Elevated Slab vs Conditioned Crawl

cashflyer · 11:06 AM

Elevated Slab vs Conditioned Crawl Space

I have been discussing this with a builder, and I thought I would ask for opinions here also.

Slab is cheaper but usually means that your utilities are not accessible.
IE: If a water line starts leaking, you may not find it until your water bill is abnormal. Then you rip up your floor covering, rent a jackhammer, and start breaking concrete.

Conditioned Crawl Space means higher construction cost and perhaps higher HVAC cost.
[edit: builder says add $15k for choosing the crawl over slab]

Is access to the utilities worth the extra expense, or are utilities so reliable that you should not have a need to break the slab in the next 30 years?

Any other pros, cons, or concerns?

krystar · 03-23-2010, 11:03 AM

after my issues with my house, i will never again get another slab. lesson learned

BeyGon · 03-23-2010, 11:06 AM

Does it rain much where you live? I always like the idea of living up, off the ground. But how much more will it cost?

pwd72s · 03-23-2010, 11:09 AM

Conditioned crawl space..definitely. If I ever had a house built, I'd want a crawl space with a slab for a bottom, lighting installed, enough clearance to be able to reach and work on everything easily...a space where a guy could go anywhere, work on everything while rolling along atop a creeper...

But, just a dream...like a garage with a lift, a rec room with 2 pool tables, etc.

stomachmonkey · 03-23-2010, 11:17 AM

Crawl spaces are awesome except for when the main sewage line cracks during the winter so everything that should be leaving your house creates a frozen lake under your house that you'll only discover as spring arrives.

Just sayin.

BeyGon · 03-23-2010, 11:22 AM

I like the house built off the ground but of the Millions of homes built on slabs, especially the way they are built in the last few years, the chance of a problem is very small.

vash · vash's Garage

Quote:

Originally Posted by stomachmonkey

Crawl spaces are awesome except for when the main sewage line cracks during the winter so everything that should be leaving your house creates a frozen lake under your house that you'll only discover as spring arrives.

Just sayin.

thanks for tonight's nightmare scenario!!!

sailchef · sailchef's Garage

I have a "Un" conditioned crawl space, dirt floor. Its @3ft clearance underneath the house. Its a little damp but I rarely go under there. Just replaced all the water pipes. got a little dirty but thats it.

My friend just built a home with a "conditioned " crawl space. She has a stairway from inside the house going down. I took one look and said "Wow!". Its really nice, 3-4 ft clearance, you could probably use some of it for storage. Access to everything and you don't have to go outside.

In the long run the little bit extra that you will spend during construction will be worth it.

IMHO

pwd72s · 03-23-2010, 11:35 AM

As far as frozen sewer & other pipes go...most folks have learned to plug foundation vent holes & add a bit of heat when temps drop really low...

berettafan · 03-23-2010, 11:39 AM

Have conditioned crawl space.

So long as your sump pump is functioning properly (fark you Ryan Homes) it's pretty darned neat. Use ours for storage. No real cold floors either. REALLY like the idea of access from inside the house....hmmmmm......

MT930 · 03-23-2010, 12:17 PM

I would go with conditioned crawl space.

Full blown basements are not that much more than conditioned crawls

It's very inexpensive sq footage if the water tables will allow it.

Most slabs will crack to some degree, most of the time it's not a big deal.

vonsmog · 03-23-2010, 01:36 PM

Why not just put in a basement? I have a 12 coarse block walls with a concrete floor. lots of room for storage and a great place for the kids to play. Have all utilities down there with no problems getting to anything. I would never own a home without a basement, it is well worth the extra $$.

berettafan · 03-23-2010, 01:59 PM

water table von. would LOVE a basement but would be a swimming pool.

URY914 · 03-23-2010, 04:21 PM

Quote:

Originally Posted by BeyGon

I like the house built off the ground but of the Millions of homes built on slabs, especially the way they are built in the last few years, the chance of a problem is very small.

