Question for the building experts on the forum: Slab or basement?

I’m in the planning stages of tearing down my lake cabin and building a house. I’m trying to decide between a monolithic slab with in floor heat vs building a full basement. I don’t need the space of the basement, so mostly just wondering if a monolithic slab is suitable and practical in northern WI.

I’m looking at about 1700sq ft for the main floor of the house and an attached 2100 sq ft garage. I’d like to heat both, and I guess that’s what makes a slab with in floor heat attractive, but I have no idea about advantages/disadvantages of each.

I’d appreciate any insight here!

We tore our cabin down about 19 years ago and were very limited by the size of our lot from a foot print stand point. My dad was also a masonry contractor. Our lot slopes to the lake. We have a walk out basement. The advantage of the basement is the mechanical/utilities are all in the basement and we have half the basement for storage. You could still put in floor heat on the main floor. Depends if you want/need the extra space. I wouldn’t think the extra cost for the basement would be outrageous.

If you go with the slab, would you put frost footings down or just on a floating slab?

Depends on lot, grade, water table, building codes actual footprint. If you don’t want a basement, you can still do a crawl space under living area and slab on grade with frost footings you have lots of options. A lot will depend on your particular circumstances and personal choices.

Oh yeah. We have an extra bathroom in the basement. This comes in handy if you ever have smelly friends up for the weekend and you don’t want them to stink up the entire main floor.

I like basements for utilities, storage, storm shelter. Also the possibility of another bedroom and bathroom. We did a house this summer that had a full walkout basement with in floor heat as well as in floor heat on the underside of the plywood subfloor on the main level. It wasn’t huge, but I liked the open floor plan. Also had a detached garage with a breezeway that isn’t heated as of yet. Homeowner said he wants to put a ceiling mounted LP heater in there. Could have easily been attached with in floor throughout. Personal preference, I guess.

Naturally, you do what’s best for you. BUT, I’ve done so many repairs to rotten bottom plates of walls, years of high snow amounts have caused leaks on the floor,and in northern WI you have a LOT of heaves from frost. Just looking at how may rocks push up through the roads is an indication of what could happen to the slab…..with your heat tubes in it.

Resale value is higher and the storage and or future use can easily come into play. At minimal I would do a 5′ crawl space. But then, the cost difference isn’t much more to do a full basement

I’m not quite clear on what you mean by a monolithic slab.
I’m a basement guy but if you don’t need/want one I would build on frost footings and put a footing between the house and garage just in case the garage doesn’t get heated. Mech room does take up space so don’t try putting 10lbs of stuff in a 5lb bag in that location. In floor heat is spectacular, however a central cooling system needs planning.
A good HVAC contractor is who I would be speaking to that could give me answers especially with options, cost, operating costs, etc.

Best to have plans and they don’t need to be final plans at this stage for getting questions answered and ballpark figures.

There are a couple questions to answer here that will direct you down the correct path.

What is your heat source going to be? gas or electric, LP or natural gas.

Is your intent to only heat your “cabin” when you are there and set the heat back when you are gone to save money. (part time use)

A slab house take a long time to warm up (huge thermal mass). Raising a slab from 50 deg. to 70 plus deg takes days. It is much easier to keep it warm than it is to raise the slab temperature.

In floor heat can be either electric cables or tubes (hot water/anti-freeze hot water). Tubes requires some kind of boiler.

My boilers (I have 2, one for the house and attached garage and one for my out building) are 95% efficient.

In floor cables are much cheaper to install but are a little more expensive to operate.

I heat a total of about 3300 sqft. (house/garage/out building – to 72 deg.) with natural gas at peak cost of about $260 a month (-40 F nights and -10 F days). My boiler in the house also provides heat for the hot water in the house. So, in effect I have a 100 K btu hot water heater and never run out of hot water. One showers after another while washing cloths and running the dish washer (mom loves it).

If you only have electric available, contact the electric company and see if they have an off-peak cost discount that you can take part in. The thermal mass in the floor makes off peak heating possible.

I have a an forced air AC system in the rafters for the summer. So it is not a cheap solution but it sure is comfortable.

A crawl space or basement changes the house dynamic and if it were my choice I would go with a forced air system.

My goal of a thickened edge shallow foundation home was to eliminate all the stairs. My home sits one step out of the ground. And if you enter from the attached garage there are none. My wife has two artificial knees. If this is your retirement home it is something to think about.

Good Luck, building a new home, it takes a lot of planning.

Eelpoutguy wrote:

I’m not quite clear on what you mean by a monolithic slab.

Same as slab on grade. Monolithic, poured in one pour.

Just because it is SOG, it wouldn’t have to be in slab heating. Ask a contractor if it is cheaper to build square footage below grade or above grade. My house is single story rambler and has a mechanical room off the laundry room.

Thanks for all the reply’s so far. To further clarify, I’m planning to tear down the cabin and build a home that will be my permanent residence. While I’m still 10 years away from retirement, we do plan to retire there and that’s weighing heavily into my decision. My folks are retired in a lake home they built many years ago and the only way in is either into the walkout basement via a tuck under garage and then up stairs to the main level, or up stairs on the outside to the front door. They are getting older, have knee replacements, etc and the house style they built will force them out of it prematurely. That is why I’m leaning towards all one level and no basement.

I do plan to continually heat both the house and garage and my source will be LP. What I’ve read about thickened edge slabs is the outside edge and 4 feet out from that are insulated so the heat in the slab from water heated floor keeps the frost away from the house. What I don’t know is if that’s always true…. I suppose another option is frost footings like EPG suggested and maybe that takes card of Randy’s concern with rotten sill plates?……

As far as A/C, I’ve got an uncle who built similar to what I’m thinking of and he has “high wall” A/C units that work great, but in all honesty, I have no idea what they are. I’m assuming it’s maybe an A/C only mini split or something similar. Anyone have any ideas here?

A slab doesn’t do much for you with storms that have tornados/straight line winds… With more extreme weather every year you may want to factor that into your decision.

Bassn Dan wrote:

A slab doesn’t do much for you with storms that have tornados/straight line winds… With more extreme weather every year you may want to factor that into your decision.

You can install these –

TornadoSafe Above Ground Garage Unit/Safe Room

Just cause you have a basement doesn’t mean you have to go up and down stairs. Have the main level at grade and basement is bonus space, again, depending on the lot.

Sent you a pm setter…

breakerbreaker wrote:

Id get quotes for both possibly might not be much different in price depending on your location If you do go for a full basement id get it quoted for icf. IMO id go icf to the roof line then isp on the roof.

Definitely top-of-the-line, however it does come with top-of-the-line price tag also

Slab on grade would be what I would go with if that is the only way to eliminate stairs….stairs suck. Our cabin has a basement with a walkout, 1 step to get down into basement or 3 steps up to get into upstairs. A friend built his cabin on grade because he didn’t have the elevation. If you have a flat enough lot I would do slab on grade in a second with in floor heat. Good landscaping so all water runs away ect. needs to be planned for.

If you dont need a basement dont build one. Do a slab heated. No rocks will push up threw your slab. It will be heated. And if done corectly there no issue of leaks or under slab frot heaves.

I do dozens of both foundations and slabs every year. Im goint to be building in northern wi. Im doing a slab. Its cheaper and mor efficient with zero concern of failure.

Good luck