Blog>Expert Advice>How to prepare your home before plastering
Last updated: 16 May 2024
How to prepare your home before plastering
When it comes to plastering, preparation is key. From practical considerations for the positioning of sockets to preparing the walls for a top-quality finish, we guide you through what to do before plastering to ensure you get the best result.
There are several reasons why homeowners seek plastering services, but more often than not, it's to create a smooth, even surface as the foundation for some smart new internal decor.
However, if you're unsure what to do before plastering, you could risk a less-than-satisfactory result. Bumps, dents, and cracks; peeling and flaking paint; and patchy walls are some of the disappointing and frustrating outcomes of poor preparation.
In this expert guide, we outline what to do before plastering walls to help ensure your finished surface is smooth, strong, and long-lasting.
See the tradespeople we've checked for your job
What to do before plastering a wall
Before you begin the actual plastering, it's well worth considering a couple of practicalities to optimise the functionality of your room.
If you've always felt you could do with an extra lamp next to the armchair or you want to remove some dated wall lights, now's the time.
Before the plastering commences, contact a qualified electrician for any electrical work needed. This might include adding or removing electrical sockets, switches, and fixtures, or wiring in better lighting.
You may also wish to contact a TV aerial specialist if you want to adjust where your TV and aerial runs will go.
Finally, many homeowners add coving as a decorative finishing touch if their property doesn't already have it. If you want to add or update the coving or skirting, make these decisions while planning your plastering project.
On Checkatrade, you'll only find trades who meet our high standards and pass up to 12 checks.
Preparing your walls for plastering, step-by-step
With a clear vision of how you want your finished room to look and feel, you can move on to physically preparing the walls for plastering. So what to do before plastering a wall?
1. Protect your floors and belongings
It's no secret that plastering is a messy job, so it's crucial you protect your floors, furniture, and nearby surfaces from plaster splatter.
Lay dust sheets over furniture, cover floors with protective sheeting and remove belongings where possible.
2. Strip any wallpaper or paint
It's hard work, but you will need to steam or scrape until every last scrap of wallpaper is gone. Failing to do this could leave you with patchy, flaky, or peeling plaster.
If you're keen to give this a go, we recommend hiring or borrowing a wallpaper steamer, which will make it much easier to then remove the paper with a scraper. If the walls are painted they will need to be sanded back.
This is a laborious job, so you'd be forgiven for not wanting to tackle this yourself. Take a look at our wallpaper removal cost guide to see how much it would cost to get a professional in.
3. A thorough clean
Once you've removed any wallpaper or sanded any paint then you should remove any residual grease by washing down the walls with sugar soap.
This step will help to reduce the likelihood of anything that may cause your plaster not to hold. You can buy sugar soap ready mixed from a DIY store.
4. Check your walls
Before plastering, you need to check for any loose plaster or cracks. If you find any small holes, fill them with filler. If you find any large areas that have flaky plaster, make these good by hacking them back and then applying a bonding agent.
5. Switch off power and remove socket faceplates and fittings
You will need to remove or unscrew light fittings or power sockets before beginning the plastering process. Before you do, make sure to switch off power to any sockets or light fittings at the consumer unit.
To keep light switches and sockets clean, unscrew them and wrap them up in a plastic bag or cling film. It might seem like a job you can bypass, but this small step will actually save you time in the long run.
6. Scrim tape any cracks
Scrim tape is a type of mesh that helps to keep plaster intact. If you find any small cracks, use this tape to cover them over. If you find larger cracks, it is best to consult with a professional to ensure that your wall is still structurally safe before plastering.
What do you put on walls before plastering?
Before plastering, it's important to understand what type of surface you will be applying plaster to as the preparation required will vary.
Any surface you may be applying plaster to has a degree of 'suction'. This professional term refers to how absorbant the underlying surface is. Managing this suction is key to getting a great finish.
Plasterboard
Plasterboard is probably the easiest surface to apply plaster to as it is low suction and you can plaster straight onto the plasterboard.
Any screws that have been used to fix the plasterboard to batons must be countersunk and filled to create a flat surface and the joins where the boards meet need to be taped.
There are some really simple taping solutions on the market that allow you to create a seamless edge when joining sections of plasterboard. They are mesh-based and are highly effective at making your joins invisible.
Brick
With new build houses, plastering directly onto brickwork isn't common. However, if you don't live in a new build home then it's possible you might need to plaster directly onto brick as a patch-up job.
As brickwork is high suction, to get a good finish you will need to brush the exposed brick with a wire brush. You must then add a layer of bonding agent before plastering to help the plaster hold.
Using PVA
If you're plastering directly onto an existing wall, you need to control the suction, as we explained earlier. How absorbent the surface is will determine how quickly the plaster dries and ultimately the quality of the finish.
Using PVA (also known as Blue Grit) helps to control the rate of suction of your existing surface. To apply it, follow the instructions on the container of the PVA you have bought. Usually, two coats of PVA mixture will give you the best surface for skimming before plastering.
Bonding agent
Instead of PVA, you could use a bonding agent. This product contains a fine aggregate making it gritty. This helps to provide a stable surface for the plaster to adhere to.
Some bonding agents have a bright colour so you can see where you have applied it to help get an even coat.
Existing plaster, wallpaper, paint, or Artex
These surfaces are slightly more tricky and require a bit more preparation before plastering.
If you're attempting to plaster on any of these surfaces, you must follow the appropriate steps outlined above to prepare your walls before plastering. For a good and stable hold, the surface underneath must be in as good and clean condition as possible before plastering.
Related content: Curious to learn more about the plastering process? Check out our guide on how to plaster.
Find an experienced plasterer near you
Prepping your walls or ceiling for plastering isn’t difficult, but it's a lot of hard work, physically demanding, and time-consuming.
When you’re prepping to plaster onto plasterboard then you’re in for slightly less work. However, if your property is older and you’re unsure about the integrity of the brick or existing plaster then it’s always best to call in an expert. These highly experienced professionals will know exactly what to do before plastering to ensure a top-quality, long-lasting result.
If you fancy saving yourself some work then it might be worth your while to hire a professional to do it all for you. Search your postcode to see who comes highly rated in your area.
See the tradespeople we've checked for your job
FAQs
How to smooth plaster walls before painting?
Freshly plastered walls should have an even surface to paint onto. However, if you run your hand over the surface of the wall and feel any bumps or textural changes, you can lightly sand the area with 120 grit sandpaper.
Do you need to prime plaster before painting?
It is really important to allow the plaster to dry fully before you paint over it. If you don't, your paint might crack or peel off.
Before painting, you should seal the plaster by applying a coat of watered-down emulsion, topcoat, or a specific plaster primer. If using a topcoat or emulsion then water down the initial layer by 10%.
Our guide to how to paint on new plaster provides more detailed information.
What do you put on plaster before painting?
As above, it is really important to seal the surface before painting onto plaster. Do not use PVA for this, follow the instructions above and use a watered-down paint layer or a specific primer.
Can you wallpaper straight onto plasterboard?
It's not recommended to wallpaper straight onto plasterboard. Plasterboard is very porous and will soak up the wallpaper paste, not leaving much for the wallpaper to stick with. Applying a primer before wallpapering will prevent this issue and make it easier to remove the paper if you choose to redecorate in the future.
Do I need to PVA before bonding coat?
It depends on the surface that you're applying plaster to, but usually, PVA is applied to help create the best possible adhesion for the first layer of plaster.
See the tradespeople we've checked for your job
See the tradespeople we've checked for your job