Crawl Space Repair in San Marcos

Why a San Marcos crawl space drops in patches

The soil record this site publishes for San Marcos names Heiden, a clay with a linear extensibility of 12.1 percent, which puts it in the very high shrink-swell band. Rumple and Comfort soils are also present in the area, where the ground thins out over rock. We will not tell you which of those is under your house, because it changes lot by lot and nobody reads that off a map. What matters is that both show up around this town and they behave in opposite directions. Clay with that much movement in it swells through a wet spring and hands the volume back through a dry late summer. Ground thinning over rock barely moves at all. You can find the series write-up on the USDA Heiden soil series page.

A slab spans that difference badly, but it spans it as one piece. A crawl space does not. Its load comes down through a grid of separate posts, blocks and piers, and each one answers only to the dirt directly beneath it. Put some of those supports on clay that cycles that hard and the rest on ground that sits still, and the floor above does not tilt evenly toward a low corner. It develops a dip in one room and a firm spot eight feet away, in the same season. Homeowners usually describe it as a soft patch or a roll in the hallway rather than a slope, and that description is normally accurate.

Beams, sills and blocking, which is most of the work

Once we are under the house the list is short and physical. Shim stacks that have walked out from under a beam get rebuilt. Post tops that have split get replaced. Beam bearing that has slipped off its block gets reset and packed. Sills gone soft from years of damp get cut back to sound wood and spliced. None of that needs excavation, and on a lot of San Marcos crawl spaces it is the entire scope. The carpentry side in detail is in our write-up on floor joist and sill repair, and the wider craft sits on our pier and beam foundation repair page.

Where a support has genuinely run out of competent ground to stand on, we drive a pier under it. We install steel and hybrid piers only, at $600 to $1,000 each, with a lifetime transferable warranty on the piers. Concrete piers were discontinued and are not something we offer. On uneven bearing like this the count is usually small and local, because the point is to catch the patch that dropped, not to ring the whole house.

The moisture half, and why it decides how long the repair lasts

Wood under a San Marcos crawl space fails where water keeps touching it. The sources are dull ones. A downspout dumping beside the skirting. Ground that slopes back toward the house. A gap at the sill line that lets rain and leaf litter in behind the trim. Damp soil under the floor also parks the clay beneath your supports at the wet end of its range, which is the end where it is biggest, and when that soil finally dries the supports standing on it come down with it.

So the water work and the framing work are one job, not two scheduled apart. Re-grade, run the downspouts out past the drip line, close the sill gaps, and the point you just re-shimmed stays where you put it. How that is done on a Central Texas house is covered on our crawl space moisture control page. Encapsulation is the other question people arrive with, and the reasoning on that one lives on the main crawl space page rather than being repeated here.

Older homes near the square

The older housing near the square is where most of our San Marcos crawl work happens, and those houses need a different target than a recent build does. A house that has been settling into the same ground for decades has found a shape. Chasing it back to dead level cracks plaster, pops tile and opens joints that were quietly fine. The goal is stable and functional, which means the floor is properly supported, the framing is sound, and the movement has stopped. It does not mean a level reads zero in every room.

That target also means a real share of these visits end with nothing to sell. About a third of our inspections finish with no repair needed, and an old crawl space with tired-looking but sound framing is one of the ordinary reasons why. If that is your house, you get it in writing, along with a dated set of readings to measure against the next time something creaks.

What the inspection covers in San Marcos

The free inspection includes going under the house, not a look at the floor from above and a guess. We shoot floor elevations in tenths of an inch, then crawl the space and read the beams, sills, posts, blocking and the moisture picture against those numbers. You get written findings saying what moved, what did not, and what a repair would cost if one is warranted. Our inspectors are ICC-certified, not engineers, so a stamped engineer letter for a lender or a sale is a separate document from an independent engineer and answers a different question. After a repair, the yearly performance follow-up inspection checks that the correction is still holding. Slab work, the corridor subdivisions and the rest of what we do in town are on the foundation repair in San Marcos page.