting for the house quote! :) I know it will all be worth it some day- just can't wait for that day to get here!!!!

I've started blogging about it, if you're interested in reading some of my thoughts. It's fairly new, and I don't post very often yet, but plan to do better as we get going on the build.

Here is a link that might be useful: Kelly's ICF blog (just getting started on it!)

    Bookmark   April 21, 2012 at 12:04AM
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Your Don Gardner inspiration home is lovely, however I always think it is a bit of a waste to have that much room in the attic space, especially with all of the dormers and not be using it for living areas. I wonder how much you are actually saving by only eliminating the extra height of the side walls, but having a larger roof and foundation with the greater footprint a 1 story requires.

One idea for reducing square footage is to not put the second floor over the entire first floor. On our house, it appears to be a full 2 stories when you view it straight on. However, tacked on the back of the house is our family room, kitchen, laundry/mudroom and garage, which do not have a second floor above them. Because we have 10 acres, we had a great deal of flexibility in our dimension and where the garage was situated.

I don't have a good photo of the exterior because we are still working on the porch railings, steps, etc., but here are a few during construction that show the general massing.

    Bookmark   April 21, 2012 at 12:38AM
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@westiegirl-'ve got me thinking! We've got 7 acres, so we're also well positioned to change the width/depth of the house. I need to step back and take another look at the design. I did consider that maybe we could build our first floor within the Cedar Ridge look, but add a couple of bedrooms and bathroom in the upper parts of the roof (utilizing the dormers). We would then keep the basement unfinished until a later date. That would cut down on sq ft, but I wonder how much it would really save, in the scheme of things. Wish we already had a builder picked out so we can discuss this with him!

    Bookmark   April 21, 2012 at 9:48PM
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