a little project yesterday whipped my wrinkled ol butt.

[1982vett]

In much of the state the soil isn't stable. I live in a almost 100-year-old house that's on blocks with a crawl space under it. This summer, when it was drier than usual, neither of my exterior doors would close all the way. I tried a soaker hose laid down along the edge of the house, but it didn't help much. Finally, this fall and winter when we got plenty of rain, they work just fine again. As you might have guessed, I wish my house was on a slab.

Basements in homes are also almost unknown in my part of the world. I think that's mostly because of the high water table in many locations. In fact, in my general area the only home I know of with a basement was built by a family with plenty of money and a wife who was unusually afraid of tornados. That house was built on a slope, so that the basement and garage were on the first level, with the living quarters above. The garage opening is at ground level in the back, and the living quarters at ground level in the front.

I'm on 32 twelve inch piers drilled 15 ft with a 3 ft bell. House is still moving...

I think if you dug a basemen here you would just end up with an indoor swimming pool part of the year.

 

[Rafter S]

I'm on 32 twelve inch piers drilled 15 ft with a 3 ft bell. House is still moving...

I think if you dug a basemen here you would just end up with an indoor swimming pool part of the year.

That reminds me of a friend of mine, who moved to my area close to 40 years ago. I drove up to his place one day when he was getting ready to move a house onto it. When I drove up he was out there with a shovel digging a hole in the ground. Me being the nosy person I am asked him what he was doing.

(His place is on a blackland hill, and this was in winter, and the ground was pretty well saturated. This will become important later.)

"I'm doing a percolation test." (He owns a plumbing company, by the way.)

"What's that?"

"You dig a hole in the ground, 12" square, fill it up with water, and see how long it takes for it all to drain out. That lets me know what kind of field lines I need for my septic system."

"Do you plan on staying out here watching it all night?"

Of course if he'd done it in the summer, when it was dry, he never would have got the hole full because the water would run out through the cracks as fast as he could pour it in.

 

[1982vett]

That reminds me of a friend of mine, who moved to my area close to 40 years ago. I drove up to his place one day when he was getting ready to move a house onto it. When I drove up he was out there with a shovel digging a hole in the ground. Me being the nosy person I am asked him what he was doing.

(His place is on a blackland hill, and this was in winter, and the ground was pretty well saturated. This will become important later.)

"I'm doing a percolation test." (He owns a plumbing company, by the way.)

"What's that?"

"You dig a hole in the ground, 12" square, fill it up with water, and see how long it takes for it all to drain out. That lets me know what kind of field lines I need for my septic system."

"Do you plan on staying out here watching it all night?"

Of course if he'd done it in the summer, when it was dry, he never would have got the hole full because the water would run out through the cracks as fast as he could pour it in.

Yup…if you stick with in when it's dry, it will stick to you when it's wet…

 

[greybeard]

It's probably a dumb question, but why are houses built on slabs in Texas? Is the soil not suitable for a foundation and crawl space? Texas is huge surely there are places that build using foundations?

You mean a pier and beam type foundation or a concrete footing all around and up from there?
I've never seen a footing poured as I don't think it would prove adequate support in wet years and back in East Texas, it would be iffy in dry years. Subsidence is areal issue in much of texas.

My old house (and many like it) was built on pilings. Had 4' of crawl space and glad of it too. They were still building on it here..

 

[Dusty Britches]

There are several ways to build foundations in Texas but the most common is called a floating slab. It literally floats as the ground expands and shrinks. The proper soil has to be placed around the floating slab and often has to be trucked in. It must be soil tested at an engineering lab. Basements are a no because they will hold water but they will also crush with the moving ground. Another type of slab is a pier - the contractor drills anchor piers down to the bed rock or limestone which could be 15-30 feet. While expensive and perhaps cost prohibitive, it will last lifetimes.

 

[Silver]

There are several ways to build foundations in Texas but the most common is called a floating slab. It literally floats as the ground expands and shrinks. The proper soil has to be placed around the floating slab and often has to be trucked in. It must be soil tested at an engineering lab. Basements are a no because they will hold water but they will also crush with the moving ground. Another type of slab is a pier - the contractor drills anchor piers down to the bed rock or limestone which could be 15-30 feet. While expensive and perhaps cost prohibitive, it will last lifetimes.

Are theses piers a screw pile, driven pile, or cement caisson? Or are they all common? To me a pier is a dock out into the water so I'm a little confused.

 

[Rafter S]

Yup…if you stick with in when it's dry, it will stick to you when it's wet…

My father said that back when he was young and they were still farming cotton they called that kind of soil "noontime dirt." You'd go to the field in the morning and it was too wet and sticking to the plow, so you'd go back after lunch when it had time to dry and it would be too hard to plow.

 

[Texas G@l]

My father said that back when he was young and they were still farming cotton they called that kind of soil "noontime dirt." You'd go to the field in the morning and it was too wet and sticking to the plow, so you'd go back after lunch when it had time to dry and it would be too hard to plow.

That's what I've heard it called, too.

 

[JJColvin]

Everything that I've heard about waterheaters says that the new ones are typically only good for 10 years or so. I remodeled the house 10 years ago, put in a new furnace, but not the water heater... That one was here when I came here 25 years ago, and as far as I can tell, it was maybe 15 years old then. Didn't think it wise to mess with it. If it ain't broke, don't fix it!

