Interior painting prep work: why it decides how long your paint job lasts

There is an old rule in the trades: a finish is only as good as what is under it. Premium paint over a dirty, glossy or poorly patched wall will still fail. It will just fail with expensive paint.

That is the real reason one painting quote can be twice another. The cheaper one often leaves out the hours that nobody sees afterwards, and they are the hours that matter. Our crew paints and does drywall in-house, so we see both sides of this every week.

What does professional prep actually involve?

1. Protect and clear. Furniture moved or covered, floors protected, hardware and plates removed.
2. Wash. Kitchens and bathrooms collect grease and residue. Paint will not hold to it.
3. Scrape. Loose or flaking paint comes off back to a sound edge.
4. Sand. Glossy surfaces are scuffed so the new coat has a mechanical grip. Edges of old paint are feathered so they do not show.
5. Fill. Nail pops, dents and cracks are filled with the right compound, then sanded flush.
6. Prime. Bare drywall, patches and stains are sealed so the finish coat looks even.
7. Caulk. Gaps at trim and casings are sealed for a crisp finished line.

Why does patch sanding matter so much?

If a repair is sanded even slightly proud, the bulge will catch light and show through the paint once it dries, especially in a hallway with side light. Good drywall repair is sanded flush to the surrounding wall profile and feathered out. This is also where drywall skill and painting skill meet, which is why it helps to have one team do both. See our drywall and taping and painting pages.

Why prime?

Raw drywall and joint compound absorb paint at different rates. Without primer, the repaired areas can look dull or patchy under the topcoat, a defect painters call flashing. Primer also blocks some stains and helps the topcoat bond. It is a step, not a luxury.

A note on older Hamilton homes

If your home is older, the existing paint may contain lead. Health Canada advises that homes built before 1960 are likely to have lead-based paint and that some built later may too. Sanding or scraping old paint can release lead dust, so have it tested before you disturb it, and ask any painter how they handle it. It is one of the things we raise at the walkthrough on older properties.

How to audit a painting proposal

• Does it list washing, scraping, sanding, filling and priming, or just "paint walls"?
• How many coats, and on which surfaces?
• Who patches drywall: the painter or a separate trade?
• What is excluded (ceilings, closets, trim, doors)?
• How are floors and furniture protected? See how a good crew protects your home.

For pricing context, our interior painting cost guide for a 2,000 sq ft house shows how prep affects the number.

"It's just painting": when the wall has other plans

On one job that was booked as painting only, we arrived to find leaks inside some of the walls. Painting over that would have been a waste of the client's money, so we had to call a plumber to fix the leak, replace the damaged drywall, and redo screws, mudding and sanding before a drop of paint went on. It took extra time and extra money, and it was the right thing to do. This is why we inspect walls at the walkthrough, and why a price based on "paint walls" can be a guess until the surfaces are checked.

Keep reading

• Interior painters in Hamilton
• Cabinet painting in Hamilton
• The true cost of cheap paint: why premium products and multi-coat specs win
• Zero over-spray, zero drips: how a good crew protects your home
• Interior painting cost for a 2,000-square-foot house in Hamilton

Sources

• Health Canada: Lead in paint

This guide is general information from a contractor, not legal advice. Rules, prices and ranges change, so confirm current details before you sign a contract.