New house foundation : concrete slab or crawl space ?

[tercel89]

The time has come to where my son is going to buy my old house and my wife and I are looking at buying a new  or newer house to retire in. We have lived in an old 1954 farm house for 25 years. It has a crawl space. We heated with wood for a few years with a wood stove. I grew up with a wood stove and cutting wood every year so that wasn't new for me. We finally got a regular heat system in 2004. I wrap the pipes every winter and close the crawl space vents to prevent frozen pipes. I am wondering if I should get a regular house with a crawl space or a house built on a concrete slab. The slab pros that I can think of is no frozen pipes but if there is ever a problem , I imagine that the slab would have to be jack hammered up to get to the pipes. The crawl space sucks cause of the pipes being exposed and will have to be wrapped and the vents closed up and such. Plus with a crawl space , if there is a leak in the toilet and any plumbing , the floor will rot and the wood floor will need to be replaced. With the slab , if there is a leak above , it wont rot the floor cause the floor is concrete. I welcome any information or experience on this . Thanks in advance. 

[peejman]

I'm not sure what you mean by wrapping the pipes every winter? That's a one and done thing.  I did mine 15 years ago.  Frozen pipes are really only a concern if you lose power/heat.   Opening or closing the vents takes 2 minutes.  Frozen pipes are also possible with a slab if they're run in exterior walls. 

Yes, leaks in a slab require a jack hammer. Leaks in a crawlspace may rot the subfloor, but slab floors have a layer of insulation under the floor too.  

 

[derf]

Put in a basement man cave. 

[seez52]

Slabs are pretty popular these days if your lot will accommodate, and it's generally cheaper to build. Most spec builder neighborhoods are all on slabs. Most of the time these days supply lines are pex and often sleeved so a repair is not horrible. Drain lines don't usually cause a problem since there is no pressure. I've looked at a lot of houses and for a retirement home I might just go with a slab. I built 18 years ago and did crawl space and it has worked out well. Makes it easy to see all the mechanicals, you can add new wiring etc pretty easily, unless it's a belly crawl space. I would definitely go with slab if it's going to be a belly crawl height. Also with a slab there is no concern with potential mold and not too much to worry about with termites if you have the grade correctly set.

[10-Ring]

I've had both.  100% crawl space. Or preferably as @derf suggested a basement. I don't ever recall having issues with frozen pipes.  I had a neighbor on a slab whose septic line collapsed in about near the middle of the house requiring major renovation to repair.  After seeing that, replacing a little bit of subfloor seems like child's play. 

[tercel89]

1 hour ago, peejman said:

I'm not sure what you mean by wrapping the pipes every winter? That's a one and done thing.  I did mine 15 years ago.  Frozen pipes are really only a concern if you lose power/heat.   Opening or closing the vents takes 2 minutes.  Frozen pipes are also possible with a slab if they're run in exterior walls. 

Yes, leaks in a slab require a jack hammer. Leaks in a crawlspace may rot the subfloor, but slab floors have a layer of insulation under the floor too.  

 

We currently have concrete blocks turned sideways in our old house that use the holes in the blocks as foundation  vents. I have to plug/cover them in the winter. I wrapped the pipes once and for good. I used to wrap them and uncover them in the summer. But now just leave them wrapped. 

[Patrick Henry]

Basement or a slab is my preference. Recently bought a house built in the early ‘80s. It is on a slab. Home inspector said a slab is much better than a crawl space due to mold concerns. I have a friend who just spent about $10k on mold mitigation. My house is one story so it is easy to drop electrical lines from attic. 

[tercel89]

At this point I'm leaning towards slab but still looking at both . 

[CMDRStormBorn]

I own 8 houses, all built & maintained by myself with a mix of both styles. My primary residence, is a result of all that I had learned (and endured from failings).  I have converted or am converting- as I continually add more rooms to the house: everything to concrete slab.  I will use but a one room example to be atypically brief.  Last year, a corner of my then waveless waterbed decided to penetrate the floor with a leg despite the floor being 2 layers of 3/4” treated plywood on 12” centered joists with multiple- really over built block supports.  I also have a shower in that room that I built on it’s own isolated concrete slab.  Thoroughly disgusted, I did my typical reaction to such things and cut out the floor and then the walls, converting them to treated 2x6 walls after getting a concrete pump truck to shoot in a 8-12” 4000 psi concrete slab.  Never wanting to see deteriorating wood again (or deal with jacked up lumber prices) I then stoned BOTH the inside and outside of the walls, doubling the size of the bedroom in the process.  The wife loves Game of Thrones, so I gave her a castle bedroom. Back to the slab as this may be of interest to you.  1- you can concrete anchor the walls down to a slab to make them tornado rated, 2- there are translucent acid concrete stains out there that will permanently make your slab look like any kind of marble or gemstone than you can imagine & the same companies make buff less, wipe-on waxes that make the floor look like deep crystal and super easy to clean/maintain.  One last word on crawlspaces: they are the natural habitat of the brown recluse spider. There is no anti-venom to them and you can’t find a heat & air crew that doesn’t have severe scars from the bites.  Who needs that?  Lastly, with modern day PEX plumbing pipe, I have never encountered a burst pipe in a slab, that material is just incredible.  I’ve converted my whole place to it.  Best of luck.

[gregintenn]

Concrete slab is a cold sumbeech on your feet in the winter.