Agree, 98% of the houses built if Florida are slab on grade. The chance that a problem "may" happen are very small. Building an elevated slab is a huge waste of money.

kaisen · 03-23-2010, 05:36 PM

Why not build a slab with hot water or electric radiant in-floor heat and thermal mass underneath? Best of both worlds and ability to heat eliminates some of the plumbing concerns.

A930Rocket · 03-23-2010, 06:35 PM

Guess it all depends where you live and your checkbook. In GA, NC and SC, I've built a 100 homes on unconditioned crawl spaces. With proper ventilation and a vapor barrier, I've never run into a problem. Some of the crawlspace been above ground and some dug in (and waterproofed with a drain).

Why condition the space? $15k seems like a lot to me. Is it a poured wall or a block wall?

Slabs seem to popular in FL.

No idea what the do up north.

Porsche-O-Phile · Porsche-O-Phile's Garage

Generally speaking conditioned crawl spaces are considered to be higher quality construction. However (as has been said) you will pay a penalty in cost - both up-front and in recurring (it costs money to condition it).

Another alternative that nobody has mentioned is having access panels or lined trenches with cover plates. Ugly as sin, yes but if you have some sort of raised floor above it with a nice finish, you'll never see it and it could potentially save you a lot of $$$.

Another nice thing about lined trenches is that they can be sloped like the piping so if there's a leak it goes away from the building, not creating a septic tank underneath it - as someone has mentioned is a potential problem with conditioned crawl spaces...

Porsche-O-Phile · Porsche-O-Phile's Garage

Quote:

Originally Posted by kaisen

Why not build a slab with hot water or electric radiant in-floor heat and thermal mass underneath? Best of both worlds and ability to heat eliminates some of the plumbing concerns.

1. Potential for leaks
2. Copper piping is extremely expensive right now
3. Need for a second HW heater
4. Not cheap to run the heating
5. steel piping can rust
6. PVC piping in the slab can spall

That said, there are a lot of these sort of under-slab or in-slab radiant heating systems that work well for a long time. The type/quality of heat provided is amazing. I had the pleasure of visiting Mies Van Der Rohe's Crown Hall at IIT in the dead of winter several years ago. It's quite something to have the brutality of a Chicago winter only inches away on the other side of large expanses of single-paned glass but the radiant heat keeping you completely comfortable. It makes the experience like watching it in just enough of a detached way to make it something one appreciates without making it SO detached it's like watching it on television (which is often what the experience is like behind double and triple-paned glass and walls so packed with insulation it's like being in a spacecraft).

Efficient? Hardly. But an amazing experience. Radiant floors rock if done correctly.

berettafan · 03-24-2010, 04:31 AM

Does anyone have pics/info on retrofitting inside access to conditioned crawl space?

Wouldn't have room for a proper door/stairs in our house but some sort of trap door thing could suit.

Taz's Master · 03-24-2010, 04:57 AM

Quote:

Originally Posted by Porsche-O-Phile

1. Potential for leaks
2. Copper piping is extremely expensive right now
3. Need for a second HW heater
4. Not cheap to run the heating
5. steel piping can rust
6. PVC piping in the slab can spall

That said, there are a lot of these sort of under-slab or in-slab radiant heating systems that work well for a long time. The type/quality of heat provided is amazing. I had the pleasure of visiting Mies Van Der Rohe's Crown Hall at IIT in the dead of winter several years ago. It's quite something to have the brutality of a Chicago winter only inches away on the other side of large expanses of single-paned glass but the radiant heat keeping you completely comfortable. It makes the experience like watching it in just enough of a detached way to make it something one appreciates without making it SO detached it's like watching it on television (which is often what the experience is like behind double and triple-paned glass and walls so packed with insulation it's like being in a spacecraft).

Efficient? Hardly. But an amazing experience. Radiant floors rock if done correctly.

I don't know about the efficiency aspect, but PoP's experience matches mine. With a wood stove I can make my indoor temp. whatever I want regardless of the outside temp. But the house is so much warmer feeling at 68 with the floor heat than 78 with the stove. Pex tubing in concrete, earth sheltered construction, no utilities (other than spetic) under the slab.