Why most Valley patios need extending
Most tract homes in the Valley came with a patio slab that covers little more than the area under the patio roof. Add a table, a grill and a couple of chairs and it is full. Extending it outward, or along the back of the house, is one of the most common small concrete jobs in Phoenix.
The work is simple; the details are what make it look right. The new slab has to meet the old one at the same height, continue the same fall away from the house, and join it with a clean, deliberate line.
| Extension | Square feet | At $7 to $12 per sq ft |
|---|---|---|
| 8x12 | 96 | about $960 to $1,540 (scaled from HomeBlue 10x10) |
| 10x20 | 200 | $1,400 to $2,400 |
| 12x24 | 288 | $2,020 to $3,460 |
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HomeBlue's published Phoenix reinforced rate; small extensions cost more per square foot. Removing rock or old pavers adds to it.
How it is joined to the old patio
- Check the old patio for cracks or settlement; extending a sinking slab carries the problem forward
- Excavate to the old slab's depth and compact a base
- Drill and set dowels into the old slab edge where the two need to stay flush
- Place an isolation joint against the house and posts, and a construction joint at the old slab
- Pour, match the height and the fall, broom finish and joint the new section
If the extension is for a spa, it needs to be flat rather than sloped; see hot tub pads. Prices for other sizes are in the concrete pad cost guide.