In this post, you’re going to learn how to plaster a ceiling.
(Step-by-step).
After learning, you’ll be able to:
- Supervise the plastering process properly, and,
- Maintain the quality of the plaster.
So, let’s start to learn the process in detail.
How To Plaster A Ceiling In 5 Easy Steps
You’re not doing the plaster work yourself. As an engineer, you’re just supervising.
And, as you know, to supervise any work properly you must understand the process of doing the work very well.
So, I’ll try to make the process as simple as possible.
Also, give you every detail in each step.
So, let’s start with the…
Step-1: Surface Preparation
It’s just to prepare the surface for plastering.
And, it’s very important. I’ll tell you why in a minute.
In residential buildings, ceilings are made of concrete.
So, I’ll discuss the preparation process for a concrete surface here.
For surface preparation, you will do three things:
- GI wiring for electrical purposes;
- Surface cleaning; and
- Hacking.
Let’s discuss all these things:
GI Wiring For Electrical Purposes:
In this task, electricians will run 16 SWG GI wires through electrical pipes concealed inside the slab.
You must do this task before starting the ceiling plaster.
The reasons for this are:
- To locate the electrical points and make them visible. So that plastering masons don’t cover them up mistakenly during plastering; and
- To make electrical pipes clear for future wiring.
Surface Cleaning:
In this task, you’ll remove unnecessary things from the surface.
For this:
- Remove the shuttering tapes that you used to make the slab formwork watertight;
- Clean the shuttering oil with a wire brush;
- Remove foams and cork sheets that you used during slab shuttering.
- Remove plain sheets that are not removed before.
To make a long story short, Remove any unwanted materials from the surface.
As you know, I often share my practical experiences.
So that you can focus deeply and overcome the obstacle that I faced during my day-to-day construction activities.
And, you don’t need to make the same mistake that I made.
It’s not that we always have masons with good work ethics. I once found that a ceiling is plastered without removing a plain sheet.
So make sure the surface is properly cleaned.
Hacking:
Hacking is a process done to make the smooth RCC surface rough.
So that a mechanical bond is created between concrete and plaster.
Normally, Hacking is done by axes.
Pro Tips: Try to hack all the RCC surfaces on a floor at a time. By doing so, you don’t have to worry about leaving some surfaces unhacked.
Step-2: Pre-Plastering Work
In this step, your masons will perform the following two tasks:
- Making stages, and
- Marking reference level
Making Stages:
A stage is a platform to stand.
Obviously, masons will require that while plastering.
Make sure the stage meets these needs:
- It can carry the load of workers,
- Can withstand a load of mortar,
- Safe enough to work on.
To make stages we generally use –
- GI pipes, and
- Plain sheets
You can use whatever materials are available in your project. But make sure it is safe. Construction is an accident-prone sector. So, be careful.
Marking Reference Level:
This is important.
The reference level marking is a task in which some marks are fixed at four corners and the center of the ceiling.
And, these are done using cement mortar.
The purpose of this is to make the ceiling truly horizontal.
And, reduce the consumption of cement mortar.
I suggest performing this task the previous day of ceiling plaster.
So that they gain strength and don’t break down during plastering.
Step-3: Mortar Preparation
We use cement mortar for plastering.
Cement mortar is a mix of cement, sand, and Water.
You can prepare this at the site or buy ready-made mortar from shops.
We mainly prepare mortar on-site.
To prepare mortar, perform the following tasks:
- Washing the sand;
- Screening the sand, and
- Mixing mortar ingredients
Let’s discuss these tasks…
Washing Sand:
Sand for plastering needs to be free from mud, dust, and most importantly salt.
That’s why we use washed sand.
If you get that from suppliers that’s fine.
If you can’t manage to buy washed sand, then wash them in your project.
To wash, make a tank in your project like the image below.
Screening The Sand:
The purpose of this is to separate unwanted granular matter from sand.
These matters are coal, pieces of stone, pieces of brick, etc.
To screen the sand properly:
First, let them completely dry after washing.
And then, use a screening net to remove granular materials.
With this, the sand is ready.
You can now…
Mix The Mortar Ingredients:
For ceiling plaster, we use cement mortar.
It’s just a mix of cement, sand, and water.
We use a 1:4 cement-sand ratio for plastering mortar.
