We are going to build a new home in the next 5 years. My dilemma is whether to build a basement or a second story? The second level will be two bedrooms for guests, and a bathroom, with a small storage area for seldom used items. All needed amenities for living will be on the main floor. My question is, which is the better value, i.e. building cost, energy cost-long term, etc., a basement for the extra two bedrooms, or a second story? The land is fairly level and will only need minimal dirt work to make a level pad. The house can however be pushed back further towards a "holler" (as we call it in arkansas) to create a walk out basement. We are in our 50's right now so our main aim is to save as much money as we can in the building cost while still maintaining a "green" footprint as far as construction materials and overall energy savings.

you should price it both ways, but the finisihed basement will probably be less expensive. Lower floor also has the benefit of being able to have it's own direct entrance, so if at some point you wanted to rent it out...

you should price it both ways, but the finisihed basement will probably be less expensive. Lower floor also has the benefit of being able to have it's own direct entrance, so if at some point you wanted to rent it out...

Basements generally cost less to heat and cool.

For Arkansas, you may need the basement for a storm shelter.

There is not question, the walkout will cost less to build, no cooling cost and minimum heating with a water heater to provide DHW and space heating. Nice place for the would stove or boiler.

IMO, once you consider slab on grade, frost protected shallow foundations, above ground space (no basement) is the better value. Even if you do add a small "safe room" for storms.

You know, I am all about FPSF since we radiate all of them. But I have owned several and currently live in a home with a walk-out. In warm climates and cold, the basement with light is usually the most consistently comfortable space in any house and usually at a third the heating load and virtually no cooling load...how do you come to that jonr?

"Better value" is definately eye of the beholder and often regional. If someone were building on a mountain and excavation for a basement would require blasting then basements likely wouldn't be a better value, in Michigan however, with a basement heating load often as little as 20%-40% of above ground loads it saves money for the life of the dwelling.

We do plan on building a separate storm shelter if there ends up being no basement. I was thinking a basement would cost more in up front costs what with excavation, drainage, waterproofing the block, etc. This is not going to be a continual living space, only used for holiday/guest purposes. I was thinking if the main living space, ceiling space, was insulated well then we wouldn't lose much heat/cooling to the upstairs area? I've heard/seen that the new spray in insulation has excellent R value. Also, a stairwell that would be closed off with a door so no updrafts to the upstairs space I believe would help with heat/cool lose to the upstairs. I don't care about resale value or renting the space out, I plan on dying in this house, lol.

Agreed, much of it is subjective and situation dependent - I have an exposed basement and prefer being above ground. Everyone I know is similar.

ANY heating load in a basement can be matched (or bettered) with above ground construction. It's only an issue of which one costs less to build.

Check out Passive House designs - most are completely above ground. Ask any real-estate agent about above ground vs below ground space valuations.

Thanks so much to all of you for your replies. Seems like there is quite a bit of collective wisdom here to glean from as far as home construction is concerned. I will be asking you all many questions I'm sure. Thanks again!

The knock against basements has traditionally been all about moisture & mold issues, but those problems are now very well understood. Foam insulated walls & slab along with better capillary breaks and ground vapor retarders can make basement as dry as any other conditioned space. In an Arkansas climate slab insulation is more about managing summertime mold in the flooring and coldest-day winter comfort than it is about NPV on heating energy use. Radiant slabs (which would require even more slab insulation) are DA BOM for mid-winter comfort, and as BadgerBoilerMN points out, the temperature evenness is hard to match on above grade rooms without going to Net Zero Energy or PassiveHouse levels of insulation.

The ICF (R16-ish) basement room below my radiant-floor heated family room has much steadier temps than the room above, and is as comfortable as any room in the house mid-winter, despite not having ANY direct heating to that room. It only has ~12 square feet of window- enough for daylighting, but I'd want a bit more if it were a bedroom (and would need more to meet egress access code for a bedroom.)

For any new home design you're planning on dying in, it's worth absorbing a bit of this document:

http://www.buildingscience.com/documents/reports/rr-1005-building-america-high-r-value-high-performance-residential-buildings-all-climate-zones

Most of Arkansas is in climate zone 3A- take a peek at table 2, p10 (after reading the first chapter), which is something of a starting point for what's long-term cost effective rather than what's code-min. And note that those are "whole assembly" R values, with all thermal bridging factored in, not center-cavity R on timber framed construction. An R20 wall isn't a 2x6 16" o.c. studwall with R20 batts. After the thermal briding of all studs/plates/headers/cripple studs/fire-blocking/subfloor is factored in, 2x6 16" o.c. studwalls with high density fiber or open cell foam comes in at about R13. Going with closed cell foam it only brings that up to about R15 the whole-wall performance, the high center-R value being severely undercut by the thermal bridging of the framing.

