The first month after your deck is poured

A poured surface keeps changing after the crew leaves, and almost nobody tells you that in advance. Here is roughly what the first month looks like, and which parts are normal.

Concrete does not dry. It cures.

The reaction that gives concrete its strength is chemical, and it needs water to continue. That is why a fresh pour gets kept damp or covered rather than left in the sun to dry out — a surface that dries too fast ends up weaker and dustier than one that was allowed to take its time.

Most of the strength arrives in the first week. It keeps climbing for a good while after, more slowly, which is why the schedule below is more patient than people expect.

Roughly what happens when

Timings shift with weather — a humid week in August behaves differently from a dry one in January, and your crew's instruction beats anything written here.

• First day or two: stay off it entirely.
• End of the first week: foot traffic is generally fine.
• A couple of weeks: furniture back, with something under the feet of

anything heavy. Point loads on a young surface are the ones that mark.

• Vehicles on a driveway: later than you want, and later than foot traffic.

Ask for the number for your pour rather than assuming.

• Sealing: last, once the surface has genuinely given up its moisture. See

the sealing post for why early sealing is the common mistake.

The things that turn up in week two and are normal

A white bloom. Efflorescence is mineral salt carried to the surface as water leaves. It looks like somebody spilled powder. It is the most common "something has gone wrong" call we get and it is usually the least serious — it typically weathers off, and can be washed off.

Colour that is not uniform yet. A surface dries unevenly, especially where one part is shaded and another is not. It evens out.

Fine cracking at the joints. Concrete shrinks as it cures, and the control joints are there to decide where that shows. A hairline at a joint is the joint doing its job.

The things that are not normal

A crack that wanders across a panel rather than following a joint, one wide enough to catch a fingernail, or a section that sounds hollow underfoot are all worth a call. So is standing water that never drains — a deck should shed toward where it was designed to shed.

None of those are common and all of them are easier to deal with in month one than in year two.

Why we write this down

The gap between "this looks wrong" and "this is what it does" is where most of the worry lives, and it is entirely avoidable. If something on your deck is not in this list, ask us. We would much rather answer a question about efflorescence than have somebody spend a month assuming their new deck is ruined.