Can I mix and pour my own concrete for a 10x10 foot backyard patio slab in Fredericton, or should I hire a contractor?

A 10x10 patio slab sits right at the upper edge of what a determined DIYer can handle — but the honest answer is that hiring a contractor will produce a significantly better result, and the cost difference may be smaller than you expect.

At 100 square feet with a proper 4-inch thickness, you're looking at roughly 1.2 cubic yards of concrete. That's too much to mix by hand and too little for a ready-mix truck to deliver economically (most Fredericton ready-mix suppliers charge a short-load surcharge of $75-$150 for orders under 3-4 cubic yards). That puts you in an awkward middle ground: either renting a small drum mixer and buying bagged concrete, or paying the short-load fee for ready-mix.

The DIY Reality for This Project

If you go the bagged route, you're looking at roughly 65-70 bags of 30 kg Bomix or Quikrete — about $400-$500 in materials alone, plus mixer rental ($80-$120/day), gravel base ($150-$250 delivered), and lumber for forms. Your total material cost lands around $700-$1,000, and you'll spend a full weekend doing very hard physical work. The bigger concern isn't the cost — it's the execution. Concrete finishing has a narrow window. Once the mix is down, you need to screed, float, edge, cut control joints, and apply the final broom finish before the surface sets. With bagged concrete mixed in batches, you're constantly racing against the clock on earlier batches while still mixing later ones. Inconsistent batch timing leads to cold joints and uneven finishing — problems that are permanent and visible.

The more serious issue is mix specification. Bagged concrete mixes sold at NB hardware stores are generally not air-entrained, and air entrainment is non-negotiable for any exterior concrete in Fredericton. The city sits in the Saint John River valley and experiences well over 150 freeze-thaw cycles per year. Non-air-entrained concrete on an exposed patio will begin spalling and scaling within 3-5 years — sometimes sooner if you use any de-icing products on it. Some specialty bags (look for "exterior" or "air-entrained" labelling) do exist, but selection is limited at most NB retailers.

What a Contractor Will Do Differently

A professional will order air-entrained ready-mix at 25-32 MPa with 4-7% air content, place wire mesh on chairs at mid-slab height, cut control joints at proper spacing (roughly every 8-10 feet), and finish the surface with the right timing and technique. For a 10x10 slab in Fredericton, expect contractor quotes in the range of $1,200-$2,000 fully installed — gravel base, forming, concrete, finishing, and cleanup included. That's not dramatically more than your DIY material cost, and the result will last 30+ years instead of 5-10.

Practical Tips If You Proceed DIY

If you're committed to doing it yourself, order ready-mix rather than going bagged — pay the short-load surcharge and specify air-entrained mix with 4-6% air content and a 4-inch slump. Have two or three helpers ready. Prepare your gravel base (6 inches of compacted 3/4-inch clear stone) and forms completely before the truck arrives. Have your screed board, bull float, edger, and broom laid out and ready. Apply a penetrating silane/siloxane sealer in the fall after the slab has cured for at least 30 days.

Time this project for May through September — Fredericton nighttime temperatures in October can flirt with freezing, and fresh concrete that drops below 10°C before reaching adequate strength will be permanently weakened.

For a project this size, New Brunswick Concrete can match you with a local Fredericton contractor for a free estimate — it costs nothing to compare what a professional quote looks like against your DIY budget before you decide.