Types, and matching them to the surface
| Primer | For | Rate / sq ft |
|---|---|---|
| Water-based wall primer | Putty, plaster, gypsum board | ₹12–20 |
| Solvent-based wall primer | Damp-prone or previously distempered walls | ₹18–30 |
| Alkali-resistant primer | New cement plaster within 90 days | ₹20–32 |
| Metal / red oxide primer | MS sections, grills, railings | ₹22–40 |
| Wood primer or sanding sealer | Timber and board before enamel | ₹28–50 |
| Stain-blocking primer | Water stains, marker, nicotine | ₹35–60 |
What happens without it
Three things, all visible. The topcoat absorbs unevenly into porous putty, producing patchy sheen that shows most on a wall lit from the side. Adhesion is weaker, so the paint chalks or peels years earlier. And coverage drops — you use more expensive topcoat to do the job a cheaper primer would have done. Saving ₹15 per sq ft on primer typically costs more than that in extra emulsion.
One coat or two
One full coat of primer is standard and correct on a puttied wall. Two are worth it in three cases: over a dark existing colour being taken to a pale one, over a stain-blocked patch, and on a ceiling where the board paper and the jointing compound will otherwise absorb differently. Thinning primer beyond the manufacturer's stated ratio to stretch it is common on site and defeats the entire purpose.
The alkali problem in new construction
Fresh cement plaster is strongly alkaline and stays so for weeks. Painting over it too early causes saponification — the alkali attacks the paint film and produces patchy discolouration and a sticky surface. In a new Mumbai building, either wait 28 days minimum after plastering, or use an alkali-resistant primer. In a redevelopment flat handed over in the monsoon, do both.
Reading it in a quotation
A painting line should read as four items: putty (two coats), primer (one coat), and topcoat (two coats), with the brand and product named. A quotation offering “paint — ₹32 per sq ft” is compressing all of that into one figure, and the primer is the coat most likely to disappear. See texture paint, the paint quantity calculator and home renovation.
Frequently asked questions
Can I paint without primer?+
You can, and the result will be patchy in sheen, weaker in adhesion and more expensive in topcoat. On a previously painted wall in sound condition, a primer can sometimes be skipped; over fresh putty or plaster, never.
How long should primer dry before painting?+
Four to six hours for a water-based primer in dry weather, overnight in the monsoon. Manufacturers state a minimum and a maximum recoat window — exceeding the maximum means light sanding before the topcoat.
Is primer needed on a new gypsum board ceiling?+
Yes. Board paper and jointing compound absorb very differently, so without a primer every joint will read as a lighter band under the ceiling lights. This is one of the most visible primer failures there is.
What primer should be used on new plaster?+
An alkali-resistant primer, or wait at least 28 days for the plaster to carbonate. In a new building where the programme will not allow the wait, the alkali-resistant product is the only safe route.