Foundation Problems in Every Direction
San Antonio's clay soil doesn't care how beautiful your 1920s bungalow is. It expands when it gets wet and shrinks when it dries out, and that constant push-pull has been working on these older foundations for a century.
In King William, I see a lot of limestone block foundations. They were built well, but the mortar joints have softened over the decades. When the clay soil pushes against them, the mortar gives before the stone does. You end up with stepped cracks along the mortar lines and sometimes entire sections that have shifted a half inch or more.
A client named Doug bought a place on Madison Street last year. The limestone foundation had three separate areas with cracked mortar joints, and the living room floor sloped about an inch over eight feet. The structural engineer quoted him on 14 pressed piers at roughly $550 each, plus $2,800 for the mortar repointing. Total came to around $10,500. Doug told me later he wished he'd budgeted more for the inspection itself so he could have caught the cast iron pipe issue at the same time.
Pier and Beam vs. Slab Foundations
Most homes built before 1950 in these neighborhoods sit on pier and beam foundations. That actually gives you more repair options than a slab, since you can access the underside and adjust individual piers. The downside is that the cedar posts used as original piers rot over time in San Antonio's soil. I regularly find deteriorated cedar posts that need replacing with concrete.
Homes from the 1950s onward tend to be slab-on-grade. Slab foundation repairs in San Antonio run higher because pressed piers have to be driven from the exterior perimeter. Getting access on older lots with mature landscaping adds complexity and cost.
Stucco and Limestone Exteriors Tell Stories
Walking the exterior of an older San Antonio home is like reading a timeline. The original stucco or limestone finish shows every foundation shift, every settling event, every repair attempt.
Stucco cracks follow foundation movement. Hairline surface cracks from normal temperature expansion are one thing. But the cracks I flag in reports are the ones that open wider than a credit card thickness, run diagonally from window corners, or show evidence of being patched over repeatedly.
In Government Hill, I inspected a 1935 Spanish Colonial Revival that had been stuccoed over original limestone. The previous owner had patched cracks at least three times based on the different patch textures I could see. Underneath, the limestone had shifted enough to create a gap you could fit your finger into at one corner. The buyer, a woman named Patricia, asked the seller for a $7,500 credit and used it toward both the structural work and a proper exterior restoration.
Limestone itself holds up well in San Antonio's climate, but the softer varieties used in some early 1900s construction do erode. Water penetration through deteriorated limestone can cause interior moisture problems that aren't immediately visible.
The Cast Iron Plumbing Situation
If there's one thing I tell every buyer looking at pre-1980 homes in San Antonio, it's this: get a sewer scope inspection. It costs $150-250 and it might save you $15,000.
Cast iron drain pipes were standard in San Antonio homes through the late 1970s. After 50-plus years in our soil conditions, many of them are corroded, cracked, or partially collapsed. The problem is invisible until a camera goes down the line.
I had a client named Raj who was buying a 1962 ranch in Alamo Heights. Beautiful home, well maintained on the surface. The standard inspection looked clean. But the sewer scope found 30 feet of cast iron main drain that was maybe 40% blocked with corrosion buildup. The plumber estimated full replacement at $8,200.
Raj negotiated a credit and still bought the house. But he told me afterwards that without the scope, he would have had a sewer backup within the first year and been stuck paying for emergency work at premium prices.
What Replacement Looks Like
Full cast iron replacement in San Antonio typically involves tunneling beneath the slab or trenching through the yard for pier and beam homes. Some plumbers offer pipe lining as a less invasive alternative for lines that aren't fully collapsed. Lining runs about 60-70% of the cost of full replacement. Either way, it's not a project you want to discover after closing.
Electrical Systems Stuck in the Past
Knob-and-tube wiring still exists in some Monte Vista and King William homes built before 1940. Most have been at least partially updated, but I find original wiring in attics and wall cavities more often than you'd expect.
The bigger issue across these older neighborhoods is undersized electrical panels. A 100-amp panel was standard for decades, but modern San Antonio living with central AC, multiple appliances, and home offices really needs 200 amps. Upgrading the panel runs $1,800-3,500 depending on the scope.
Older homes also lack GFCI protection in kitchens, bathrooms, and exterior outlets. Texas building code requires it for new work, but existing homes are often grandfathered. I note the absence in reports because it's a safety concern regardless of code requirements.
One thing specific to San Antonio's historic districts: any exterior electrical work in King William or Monte Vista needs to comply with the Historic and Design Review Commission guidelines. That can limit where you place new panels, conduit runs, or exterior outlets. A buyer named Claudia found this out when her electrician's panel upgrade plan got rejected because it would have required visible conduit on the home's front elevation.
HVAC in Homes That Weren't Built for AC
These older homes were designed for San Antonio summers before air conditioning was widespread. High ceilings, covered porches, and cross-ventilation were the cooling strategy. When central AC was retrofitted, the ductwork had to go somewhere, and the results aren't always pretty.
I see ductwork crammed into attic spaces with minimal insulation, running through closets, or routed in ways that create long runs with reduced airflow. The AC unit might be sized correctly for the square footage, but if the duct system can't deliver the air efficiently, rooms end up uneven. The back bedroom is 82 degrees while the living room is 70.
In Monte Vista especially, some homes have window units supplementing central systems in rooms where the ductwork just can't keep up. That's a sign the HVAC system was never properly designed for the space.
Replacing a central AC system in San Antonio runs $6,000-12,000 depending on size and efficiency rating. For these older homes, adding or replacing ductwork pushes costs higher. I always recommend buyers get a dedicated HVAC evaluation in addition to the standard inspection if the system is more than 12 years old.
What Historic District Rules Mean for Repairs
King William was one of the first historic districts designated in Texas. Monte Vista followed. If you're buying in either area, the Historic and Design Review Commission has authority over exterior changes. This matters for inspection findings because some typical repair approaches aren't allowed.
You can't replace original wood windows with vinyl. You can't put on a metal roof if the original was composition shingle. Stucco repairs have to match the original texture and color. Even foundation repair methods that require exterior access may need review if they affect the home's visible profile.
This doesn't make repairs impossible, just more specific and sometimes more expensive. A standard vinyl window replacement might cost $300-500 per window. A historically appropriate wood window restoration or custom replacement can run $800-1,500 per window.
For buyers, the inspection report on a historic district home needs to be read with these constraints in mind. The repair isn't just "replace the windows" but "replace the windows in a way the commission will approve." Budget accordingly.