# Pier-and-Beam vs. Slab: How Repairs Differ | Guide > How repair differs by foundation type: construction and method differences, access and disruption, and why foundation type shapes the scope. URL: https://sanantoniofoundationrepair.net/guide/pier-and-beam-vs-slab-how-repairs-differ/ Last-Modified: 2026-09-16 Decision guide # Pier-and-Beam vs. Slab: How Repairs Differ How repair differs by foundation type: construction and method differences, access and disruption, and why foundation type shapes the scope. Published September 16, 2026 · 5 min read ![Split view of a slab perimeter pier pit and a pier-and-beam crawlspace entrance](/images/featured/split-view-showing-a-slab-perimeter-pier-pit-on-on.webp) ## Two Different Machines A slab-on-grade foundation is one large concrete element bearing directly on the ground. A pier-and-beam foundation is an assembly of discrete supports and wood members holding the structure above the ground. They respond to the same soil conditions, but because they are built differently they fail differently and they are repaired differently. Understanding that is what lets you read a proposal for your own foundation type rather than applying general assumptions. Our slab foundation repair [/slab-foundation-repair/ →](/slab-foundation-repair/) and pier-and-beam repair [/pier-and-beam-repair/ →](/pier-and-beam-repair/) pages cover each service in full, and our guide on what pier-and-beam repair involves [/guide/what-pier-and-beam-repair-involves/ →](/guide/what-pier-and-beam-repair-involves/) goes through the raised-home side step by step. ## How They Move **Slab.** A rigid element. When the ground under part of it changes, the slab bends across a broad area. The symptoms appear as a pattern over a section of the house rather than in one spot. Movement can also be upward, as center heave or edge lift, which complicates the diagnosis considerably. **Pier-and-beam.** An assembly. A single settled pier affects the members it supports and comparatively little else. A single failing joist affects one bay of floor. Symptoms tend to be more local and more precisely locatable. That difference has a practical consequence for assessment. On a slab, an elevation profile across the whole plan is essential because the shape of the movement is the diagnosis. On a raised home, an elevation profile plus a crawlspace inspection is needed, because the cause may be beneath the floor rather than beneath the house. ![A concrete slab edge next to a raised pier-and-beam skirt](/images/content/a-concrete-slab-edge-next-to-a-raised-pier-and-bea.webp) ## Side by Side | | Slab-on-grade | Pier-and-beam | | --- | --- | --- | | Structure | One concrete element on the ground | Piers, girders, joists over a crawlspace | | Typical era in San Antonio | 1960s onward | Pre-1960s | | Access to the underside | Excavation, tunnelling, or cutting the floor | Crawl in | | Main failure mode | Differential soil movement | Support settlement and wood decay | | Wood decay risk | Not applicable | Significant | | Termite exposure | Lower | Higher | | Repair method | Underpinning with piers | Shimming, sistering, pier and footing work | | Repair granularity | Broad sections | Individual members | | Typical disruption | Perimeter excavation, possible floor opening | Crawlspace work, minimal interior impact | | Re-leveling in future | Requires new work | Adjustable at support points | | Plumbing access | Beneath the slab, difficult | In the crawlspace, accessible | ## Where the Repair Differs Most **Getting to the problem.** This is the single biggest practical difference. On a slab, reaching an interior load line means either opening the floor or tunnelling from outside. On a raised home, it means crawling to it. That difference drives both cost and disruption more than anything else. **What can be adjusted later.** A pier-and-beam home can be re-shimmed and re-levelled repeatedly over its life. A slab, once underpinned, is supported at fixed points. Neither is better; they are different maintenance profiles. **What the assessment looks for.** A slab evaluation is dominated by the elevation profile and site conditions. A raised-home evaluation adds a full crawlspace inspection: pier condition, girder bearing points, joist condition, moisture, and termite evidence. **The role of plumbing.** On a slab, a leaking line beneath the floor is both a significant cause of movement and difficult to reach. On a raised home, crawlspace plumbing is visible and accessible, which makes both diagnosis and repair simpler. > **On homes that have both** > > Older San Antonio properties frequently have an original raised structure with a later slab-on-grade addition. The two foundation types respond differently to the same conditions, so the junction between them is often where movement shows first. An evaluation covers both parts and the scope addresses each on its own terms rather than treating the house as one system. ## What Does Not Differ **The soil.** Expansive clay behaves the same way regardless of what is built on it. Moisture consistency around the perimeter matters for both. **Drainage.** Directing water away from the structure benefits both foundation types, and is arguably more important for raised homes because water reaching the crawlspace causes wood problems as well as soil ones. **The assessment principle.** Measure first, diagnose second, select a method third. That order applies to both. **The documentation you should receive.** Findings, an elevation record, a written scope with exclusions, warranty terms, and a completion record. Neither foundation type justifies less than that. ## Which Do You Have? If there is a vented skirt around the perimeter, an access hatch, and the floor sits noticeably above grade, it is pier-and-beam. If the floor is at or near grade with a visible concrete edge below the brick ledge, it is slab-on-grade. Floors that flex slightly underfoot suggest a wood subfloor rather than concrete. The evaluation confirms it, and the confirmation matters, because access, method, scope, and cost all follow from it. Quick answers ## Questions About This Topic ### Which foundation type is easier to repair? expand\_more Pier-and-beam is generally more accessible, since every structural member can be reached from the crawlspace, which usually makes targeted repairs less disruptive and less expensive. That does not make it easier overall, because it introduces wood decay and termite considerations that slabs do not have. Each type has a characteristic set of problems. ### How do I know which foundation I have? expand\_more A vented skirt around the perimeter, an access hatch, and a floor sitting noticeably above grade indicate pier-and-beam. A floor at or near grade with a visible concrete edge below the brick ledge indicates slab-on-grade. Floors that flex slightly underfoot suggest a wood subfloor. An evaluation confirms it, and homes with additions sometimes have both. ### Do the two types need repair at the same rate? expand\_more They respond to the same soil conditions but in different ways, and a general rate comparison is not meaningful. What matters is the specific property: its soil, its drainage, its construction quality, and its history. Using foundation type as a proxy for risk is the same error as using a ZIP code. ## Related Guides ### Crawl Space Moisture and Wood Rot in San Antonio Homes Crawlspace humidity, wood rot, and moisture mitigation in older San Antonio homes: sources, risks, vapor barrier concepts, and what an assessment checks. Read guide arrow\_forward [Crawl Space Moisture and Wood Rot in San Antonio Homes →](/guide/crawl-space-moisture-and-wood-rot-san-antonio/) ### How Beams, Joists, and Piers Are Repaired The mechanics of pier-and-beam restoration: beam shimming and replacement, sistering joists, pad-and-block work, re-leveling, and restoration. Read guide arrow\_forward [How Beams, Joists, and Piers Are Repaired →](/guide/how-beams-joists-and-piers-are-repaired/) ### Signs of Pier-and-Beam Foundation Problems How pier-and-beam home owners recognize problems: bouncy or sloping floors, gaps, moisture indicators, and when to request an evaluation. Read guide arrow\_forward [Signs of Pier-and-Beam Foundation Problems →](/guide/signs-of-pier-and-beam-foundation-problems/) ### What Pier-and-Beam Repair Involves The scope of pier-and-beam repair: construction basics, common repair scope like shimming and sistering, pier work, and crawlspace access. Read guide arrow\_forward [What Pier-and-Beam Repair Involves →](/guide/what-pier-and-beam-repair-involves/) Browse all guides [/guide/ →](/guide/)