The plastering process: skim, render and lime explained
Preparation to painting: what a plasterer does on each visit, drying times, and how skim, render and lime differ.
Updated 2 September 2026
Every plastering job runs through three stages: preparation, application and drying. A reskim on sound plasterboard can be done in a single visit at about 18 m² a day for the £230 day rate. Bare brick needs a bonding coat, a day to cure, then a finish skim on a second visit. External rendering follows the same rhythm but slower, at about 12 m² per day. It is tempting to treat plastering as one visit from a man with a trowel — an easy assumption, because the stages blur together on the day. But the stages are where jobs are quietly rushed, and a finish applied over an under-dried or un-prepped wall is prone to cracking. Knowing the three stages is how you spot that before you pay for it. This guide covers standard gypsum skimming in domestic rooms — not ornate cornice restoration, polished plaster or commercial contracts.
Stage 1: Preparation
The plasterer clears the room, sheets the floor and protects what cannot be moved. New plasterboard gets joint tape over the seams; previously painted walls usually get a PVA bonding agent; bare brick gets a scratch coat to give the finish something to grip. Artex ceilings should be tested for asbestos before anything is disturbed. Good preparation is where most of the difference between a good and a bad finish is made, and it is why two identical rooms can take very different amounts of time. Skirting and sockets should be protected or removed before plaster touches them.
Stage 2: Application — skim, bonding and render
A skim coat is two thin layers of multi-finish applied wet-on-wet, two to three hours apart. A bonding coat goes onto bare brick and is left to cure overnight before the finish skim the next day. External rendering is done in two passes: a scratch coat, then a float coat, ruled flat with a straight edge. Lime plaster is applied the same way but dries more slowly and is chosen for older solid-wall homes so the wall can still breathe. Each method has its own pace, which is why the number of visits differs from job to job.
Stage 3: Drying and decorating
Plaster must dry fully before it is painted, usually one to two weeks for a standard skim, longer in winter or a damp house. Painting too soon traps moisture and causes the finish to fail. The first coat should be a watered-down mist coat of emulsion, not a full-strength paint, so the plaster can still breathe as it cures. If you see dark patches that never dry, the room needs more ventilation before decorating. Resist the temptation to speed things up with a dehumidifier pointed straight at fresh plaster, which can dry the surface too fast and cause it to crack.
How long the job takes — and why you cannot rush stage three
A single skimmed room is usually finished in one or two days of work, spread across visits if bonding is involved. A full replaster of a room with bare brick can take three to four days. External rendering of one elevation is typically two or more visits because each coat has to set before the next. Drying time is on top of all of that, so allow a week or two after the plasterer leaves before the decorator arrives. Agree the programme up front so you know how many visits to expect and when the room comes back into use.
What to ask on the day
Confirm the plasterer will protect floors and skirting, will skim right into the corners, and will leave the surface ready for a mist coat. Ask how long the job should dry before painting. If anything in the plan changes once walls are opened up, a good plasterer says so before cutting corners. After the work, hold the bulk of payment until you have checked the finish in good light and the room has started to dry evenly.
Choosing the right method
Skimming suits sound surfaces that just need a fresh face. Bonding and skimming is for bare brick. Rendering is for outside walls. Lime is for solid-walled older homes. If you are not sure which applies, a local plasterer can assess the wall and recommend the method before quoting, so you are not paying for a full replaster when a skim would do. Matching the method to the wall is the single biggest factor in how long the finish lasts.
The three stages, now yours to check
The promise at the top of this guide is now kept: you know the three stages — preparation, application, drying — what each one involves and how long it takes. That changes what you can do on the day: a plasterer who skips the PVA, floats over dust or paints too early is no longer a detail you miss, it is a question you ask. You are no longer watching a job happen — you are auditing it. The same thinking applied before the job starts is what choosing the right plasterer is about.
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The plastering process: skim, render and lime explained: quick questions
Can I stay in the house while the plasterer works?
Yes, but the room being plastered will be out of use. Plastering creates fine dust, so close internal doors and cover furniture in neighbouring rooms. Tell the plasterer if you need a clear path to a toilet or the kitchen so they can keep it swept.
How long before I can paint?
The surface feels firm within a day or two, but wait one to two weeks for it to dry before painting. Darker or damper rooms take longer. A skim coat dries faster than a bonding or render coat.
What is the difference between skimming and rendering?
Skimming is a thin indoor finish over plasterboard or old plaster. Rendering is a thicker weatherproof coating for outside walls. Rendering is slower and costlier per square metre because it has to shed rain and survive frost.
What does lime plaster cost compared to normal plaster?
Lime plaster is more expensive than gypsum because the materials cost more and it dries more slowly, so the job takes longer. It is worth the extra on older solid-wall homes where the wall needs to breathe. For most modern homes a standard gypsum skim is the right and cheaper choice.