No I don't believe it would be effective. It would just add to the shifting of the slab as the compost degrades.

Suggest you consult with a soil engineer familiar with your region's soil. Stabilizing your house isn't something you should experiment with.

AS far as the soaker hoses go, don't know why they work for only a season. I used to live in So Cal where we dealt with nasty water -- never had soakers go out after only a year.

Dogwind - One of the very best irrigation hoses, (systems), on the market (IMO) is Netafim: http://www.netafimusa.com/ I've had Netafim drip hoses out in my garden for (10) years and none of them have ever split-cracked or leaked, nor have any of the emitters clogged-up. You may want to check them out if you decide to go that way.

g'day dogwind,

using any organic type material that close to the house would make a good termite attractant.

we have same/similar issues over here with clay sub soils and drought and wet seasons, first thing is to be sure you don't have any moisture hungry trees near by, most shrubs and small trees are ok but must be further than 2 meters from the house foundations.

shrubs like mock orange are very moisture thirsty and usually at least affect the soil to a meter or more beyond their drip line, as do those conifer type pines, book leaf or pencil types that people plant they also suck the soil around them dry.

some larger fruit trees spread roots far and wide the mango is one mullberries and figs are others.

reckon by far teh best would be stone mulch of some type ie.,. limestone or blue metal crusher dust, anything to stop moisture loss due to bare ground being contacted by the sun after good rain. stones and rocks even trap moisture under them and can actually condense moister when they are warm and outside air cool or the like.

whether you can just simply lay it or you may have to get small excavator in and remove about 4"s of the soil then lay the stone to about 1 meter out a cement path about a meter wide or quik kerb around that would neaten it up and stop grass growing into the stones.

then all you need do is wait for the next heavy rain to replenish the sub soil moisture or alternatively run your laundry or bathroom water over the area the detergents will also help to make the soil less hydrophobic that is not be resistant to lighter rains. only needs to be done to achieve your aims and maybe in long dry periods.

also be sure you have your termite plan in action for regular checks et.,. what we did was when we did recent additions outside cement slabs etc anywhere we could get to that wasn't already covered with cement we dug a 300mm X 300mm trench fille it with builders sand and applied our temite treatmet into that, so now when we have new treatments the protection will work better, should be done around all homes at time of construction.

termites preffer moist ground a real catch 22 hey?

len

Here is a link that might be useful: lens garden page

dogwind - the correct fix for expansive soil is a properly constructed slab that "floats" on the soil.

the rest is just band-aids on smallpox sores.

One or more of the This Old House episodes about their Austin project dealt with a foundation problem related to soil conditions. Can't remember if the problem was clay soil or not.

Here is a link that might be useful: This Old House - Austin

Here in Colorado with our bentonite clay everything that I have ever read was to keep water away from the foundation. What kind of clay is it that you have in Texas?

The problem is due to the water absorption properties of bentonite and montmorillonite clays. In dry weather, the clays contract and the footings and slabs sink. In excessively wet weather, the clays expand more than usual and and the footings and slab heave up.

Bentonite, for example, can expand 19 times its size as it absorbs water. This makes it a useful additive in drilling muds.

The only way to ensure stability is to put concrete posts deep enough that they are not affected by moisture changes. Then the footings are put on these posts and the slab is attached to the footings. This works but it is expensive.

To prevent the soil movement otherwise, the best solution is to maintain a constant moisture level in the soil. Soaker hoses solve this problem. Last year was a very dry year in Texas and many people had sinking slabs. I have a daughter in Austin so I am familiar with the issue.

I cannot see how a floating slab is any good. To me, it's just a boat in a storm.

Thank you for all of the responses.