But adding 2" of rigid EPS foam between the sheathing & siding of a high-density fiber or open cell foam 2x6 wall brings it up to ~R20 relatively cheaply. Another example of an R20 wall would be 2 x 4 16" R13s with 2" of rigid polyiso between the sheathing and siding, or (usually more expensive, but highly hurricane resistant) an insulated concrete form wall with 2.5" of EPS on each side.

Spray foam insulation has many issues, but it makes it far easier to air-seal than other insulation types, not that you can't get there by other means. Most closed cell spray foam is still blown with HFC245fa which has more than 1000x the global warming potential of CO2, and past the first couple of inches would have a larger lifecycle global warming impact than the energy it saves. Extruded expanded poly styrene (XPS) has similar issues, blown primarly with HFC134a, with ~1400x CO2 GWP. Open cell foam is typically blown with water, for low GWP, EPS and polyiso are typically blown with pentane at a mere 7x CO2 GWP. While there are new lower-potential blowing agents under development (Honeywall Solstice was released in the US only a few months ago), for the time being it's greener to be very stingy about using closed cell polyurethane in places where it can be designed out. (Open cell foam does a slightly better job of air sealing in studwalls than closed cell too, according to recent Building Science Corp data.)

Even in a code-min house air-leakage can be the single largest heat loss that can be avoided at very low cost by meticulous air sealing at every step of the way during construction. Gasketed and foam-sealed foundation sills, caulking every stud bay to the sheathing, between the bottom plate & subfloor, and between doubled-up top plates etc all add up. Around windows an doors packing fiber insulation in fairly densely, leaving ~1/2" for sealing with a low-expansion can foam works too. Casement & awning windows are inherently tighter than sliders and double-hungs, swinging patio doors are tighter than sliders (and offer nearly the full width access area rather than slightly less than half with sliders, so you can get by with less glazed area.)

The orientation and the shading factors all count too. With a west-facing wall that's mostly glass it's pretty easy to hit a 4-5 ton cooling load on a 1000' house, whereas if you turned the same house 90 degrees counterclockwise with a couple of shade trees or window awnings out front it might be less than 1 ton. There's a lot to think about, but it's possible to hit Net Zero Energy without breaking the bank in an Arkansas climate with an earth-tempered walk-out basement type house, provide you design it taking R-values, orientation, and site factors all into account.

We do plan on doing air sealing at every step of the way. Both my husband and I have worked on construction of new homes, and done remodeling as well. I have worked for people who would upgrade to very $$$ kitchen cabinets and counter tops, but not spend the extra $$ on caulk, foam, etc, to seal every nook and cranny of the new windows and walls. Enjoy those new cabinets with your coat on !

I have put quite a bit of thought into the orientation of the house, windows, doors, as well as an overhanging porch to cut down on direct sun (heat). Don't plan on having any large doors, I want to keep all openings to the outside down to a minimum. It will be a slab foundation if we go without the basement so I will want some radiant floor heating. We will also have a wood stove and my husband seems to think there is a way to duct/blow that heat into the rest of the house. I don't quite understand that concept.

Thanks so much for the information, it gives me much food for thought!

Hey Valree,
I built a SIP home in KY with radiant heat floors, and built both a front (north) airlock entry (unheated, and very cool in the summer) and a south facing sun room where I put a wood stove. I ran a 14 inch insulated tube from south sun room to north airlock and put a squirrel cage blower in the middle to move warm air from south to north. It cost about $150. The blower pulls warm air from the south ceiling to the north ceiling. If you can open the doors to allow air circulation you will notice a convective air current flowing from the north airlock to the south sun room. It worked for me and was dead simple.
As far as the radiant floors, Insulate, insulate, insulate, then don't over design it like I did. I keep half the valves closed. It is the best heat I've ever had, and a big plus NO DUCTING especially if you use a mini-split air conditioning system.
Hope this helped.
DanD

As Dana says, builders know how to build a basement that's free of humidity and mold -- in climates where basements are common. If that's not AR, and I'm thinking it isn't, then the person in charge of building a livable basement is you. Not impossible, but it's much much easier going with the flow.

Where are you located in Arkansas? I'm currently building my home with ICF walkout basement and ICF main floor in central Arkansas. There are a few contractors in the area that specialize in this work. I could give you some ideas. I also had a friend at work build a half basement using conventional poured walls.

Hey Arki, I live in NW Ark.

Thanks, Dand! I was not able to imagine how to duct the wood stove to the rest of the house. I do however want a conventional furnace backup ducted in for the future when we get to aged to cut wood. Probably better to have it put in at construction time than to find we need it later and have to put it into the existing structure.

