How to plaster a ceiling

Inspired by the Plastering For Beginners channel. This walk-through is based on the tutorial "How To Plaster A Ceiling with Plastering For Beginners" from the UK-based plastering training resource at plasteringforbeginners.co.uk. They do a solid job of breaking down the two-coat process for someone who hasn't skimmed before - the section on getting the mix right is worth watching twice.

1. Prepare the room and the ceiling surface

Clear the room as much as you can and protect the floor with dust sheets. Plaster drips and spatters constantly, and finishing plaster stains wood and carpet.

Check the ceiling for loose or flaking material. Scrape back anything that isn't firmly bonded. If there are damp patches or staining, sort the cause before you plaster - covering a water mark just hides the problem temporarily.

New plasterboard needs PVA diluted roughly 1:4 with water, brushed on and allowed to go tacky before you start. Old painted surfaces need misting with water or a diluted bonding agent. The idea is to stop the background pulling moisture out of your plaster before it has chance to go off properly.

2. Set up your tools and mixing area

You'll need a hawk and trowel, a mixing bucket, a clean drill and paddle, a corner tool or angle bead for neat edges, and a spray bottle filled with water. Have everything to hand before you mix.

Finishing plaster goes off quickly, especially in a warm room. Work in manageable batches - roughly a third of a bag at a time. Trying to apply too much at once means the first section is already going stiff while you're still putting the second coat on the far end.

3. Mix the plaster to the right consistency

Add the plaster to the water - not water to plaster. Put clean water in your bucket first, then sift the plaster in while mixing. This keeps lumps down.

The mix should be smooth and creamy, somewhere between thick yogurt and soft whipped butter. Too sloppy and it slides off the ceiling. Too stiff and it drags and tears when you try to trowel it out.

Rinse your bucket between batches. Old plaster left in the bucket will contaminate the next mix and make it go off faster.

4. Apply the first coat

Work from one corner and keep moving. Load your hawk with a good amount of plaster, then transfer it to the ceiling with your trowel at a shallow angle - around 20 to 30 degrees. Push the plaster firmly onto the surface and spread it thinly and evenly in overlapping passes.

Aim for around 2mm thickness on the first coat. It doesn't need to be perfect at this stage - you're building a base. But try to keep the thickness consistent rather than thick in some spots and thin in others.

Work in sections, joining each new section to the last with wet plaster. That wet edge is important - if one area starts to go off before you reach it, you'll get a line or ridge that's very hard to remove.

5. Apply the second coat

Wait until the first coat has firmed up but not dried completely. It should feel solid to the touch but still slightly cool - usually 20 to 40 minutes depending on the room temperature.

Mix a fresh batch and apply the second coat at around 1 to 2mm, working across the first in the opposite direction. This cross-hatching helps fill any lines left by the trowel on the first pass.

Keep a spray bottle to hand. Misting the surface lightly as you work keeps the plaster workable a little longer, particularly in warm weather or a dry room.

6. Flatten and polish the finish

Once the second coat has firmed up - typically 30 to 50 minutes after application - you can start to flatten and polish the surface. Use a clean, damp trowel at a very shallow angle, applying firm pressure in long strokes.

Mist the surface lightly if it feels too dry to trowel. The plaster should be producing a faint sheen as you work it. Too much water and you'll drag it; too little and the trowel will catch and tear.

Work methodically across the whole ceiling in one direction, then cross back the other way. The surface should look smooth and slightly shiny when you're done. Any marks or scratches will fade as it dries fully over the next 24 to 48 hours.

7. Allow to dry properly before painting

Freshly plastered ceilings need at least 24 hours before painting, and ideally longer in damp or cold conditions. The plaster will lighten as it dries - starting pink or grey and turning a consistent pale cream or off-white when it's ready.

The first coat of paint should be a mist coat: emulsion thinned with water (roughly 80% paint, 20% water). This seals the surface without trapping moisture underneath. Once that's dry, finish with two full coats of ceiling paint.

When to call a handyman

Ceiling plastering is a skilled job. If you've never plastered before and the ceiling is large, the cost of a professional finish is usually worth it. Richard can also help if the surface is badly damaged, there's an uneven substrate, or the area involves tricky edges like coving or beams. Sometimes the best DIY decision is knowing when not to.