I've changed out several in the last 20 years. The warranty on all of them was 7 years. All lasted less than 7 except one that lasted 3 years. An old plumber told me to always change them out before the warranty expires because the manufacturer knows how long they will last. When I put one in I write the install date on it and put that into my reminders to alert me when it's due.

 

[Ouachita]

Are theses piers a screw pile, driven pile, or cement caisson? Or are they all common? To me a pier is a dock out into the water so I'm a little confused.

It's confusing to me too. I finally figured out that a pier is a pilling and/or vertical support column, and together with other piers can support a largish horizontal structure, such as a bridge or a slab.

But a dock can also be a pier, extending out over the water, but only because they are usually built upon piers……but that's a bit like calling somebody else's soup "chili".

 

[Dusty Britches]

Have you ever heard of a pier and beam house? Its the same concept only much deeper, bigger and stronger.

12 years ago when we build our house it would have added $50,000 to the cost. Now, it would be closer to $100,000. Just for the slab.

 

[bird dog]

Silver, the piers are every shape, size and style you can think of. Most are screwed in or pushed in with a jacking system. There are hundreds of slab leveling outfits around and all swear there method is best. Dusty's floating slab is what a lot of folks are going to on new construction. Dig out 4' and bring in some low viscosity soil. If that fails, then you go to plan B and hire one of the pier guys. A big problem for piers is there is nothing they can reach that is solid in a lot of areas. Slab leaks are problems. The house settles, the home owner gets it raised back up but the plumbing doesn't follow. Most repair crews gone to tunneling rather than the jackhammer route as you usually have to replace a length of pipe. Very expensive.

Bedrock, forget about it. Most pier drillers or pier pushers just go until they can't go no further (hopefully a shale) and hope for the best. The commercial slabs I worked on always tried to go to "blue" shale if its present. Its stable in most cases. Its also very deep in some places.

 

[Travlr]

I've changed out several in the last 20 years. The warranty on all of them was 7 years. All lasted less than 7 except one that lasted 3 years. An old plumber told me to always change them out before the warranty expires because the manufacturer knows how long they will last. When I put one in I write the install date on it and put that into my reminders to alert me when it's due.

We bought our present house almost fourteen years ago with the present water heater in it. I have no idea how old it is.

(knock on wood)

 

[RDFF]

It's probably a dumb question, but why are houses built on slabs in Texas? Is the soil not suitable for a foundation and crawl space? Texas is huge surely there are places that build using foundations?

My expectation would be that as you get further south, the cost of building a basement vs. slab on grade becomes more of a factor. Up here, our footings have to be 48" below grade by code to avoid frost heaving... you're pretty much there with the foundation wall anyway, so you might as well make it into a basement and gain the extra floor space for not alot more $$$. You can have a smaller "footprint"... more interior sq. ft. for the same amount of roof, with less exterior wall exposed to the elements, so it's more efficient to heat and cool. Basements pretty much maintain their temp pretty easily... but add some to the humidity in summer. Normal level of AC takes care of that though.

In much of the state the soil isn't stable. I live in a almost 100-year-old house that's on blocks with a crawl space under it. This summer, when it was drier than usual, neither of my exterior doors would close all the way. I tried a soaker hose laid down along the edge of the house, but it didn't help much. Finally, this fall and winter when we got plenty of rain, they work just fine again. As you might have guessed, I wish my house was on a slab.

Chances are, if you dug your "footings" in as deep down there as we have to by code up here, your house would be sitting on more stable, undisturbed soil and it wouldn't move either, and your doors would work more reliably. But of course, you'd have more $$$ invested...

 

[RDFF]

I'm on 32 twelve inch piers drilled 15 ft with a 3 ft bell. House is still moving...

I think if you dug a basemen here you would just end up with an indoor swimming pool part of the year.

Well, I guess that blows my theory out of the water! Glad I'm living on permafrost!

 

[gman4691]

Where I live, you wouldn't want to put a slab directly on the ground. The swelling & shrinking of the clays as they alternate between being wet (swelling) and drying out (shrinking) will end up cracking the slab. What most contractors around here do is to scrape a good bit of clay off of the footprint and replace it with some dirt with a higher sand content. The sand grains serve as a kind of shock absorber for the swelling/shrinking of the clays. For the perimeter and load bearing walls, a trench is dug (usually 18" - 24" deep) which is filled with steel reinforced concrete and poured at the same time the slab is poured. My explanation is probably over-simplified but the point is that the sand grains underlying soil distribute the force of shrinking and swelling so it isn't placed directly on the bottom side of the concrete. I've used sand underneath smaller concrete pads in the past located where clays are at the surface and haven't had any problems with them cracking over a period of 20+ years and counting. In some areas of the county, sand is at the surface and the shrinking/swelling isn't really an issue. Clays take on water in the crystal lattice and it tends to make them swell (some clays more than others). Wet sands however can shift depending on compaction, slope, and load. My contractor called the stuff he used "clay-sand". Enough sand in it to absorb the shock from shrinking and swelling but enough clay for the trenches to maintain their shape without the sides caving in.