Checklist for Plastering Work (Site QC)

Use this checklist at three gates — before plastering starts, while it's going on, and before you pay for it. Plaster defects (hollowness, cracks, undulation) are cheap to prevent and maddening to fix after painting.

1. 1

   Gate 1 — before the first trowel

   Masonry cured 7 days, joints raked, chases meshed, wall wetted, level dots fixed. Everything here is free; everything after it is expensive.

2. 2

   Gate 2 — while it goes on

   Mortar used within 45 min, pressed not spread, straight edge run continuously, grooves cut at RCC junctions.

3. 3

   Gate 3 — before you pay

   Tap-test for hollows, ≤4 mm under a 2 m edge, plumb ≤5 mm per storey, then 7 days of curing.

Plaster defects are almost never a material problem. Each gate catches faults while they still cost nothing to fix.

The three phases — tick as you go

Common defects and their cause

Rates for this work: building work labour rates. Short version of this list: plastering checklist (compact).

Measuring and paying for plaster work

Plaster is measured by area and paid by area, and the deductions are where every plastering dispute on an Indian site begins.

The measurement rules (IS 1200 conventions):

• Plaster is measured in square metres of finished surface.
• Openings up to 0.5 m² are generally not deducted — the reasoning is that the extra work of plastering the reveals around a small opening offsets the area saved.
• Openings 0.5–3 m² — deduct one face.
• Openings over 3 m² — deduct both faces, but the reveals and soffits are then measured separately and paid.
• Jambs, soffits and sills of deducted openings are measured as plaster.
• Ends of joists, beams and posts up to 0.5 m² are not deducted.

Why this causes arguments: a contractor measuring gross wall area with no deductions and an owner measuring net area with every opening removed can be 10–15% apart on a house — real money, and both will believe they are right. Settle the measurement convention in the contract, before work starts, naming IS 1200. Afterwards it is a negotiation about memory.

Different thicknesses are different items. 12 mm internal and 20 mm external are separate rates. A single blended "plaster rate" for the whole house hides which surfaces got which thickness, and the thin ones are where it is being taken out of.

What the rate includes and excludes. Scaffolding is the usual dispute — external plaster above about 3 m needs it, and whether it sits in the plastering rate or as a separate line should be explicit. Chicken mesh at junctions, curing water, and making good after other trades are the others.

Sequencing: what must happen before plaster

Plaster covers things permanently. Everything that belongs behind it has exactly one window, and it closes the moment the mason starts.

The order:

1. Masonry complete and cured. Fresh brickwork is still shrinking. Plaster on green masonry cracks as the wall settles beneath it. Allow the masonry to cure and settle — a fortnight is a reasonable minimum on a house.
2. All chasing done. Electrical conduits, plumbing chases, AC piping, network cable — every groove cut, every conduit fixed, every chase filled flush with mortar and meshed. Cutting a chase into finished plaster is destructive, dusty, and the patch never quite disappears.
3. Frames fixed. Door and window frames in place, plumb, and packed — plaster finishes against them and covers the fixing.
4. Fixtures anchored. Anything needing a bolt into masonry — heavy brackets, railings, grills — goes in before the plaster covers where the bolt has to land.
5. Roof watertight. Plastering an interior under a roof that still leaks is plastering a surface that will be wet again next week.
6. Then plaster. Then curing. Then, a week later, painting.

The step that gets reversed: electrical chasing after plastering, because the electrician came late. It is common, it is visible for the life of the building, and it is a scheduling failure rather than a technical one.

Acceptance: what to check before you pay

Plaster is easy to inspect and almost nobody does it properly. Six checks, none of which need an engineer:

Plumb. A 2 m spirit level or a plumb bob against the wall. Tolerance on internal plaster is about 3 mm over 2 m. Out-of-plumb plaster shows up later as a wardrobe that will not sit flush and a skirting with a tapering gap.

Flatness. A 2 m straight edge held against the surface. The gap under it should not exceed about 3–4 mm. Undulation is what makes a painted wall look cheap under raking light, and it cannot be fixed by paint.

Hollowness. Tap the whole surface with your knuckle or a coin. A hollow sound is debonded plaster. It will fall off. Mark it and have it redone now, not after the painting.

Corners. Internal and external corners should be sharp, straight and plumb. A wavy corner is visible from across a room and is the fastest way to read the quality of a plastering job.

Thickness at openings. Check the reveals — this is where thickness is quietly reduced because it is fiddly work.

Cracks. Any crack at all before painting is a signal. Hairline map cracking means curing failed. Straight cracks at brick/RCC junctions mean the mesh was skipped. Both are worth resolving before paint, because paint hides them for about one monsoon.

Do these checks before the scaffolding comes down. After that, reaching the external walls costs money, and everyone knows it — which is why the pressure to sign off arrives just as the scaffold is being dismantled.

Common defects and what causes each

A short diagnostic table, because the cause is usually readable from the symptom.

