Residential Concrete for Residential Homeowners in Bristol

A durable slab depends on what lies beneath it. The contractor should dig out soft ground and roots, lay and compact a granular sub-base, and set the concrete thickness and any steel mesh for the load, which is very different for a patio than for a driveway used by a van. For external paving, BS 8500 includes designated concretes intended for house drives and heavier paving, with air entrainment to resist freeze-thaw damage. Ask which mix is proposed and why. Manhole covers within the area will need raising or replacing to the new level.

Drainage has legal as well as practical consequences. In England, covering more than five square metres of a front garden with an impermeable surface that drains onto the road needs planning permission; permeable surfaces, or water directed to a lawn, border or soakaway within the property, avoid that. A concrete drive should be laid to falls so water runs away from the house, and it must not bridge the damp-proof course. New or widened access onto a road usually needs a dropped kerb approved, and often built, by the council.

Joints stop concrete cracking at random. Larger slabs need movement and contraction joints at planned spacings, and the contractor should explain where they will go and how they will be finished. Surface finish is a balance between looks and grip: a brushed finish is common on drives and paths because it gives traction in wet and icy weather, while pattern-imprinted or exposed aggregate finishes change the appearance and may need periodic resealing.

Weather affects the result more than most people expect. Concrete should not be placed onto frozen ground or when frost is forecast without protection, and in hot, dry or windy conditions it has to be kept from drying too quickly. The contractor should say how the surface will be protected while it cures, when it can be walked on and when it can take a car. Driving on a new slab too early is a frequent cause of early damage.

Access and waste on the day need planning. Ready-mixed concrete often arrives in a truck mixer that needs to park close to the work; if it cannot, the concrete may be pumped or barrowed, which affects the price. Old concrete or tarmac being broken out has to go somewhere, so ask whether skips or grab lorries are allowed for and where they will stand. Check that neighbours' access will not be blocked, and that any skip on the road has a council permit.

When comparing quotes from the concrete contractors you are introduced to, check the excavation depth, sub-base thickness, concrete thickness and mix, reinforcement, joint layout, drainage arrangements and finish, and who handles any dropped kerb application. A quote that states these clearly can be checked on site; a single figure for "a new driveway" cannot.