Add "Building Foundation" Zone Type (for us Texans)

A more explicit ask than this thread, it would be nice to have a “Building Foundation” zone type for dedicated Building Foundation watering zones which have no actual vegetation in them.

Here in Texas we absolutely have to water our foundations year round or we risk the clay drying out and the foundation shifting/cracking. The moisture tracking that the Rachio would be very useful for these types of zones and saving money if the proper soil moisture ratios could be figured out.

I just heard about this concept from a friend who lived in San Antonio for a few years. Being from Arizona, they had never heard about this, and no one told them this was needed when they bought a brand new house, and within months they had MAJOR foundation issues…

As for an answer, is there a rule of thumb for how moist the ground should be? What do you use to distribute water? Does this run just around the perimeter, or under the slab?

Interestingly enough, it’s about maintaining a moisture level around the perimeter of the foundation (where the sun is baking the clay soil and drying it out) that matches the moisture level underneath the house that is protected from the sun and not drying out. The guideline is to run a drip-line type sprinkler for about 30 minutes 2-3 times a week, although there are those without a dripline that use other distribution methods.

The indication that you need to water is that the soil around your foundation begins to pull away from the foundation.

Hmmmm… I know nothing about this concept, so I’m taking a WAG…

First option would be to use a fixed schedule set up to run 2-3 times a week for 30 minutes. Have the zone set up with weather intelligence so that it won’t water when it’s raining and waste water.

If you wanted to get fancier, you could set up a flex daily drip zone as a shrub zone in order to keep the shallower soils moist. Set the PR of your drip line to match whatever you are using, and set the root depth of that zone to 8" or so. There will most likely be some fine tuning to get it right, but might do a better job of accurately tracking moisture levels once dialed in…

I already did set up a flex daily zone as shubs. This thread was meant as a product enhancement suggestion for the Rachio coding team.

Wow. First I’ve heard of this, too. Fascinating. Those are some insane soils! General wisdom, which is correct in my case, is to keep water away from the slab foundation and I’ve spent a good deal of time doing so. When we moved in to this 80’s house there were big time drainage issues so I made some shallow relief trenches and did a bit of hand grading to get standing water away from the slab. Glad Rachio is flexible enough for you to get to a solution.

The general wisdom you’re quoting is still the general wisdom here in Texas, keep the water away from the foundation. In fact, the soil around my house is graded in such a way that the water drains away from it and my pool decking also has drainage to get the water away from the foundation.

This is part of the “why” you want a drip line/soaker hose around the foundation. We have these nasty sandy clay soils here in Texas that expand and contract with water, but don’t do a good job of transmitting it. So the clay underneath the foundation is retaining a certain amount of water while the clay that is exposed to hot sun during the summer is not retaining any water at all. The net effect is that the soil will “pull away” from the house foundation and consequently the foundation loses the support of the soil on the outside of the foundation (or worse, some of the soil up underneath the foundation manages to dry out because a hole opened up from the outside, and suddenly you have cracks in your walls and maybe even your foundation).

By keeping the soil around the foundation at a consistent moisture level you keep this from happening. Where I live, city code requires that builders install drip lines around the foundation for this exact reason.

The nice thing here is that the Rachio is tracking the moisture levels, so it can maintain that moisture level around the foundation for me. That said, and why I started the thread, it would be nice to have a zone type that was explicitly called “Building Foundation” that maybe has some better foundation maintenance algorithms build in, especially since we’re not necessarily trying to keep any plants alive here.

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Thank you for taking the time to write that excellent overview! Very informative.

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