CD Designs Blog
As your pattern imprinted concrete driveway or patio cures, it’ll contract slightly. And even after curing, concrete can swell and contract by minute, unnoticeable amounts. Unnoticeable, that is, except for the surface cracking which this can cause. Which is why experienced contractors – like ourselves – understand the importance of designing and installing areas of concrete which include expansion joints.
Expansion joints afford the concrete fields which have been laid a small margin of space for expansion. This space means that any expansion or contraction can take place without potential pressure-damage to the concrete itself, and to any other elements of the installation. If, for example, you need to include drain access in the area you want surfaced, then expansion joints would be part of the border around your manhole cover.
Although “gaps in the concrete” might sound like the kind of thing that’d ruin the visual appeal of a concrete surface, expansion joints are actually very subtle features. It’s unlikely that you’d be able to spot where they were, or have any idea what purpose they served, unless you knew about them beforehand.
There are a number of techniques for creating expansion joints. Whilst the joints occur at definite breaks between fields of concrete, the fields are usually pinned together using mild steel dowels, with a variety of different materials filling (and weather-sealing) the small space between concrete fields.
As always, which option your contractor picks will reflect the design necessities of your project.
12th March 2010