pva for plastering

Why You Should Use PVA for Plastering (and how best to use it)

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If you’ve got some plastering work that needs doing, 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 in the course of their renovations.

We’re going to give you some useful tips and advice about preparing a wall or other surface for plaster. We’ll explain why you should use PVA for plastering, and talk you through how to apply it.

Cost

Time

Difficulty


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 ultimate plastering job)

Why You Should Use PVA for Plastering

PVA stands for Polyvinyl Acetate, but you’ll probably know it as ‘glue’. Carpenters and joiners, as well as fans of arts and crafts, use it all the time. In fact, as DIY Doctor explains, it has a multitude of uses.

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 own rate of suction; that’s why paint ‘soaks in’ when you’re decorating.

Brick walls are the thirstiest of all, whereas plasterboard has the lowest suction rate around. Thanks to the suction rate, when you apply plaster to a surface, some of the plaster’s moisture is sucked out.

Dryer plaster is not good news. It can cause the plaster to crack rather than achieving 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 rate of suction. The only time when you may not need to use PVA in this way is when you’re using plasterboard.

2. PVA for Bonding

The other way that PVA becomes useful when plastering is more obvious. Adding a coat of the glue to your wall surface just before you start plastering helps to bond the plaster to the wall.  

The PVA literally helps to stick the plaster in place in the same way it can bond two pieces of wood together.


Step-By-Step Guide to Applying PVA for Plastering

plaster on a wall

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:

Preparing the Room

If you’re going to do any significant plastering, you need to get the room ready in advance. 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. In some cases, you might need to get a little more creative, as The Carpenter’s Daughter did when plastering a wall with chased cables.

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Pro TipYou might find yourself needing to plaster straight onto newly 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.

Choosing & Mixing Your PVA

Most of the big DIY brands have their own versions of PVA on sale. 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 a simple three parts water, one part PVA ratio. Mix that solution up in a bucket or something similar and you’re ready to roll.

Applying the PVA Primer

The first coat of PVA acts as your primer. You can simply paint it onto your wall in the same way as you’d paint while decorating.

Depending on the size of the area 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.

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 that the PVA can help it bond to the wall surface.

Below is a great video from Whiter Interiors on how to apply the second coat:

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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.


Final Thoughts

Plastering can seem like a daunting task, 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.

If you’ve enjoyed our guide or have any questions, don’t hesitate to leave us a comment. You can also share this post on social media if you think our advice might help your friends or relatives.

About the Author Neil Cumins

I’ve been a property journalist since 2003, writing about everything from architecture and construction to interior design and home improvements, for property clients all over the world

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