This is an easy-to-follow guide on how to make concrete countertops.
As soon as you start making masonry walls in your project, you’ll need to build these.
So if you want to learn the right process of making countertops, let’s dive right in.
How To Make Concrete Countertops
Countertops are commonly made in kitchens.
It’s a platform for burners and sinks.
And, used as an arrangement for cooking food and washing plates, vegetables, etc.
Initially, we make these with reinforced cement concrete (RCC).
Later, they’re finished with tiles or granite on top of it.
Here, I’ll show you how you can make concrete countertops for a kitchen.
Get The Drawing Of Kitchen Countertops
That is looked like this:
This is an example of a kitchen drawing showing the burner and sink locations.
All the apartments of a building project should have drawings like this.
And, You’ll find them in your project’s architectural drawing book.
If you don’t find one, contact the architect to provide one.
With the drawing:
Build The Masonry Wall
We build kitchen countertop slabs on masonry walls.
A portion of the slab is on the wall and the rest is hanging.
So, you first need to build the wall up to the bottom of the slab.
To do that:
First, get the thickness of the slab.
You’ll get that in the cross-sectional drawing of the slab.
As shown in the drawing above, the slab thickness is 3 inches.
But practically we make it 2½”.
Because after installing finishing materials (granite or tiles) on top of it the thickness of the slab is increased. That looks ugly.
Next, Calculate The Wall Height.
The top of the kitchen slab is 33 inches from the unfinished floor.
This is the standard we maintain for all the kitchen countertops.
Sometimes it’s shown in the drawing. And, sometimes not.
If we deduct the slab thickness from this height we’ll get the wall height.
= 33″ – 2½”
But, the burner slab is 6″ down from the rest of the slab.
That means the burner slab height is 27″ from the unfinished floor.
So, the wall height below the burner slab will be,
= 27″ – 2½”
After that, get the length of the burner slab.
You need to understand this carefully.
See the drawing below:
Here the length of the burner slab is 36 inches.
But that is the finishing dimension.
You’ll get that length after installing granite or tiles on it.
And, we consider 1½” thickness on both sides of the burner slab for that like the image below.
For this, make the burner slab length 39 inches.
So that you get the exact 36 inches after installing tiles.
Now, make the masonry wall.
The wall height below the kitchen slab is 30½”;
The wall height below the burner slab is 24½”, and
The length of the burner slab is 39″.
With all these, you can now start making brick walls.
Fortunately, I’ve talked about how to build brick walls before. Read the post to get step-by-step instructions.
Once you’ve completed the wall-making…
Finally, start curing.
And, leave the wall there for three days to gain sufficient strength.
So that you can begin to…
Make The Form For The Kitchen Slab
A form is just a mold to hold fresh concrete till it becomes hardened.
And, we use wood as formwork materials for concrete countertops.
As kitchen countertop slabs are minor structures, I don’t want to discuss details about making formwork here.
Just make sure the form follows the dimensions specified in the drawing.
But I want to discuss an important thing about the width of the kitchen slab.
See the plan below:
As you can see, the width of the kitchen slab is 22 inches.
Again, it’s also a finishing dimension.
You may think that you need to reduce the width because of finishing materials.
But you don’t.
See the section below:
As you can see, we use tiles in kitchen walls also.
So the countertop slab’s width will remain the same after installing the finishing materials on the slab.
Once the form is ready, start…
Rebar Fabrication Of The Kitchen Slab
First, get the structural drawing of the kitchen countertop slab.
That looks like this:
Often, you won’t get the drawing in the project’s structural drawing book.
In that case, ask the structural engineer to provide one.
In our case, we use a common drawing for all projects.
With the drawing, complete the rebar fabrication.
Mix And Pour Concrete
Brick wall making – done!
Formwork – Done!
Rebar fabrication – Done!
Now it’s time to pour concrete.
First, keep a hole for the sink bowl
Commonly, we use a single bowl and single tray sink in our projects.
For this, we keep a 17″ by 14″ hole.
Make sure you keep this hole before casting.
[Note: It’s better to get a sink as a sample to know the size of the bowl. Another thing, someone may want to use a double bowl sink. In that case, the size of the hole will differ.]
Next, Prepare Concrete.
We use a 1:2:4 ratio of concrete materials for kitchen countertop slabs.
And, we mix them by hand.
Here is a guideline on how to mix concrete by hand.
Once the concrete is prepared…
Finally, Pour the fresh mix of concrete into the form.
With this, you’ve successfully built the kitchen countertop slab.
But, don’t forget to…
Cure The Concrete Slab
Curing is crucial for gaining the strength of concrete members.
Kitchen slabs are no different.
So, cure them properly for at least 7 days.
For that, cover the slab with hessian clothes.
And, make sure the cloth remains wet for 7 days by spraying water.
Now, it’s time to…
Remove The Form
We normally remove the form after 10 days of casting.
And use the form to build another kitchen slab.
That’s it for now.
I hope you can now easily make concrete countertops for kitchens.
And, I’m happy to help you with this.
Now I’d like to hear from you:
Do you use single-bowl or double-bowl sinks in your project?
If you use double bowl sinks, what is the hole size you usually keep for that?
Let me know by leaving a comment below.