How to plaster a bathroom: part 1 - how to mix bonding plaster

Craig Phillips demonstrates how to mix bonding plaster properly. This project was featured in the series If It’s Broke, Fix It, which is exclusive to the Home TV channel.

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How to plaster a bathroom: part 1 - how to mix bonding plaster

How to mix bonding plaster

You will need

  • Plasterer's trowel
  • Plasterer's hawk
  • Bucket trowel
  • Bonding plaster
  • Water
  • Large bucket
  • Electric drill or mixer
  • Mixing paddle

DIY expert Craig Phillips demonstrates how to plaster your bathroom. This easy-to-follow step-by-step guide shows how to mix and start applying bonding plaster to the wall.

Don't forget to watch Part 2 - how to get the bonding plaster level.

Bonding plaster is used to build up a thick layer of plaster on a wall, ready for a finish or skim plaster to be applied over the bonding plaster.

Check out Patching plaster part 2: How to skim plaster for how to apply skim plaster to a wall.

  • <b>Step 1: Mix the plaster</b>

    Step 1: Mix the plaster

    It's very important to get the texture of the bonding plaster correct - it wants to be a thick mousse that will keep it's shape on the trowel or hawk.

    To mix a batch always add the plaster to the water - and wear safety glasses and a dust mask as the dry plaster is very fine and gets everywhere. You might want to wear very lightweight gloves as well, as the plaster really dries your skin out.

    So, fill the bucket about a quarter full of water, then add a good load of the plaster - don't put too much in at first. Using a paddle whisk, start off at a slow speed, and mix the plaster into the water to create a paste. Add more plaster until you get the right consistency.

  • <b>Step 2: Handle the plaster</b>

    Step 2: Handle the plaster

    Once you've achieved the correct consistency, put some plaster onto your mortar board and, using a bucket trowel, put a good dollop of it on your hawk.

    The basic action for handling the plaster, is to tip the hawk on it's side, and slide the trowel up to the plaster along the hawk, picking up the plaster as you go. Then redump the plaster on the hawk, and do this again a few times.

    A plasterer performs this action automatically, to get the dollop of plaster into a good shape to go on the hawk, and then on the wall.

    You can hold the trowel either backhand or forehand... most people the plaster to the wall with a backhand hold.

  • <b>Step 3: Apply the plaster</b>

    Step 3: Apply the plaster

    You have around 10minutes to work with the plaster until it starts to dry so start applying it to the walls using a trowel.

    You want to create a depth of about 1 inch. Having the same depth down the entire length of the wall is important to ensure a flat finish.

    It's a good idea to practise applying plaster a little before plastering for real.

    So, load up your trowel, and then hold the trowel at the bottom of the wall with the plaster pressed to the wall.

    You then want to sweep the trowel confidently and steadily up the wall, with the top edge of the trowel lifted slightly away from the wall, so that the bottom edge of the trowel is at the distance from the wall you want your layer of plaster to be.

    Don't be afraid of the plaster, and don't worry if you drop the plaster on the floor... until you get the knack of this you will often have spills!

    To plaster gaps in edges and corners, you need to load the trowel with a small ammount of plaster on the edge of the trowel adjacent to the wall edge and then sweep the trowel inwards.

    Don't miss: Part 2 - how to get the bonding plaster level.