Watering the foundation: Good? Unnecessary? Method?

[Nadine]

I think I know the answer to this, but my mom wants me to inquire on the subject. She has a sprinkler system, but a structural engineer told her she also needs a soaker hose around the perimeter of the foundation (slab).
By the way, this person does not sell or recommend anyone to do this work, so I do not think he's in it for the money...

She has problems with cracks in the walls (has high ceilings) and is continually having them repaired. She has been told by more than one foundation repair company that foundation repair will not fix the problem in her situation (unless she levels the house and does the big commercial building type foundation which is more money than it would be worth).
:?
Can I get some input from those of you who are knowledgeable on the subject? Thank you!

[Tricky Grama]

Nadine-

I'm sure somone who really knows what they are talking about will chime in, but what I know is: everyone w/slab home needs to have a soaker hose all around the foundation. Every 2 weeks at least, if there is no rain, give it a good soak-I think about 2 hrs worth. It is b/c our soil is so rock hard & cracks & shifts. This can harm the slab.

Patty

[Pamzilla1]

Thick evergreen bushes along the foundation help to regulate the change in moisture levels too. Also I would think if you irrigate your entire landscape regularly that would be sufficient. What you want is a steady moisture level.

[kmbrandon]

OK, I can get more detailed info if needed, but here's the simple answer: Like Pamzilla said, you just need to keep the moisture levels relatively consistent. Your goal is to maintain to same moisture level of the surrounding soil and the soil under the slab. The soil under the slab stays relatively the same year round since it is not exposed to weather (think about how a cave is the same temp year round). That being said, the surrounding soil obviously is exposed to our wonderful hot, dry summers which causes the ground to dry out around the foundation & contract. Since the moisture under the slab is still there, the home only has room to "shift" toward the dry areas.

That being said, overwatering your foundation can be a problem too for the same reasons. The recommendation from our builder (Fox & Jacobs) is to water TWO FEET OUT from the foundation with either your sprinklers or a soaker hose. They were very specific about not watering up against the foundation, but I don't recall the exact reasoning. In my case, my sprinkler heads are about 2" from the foundation & spray out into the yard so I'm well covered at the recommended two foot mark. Also, it was mentioned NOT to plant anything closer than two feet from the foundation.

Kevin

[Nadine]

Thanks!

She already has a sprinkler system; my thoughts are that this should be sufficient. Any further comments are welcome. I'm sure this is a topic most folks living in the North Texas area can appreciate.

Did you know the DFW metroplex has more foundation problems and more foundation repair companies than anywhere else does in the world? :o This fact is per a professor at UNT in the geology department. It is because of the different soils that come together in combination with the rock (types?) below. Hmm...

[tommyr]

Nadine, in heavy clay soil under dry conditions, the foundation certainly needs watering. I used to live in a 2 story house that was built in the 20's. Full covered porch on 2 sides, but at the back of the house there was a back door that was not covered. In dry conditions the door would get hard to close. Would water the foundation around the door and results would be almost immediate and the door would be closing fine. But in heavy clay during dry conditions, the heavy clay will crack. So will your foundation.

[kgolf]

here is my 2cents worth based on my own frustrating foundation problems in addition to what has already been said.
i live in dallas with the black soil which resides on top of the 'river' of limestone that runs through this part of the state.
definately water your foundation, however, it is very hard, if not impossible to keep up with the drying up of the ground during these rainless and 100+ temp days. 2ft out is what they recommend. the fireplace (if you have one) is the heaviest section, so it will pull the surrounding area down with it so pay attention to that when watering. if your foundation moves alot, it may be creating cracks in the slab which may allow termites access. :cry: also, it can pull your plumbing lines loose underneath the slab where it hooks up to your bathrooms, kitchen, etc like it did mine ($9k total repair covered mostly by insurance). there are several plumbing lines below your home for the bathrooms, kitchen, and clothes washer. also, tree roots can suck away any remaining moisture in the ground around the house. they are seeking moisture underneath the edges of the house as you already know. these are all potential things that can happen, like at my house. scary, because all said and done with foundation repair, plumbing repair, outside brick repair, drywall repair, etc. it can add up to $20-25k+ in repairs.
no need to keep paying money to fix drywall cracks if you don't fix the source of the problem. that gets expensive and messy.
so... it pays to attend to foundation problems as soon as you can, even though there is no great technique out there that i can see to permantly solve the problem forever. there are multiple techniques and technologies available in foundation repair as well, and every company claims theirs is the best. very frustrating !

[Nadine]

Wow, kgolf, I am sorry to hear about all your trouble with plumbing issues and all. I never thought of that. Her fireplace is not on an outside wall, so I don't know what to say about that...

Thanks for the information, though.

Does anyone else have anything to add?