Read More: How to prepare mortar.
Step-4: Start Plastering
Once the mortar is ready you can now start plastering the ceiling.
For this, perform the following tasks:
- Applying cement slurry;
- Applying mortar;
- Leveling the surface, and
- Finishing the surface
Applying Cement Slurry:
Cement slurry is a mix of cement and water.
Sometimes, coarse sand is also added to cement slurry. In that case, the proportion of cement and sand is 1:1½.
The water is added as required to make the slurry sticky.
The purpose of applying cement slurry is to make a strong bond between the ceiling & mortar.
In this task, you’ll apply the slurry on the surface with a trowel.
Applying Mortar:
After completing the cement slurry application you can now start applying mortar on the ceiling.
We do this with hand shovels.
Apply mortar with some force. So that the mortar is stuck with the ceiling and no gaps are left in between the ceiling and the mortar.
The thickness of the mortar on the ceiling is somewhere between 8 mm to 12 mm.
But not more than 12 mm.
Leveling The Surface:
Once you finish the mortar application on the whole ceiling, you can now start working on the surface leveling.
And, it is done using trowels, floats, and aluminum straight edges.
To make the surface leveled:
First, bring the surface to a certain level using a straight edge.
But what is the certain level?
I think you remember we have taken some reference levels on the ceiling in step-2.
The mortar should be leveled with those reference levels.
Thus you can make sure the ceiling is truly horizontal.
Now, use the wooden float.
After using the aluminum straight edge, you’ll see that there are some undulating surfaces in some places.
You can’t correct those using the straight edge.
You must use floats.
If the surface is concave, apply more mortar using a trowel and make corrections with the float.
If the surface is convex, just use float to remove the excess mortar from the surface.
Finishing The Surface:
Cement slurry applied — done.
Mortar application — done.
Surface leveling — done.
One last task is remaining.
That is surface finishing.
After leveling, you’ll see some loose sand appear on the surface.
They should be removed.
And it’s done using plastering foam and flower brooms.
Step-5: Finalization
This is the last step of ceiling plaster.
In this step, you’ll do some simple tasks.
- Removing the stage;
- Cleaning the floor;
- Writing production date, and
- Beginning the curing.
Let’s discuss these tasks…
Removing The Stage:
We’ve built this stage before starting ceiling plaster in step-2.
Remember!
After completing the plaster we need to remove that.
After removing you can stack these staging materials in one place.
Or, you can take them where you need to start a new ceiling the next day.
In my case, I normally make the stage for the next day’s ceiling plaster immediately after opening.
And, it’s good practice as you can complete the surface preparation and reference marking that day.
So that you can start the plaster the next day immediately.
Cleaning The Floor:
Obviously, the floor below the ceiling became dirty with cement slurry, plastering mortar, etc.
So clean them after removing the stage.
As well as, clean ceilings beside the freshly plastered ceiling. Because during applying cement slurry and mortar you certainly made those ceilings dirty.
Writing Production Date:
This is not related to the process of ceiling plaster.
But, it’s important to ensure quality plasterwork.
And, it’s helpful to track the curing period.
Writing production dates is simple.
You just need to write a date on the ceiling, the next day of plastering.
For example, today is June 12th. The ceiling has been plastered today.
On 13th June, you just need to write “12/06/23” on the surface of the ceiling.
Do this with a marking pen.
Beginning The Curing:
As you know, curing is the most essential thing for cement-based products.
It helps to gain strength. If the ceiling plaster isn’t properly cured:
- Cracks will develop;
- Sand from the plaster surface will be loosened up during applying stone for paintwork.
So proper curing is a must.
To cure you need to know two things — The method of curing and the duration of curing.
Method of curing: Ceiling plaster is cured by spraying water.
Duration of curing: Although cement-based materials should be cured for 28 days, we can’t do so long due to the tight work schedule.
But we spray water on the ceiling surface 3 times a day for 14 days.
Oh! start the curing after 24 hours of finishing the plaster.
Now It’s Your Turn:
I hope this post showed you how to plaster a ceiling.
Now I’d like to turn it over to you:
Have you learned anything new from this post? Do you complete “GI wiring for electrical purposes” during the surface preparation?
Or maybe you have a question about something you read.
Either way, let me know by leaving a comment below right now.