The reason soaker hoses only work for 1 season for me is because they break, split, crack, lose parts, or otherwise get mowed over. The ones I buy at the big box stores are very poor quality. I realize I could pay a professional to install good quality drip line irrigation system down the sides of my house where it is needed. I had this done recently for some new flowerbeds I wanted installed. It cost me $1300. I don't want to do that again. My house foundation is currently fine, but I am looking for a long term solution to an ongoing problem in my area. During the summer I usually water my lawn once or twice a week depending on rain. This is probably enough to keep the foundation stable, but if adding lots of compost around the current foundation (not underneath the house) would help sustain the moisture retaining ability of the clay soil, I will do it. The clay here is in the blackland prarie region of Texas. Sometimes it's referred to as "black gumbo" or "caliche". It's very hard, almost rocklike when dry. And is easlily rolled into balls when wet.
I've also never heard that compost is a termite attractant. I don't believe that. I've heard the same thing about using shredded wood mulch. I think it's bunk. Compost is full of microbial life. I've never found termites in my compost piles. I wouldn't expect they would like it there very much. I'm willing to listen if you can site an alternate source for your "theory" though. I have read that sand creates an effective barrier for termites. As common as they are, I don't currently have a termite problem, so won't be trying that out soon.
I was mainly soliciting input on a theory I had, but apparently am not getting much agreement on it. So I'll stick with the cheap soaker hose from the big box stores as that seems like the only inexpensive solution.

I wasn't aware of this issue re: foundations, so I am finding this thread interesting. I do find it somewhat humorous that a soaker hose would be at fault for losing it's own parts or getting "mowed over". I'd guess that mowing over them isn't recommended. ;-)

Lloyd

I've had three cheap soaker hoses break within months this year. The key seems to be keeping them under the mulch instead of in the sun.
So far, the flat nylon ones seem better.
When I lived in SW OK we had the same problem with clay. We'd get cracks so large you could lose your car in them during heat and dry weather!
Don't know about the foundation but the more wheelbarrow loads of stall cleanings that I spread (horse or cow manure plus pen shavings) the less cracking that I got. If that's any help to you!

In our area we can get "mushroom compost" or more properly called Spent Mushroom Substrate (SMS). Some years ago I got a load of it but had to store it in an excavation which was to become a garden bed. The top soil was screened and also stored in the excavation. The clay at the bottom was removed leaving room for the SMS and other additives. The excavation was only about 18" deep.

It was a very dry year and when it came to spread the soil and SMS into the excavation, I noticed that even though the soil was completly dry, the SMS was still moist. It held moisture very well.

SMS can be made from many things. In this case it was just composted straw. So it certainly is possible that a trench around the footings filled with composted straw will work better than just soil. A soaker hose buried in this would certainly solve your problems.

You could always experiment with different composted materials to find the most effective composition. There may even be commercial potential in finding a cheap effective mix. One could offer a service to home builders by putting this material next to footings with soaker hoses installed. The sod is layed on top and the homeowner just has to turn the water on every now and then. Kind of the reverse of weeping tile for houses with basements.

It seems to me that over time the organic material would completely decay and gas away. Doesn't seem like a long term solution at all.

What about adding shredded rubber like they use for horse arena footing? Expensive but permanent.

While doing some googling on composting I happened to run across this thread. I have been studying expansive clay soils for the past 20 years. I thought I may be able to contribute a little. First off compost is expansive. You want to remove all organic material from any proposed building site. If you intend on building a new home hire an engineer. No one type of foundation will work on all soils. If you have ever had to have a foundation repaired you know that the expense if hiring the engineer is money well spent. After the home is built drainage is very important (Keep this in mind when determining the elevation of the foundation.) The dehydrated soil you are building on is currently shrunk due to our present drought. It can expand if drainage is not adequate.
If you have an existing home adding compost will help only because it helps to retain moisture. The secret is to have moisture consistency. So if the home was built on dry ground then keep it dry. If the home was build on moist ground then keep it that way.
I do not like soaker hoses. They tend to put out more water at the low points and less at the high points. A regulated drip system is my preference. If you take care of the upper layers of dirt it will help prevent moisture loss from the lower layers. Tree roots are the biggest problem. It takes several hundred gallons of water per day to maintain them. They will inevitable travel under the house for moisture, way past the drip line.
Termites. All the ground in Texas is infested with termites. Foundations should have 6" of foundation exposure. All homes should have a regular program of termite control.

