Plastering Basics: A Beginner's Guide

Plastering has a reputation for being one of those trades that looks simple and turns out to be anything but. The good news: the fundamentals aren't complicated, and most of what separates a rough first attempt from a smooth, professional-looking wall is technique and timing—both of which come with practice.

This guide covers what you need, how to prepare, and the basic step-by-step process for skimming a wall. It's a good primer before you pick up a trowel—but plaster sets fast and rewards a steady hand, so if you're doing this for the first time on a room that matters, a guided session will save you a lot of scraped-off first coats.

Tools and Materials You'll Need

• Hawk and trowel (a mid-size finishing trowel is easiest to start with)
• Mixing paddle and drill, plus a clean bucket
• Multi-finish plaster (for most internal wall and ceiling jobs)
• PVA bonding agent (to seal and prime the surface)
• Corner beads and scrim tape for joints and edges
• Spirit level, dust sheets, and a stiff brush for prep

Step 1: Prepare the Surface

Plaster needs something stable to grip. Knock back any loose or flaking material, brush off dust, and fill any large holes or gaps first. Fit corner beads on external corners and scrim tape over joints between boards—skipping this step is one of the most common causes of cracking later on. Once the surface is sound, seal it with a coat of diluted PVA and let it go tacky before you start mixing plaster.

Step 2: Mix to the Right Consistency

Add plaster powder to water (not the other way around) and mix with a paddle drill until it's the consistency of thick double cream—smooth, no lumps, and holding its shape on the hawk without sliding off. Multi-finish plaster typically gives you 60-90 minutes of working time before it starts to go off, so only mix as much as you can comfortably apply.

Step 3: Apply the First Coat

Load the trowel from the hawk and apply plaster in upward, sweeping strokes, working in manageable sections rather than trying to cover the whole wall at once. Aim for an even thickness of around 2mm for the first coat. Don't worry about a perfect finish here—this coat is about even coverage, not polish.

Step 4: Apply the Second Coat and Flatten

Once the first coat has firmed up slightly (still workable, not wet), apply a second, thinner coat to fill any low spots and even out the surface. Use a flat, controlled trowel angle to level it off, checking for high and low spots with a straightedge as you go.

Step 5: Trowel Up and Finish

As the plaster starts to go off, "trowel up" with a clean, damp trowel in light, overlapping passes to close the surface and bring up a smooth sheen. Timing is everything here—too early and you'll drag the surface; too late and it'll be too hard to work. This is the step that takes the most practice to get right.

Common Mistakes to Avoid

• Skipping PVA sealing, leading to plaster drying too fast and cracking
• Mixing too much plaster at once and racing the clock before it sets
• Applying coats too thick, which causes slumping and uneven drying
• Troweling up too early and dragging the surface, or too late and losing the finish
• Rushing corners and edges instead of using beads and scrim properly

When to Book a Course Instead

Reading through the steps is useful, but plastering is a hands-feel skill—knowing when the surface is ready to trowel up is something you learn by doing it under guidance, not from a diagram. Our 3-day Plastering course (or the 5-day option with boarding) puts you through this exact process multiple times, with a qualified instructor correcting your technique as you go, on materials and tools we supply.