Basement, crawl space or slab foundation?

Run through this thought exercise.

First, let's ass u&me that if you use a floor of the level above as a ceiling it costs nothing extra - that you've already covered the cost as a floor (I know, but it's an approximation).

OK, now let's assume a building that has a floor area of three squares, each thirty feet by thirty feet, on one level. (we used to use a "square" as a building measure here, back in the primitive days before we went metric. A "square" is a floor area ten feet by ten feet). Thus, this building is 27 squares. You pay for 27 squares of floor, 27 squares of roof, and 24x10feet of wall.

Now, roofs and floors are more expensive than walls.

Let's assume that we make that a two-storey house, each level 13.5 squares. That's 45x30 feet. That's 30x10 feet of wall, but only 13.5 squares of roof, and still 27 squares of floor. We're saving money by getting towards a cubical shape.

In fact, the closer we get to a regular shape, the less the proportion of "skin" to volume will be. The least would be a sphere, but since we're not living in orbit yet that isn't really practically. Tending towards the cubical is, though.

So, last step in this thought exercise - let's assume our house is three stories - basement, main floor, second storey - each nine squares. We have a (cheap) wall length of 36x10 feet; we have a roof area of 9 squares, and we still have a floor area of 27 squares. So - cheapest construction.

I agree with your concerns to an extent - I would tend to minimise stairs myself. However, there is another concern. I live in a HOT climate, and I'd build spread-out because it maximises surface area for the volume of the house. That means easy to cool. I don't think you want to think this way - you want to RETAIN heat - not maximise its loss.

I think Ken has an interesting idea, in building a rental "efficiency apartment" in the basement. This has other aspects to it. The way things run these days, you may find yourself needing to give accomodation to adult children later in life. BUT ALSO, you may, even later in life, find yourself needing to have adult children give live-in accomodation to you. If you build a "granny-flat" into the basement now, with either elevator or some other form of mechanical transport to upper floors, then you may be able to live there in later years, with children (or even tenants) providing live-in care for you.

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ô¿ô Don Armstrong,Terra Australis

Grandad, tell us a story about the olden days, when you were young and men could walk on the moon.

This doesn't make sense to me. I always thought that a two-story building is better in the heat because the downstairs stays cooler. I would think that - in either extreme hot *or* cold - you'd want to minimize surface area (since that is where the hot/cold air comes from).

Insulation can lower heat gain through the roof, and spread-out means big area adjacent to the cooler ground for thermal mass.

You can live with hot temperatures during the day, but you REALLY need it to cool down fast and completely during the night, which is what spread-out gives you.

I can see the argument for "cooler downstairs" in a BIG building. In fact, there are some marvellous examples of the type in our town - old bank buildings where the ground-floor business area is cool, the upstairs was the manager's residence (lived on top of the money for built-in security; uncomfortable during the day but heck, it was only the manager's wife and babies who were there during the day - would they complain when they were getting it for free?) Two of them have magnificent rococco towers as well - most people can't understand them. They're actually a passive air-conditioning device - top of the (hollow) tower heats up, air is exhausted, draws fresh air in at lower levels.

However, those are BIG buildings compared to a home. You can't do it with the average home (which used to be ten squares - remember, hot and dry - lot of outdoor living). If you halved the space per floor and made two floors, then all the downstairs would be too close to the outside walls and heat up too much.

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ô¿ô Don Armstrong,Terra Australis

Grandad, tell us a story about the olden days, when you were young and men could walk on the moon.

You touched on the very thing that you really need to consider when deciding between a slab, a pier and beam, or a basement: The land. If it is a clay or clay loam soil, NO slab. Clay soaks up water and puffs up like a sponge then cracks widely when it dries out. A slab will tear up in no time. Bedrock too close to the surface means blasting to create a basement. A pier and beam is suggested for clay and clay loam types of soils. Basements are nice to have if you don't have to fight rock for it for all the reasons given.

If you don't have to blast bedrock, let your husband have his basement. He can set himself up a cozy corner in it and stay out from under foot or use it to keep the kids out of trouble with their own entertainment corner instead of roaming the streets. You're looking at it as wasted space. Look at it from a different angle: how can you make the best use of that space while you're young and healthy? Judi

My humble experience....

When you put that basement in include a drainage plan to a sump pump placed in a garbage can to take care of any future potential water issues. Dont put the drain line into the septic, use a graywater. It is VERY expensive to have done after foundation is in....about $5000 from my own experience.

Basements are wonderful things! For plumbing heating electrical backup generator (vented) Insualating a corner room will give you a root cellar. Your oil tank can go down there and not rust. The kids can go down there. Hubby can watch football down there with his annoying friends;-)
If you put in a double flue chimney you could have a woodstove for power outages or just to reduce oil consumption. Do not stack wood in your basement though because it is buggy and can lead to moisture problems. Build whats called a doghouse (instead of bulkhead) if its not a walkout(daylight). Any painting can be done down there(for crafts) without worry of spattering the floor.

Insulating the outside of the walls before you backfill will give you a steadier basement temp. They are cool in the summer too. Save on the AC by using it !

If you have forced air heat a plenum can be made for woodstove and conected to furnace ductwork. With baseboard, just warming the floors of the main story will provide heat savings.

My vote is for the basement. My camp is on posts....cold floors.....my current home is a crawl space with slab addition (cold floors)and I really miss my basement!