Poured-in-Place Concrete Countertops: Step by Step

Pouring a countertop in place means casting it on the cabinets rather than casting it elsewhere and lifting it on. For a heavy top it is often the only sensible option — the average concrete countertop weighs up to 900 lb — but it brings the mess into your kitchen for the duration. Here is the method, and an honest account of the trade-offs.

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Time needed

17 days, including a 15-day minimum cure

Weight

Up to 900 lb — the cabinets must be reinforced first

Best for

Large or awkward tops, outdoor kitchens, anywhere lifting a slab is impractical

The method

1

Calculate your mix quantity and add 10% for waste and for slurry to fill pinholes

2

Reinforce the cabinetry to carry the weight — up to 900 lb

3

Build the forms. Plexiglas or melamine gives an extra-smooth face that needs less polishing

4

If coloring integrally, calculate the pigment for your batch size and blend it thoroughly into the dry mix until the color is uniform — this is what prevents streaking

5

Mix in a 5-gallon pail with a hand mixer and birdcage paddle: one gallon of water per 50 lb box, adding the mix a quarter at a time

6

Coat the forms thoroughly with a form release agent

7

Pour 3/8 inch of mix, press the first layer of fibreglass net into place and vibrate

8

Keep the net at least ¼ inch below the finished surface or it will shadow through

9

Pour the remaining mix and float the surface

10

Lay a second cut-to-fit sheet of net on the surface, vibrate, and press it in until fully covered — this face becomes the bottom of the countertop

11

Cure a minimum of 15 days

12

Polishing to 3000 grit? Apply a penetrating sealer and keep polishing. Using polyurethane instead? Do not polish beyond 800 grit before you seal

Advantages

No lifting

The top never has to be moved — the single biggest argument for this method

Fewer bubbles

Air bubbles are only a problem at the edges, so less vibrating is needed

Aggregate

Glass or natural stone can be broadcast onto the surface and trowelled in

Easier reinforcement

Laying the fibreglass net in place is simpler than in a pre-cast form

Outdoors

Ideal for outdoor kitchens

Disadvantages

Mess

Mixing and pouring happens in the room — equipment can damage flooring

Disruption

Construction plus cure can run to 30 days with the kitchen out of action

Finish

A trowelled poured-in-place top is not as smooth as a pre-cast one without polishing

If that disruption is unworkable, the alternative is to skim-coat the countertop you already have — see refinishing an existing countertop, which is a one- or two-day job instead.

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What's Next

1. Color it → Acid Stain Countertops
2. A full build → Outdoor Kitchen Countertop, Start to Finish
3. All countertop projects → DIY Concrete Countertop Ideas
4. Applying stain outdoors → How to Apply Outdoor Concrete Stain
5. Choosing a sealer → The Best Concrete Sealer
6. Prefer a reactive, mottled look? → Acid Stain Colors Guide
7. Shop → EverStain™ Kits · ColorWave® · Trial Kits

Direct Colors. Shawnee, OK. Manufacturing the full decorative concrete system since 1997.