As far as the radiant heat in the flooring, I have seen on tv that it is some sort of webbing with the heating element running through it? Have also heard, I think, of people running some sort of tubing through the slab with hot water running through it? I'm not to keen on having water run through the slab, but the electrical unit seems feasible and "safe". Are those the only options? I don't plan on doing any floor coverings except for carpet in the master bedroom, and a wood floor in the kitchen. The rest of the slab will be painted to look like marble or something like that. So, the radiant heat will pretty much have to be put in the slab.

Depends on how far north you are, but Sherwood Engineering in Clarksville, AR does ICF basements and that is who I worked with to build mine.

How big of a home are you looking to build? How many square feet on main floor and basement or second floor?

The electric heating mats aren't really economical for heating an entire slab. They are really intended just to be supplemental floor heat in a bathroom with tile floor or something similar. I don't believe that are designed to be installed in the concrete during the pour, but rather installed on top then tile installed over the mat. If you have plenty of woods and don't mind cutting wood and feeding a stove, there are outdoor wood furnaces that you could use to heat water for in floor heating. But if you have natural gas available, that would be the most economical and lowest up front cost way to heat water for in slab heat based on today's gas prices and price forecasts into the foreseeable future. The radiant tubing for in floor heating has been used for many years without issues.

Posted By Valree on 05 Apr 2013 11:22 AM
Hey Arki, I live in NW Ark.

Thanks, Dand! I was not able to imagine how to duct the wood stove to the rest of the house. I do however want a conventional furnace backup ducted in for the future when we get to aged to cut wood. Probably better to have it put in at construction time than to find we need it later and have to put it into the existing structure.

As far as the radiant heat in the flooring, I have seen on tv that it is some sort of webbing with the heating element running through it? Have also heard, I think, of people running some sort of tubing through the slab with hot water running through it? I'm not to keen on having water run through the slab, but the electrical unit seems feasible and "safe". Are those the only options? I don't plan on doing any floor coverings except for carpet in the master bedroom, and a wood floor in the kitchen. The rest of the slab will be painted to look like marble or something like that. So, the radiant heat will pretty much have to be put in the slab.

Those a pretty much the radiant floor options, but mind you, heating with hot water is usually less than half the cost of resistance electricity if you can heat that hot water with natural gas, or heat pumps.

In a modest sized house with better-than-code R-values & windows the room-to-room temperature differences aren't very big and the more open the floor plan is the more amenable it is to "point source" heating like wood stoves, especially if you take care to design the doored-off areas to have lower heating & cooling loads.  In a decent design you can heat the place with mini-split heat pumps, as has become popular amongst performance-home builders in New England.  In an AR climate the average seasonal heating efficiency would be comparable to ground source heat pumps, as long as you don't have to oversize them too much to be able to handle peak cooling loads.  It's not uncommon for high-R houses in my area to be heated & cooled by one mini-split per floor, but code-min houses would need more heads, adding quite a bit to the expense. (A high efficiency 2-ton from a name-brand manufacturer generally runs ~$5K USD- installed, a 2-ton unit with 2-heads runs ~$6.5K.)  They're not nearly as cushy as a radiant floor in the dead of winter, but they're more comfortable and quieter than most hot-air furnaces, and they're as cheap to run as natural gas (or cheaper, depending on your local gas/electricity rates), WAY cheaper than propane or resistance electricity.  And they're highly efficient as air conditioners too.

It's important to keep re-calculating the heat loads as you tweak the design to be able to size the heating correctly.  If you oversize a hot-air gas furnace it's efficiency doesn't suffer much, but your comfort does.  If you oversize a hydronic (pumped hot water) boiler it affects both efficiency and system design. At low loads (like you would achieve in modest-sized high-R construction) you may be better off using a condensing gas hot water heater for the radiant floors if you go with radiant floor or with low-temp panel radiators.  It's also an important factor when sizing a wood stove.  If the max-firing rate of the wood stove is 2x what it takes to heat the place it's difficult keep it in an efficient/low-pollution burn mode without roasting yourself out of the place. This can be mitigated somewhat by using a high-mass ceramic or soapstone wood burner, but a 75KBTU/hr high-mass stove in a house with a 20KBTU/hr design day heat load is still going to be higher polluting than a 35KBTU/hr stove. EPA rated woodstoves running at a rate where the secondary-burners are engaged are GREAT from an efficiency or soot-emissions point of view, but the low-limit where that happens is somewhere around 1/3 of full-fire. The average heat load of a house is well below the peak- figure it's about half the peak as a winter-average. Ideally a wood stove's peak firing rate would then be no bigger than 1.5x the design-condition heat load, but 2x won't be the uncomfortable & sooty show-stopper that 3x or more would be.  Mini-splits are fully modulating and relatively easy to size for low load homes, but even there it's possible to oversize beyond where it's efficiency suffers.