Shop slabs, RV pads and foundations built for Williamson County ground
A metal building is only as good as the slab it's bolted to. We pour shop and barn slabs, RV and boat pads, casita and addition foundations — with the thickened edges, grade beams and void boxes the clay side of the county demands, and the engineer's letter when the city or your lender asks for one.
Half the calls we get from Weir, Walburg, Jarrell, Florence and the acreage lots along Highway 29 are for the same thing: a slab for a metal building. A 30-by-40 shop, an RV cover, a barn with a tack room, a workshop with a lift. The steel kit comes with an anchor-bolt plan; it doesn't come with a slab designed for black clay, and the kit company's generic drawing — four inches, wire mesh — is how you end up with a shop door that won't close two summers later.
Our shop slabs are a monolithic pour: a four- to six-inch slab with a thickened perimeter beam (usually 12 by 24 inches) and interior beams where the building's columns land, #4 rebar in the beams and #3 in the slab on chairs, a vapor barrier where the shop will be conditioned, and anchor bolts or embed plates set to the building manufacturer's template. On the clay side we add moisture conditioning, a wider beam and, for anything you'll live in, void boxes under the beams so the soil can heave without lifting the building.
For casitas, ADUs, room additions and anything with plumbing or a conditioned space, the City of Georgetown requires a building permit and, in most cases, an engineered foundation plan. We work from the engineer's drawing, pour to it, and schedule the city's inspections. If you don't have an engineer yet, we'll point you to ones who know Williamson County soil.
What's included
Slab design for the soil
Monolithic slab with perimeter and interior grade beams sized for the building and the soil, not a one-size kit drawing.
Engineered when required
Casitas, ADUs, additions and conditioned shops poured to the engineer's plan; anchor bolts and embeds set to the manufacturer's template.
Site prep
Pad graded and built up with select fill where the lot is low, compacted in lifts, drainage away from the slab.
Void boxes & vapor barrier
Cardboard void forms under beams on expansive clay for occupied buildings; 10-mil vapor barrier under conditioned slabs.
Inspections
City of Georgetown or Williamson County pre-pour inspection met with the engineer's letter where needed.
Flatness for equipment
Power-troweled, flat slabs for lifts, machinery and epoxy floors; broom finish for barns and RV pads.
Slab and foundation costs in Georgetown, TX
| Job | Typical price | Notes |
|---|---|---|
| RV / boat pad, 12×40, 5" reinforced | $4,500 – $7,500 | Broom finish, side-yard access |
| Shop slab, 30×40 (1,200 sq ft), with perimeter beam | $13,000 – $20,000 | Anchor bolts set to template |
| Shop slab, 40×60 (2,400 sq ft), with interior beams | $26,000 – $40,000 | Power-troweled |
| Casita / ADU foundation, 600–800 sq ft, engineered | $14,000 – $24,000 | To engineer's plan; void boxes on clay |
| Room addition foundation, 300–400 sq ft | $7,000 – $13,000 | Tied to existing per engineer |
| Pad grading and select fill | $1,500 – $6,000 | Depends on how low the lot sits |
Slab pricing depends heavily on the soil side, pad grading and the engineer's beam design, so these are 2026 Williamson County ranges for budgeting. Your quote itemizes grading, fill, steel, beams, void boxes, vapor barrier, concrete and finish.
Recent work
Questions we get about slabs, shops & foundations
How thick should a shop slab be?
Four inches is fine for a shop with light vehicles on limestone ground; five is our standard, and six with heavier rebar where you'll park a truck, run a lift or store equipment. The perimeter beam matters more than the slab thickness — that's what carries the building's columns and keeps the edge from curling on clay.
Do I need a permit for a shop slab in Georgetown?
Inside the city limits, an accessory building over a certain size needs a building permit, and the slab is inspected as part of it. In unincorporated Williamson County there's no building permit for most agricultural and accessory buildings, but a development permit and floodplain check may still apply. We'll tell you which one your address falls under.
What are void boxes and do I need them?
Cardboard forms placed under grade beams before the pour. They hold the beam up while the concrete cures, then soften and collapse, leaving a gap so expansive clay can swell into the void instead of lifting the building. On the Blackland side, any foundation you'll live in should have them; a shop slab usually doesn't need them, but a wider beam.
Can you pour a slab for a metal building kit I already bought?
Yes — send us the anchor-bolt plan and the reaction loads from the kit manufacturer and we'll pour to it. We set the bolts in a template so the columns land where they're supposed to.
How long before the building can go up?
Anchor bolts can be loaded after seven days; most erectors want 14. Full strength at 28. We'll schedule the pour so the building crew isn't waiting.