Block, limestone and timber walls built with drainage behind them, on Hill Country slopes that move water fast. Rated 5.0 by 74 homeowners.
Almost every failed retaining wall we are called out to look at failed for the same reason, and it is not the blocks. It is water.
Soil behind a wall gets saturated. Saturated soil is heavier and it pushes, and that pressure, called hydrostatic pressure, is what leans a wall out and eventually rolls the top course off. On ground that drains, this builds slowly. On limestone and caliche, where water arrives fast and has nowhere to go, it builds every time it rains hard.
So a retaining wall is a drainage structure first and a stone structure second. Four things do the work:
The workhorse. Engineered units that lock together, available in colours that read as stone from a few feet away, and the material that most engineered walls here are built from because the manufacturers publish tested design tables for them. Best value for a wall that has real work to do.
What looks right on a Hill Country property, especially where the house is faced in the same stone. Chopped block for a structured look, or larger irregular stone for something more rustic. More expensive per square foot of face than block, and worth it where the wall is a feature rather than just a solution.
For tall walls, tight spaces and situations where an engineer specifies it. Can be veneered in stone afterwards so it reads as masonry. Highest cost, highest capability.
Least expensive, and honest about it. Treated timber walls work for low garden terraces and they will not last as long as block or stone in this climate. We build them where the budget calls for it and we tell you what you are buying.
This is the part homeowners are never told, and it is worth knowing before you accept a quote.
In San Antonio, a retaining wall does not require a permit if it is 4 feet or less in height along its entire length and there is no surcharge on it. Above that, or with a surcharge, it requires a permit. And a wall that requires a permit has to be designed by a Texas licensed professional engineer, with the design professional inspecting the work and providing a letter before the permit can be closed.
A surcharge is any vertical load sitting on top of the wall or on the soil it retains. In practice that means soil sloping up behind the wall steeper than 3 to 1, a building foundation, a driveway or parking area, or a fence attached to the wall. A structure further back from the wall than one and a half times the wall exposed height is not treated as a surcharge. There is a specific carve-out worth knowing: a residential wall 4 feet or less carrying only a fence surcharge is still exempt from permitting, except in precast concrete or CMU.
Tiered walls, walls of 10 feet and over, and walls over expansive soils or groundwater need a global stability analysis on top of the individual wall design.
Why this matters to you: “we can build that 6 foot wall next week, no permit needed” is not a shortcut, it is a wall that has not been engineered, on ground that pushes. If your project crosses the line, we will tell you, and we will work with an engineer rather than around one. Boerne and Kendall County have their own requirements and we check them for your address rather than assuming San Antonio rules apply.
On a lot that drops several feet across the back yard, the instinct is one tall wall. Frequently the better answer is two or three shorter ones stepped back from each other, and the reasons are practical as much as aesthetic.
Shorter walls may stay under the height where an engineer and a permit are required, though only if each one is genuinely independent. Stacked too close together, tiered walls behave structurally as one tall wall, and San Antonio treats them that way, requiring a global stability analysis. The rule of thumb is that the upper wall needs to sit back from the lower one by at least twice the height of the lower wall to be considered separate. Closer than that and you are building a tall wall in disguise.
What terracing buys you when it is done properly: usable flat ground at each level instead of one strip at the bottom, planting beds that hold water rather than shedding it, a slope that reads as garden rather than as engineering, and a much less imposing structure from the house.
Each terrace is a wall in its own right, with its own base, its own drain and its own backfill. Skipping the drain on the upper terraces because they are short is how you get water arriving behind the bottom wall from above.
We repair walls other people built, and we get called about the same handful of symptoms.
The wall is leaning out. Hydrostatic pressure, nearly always. If it has moved a little and the base is sound, the fix can be dismantling the top courses, installing the drain and gravel backfill that was never there, and rebuilding. If it has rotated at the base, it is coming down and going back up.
A bulge in the middle. Usually a localised drainage failure or a section where the backfill was soil rather than gravel. Sometimes repairable in a section.
The top course is walking off. Common on dry laid block walls with no cap adhesive and no drainage. Often the cheapest of the repairs.
Cracking through a mortared stone wall. Either movement at the base or water freezing in a joint over several winters. Repointing without solving the cause buys a year or two.
Soil washing out from behind the wall. Missing filter fabric. The soil is migrating through the gravel and out through the joints, and you can see it as a stain down the face.
The first thing we do on any repair call is work out why it moved, because a wall rebuilt without fixing the water will move again. Sometimes the honest answer is that the wall is beyond repair and rebuilding costs less than a repair that will not hold, and we will say so.
Retaining walls are priced by square foot of exposed face, not by linear foot, because a 3 foot wall and a 6 foot wall of the same length are entirely different jobs. Typical installed ranges, not a quote.
For scale, a 40 foot wall at 3 feet high is 120 square feet of face. In block that is a mid four figure job before drainage and access are considered.
What moves the number here: height first, because height drives base depth, geogrid and whether an engineer is involved. Then access, because every block and every ton of gravel has to reach the wall, and a back yard behind a 36 inch gate is a wheelbarrow job. Then rock, because on a Hill Country lot the base trench often has to be cut rather than dug. Then the drainage and the backfill, which are not optional and which we would rather include in the quote than value engineer out of it.
In San Antonio, not if it is 4 feet or less along its whole length with no surcharge on it. Above that, or with a surcharge such as a slope steeper than 3 to 1, a foundation, a driveway or an attached fence, yes, and then it has to be engineered by a Texas licensed professional engineer. Boerne and Kendall County have their own rules and we check for your address.
Water, in the overwhelming majority of cases. No drain behind the wall, or soil backfill instead of gravel, so pressure builds every time it rains hard. The blocks are almost never the problem.
A properly built block or stone wall with drainage should outlast you. Timber is a different conversation and will need replacing far sooner in this climate.
Yes, and it softens the whole structure. Keep it to shallow rooted, drought tolerant plants and remember that the bed behind the wall drains fast, so it wants plants that like that.
Often several, for cost, for usable space and for how it looks. But they have to be genuinely separate. Set the upper wall back from the lower one by at least twice the lower wall height, or the two behave as one tall wall and get treated as one.
Depends on whether the base has rotated. Movement in the upper courses with a sound base can often be repaired by dismantling, adding the drainage that was missing, and rebuilding those courses. Movement at the base means rebuilding.
They let water that has collected behind the wall escape through the face rather than pushing on it. They are one way of outletting the drain behind the wall, and a wall with neither weep holes nor an end outlet has no way to relieve pressure.
Yes. Walls next to pools and patios are frequently surcharged by the structure beside them, which changes what the wall has to be designed to do. That is exactly the situation the permit rules exist for.
The flat ground a wall usually exists to create.
Water behind a wall is the same problem as water in a yard.
Seat walls, steps, borders and stone.
No charge and no salesperson. Someone comes out, looks at the yard, and tells you what it needs. We work in Boerne, Fair Oaks Ranch, Helotes and northwest San Antonio, Monday to Friday from 8:00 AM to 6:00 PM.
28991 IH-10 W, Suite 104, Boerne, TX 78006
travislandscapingtx@gmail.com
