Patios

North Texas clay swells when it rains and shrinks when it bakes, and a patio poured straight on it rides that movement up and down. We strip the topsoil, compact the subgrade and set the slab on a compacted base so the concrete has something stable to bear on.

The slab is 4 inches with rebar on chairs at mid-depth, which adds roughly $0.60 to $1.10 per sq ft and is money well spent on clay. We set forms to fall a quarter inch per foot away from the house — the 2 percent the residential code Arlington has adopted requires within 10 feet of the foundation — so rain leaves the slab instead of pooling against it.

New concrete does not bond to old concrete on its own. Pour against the existing edge and you get a cold joint: the two pieces move independently and a lip shows up at the seam. That is the most common extension we get called to fix.

Where the old slab is sound we drill and epoxy rebar dowels into its edge so the new pour is pinned to it. Where it is cracked or heaving, tearing it out and pouring one slab is the honest answer, and demo runs $2.50 to $4.50 per sq ft. Fresh concrete is lighter than a slab that has weathered ten summers and evens out over a year; a saw-cut joint placed on purpose at the seam reads as a design line instead of a patch.

A masonry island with a built-in grill, a counter and a fridge concentrates more load on a few square feet than the rest of the patio carries in total. We thicken the slab and run extra steel under it, and we need the island location and any gas, water or electrical sleeves before we pour, because cutting them in later is the expensive way.

Pergola posts need footings, not just a slab. We pour the pad and set the footings or anchor points where the steel lands, and CJM Metals builds steel pergolas on top, so the layout is worked out between the two crews. A patio cover needs a City building permit and gas or electrical runs need their own trade permits; we confirm what yours needs before we dig.

Broom finish is the workhorse at $8 to $14 per sq ft. The texture grips when the slab is wet and hides minor variation, and it is what we recommend for most back patios and pool decks. Smooth trowel looks clean but gets slick, so we steer it toward covered areas.

Exposed aggregate, $11 to $18 per sq ft, is tough, hides dirt and is barefoot-friendly once sealed. Salt finish, $9 to $15, gives a pitted, old-world texture. Stamped, $14 to $24, reads as flagstone, slate or wood plank and needs a sealer every two to three years. We break down stamped versus broom on its own page.

Concrete shrinks as it cures and it will crack; control joints decide where. On a 4 in. slab we cut every 8 to 10 feet within the first day, laid out to hit the inside corners around houses and planters, which is where uncontrolled cracks start. More in why concrete cracks.

Walk on it after 24 hours, set furniture on it after about 3 days, and seal at 28. Texas heat pulls the surface dry fast, so in summer we wet-cure or spray a curing compound — see curing time. A 12 by 20 patio is only about 3.3 cubic yards, which is why our job minimum is $1,800; pouring a walkway or steps the same day spreads the truck cost.