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How to Prep Walls for Painting

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Matt is a professional painter who owns and operates his own painting business, specializing in interior and exterior house painting.

Learn important tips for prepping your walls for paint

Learn important tips for prepping your walls for paint

Preparing Walls for Paint

Nobody likes paint prep, but it's very important if you want your newly painted walls to be durable and look awesome. Paint doesn't bond well to dirty walls, so the first step is to clean them if needed. Regular dish soap, Krud Kutter, or TSP, are all good options for removing grime from walls. Let the walls fully dry before doing any drywall repairs.

Sand the Walls

Always wear a respirator while sanding walls and patching compound. A dust mask works too, but a respirator protects your lungs better. Most paints contain silica particles, which can cause silicosis and cancer from long-term exposure.

Use an extension pole and a sanding head equipped with 80- to 100-grit sandpaper to sand the walls smooth for paint. Using a sanding head on a pole is a lot easier than sanding with only a sponge in your hand. Sand the walls from top to bottom to smooth out the surface.

Be sure to repair any holes in your walls with joint compound and a putty knife

Be sure to repair any holes in your walls with joint compound and a putty knife

Repairing Holes and Cracks With Joint Compound

The best patching material for drywall hole repair is Easy Sand drywall compound (powder form) that comes in a bag. You can buy this product at any major home improvement store selling drywall supplies. I use the 20-minute version the most because the patches dry in only twenty minutes for sanding. You'll need a mud pan to mix the compound with water.

Fill Nail and Screw Holes

Fill wall holes with joint compound, using a putty knife, or a taping knife. Larger holes from drywall anchors usually require two to three coats of compound to blend the patch in with the wall. Don't use spackle to patch large holes. Spackle is too soft, shrinks, and takes too long to dry.

Repair Big Cracks With Drywall Tape

The best way to repair big cracks in drywall is with fiberglass drywall tape or paper tape. In my experience, paper drywall tape works better than fiberglass mesh tape with small holes that allow the crack to reform again over time.

To permanently fix big cracks with drywall tape, lightly gouge the entire length of the crack with a taping knife so nothing protrudes from the surface. Pre-fill the crack with compound and place a piece of drywall tape directly over it, pressing down on the tape with your knife to squeeze out the excess compound underneath. Apply two to three coats of joint compound over the tape, sand, prime, and paint.

Check to see if you need bonding primer before painting your walls. Use a quality paint roller!

Check to see if you need bonding primer before painting your walls. Use a quality paint roller!

Priming the Walls for Painting

Whether or not you need to use primer depends on different factors. There are many primer products that serve different purposes. Some serve as a bond coat, while others seal surfaces to prevent bleed-through from tough stains.

Are the Walls Painted With Glossy, Oil-Based Paint?

Latex paint doesn't bond well with oil-based paint or super glossy walls, especially faux finish glaze. Oil paint and enamel is too hard, glossy, and latex paint is unable to penetrate the drywall underneath. As a result, paint rub-off can occur. A bonding primer should always be used first before painting. A good product for this purpose is Extreme Bond Primer from Sherwin Williams.

Are There Stains on the Walls?

Most latex paints won't block wall stains from water, nicotine or permanent marker. The only way to prevent these stains from bleeding through the paint is by using an oil-based primer first. Shellac-based primer works great too. Kilz primer is good (oil, not latex), as well as ProBlock from Sherwin Williams, both of which are available in a spray can for easier application.

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Is the Drywall Torn?

When the top layer of drywall tears open from removal of drywall anchors and fixtures, the brown paper beneath becomes exposed. When the brown paper is exposed it needs to be primed first otherwise painting over it causes bubbles to form. The best way to prevent bubbles is to prime the torn areas with a spray can of the shellac-based primer BIN. The primer dries in less than thirty minutes and seals the paper for paint.

Are You Painting Red Over White?

To avoid having to paint multiple coats of red, white walls should always be primed with a tinted primer first. When painting red on white walls, a grey tinted primer works best, tinted to a shade similar to the red being used. The red paint will cover usually in no more than two coats over the gray prime coat. A good product to use for this purpose is the Multi-Purpose latex primer from Sherwin Williams.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: How do I paint a red wall white?

Answer: You'll need to prime the wall white with a good latex primer. I use Sherwin Williams products the most. Their Premium Wall and Wood Primer or Multi-Purpose Primer both work well for this purpose. But any quality latex primer will do the job.

Question: Do you sand the wall between coats of paint?

Answer: I always sand walls before painting, but usually not between coats, unless the walls aren't smooth from the initial sanding. I keep a sanding sponge in my pocket so I can spot sand rough spots if I need to.

Question: Do painters typically paint over drywall anchors?

Answer: I always remove them if possible, or knock them into the wall and patch the hole. If the anchor is metal and close to the surface of the drywall though, it should be primed first to prevent corrosion.

© 2012 Matt G.

Comments

Matt G. (author) from United States on May 01, 2012:

Thank you.

Ed on May 01, 2012:

Clearly explained, good job.

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