Rolling paint onto a wall is the quick part of painting a room. What makes it look professionally done mostly happens before the can is even opened.
This interior painting prep guide goes through the steps we follow in every room, in the order we do them. You can skip a few and the paint will still go on. It won't look as good, though, and it won't last as long.
Interior Painting Prep Starts With a Clean Room
Push the furniture to the middle of the room, cover it with plastic, and lay drop cloths along every wall. Take off switch plates and outlet covers, and tape each plate's screws to its back so they don't wander off.
Then wash the walls. Paint doesn't bond well to dust or grease. On most walls a sponge and warm water is enough. For kitchens, Benjamin Moore recommends water and a grease-cutting detergent, followed by a clean-water rinse so no cleaner is left behind. Let everything dry completely, because primer or paint over a damp wall can blister.
If you find mildew, usually in a bathroom or on a cold outside wall, deal with it first. Never paint over it. It grows right back through new paint.
Patch, Caulk and Sand
This step takes the longest, and it's the one most people rush.
- Fill nail holes and small dents with spackle or joint compound. Overfill a little, then sand flush once it's dry.
- Bigger damage, like a doorknob hole, needs a proper drywall repair. A dab of filler won't hold.
- Scrape or sand off flaking and cracked paint. New paint over loose paint comes off with it.
- Caulk the gaps between trim and walls with a paintable acrylic-latex caulk
- Scuff-sand glossy surfaces such as old semi-gloss trim. Benjamin Moore suggests fine-grit paper over water-based paint and 100 to 150 grit over oil-based.
- When you're done, wipe off the dust with a damp cloth and let the wall dry before priming
Lead Paint in Older Homes
If your home was built before 1960, Health Canada says it probably has lead-based paint. In homes built between 1960 and 1990, the exterior may have it, and interior paint from those years can contain smaller amounts that are still harmful, especially to young children. Houses built after 1990 shouldn't contain lead paint.
Don't sand or use a heat gun on old paint until you know what's in it. Health Canada suggests sending paint chips to a lab, or hiring a contractor with x-ray equipment that detects lead on painted surfaces. If the paint isn't chipping and kids can't reach it, leaving it alone is sometimes safer than removing it.
When You Need Primer
Not every wall needs a full coat of primer. A clean, sound wall that's already painted and is going a similar colour often just needs the repaired spots primed. Primer is worth the extra step in these cases:
- Patches and bare joint compound. Left unprimed, they're more porous than the wall around them and tend to show through the topcoat.
- Water stains, smoke stains and marker, which need a stain-blocking primer or they'll bleed through
- Old oil-based paint, common on trim and doors in older houses. Glidden's test is to rub a hidden spot with a cotton ball dipped in denatured alcohol. If no paint comes off, it's oil-based, and you'll need a bonding primer before latex goes on.
- Going dark over light. Glidden suggests having the primer tinted grey, which can cut down on coats.
- Stained wood trim getting painted for the first time. Without a stain-blocking primer, tannins in the wood can come through as a brown tinge.
Paint, Then Leave It Alone
Once the primer is dry, tape the lines that matter most, like the trim and the ceiling edge, and start painting. We usually put two coats on the walls and two on the trim.
Go easy on the walls for a while afterward. Benjamin Moore recommends waiting at least two weeks for fresh paint to cure before you clean it. If something spills before then, wait until the paint is dry and wipe it gently with plain water.
DIY or Hire It Out?
Prep is where most DIY paint jobs fall short. It's slow and nobody enjoys it, and it's a big part of what you're paying a painter for. Our interior painting usually costs $300 to $800 per room. Size, ceiling height and the amount of prep all move the number. Painting the full interior of a 3-bedroom home generally comes to $2,000 to $5,000.
We price painting by the project, and every job starts with a free written estimate. Call (289) 928-5689, or send us a few photos of the rooms you want done.
Owner of Handy Man And Home Repairs. 16 years in construction, 15 of them as a Home Inspector. Works across Durham Region, Kawartha Lakes and Northumberland.