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What is hardwall plastering and when is it used?

Hardwall is a gypsum backing plaster that a plasterer applies straight onto brick or block walls, then covers with a thin finish coat. It is used when a solid wall needs a new base coat, for example after old plaster has been hacked off.

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By the QuoteZila editorial team. Editorial policy.

What is hardwall plaster?

Hardwall is a gypsum undercoat, sometimes called a backing coat or browning coat by older plasterers. It goes straight onto a solid background such as brick or blockwork, is ruled flat, and then covered with a thin finishing plaster. The two coats together give a wall that is straight, smooth and ready to paint.

Plasterers use the name for this kind of backing coat. Other makers sell similar backing plasters under their own names, so a plasterer may say "hardwall" to mean the type of coat rather than one brand. Ask which product they will use, and why it suits the wall.

QuoteZila is starting in Cheshire, with Crewe, Nantwich and Sandbach among the first towns, and anyone in the UK can post a job. This page explains what hardwall plastering involves so you can describe your job clearly.

When is hardwall used?

A plasterer will usually suggest a backing coat when there is no sound surface left to skim. Typical cases are:

  • After hacking off. Old plaster has blown, cracked or crumbled and has been removed back to the brick.
  • After a new opening or a chase. A doorway has been moved, a chimney breast removed, or cables and pipes have been chased into the wall, leaving bare masonry to patch.
  • After damp treatment. Once the cause of damp has been dealt with and the wall has been allowed to dry, the specialist may specify how the wall should be replastered. Follow their specification.
  • New blockwork. An internal block wall in an extension, if it is being plastered wet rather than dry lined.

If the walls are already flat and sound, a skim on its own may be enough. If they are uneven but dry, some plasterers will suggest plasterboard on dabs instead of a full backing coat. Ask why they recommend one method over another.

How does hardwall differ from other plasters?

There are several undercoat plasters, and the choice depends on what the wall is made of:

  • Hardwall is the name plasterers often use for a backing coat on brick and block. Ask why it suits your wall.
  • Bonding coats are generally used on low suction or smooth surfaces such as dense concrete or engineering brick, where a hardwall coat might not grip as well.
  • One-coat plasters combine backing and finish in a single, thicker application, often used for patching.
  • Lime plasters are traditional on older solid-walled houses. They behave differently from gypsum, and a building with original lime plaster may need a different approach.

If your house is old, has solid walls, or is listed, ask the plasterer whether a gypsum backing coat suits it before work starts. That is a question about the building, not just the plaster. If the job changes the structure, such as removing a chimney breast, ask building control before work starts. GOV.UK says you must check if you need approval before you construct or change buildings [S1].

What happens on the day?

A hardwall job is messy and takes more time than a skim, because the backing coat needs to be built up and left to firm up before the finish goes on. The plasterer will usually:

  1. Protect floors, doors and anything left in the room.
  2. Prepare the wall, which may include removing loose material and fitting metal beads to corners.
  3. Apply and rule off the backing coat, keying it ready for the finish.
  4. Apply the finish coat once the backing has set enough.

Hacking off old plaster creates a lot of dust and rubble. Ask who removes it and whether it is in the price. Ask too how long the wall should be left to dry before you paint, and what mist coat they recommend for new plaster.

What should you ask a plasterer?

When you compare quotes, ask each plasterer the same things:

  • Is the price for hacking off, backing coat and finish, or only some of those?
  • Which plaster will you use for the backing coat, and why for this wall?
  • Will you fit new beads to corners and around windows?
  • Who takes away the old plaster and rubble?
  • What happens if more of the wall is loose than expected?
  • How long should the wall dry before decorating?

Citizens Advice says a quote is a fixed price, while an estimate is a rough guess at the cost [S2]. Ask which one you have been given, and get it in writing.

Jobs you might post

These are examples, not taken from real job posts.

  • "Old plaster in the back bedroom is blown and coming away. Needs hacking off and replastering on two walls."
  • "New doorway knocked through between kitchen and dining room. Brick reveals and a strip of wall need plastering."
  • "Damp treatment finished on a chimney breast. Specialist has given a plaster specification. Need a plasterer to follow it."

Get quotes from plasterers

Say which walls, roughly how big they are, and whether the old plaster is already off. Up to five matched local businesses can send you a quote [QZ2]. QuoteZila is free for customers and local businesses [QZ1].

Honest status: QuoteZila is new. We're starting in Cheshire, beginning with Crewe, Nantwich and Sandbach, and growing area by area. Anyone in the UK can still post a job or register a business. How fast you get quotes depends on how many local businesses have joined near you. Businesses can register and receive jobs straight away. We don't check insurance, qualifications or registrations, so please check these yourself before you hire.

Posting a job is not open yet

See our plasterers page and, if damp is part of the job, damp proofing. For other wall finishes, see what changes the cost of acoustic plaster.

Questions about hardwall plastering

What is hardwall plaster used for?

It is a backing or undercoat plaster for masonry walls such as brick and block. A finish coat goes on top to give the smooth surface you decorate. Ask the plasterer which backing plaster they will use on your wall and why.

Is hardwall the same as skimming?

No. Skimming is a thin finish coat over a surface that is already flat, such as plasterboard or sound old plaster. Hardwall is the thicker backing coat that builds a wall back up when the old plaster has gone. A job described as hardwall and skim means both coats.

Can hardwall go on a damp wall?

If a wall is damp, the cause needs sorting first. Ask a damp specialist or surveyor before replastering, rather than plastering over the problem. GOV.UK says you must check if you need approval before you construct or change buildings. If the job changes the structure, such as taking out a chimney breast, ask building control before work starts.

Does QuoteZila check the businesses?

No. We don't check insurance, qualifications or registrations, so please check these yourself before you hire. You can report a quote or a business from your job page.

This page is general information, not professional or legal advice. QuoteZila does not check Gas Safe, WaterSafe, NFRC, NICEIC or other registrations against the register on your behalf: look them up yourself.

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Sources

  1. QZ1: QuoteZila product fact. QuoteZila home and jobs-for-tradesmen copy.
  2. QZ2: QuoteZila product fact. QuoteZila FAQ and app README.
  3. S1: Building regulations approval, GOV.UK. Accessed 2026-10-27. https://www.gov.uk/building-regulations-approval
  4. S2: Before you get work done on your home, Citizens Advice. Accessed 2026-10-27. https://www.citizensadvice.org.uk/consumer/getting-home-improvements-done/before-you-get-building-work-done/