How To Plaster A Precast Wall Concrete Surface

Building Warehouse
5 min readNov 6, 2022

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How To Plaster A Precast Wall Concrete Surface

Do you want to know the method of How to plaster a precast wall concrete surface in South Africa? This post will tell you very quickly a simple but effective way to plaster a precast walling or concrete wall.

It costs a lot of money to break your existing precast walling and to build a new wall. That’s why it is a wise decision to at least renovate your existing precast wall..

Just be aware that the method I will give here is universal and has worked very well for me. I have done this work at Jibby John’s Construction Company.

But I would like you to know that plastering a precast wall isn’t just the fact of throwing plaster on concrete slabs of your wall.

It’s hard for plaster to adhere on a concrete surface without proper preparations. So the techniques I am about to share can be used by anyone.

If you want to try this yourself at home, go ahead or if you are a builder this can save you trouble.

The nature of precast wall

Many people complain that precast walling isn’t a good or long term wall to rely on. These walls always tend to break as time goes or to lean over.

Well, if you want to install a new precast walling, first of all rely on good builders or contractors who know these things.

Always do not go for cheap quotations as this will cost a fortune fews years later. When a precast walling is installed properly following all the regulations, it will stay almost forever.

Precast walling is really beautiful and cost effective. All you have to do is to know how it must be installed or find people who aren’t there just to grab your money and go.

In my next post, I will share the approved way or technique to install a precast walling. Just subscribe to the newsletter to receive notification alerts.

How to plaster a precast wall or a concrete surface

The method I will give here is the same that can be applied on a precast walling slab or a concrete surface.

Then below i will give in detail every thing that you will need in order to achieve just this. With your mesh, this can be plaster mesh or chicken mesh, cover the wall or the concrete surface you want to plaster.

The size of the chicken mesh is different. It is better if you buy the one with smaller holes. Or in case you bought the one with big holes, you can fold it into two and cover the wall.

The plaster mesh is a completely different mesh compared to chicken mesh. It is made just for plaster as the name suggests.

Not all building material suppliers sell plaster mesh. Because they think the role of a chicken mesh is equal to that of a plaster mesh. In reality, when it comes to practice, plaster mesh is much better and professional.

If you wonder where to buy the plaster mesh, the only place I found it, was at a building material store called Build it.

So after covering your precast wall or concrete surface with the mesh, the next step is to roughen the surface.

Yes, this is the best method and risk free. This will save you trouble and money. Because if you don’t follow these methods of plastering a precast walling or concrete surface, you will be begging for the cracks to refrain from showing after your work.

How to roughen the concrete surface? To make the surface rough and to facilitate plaster adhesion, you will need to buy a product called plaster key.

The plaster key is a bonding agent and the quantity that you will need will depend on wall size.

Method to plaster a precast walling or concrete surface

Take a bucket and pour inside your plaster key, and then take river sand also known as sharp sand mix it in the same bucket with plaster key. Take a small quantity of plaster and add in your bucket and mix.

The quantity and the mixing ratio here does not really matter. Be creative and make sure you get a watery past that you can throw on the surface using a brush or throwfall or even a cup.

What I have learned is that, if you don’t add water, the bondinding will be extremely fantastic. But for budget reasons you can add a small amount of water in your bucket and mix.

After covering the precast walling with a mesh, then throwing this mixture on the same wall, give it a time to cure.

When it is completely dry, now you are ready to plaster your precast wall.

The secret of zero cracks on the newly plastered precast walling or concrete surface

If you are like me and want peace of mind, please be willing to spend money. If you think the precast walling renovation will take a lot of money, you may just break it down and build a normal double skin brick wall.

But if you think that you want to do plaster on the precast wall no matter what, accept to spend money on a lot of materials.

There is a secret to zero cracks on a newly plastered precast wall. Why am I saying this? It’s because, no matter what you can do to plaster your precast walling, there is a 90 Percent chance for cracks to return and fast.

So the secret to zero cracks is as follow

Above all make sure that your precast walling is straight. If it is not straight get it fixed, but you can plaster it even if it is not straight.

I recommend you straighten your wall before plastering it. The wind tends to move precast walling, and this movement or motion can bring cracks. So it is wise to realign and fix it or reinforce it. Consult with the professionals.

Cover the precast wall with a mesh as mentioned above. Then roughen the wall as explained above. And then give the wall a first coat plaster.

The first coat of plaster can stay like that or you simply scratch it using a strelish to make it a bit surfaced. Now after that, let it dry but not fully.

Now cover another mesh on top of the first coat plaster. After covering the mesh for a second time you can now plaster your wall with a desired finish

Things you will need in order to plaster a precast wall or concrete surface

These are the must be present tools that will help you achieve this project.

Tools:

Straight edge. Trowel . Spirit level. Wheelbarrow. Hummer. Cup. Bucket. Float (optional).

Materials: Plaster mesh or chicken mesh. Plaster key bonding agent. Cement. Plaster sand. River sand.

Note: You may have difficulty nailing the mesh on the precast wall. Just because it isn’t thick and also nails don’t stuck in a concrete wall directly.

So you have the option to drill and put in the holes some wall plugs. This method is time consuming.

Try to be creative, what I did was to install a full sheet of mesh by throwing it from one side to another and nail it straight on the ground.

If there is something that is not clear in my post, please comment below and I will reply. Or if you would like to share your method to plaster a precast wall or concrete surface, share in the comment section below.

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Building Warehouse
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