Foundation Repair? Contracting Soil or Solid Rock in Austin? (Houston: construction, live in)

[joebaldknobber]

Is the ground in Austin solid Hill Country Rock or contracting soil that expands and contracts much like Dallas?

Is foundation repair common in Austin, or does it depend on where you live in the area?

[Austin97]

Originally Posted by joebaldknobber

Is the ground in Austin solid Hill Country Rock or contracting soil that expands and contracts much like Dallas?

Is foundation repair common in Austin, or does it depend on where you live in the area?

both, west of i35 it is rock, east of i35 is it contracting soil

[CptnRn]

Originally Posted by Austin97

both, west of i35 it is rock, east of i35 is it contracting soil

That is not entirely true, while most of the worst areas of expansive soils are East of IH-35, there are pockets of expansive soils West of IH-35. Alandale has some of them and there are probably others. There are also some areas East of IH-35 where the soils are not a problem.

larger map here http://texashistory.unt.edu/ark:/675...m1/1/high_res/





To the O.P. Foundation repair is often needed in many parts of Austin.

[mickey65]

So what are we looking at on this map? What colors are good and which are bad??

[CptnRn]

Originally Posted by mickey65

So what are we looking at on this map? What colors are good and which are bad??

Clay soils are problematic for constructing foundations on but often make great soil for different kinds of crops. Texas Blackland Prairie is some of the best farming land you can get, but can be a very poor soil to put a foundation on. That is a complex subject. In general anything described as clay is an expansive soil, but some are worse then others. If you view the larger sizes diagram you can see in the color chart legend along the right border which soils are types of clay. Counting down from the top of the legend, 1, 2, 3, 7, 8, 9 are clays. The white area indicates rock outcroppings, a lot more of the area west of Austin, not shown on this map, is limestone rock outcroppings. The Light grey area out around Manor is Houston Black Clay, some of the worst soil, most expansive, that I have seen for construction. That clay is also usually found in thick deep layers, which makes building a foundation on it more problematic. Austin Clay, the dark pink areas, and Colton Stony Clay, the dark grey areas, are usually found in thinner layers, which can be scrapped off and replaced with a better base for foundations without too much difficulty.

This website has a good description of the issues regarding soil problems: Foundation Repair Austin, Texas TX

Foundations
Shrink-swell characteristics of the soil need to be considered in designing a building foundation, particularly if piers are not used below the slab. Such clay soils as those of the Houston Black, San Saba, and Ferris series are particularly poorly suited to building sites. They swell when wet and shrink when dry. This shrinking and swelling exerts such pressure that walls and foundations crack unless they are specially reinforced, sidewalks and driveways crack, and streets and sidewalks deteriorate more quickly (plate V).

[oldtoiletsmkgdflrpots]

I was reading the October issue of National Geographic, "Rebuilding Buddhas", and saw they used to put goat hair in the clay to prevent cracking when the clay dried. (5th -6th Century) Why isn't it done today?

[CptnRn]

Originally Posted by oldtoiletsmkgdflrpots

I was reading the October issue of National Geographic, "Rebuilding Buddhas", and saw they used to put goat hair in the clay to prevent cracking when the clay dried. (5th -6th Century) Why isn't done today?

Not enough goats.

[oldtoiletsmkgdflrpots]

I had a goat knock on my door once.

[CptnRn]

Originally Posted by oldtoiletsmkgdflrpots

I was reading the October issue of National Geographic, "Rebuilding Buddhas", and saw they used to put goat hair in the clay to prevent cracking when the clay dried. (5th -6th Century) Why isn't done today?

Also there are more effective ways to build foundations these days. I assume that method you described was for building statues out of clay and not necessarily used for building foundations. I know that 100 years ago animal hair was commonly used in plaster for the same reason, to reinforce it.

[CptnRn]

Originally Posted by oldtoiletsmkgdflrpots

I had a goat knock on my door once.

Was he selling something?