How to lay a concrete slab?

To achieve a screed for a garage or a patio, or to pour an indoors concrete slab, you'll need the proper equipment and you'll have to carefully follow the instructions and construction rules all along: the form work, the pouring and the drying time.

9 Advices for a successful work:

  1. Lay a film of polyane to block rising damp.
  2. Use plastic sheets to protect the walls from splashes.
  3. Anticipate electrical and plumbing networks according to current regulations.
  4. For a more resistant screed, reinforce the concrete slab with a wire mesh.
  5. Spread the concrete from the furthest parts to the closest ones, next to the exit.
  6. After laying the concrete, spray a treatment to ensure waterproofing and block evaporation.
  7. Provide an additional space all around the slab to ensure sealing and expansion.
  8. Let the concrete dry for the required time and avoid any stamping.
  9. To make large construction projects easier or to be sure to use a good quality cement, have it delivered by a professional builder.

Outdoor concrete slab advices:

  • After digging the form work, place a layer of gravel to stabilise, smooth the surface then cover with polyane.
  • When building a non-covered patio, the slab will have to be gently sloping.

Pay attention to the weather:

  • The weather may affect the final quality of the work. It's essential to use the right concrete if you're working during hot or cold weather. In both cases, cover the slab during the drying time to protect it from cold air stream or sunshine. Use the correct mix depending on your needs: speeding or slowing down the drying time.
  • If temperature is under 5°C / 41°F, use a mix with a higher concrete dosed and as little as possible water. Never pour concrete on a frozen ground.
  • If case of hot weather, don't work during the hottest part of the day, add more water to the mix or damp the surface to slow the drying down, and choose a lightly exothermic cement (low hydration heat).

How To Lay A Concrete Slab

Tools and supplies:

  • Pre-mixed concrete
  • Form work
  • Reinforced mesh
  • Measuring tape
  • String line
  • Steel pegs
  • Level
  • Shovel
  • Rake
  • Wheel barrow
  • Trowels
  • Concrete edger

Key steps:

  1. Dig out a level to fit the form work.
  2. Brace the form work with steel pegs.
  3. Lay the reinforced mesh.
  4. Pour the concrete, then rake and screed it evenly.
  5. Smooth the surface with a float and a trowel.
  6. Let the slab dry properly then remove the form work.

How to Lay a Concrete Slab

Tools and supplies:

  • Barrow
  • Hammer
  • Reinforced mesh
  • Measuring, digging and finishing tools

Key steps:

  1. Delineate and dig out your site.
  2. Check your measurements and place the form work.
  3. Lay the mesh in the form work.
  4. Pour and spread the concrete.
  5. Smooth the surface, starting from the corners.

Pouring a sloped concrete driveway

In this video, you'll see how a sloped concrete driveway gets done: the work is already framed so the concrete is ready to be laid, starting at the top of the driveway.

How to Stain Concrete Fast, Easy & Safe

You may be giving your home a makeover and chose a concrete floor: here's how to stain it.

Tools and supplies:

  • Sponge
  • Paint
  • Paint tray
  • Floor coating applicator
  • Tape
  • Water
  • Degreaser mix
  • Black pad
  • Razor blade scraper
  • Paint and mastic remover
  • Natural satin finish sealer

Key steps:

  1. Sweep the concrete slab.
  2. Start with a stain sample test.
  3. Clean thoroughly. Remove residue and clean a second time.
  4. Etch the concrete to ensure an even job. Clean twice again and let dry completely.
  5. Spread the stain into the concrete as shown in the clip.
  6. You can decorate your floor with designs, using the tape and different shades of paint with a sponge.
  7. Spray a finish sealer, and a floor wax if you want a shiny surface.

This article to learn how to lay a concrete slab was written by Cécile Lessard

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