How to Place Concrete in the Rain
- 1). Find out whether the rain will truly impact your project. If it is simply drizzling outside, concrete will usually not be adversely affected, but a heavy downpour usually signals problems for most concrete projects. Check your local weather to see how much rain is in the forecast, and for how long. For downpours, stop pouring concrete and place two-by-fours around the concreted area in a square to see if you can salvage as much of the job as possible. Place the boards so they are resting on the ground, acting as a box for the concrete.
- 2). Continue pouring concrete if the rain is light. Fill the forms and smooth out the concrete using a trowel until you are finished. Immediately cover the slab with a concrete insulating blanket if you have one; if you don't, a tarp will also work. Carefully staple the blanket or tarp to the forms, tightly so that its weight does not rest on the concrete. The cover will keep the concrete dry and act as a heat concealer, which will speed up the drying process by keeping out moist air. If the blanket or tarp does not protect the entire area, cover as much of the pour as you can.
- 3). Remove the blanket or tarp after the rain has stopped. Trowel the concrete in a broad sweeping motion, holding the trowel at a 35-degree angle to the surface; this angle will help bring excess water to the surface. Start working from the top of the concrete and move toward the bottom. Cover the concrete again to let it cure.
- 4). Allow the concrete time to properly cure, or set up. Cured concrete is free of air bubbles on top. Because of the humidity, curing may take longer than normal. Uncover the concrete and fill any dips with a touch of leftover concrete mix and re-trowel. Recover the concrete once the job is complete. Allow another 12 hours for drying, after which the concrete will be ready for use.