 

If you can swing it and your building site will accommodate, a basement is the cheapest square footage you can get. An added advantage is that it makes your house easier to heat and cool. The basement stays at a pretty much even temperature all on it’s own, like a cave. Further, you have somewhere to go when the tornado alarms go off.

Edited March 18, 2023 by gregintenn

[billyblazes]

My choice would be concrete slab on grade with overhead plumbing.  Having experienced in-slab plumbing failures and needing to re-pipe the house from the attic, that's the way I would start.

[peejman]

A raised ranch with a basement is ideal. That's what I wanted but I couldn't find one that didn't have drainage/moisture issues from not being built properly. 

I've not heard of burst pex, but I know several people who've had mold and water damage from leaky fittings. 

[jpx2rk]

If you are looking at a newer built house with crawl space, just insulate the water pipes with the foam pipe insulation one time,  leave on year round, just do a good job on it, especially with any pipes that are close or on the exterior walls.  Closing the vents is easy, and use those insulated facet covers, no problems.

[RED333]

3 hours ago, jpx2rk said:

and use those insulated facet covers, no problems.

Use a sill-cock and not worry about it.

[tercel89]

My wife and I have been walking through some of the new built houses that are left unlocked. We are seeing brand new houses with walls that are not straight and door frames that are crooked. It is unreal ! One of the ceilings in a kitchen went downhill from one end to the other. I measured and the angle of the downhill was 2 inches ! I know you cant get anything perfect and I am no craftsman , but dang we saw some terrible stuff. 

[-boatman-]

40 minutes ago, tercel89 said:

My wife and I have been walking through some of the new built houses that are left unlocked. We are seeing brand new houses with walls that are not straight and door frames that are crooked. It is unreal ! One of the ceilings in a kitchen went downhill from one end to the other. I measured and the angle of the downhill was 2 inches ! I know you cant get anything perfect and I am no craftsman , but dang we saw some terrible stuff. 

As fast as houses are going up in some places this doesn't surprise me. My dad was a carpenter and cabinet maker would not have stood for something like this no matter how long it took. He was like a artist that worked with wood.

[hipower]

On 3/17/2023 at 7:52 PM, peejman said:

I'm not sure what you mean by wrapping the pipes every winter? That's a one and done thing.  I did mine 15 years ago.  Frozen pipes are really only a concern if you lose power/heat.   Opening or closing the vents takes 2 minutes.  Frozen pipes are also possible with a slab if they're run in exterior walls. 

Yes, leaks in a slab require a jack hammer. Leaks in a crawlspace may rot the subfloor, but slab floors have a layer of insulation under the floor too.  

 

On the vent issue...we have auto opening and closing vents. They are set to change on 40 something degrees. I forget what. They have worked well for us for 20 years. Had to replace them 10 years ago after flooding though. If it looks to be real cold, I have some cardboard cut to put in front of the vents. Onle done that 2 times here. Oh, yeah...we have a crawlspace. Hasn't been a problem but for dring out after that flooding I mentioned.

[peejman]

9 hours ago, hipower said:

On the vent issue...we have auto opening and closing vents. They are set to change on 40 something degrees. I forget what. They have worked well for us for 20 years. Had to replace them 10 years ago after flooding though. If it looks to be real cold, I have some cardboard cut to put in front of the vents. Onle done that 2 times here. Oh, yeah...we have a crawlspace. Hasn't been a problem but for dring out after that flooding I mentioned.

Didn't know automatic vents were a thing. Interesting. 

[Erik88]

Is anyone with a basement monitoring their radon gas levels? #2 cause of lung cancer in the US. I did one of those free tests and it came back at 2.7 which isn't ideal. 

[Patrick Henry]

My home is on a slab as are many in my neighborhood. Many of these houses have failed radon tests and thus have radon mitigation systems. So a slab does not stop radon. 

[hipower]

12 hours ago, peejman said:

Didn't know automatic vents were a thing. Interesting. 

Not terribly expensive at all. Got mine at Home Depot. IIRC, a little mercury sensor opens and closes the vents according to temperature.

[peejman]

21 hours ago, Erik88 said:

Is anyone with a basement monitoring their radon gas levels? #2 cause of lung cancer in the US. I did one of those free tests and it came back at 2.7 which isn't ideal. 

My house was tested when I bought and I  recall the result was very low, almost immeasurable. 

[gregintenn]

On 4/5/2023 at 10:39 AM, Erik88 said:

Is anyone with a basement monitoring their radon gas levels? #2 cause of lung cancer in the US. I did one of those free tests and it came back at 2.7 which isn't ideal. 

Nope.

[BigK]

On 4/5/2023 at 10:39 AM, Erik88 said:

Is anyone with a basement monitoring their radon gas levels? #2 cause of lung cancer in the US. I did one of those free tests and it came back at 2.7 which isn't ideal. 

I know nothing about the linkage between basements and radon gas. Is it because the gas can't get out or is it something else?

[OldIronFan]

Some of it depends on your lot and the make up of your soil/ground. I know crawl spaces or walkout basements are popular in the hilly areas of Middle Tennessee since they are the cheaper option. Full basements are expensive to dig out here and the more unlevel the lot the more costly it is to dig for a level slab as well. In some areas of West TN where things are very level but the water table is high slabs are popular. Basements are uncommon with the high water table due to moisture issues and slabs are the economical choice. 

Last two houses were crawlspace. House before that was a walkout basement. When I lived in the greater Memphis area the two houses there were both slab. 
If I can afford it I am going with a Basement. If not I am going with a crawl space. My last choice is slab.