Plasterboard Fireplace: Yes Or No?

A fireplace is the hub of your home. It’s where everyone gathers after a long day to warm up and feel a bit cosier than they entered. If you’re tired of the bare brick look, you may be tempted to plaster it up and make it a bit more modern looking. You’re likely thinking that plastering will tie the room together, removing the bare brick eyesore in the middle of the room, and you would be right to an extent. By that, I mean the following fire would certainly bring a new look to your home.

A plasterboard fireplace (or lining your fireplace with plaster and plasterboard) is not a good idea. Plasterboard is not rated as non-combustible, making it a terrible choice for lining your fireplace. It can, however, be used to surround the fireplace.

There’s a lot to cover here, so let’s just dive right in.

Fireplace Renovation: The Basics

Okay, your fireplace is in dire need of a makeover. We’ve said that plaster is not the way to go, but why? That’s our first issue to tackle before we talk about what you should do.

Plasterboard Basics

First things first – you cannot line your fireplace with plasterboard – even the pink “fire-resistant” stuff. That’s because fire-resistant and fireproof are different things. It’s like water resistance vs. waterproofing – water resistance stops as much water from getting through, but not all. The same concept applies here. You’ll stop some, but not all of the heat from getting to your plasterboard.

The second thing to note is that plasterboard is okay in front of the chimney breast. Plastering the chimney return, however, shouldn’t be plastered – heat will cause it to crack. In other words, you can go wild with plaster right up to the fireplace, but you cannot apply it inside the recess or chimney section. Putting plaster and plasterboard around the fireplace recess is exactly the same as applying plaster in just about any other way. Prime, skim, final skim, and you’re done.

What is the Correct Lining Board?

Okay, we know not to use plasterboard as a fireplace liner. What can you use? Finding a cement backerboard specifically designed for fireplaces is your best bet here if you want a new look. A cement backerboard is designed to, well, line your fireplace safely. It won’t crack if installed properly in the right sized space and can be painted with basic emulsion paint. Any cracks that do pop up can be easily repaired with decorator’s caulking.

Other recommendations include a compressed Vermiculite board, though it’s both expensive and thick, making it harder to reach into your fireplace. Another option is multi-pro board. While I haven’t personally tried it, I’ve heard that it stands up very well to heat (better than cement backerboard) and can be scored and snapped using a knife, making it easy to install.

Finally, if you’re looking for a truly unified look, you can apply a layer of thin steel (1-2 mm) to your backerboard and paint over it as normal.

Decoration Options

If you’re realising that you can’t just plaster over the fireplace and call it good, you’re likely wondering what you can do to beautify the fireplace. You have three options that are certain to work – patch up and clean your masonry, apply a concrete render, or paint your masonry!

The first option is rather self-explanatory. You can use mortar to patch up holes in the masonry and (once the mortar has dried), go over the whole space with a stiff, metal bristle brush. Once your space is clean, you can either leave it as-is or paint the space. Standard emulsion works here, though a mist coat is recommended to ensure your paint properly sticks. To read more about painting masonry, click here.

The second option is to apply a concrete render. Once again, we’ve already covered this, but here’s a brief refresher. To apply a concrete render, you’re essentially placing a thin layer of a concrete mixture over your masonry that can then be painted and decorated to fit your home’s aesthetic. It’s great for bringing new life to old, tired masonry that you either can’t or don’t want to entirely rid yourself of.

The final option is also rather self-explanatory. Begin by cleaning your masonry with a metal bristle brush and rag. Once that’s done, apply a mist coat (we’ll talk more about that in a moment). Finalaly, once your mist coat has set, you can paint as usual. Apply 2-3 layers of your emulsion paint of choice and you’re set!

Mist Coat

  1. Get a non vinyl emulsion paint. Its colour will need to match the top coat (I just use white).
  2. Combine equal parts water and paint, mixing until it’s thin – it’ll appear watery, that’s the goal.
  3. Apply the mist coat in a thin, even layer to your masonry.
    1. Work your way top to bottom to prevent drips.
  4. Apply a topcoat in several layers once the mist coat has fully dried.

In short, a mist coat is the same as a primer, but it’s better for extremely “thirsty” or porous surfaces, masonry included. This will allow your topcoat something that it can bond to, as it won’t attach properly to bare masonry.

Final Thoughts

Masonry is one of my favourite features of just about any home, but it’s becoming apparent that not everyone feels the same. That homey, rustic look just doesn’t mesh for some people, and that’s okay! If you’re looking to renovate your home’s fireplace, there are a few things to know before you get started.

While it’s entirely okay to plaster around the fireplace recess, there is no form of plasterboard fireplace that will be entirely safe. In other words, you need to keep the recess with some form of masonry or fireproof material. Some people like a concrete backboard, others prefer specialised materials, and some even like a thin bit of metal sheeting over the recess. All work, but come with their own weigh-offs. If you can’t bring yourself to fully rid the fireplace of masonry, paint, concrete rendering, and a good clean can all bring new life to your home’s hub.

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About the Author Harry Thompson

Involved in home renovations throughout his life, Harry is an expert in everything to do with home and garden DIY. In his spare time, he enjoys cooking and tending to his garden.