It was said: "I do not like soaker hoses. They tend to put out more water at the low points and less at the high points"

That's because they're supposed to be used on level ground.

If you have high & low areas, you'll have even moisture distribution only if you have pressure-compensated drippers. A soaker hose definitely isn't pressure-compensated.

The problem, as I recall, with the TOH in Austin was that when wet clay soils expand and create tremendous hydraulic pressure that can move mountains and the solution they used there was to install a drainage system in the soil around the house. Clay soils expand when wet and contract when dry although maybe, possibly, keeping a clay soil wet all the time might even that out some.
When sons house was built the contractor installed a drainage system around the footings at the basement level to prevent, or at least help keep, the moisture level of the clay soils low so it would not expand and cause the block basement walls to move and crack.

A cut and paste.
Prevention for a Slab Foundation

1.Do not focus on watering your foundation. Focus on watering your lawn, trees, & flower beds. The vegetation will tell you when it needs water & when it's had enough water.
2.A drip system can be installed around your foundation with emitters on your plants. Drip systems can be controlled better than soaker hoses. With soaker hoses more water comes out in lower areas & hardly any water comes out in high areas.
3.Gutter systems with extensions on the downspouts can also be installed to control rainwater flow. Gutters today are hardly noticeable, they match the exterior. The most important note is the extensions on the downspouts or having a drain system installed so that the downspouts empty into them.
4.Proper drainage should be in affect around the structure as to allow the flow of water to move away.
5.There should be a positive slope moving away from the foundation in the soil adjacent to the foundation.
6.Make sure the soil from flower beds and such is not above the foundation line.
7.Water should not be allowed to pond around the structure.
8.A root barrier system can be installed to control the roots of any trees close to the structure.
Doing everything you can to ensure the longevity of your foundation, will give you peace of mind. Now even if you do all the preventative maintenance for your home, there is no guarantee that it won't move at all. You may still experience minor movment, but that is still better than having structural damage occur.

I was thinking about how much graywater the average household sends down the drain every day, and wouldn't it be nice to redirect some of that to the foundation area during dry weather. Of course it would not be allowed by building codes in most places, but there's always the Kitchen Bucket which I use in the summer and fling out the back door or use on potted plants on the porch. One could even make a gravity-fed drip system with a small tank or hopper to dump dishwater etc. into. Kinda like a rain barrel system connected to foundation drippers. Rather fiddly and labor intensive but for the intrepid DIYer it is certainly possible.

We had a member who did that some years ago- Revamped the kitchen plumbing so that gray water from the sink dumped into a bog garden. The garden was beautiful as I remember.

I can't remember who that member was? This drives me nuts!

Karen

Some areas allow the diversion of grey water while others prohibit it. You need to know what your local and state health codes permit before looking into this diversion.
Because clay soils expand when wet diverting grey water, or any other water around the foundation of a house would not be a good idea. There is a very good reason rain diversion systems (eavetroughs, gutters) are put on houses aside form keeping water out if the basement.

kimmsr, they're already using drippers to maintain a more constant moisture content in the clay, which is how to prevent foundation cracking. I'm just suggesting graywater could be used instead of drinking water during those dry periods. The point is to keep the moisture content more level, rather than the winter wet/swell followed by summer dry/shrink cycles.

I agree that too much water around the foundation can be a problem, so you would have to do it right, but this is already true with the drippers everyone's using down there.

It's hard to imagine how it is if you don't live in that kind of soil/climate area. Here in Missouri, the Poor Drainage State of the Midwest, we're always trying to get rid of water, but there are folks with the opposite problem.

Son lives on the east side of the sate where the soil is clay. When his house was built, after the foundation was in, but the first floor deck was not yet on, there was a rain storm and the clay soil moved and cracked the foundation enough so that it had the be rebuilt. I am very familiar with clay soils having gardened in Oklahoma, Tennessee, Indiana, Ohio, and California.

I once heard a soil science professor here at the U. of Missouri say that with our clay soil it is not a matter of whether your basement will leak, but when.