If you’ve got some plastering work, you’re probably wondering whether you should try it yourself. Plastering is something of an art form, and it can go badly wrong if you don’t know what you’re doing.
With the right guidance, even an enthusiastic amateur can achieve great results. Jan and Christine, writers of the Little House on the Corner blog, discovered this during their renovations.
This guide provides useful tips and advice about preparing a wall or other surface for plaster. We’ll explain why you should use PVA for plastering and how to apply it.
Tools & Materials
Tools:
- Dustsheet
- Rags
- Bucket
- Paintbrush or roller
- Plastering tools (to use after you’ve applied the PVA)
Materials:
- Sugar soap
- Polyfilla
- Screen tape
- PVA
- Water
- Mixed plaster (for the best plastering job)
Why You should be Using PVA for Plastering
PVA stands for Polyvinyl Acetate, but you’ll probably know it as ‘glue’. Carpenters, joiners, and fans of arts and crafts use it all the time.
When it comes to plastering, you use it for two specific reasons:
1. As a primer for your wall surface
2. To help bond your plaster to the surface
1. PVA as a Primer
You might not know it, but every wall is thirsty. Each surface has its suction rate; that’s why paint ‘soaks in’ when decorating.
Brick walls are the thirstiest, whereas plasterboard has the lowest suction rate. Thanks to the suction rate, some moisture is sucked out when applying plaster to a wall.
Dryer plaster is not good news. It can cause the plaster to crack and ruin a nice smooth finish. In extreme circumstances, lumps of the plaster might even fall straight off the wall!
Applying PVA to a wall as a primer seals the surface and lowers the suction rate.
2. PVA for Bonding
The other way that PVA becomes useful when plastering is more obvious. Adding a coat of glue to your wall surface before you start plastering helps bond the plaster to the wall.
The PVA helps to stick the plaster in place, just like it bonds two pieces of wood together.
What PVA Product Should I Buy?
At PWS, we’re big fans of the PVA below. It works great for bonding and as a primer.
Everbuild Universal PVA Bond
- Fully complies with BS 5270
- Improves the flexibility of sand & cement products
- A lower water-to-cement ratio for equivalent performance
- Lowers surface porosity of mortar and plaster
- Enhanced frost resistance
Applying PVA for Plastering — Step-by-Step Instructions
Now you know why PVA is so beneficial for plastering, you’ll want to know how to use it. The process is pretty straightforward and involves the following simple steps:
1. Preparing the Room
You must prepare the room in advance if you do any significant plastering. You should remove as much furniture from the area as possible to give you room to work.
You’ll also want to cover anything you can’t move out of the way with a dustsheet. No matter how careful you are, plastering is a messy job. For more info on reducing the mess, check out this guide on painting with no mess.
Your next job is to remove any dust or grime from the area you’re going to plaster. A quick going over with a rag and some sugar soap should suffice. You also need to fill or cover any holes or cracks in the surface you’re going to plaster.
Small holes can be patched with Polyfilla, and you can cover cracks with screen tape. You might need to get a little more creative in some cases, as The Carpenter’s Daughter did when plastering a wall with chased cables.
Pro Tip: You might need to plaster straight onto freshly erected plasterboard. If so, you’ll want to cover the joints between the boards. Once again, screen tape is your best option for masking joints. For more info, check out this post that includes a section on taping and jointing.
2. Choosing and Mixing PVA
Most big DIY brands have their versions of PVA. Choose one that’s nice and thick, as that’s best for plastering.
However, don’t use the PVA straight out of the bottle. You have to mix it into a more dilute solution.
Theories differ as to the perfect PVA solution for plastering. Some plasterers use a little more water, and some a little less. You can’t go far wrong with three-parts water, one-part PVA ratio. Mix that solution up in a bucket or something similar, and you’re ready to roll.
3. Applying PVA as a Primer
The first coat of PVA acts as your primer. You can paint it onto your wall the same way you’d paint while decorating.
Depending on the area size you’re plastering, you may want to use a paint roller rather than a brush. Once you’ve covered the required surface, leave the PVA to dry completely.
4. Using PVA to Bond your Plaster
Your second coat of PVA is a bit different. You want to apply it immediately before you start the plastering. Roll or brush the PVA onto the surface and then wait briefly for it to take up, but don’t let it get completely dry. Mix your plaster and start skimming so the PVA can help it bond to the wall surface.
Pro Tip: During the drying process, there’s a time when your PVA will start to feel especially sticky. That’s when you want to start plastering. If you’re plastering a large area, you might need to delegate the application of the PVA to be sure to get the plastering done at the right time.
Using PVA for Plastering — Final Thoughts
Plastering can seem daunting, especially if it’s not your trade. With the right know-how, it is possible to get top-notch results. Knowing why you should use PVA for plastering (and how to do it) is a good place to start.
For more tips on using PVA, check out our guide to using PVA to seal a concrete floor.