On efflorescence specifically, because it worries owners more than it should: it is salt carried to the surface by evaporating water. It means the wall was wet and is drying, and the salts came from the bricks, the sand or the ground. Brush it off dry — do not wash it, which drives the salt back in to re-emerge later. If it keeps returning, the wall has a moisture source: a failed DPC, a leak, or rising damp. That is what needs fixing; the bloom is only the messenger.

Repairing plaster properly

Patching plaster badly is worse than not patching it, because the patch is visible forever.

For hollow or debonded areas: cut it out back to sound plaster, square the edges (never feather them), rake the exposed masonry, wet it, and re-plaster in the same mix and thickness. A patch thinner than its surround will crack at the boundary.

For cracks that are shrinkage or thermal: open the crack into a V-groove 6–10 mm wide, clean it, wet it, fill with mortar or a proprietary crack filler, and cure it. Filling a hairline crack by smearing putty over it means the crack reappears through the paint within a season — the movement is still happening under the smear.

For a chased conduit line that keeps cracking: the chase was not filled flush before plastering. Cut it out, fill with mortar, fix mesh over the line with 100 mm each side, and re-plaster.

For cracks that are structural: stop. Do not fill them. A crack that is widening, diagonal, passing through the masonry, or accompanied by cracks elsewhere is the structure moving. Filling it removes your only evidence and your only monitoring device. Photograph it with a scale and a date, watch it for three months, and get a structural engineer to look at it.

Painting over plaster — the wait nobody wants

The last dispute on every plastering job is when painting can start.

New plaster must dry AND its alkalinity must fall. Fresh cement plaster is strongly alkaline, and alkali attacks paint binders — this is what causes peeling, discolouration and saponification on newly painted walls. The plaster needs to carbonate before it will accept paint reliably.

The conventional wait is 28 days after curing finishes, and it exists for this reason, not out of tradition. On a site running late, this is the wait everyone tries to negotiate away.

What happens if you paint early: the paint may look fine for months, then blister, peel or show patchy discolouration as alkali and residual moisture migrate out. Repainting means stripping, which means the original economy cost more than it saved.

If you genuinely cannot wait, an alkali-resistant primer is the mitigation — not a substitute for drying, but it buys real tolerance. Use a moisture meter if the schedule is tight; readings should be low and stable before anything goes on.

And putty is not a fix for bad plaster. Wall putty is a thin skim to smooth a surface, not a way to flatten an undulating wall or hide crazing. Putty over map-cracked plaster cracks in exactly the same pattern within a year, because the substrate is still moving underneath it.

The handover conversation

The moment to raise plaster quality is before the scaffolding comes down, and everyone on site knows it — which is why the sign-off request tends to arrive exactly as the scaffold is being loaded onto a truck.

Once external access is gone, fixing a hollow patch three metres up means re-erecting scaffold, and the cost of that is enough to make everyone decide the patch is acceptable. Do the tapping, the straight edge and the plumb check while access is free. It takes an hour for a whole house.

For internal walls, the equivalent deadline is before painting starts — once putty and two coats are on, every defect underneath has been paid for twice and is now expensive to reach.

Storing and mixing on site

Two habits cost more plaster than any technical decision on this page.

Mixing on bare soil. Earth gets into the mortar, and earth is silt. Silt-contaminated plaster dusts off under a fingernail and never reaches strength. A steel tray or a clean concrete platform removes the problem entirely and costs nothing.

Mixing too much at once. Cement mortar has a working life of about 30 minutes once water is added. A large batch that sits while the mason works through it is partially set by the time it reaches the wall — and re-tempering it with more water, which is what always happens, destroys whatever strength was left. Mix what can be used in half an hour, and no more.

And keep the cement dry. Bags stacked against a damp wall or on a wet floor hydrate quietly, and a bag that has gone lumpy has already reacted. Raised platform, off the walls, oldest stock first, covered.

Before you sign

Tap every wall. Run a straight edge over it. Check the corners are plumb. Confirm the mesh went in at the junctions. Do it while the scaffold is still standing and before the painter arrives — those are the two deadlines, and both of them pass quietly.

Frequently asked questions

What is the correct mortar ratio for plastering? 1:6 (cement:sand) for internal walls, 1:4 for external walls and ceilings — external work with an integral waterproofing compound.

What thickness should plaster be? 12 mm internal, 15–20 mm external (in two coats beyond 15 mm), and only 6–10 mm on RCC ceilings.

How long should plaster be cured? Minimum 7 days of wetting 2–3 times daily; longer for external faces in hot, dry weather.

How do I check plaster quality before paying? Tap for hollows, run a 2 m straight edge (≤4 mm gap), check plumb (≤5 mm per storey), corners square, and confirm mesh was used over chases.

---

Related checklists

• Plastering Checklist (Compact)
• Beam & Column Shuttering Checklist
• Plumbing Work Checklist
• All checklists →