When can patio furniture go back on new concrete in Kanata?

We found no published source that gives a specific number of days or hours before patio furniture can go back on new concrete. The right answer depends on the mix, the weather and what the contractor specifies, so follow the contractor's written instructions for your particular pour.

What the 2024 Ontario Building Code does say is that when the air temperature is below 5 °C, concrete must be kept at not less than 10 °C for 72 hours after placing. That is a cold-weather protection rule, not a furniture rule, but it gives you a sense of how sensitive fresh concrete is in its earliest stage. The Code measures strength at 28 days, but that does not mean the slab is ready for furniture at 28 days or that it is not ready before then.

The Ready Mixed Concrete Association of Ontario, an industry association, advises keeping vehicles off freshly placed concrete for at least 7 days. That guidance is about vehicles, not patio furniture, so it is not a direct answer either.

A few things worth asking your contractor before the pour:

• What is the specified compressive strength of the mix, and when does the slab reach enough strength for light foot traffic and furniture?
• Will there be a written curing plan, and what protection is planned if temperatures drop below 5 °C in the days after the pour?
• At what point is it safe to place heavy items such as a stone-top table or a large planter?

The contractor who designs and places the slab is the right person to give you a date, because they know the mix design, the base conditions and the forecast.

Before the work starts, ask the contractor to show you their City of Ottawa hardscaping contractor licence and then check their name against the City's published list of licensed contractors yourself.