This story covers some of the problems you may run into with existing interior surfaces and how to cure those problems before you repaint.
Sometimes you'll encounter problems in the existing surface that you must fix before repainting. Some of the problems are the result of poor-quality paint. Others are the consequence of inadequate preparation or poor application techniques. Some of the most common problems are shown here, along with an explanation of their causes (so you can avoid repeating them) and solutions (so you can fix them before applying your new paint).
Sagging can be caused by:
-- Applying the paint too heavily
-- Painting in humid or cool weather
-- Thinning the paint
-- Spraying with the spray head too close
-- Before repainting -- Sand all glossy surfaces. Sand sags flat and reapply a new coat of paint.
-- During application -- Do not thin the paint or overapply it. Two coats at the recommended spread rate are better than one heavy coat. Avoid cool or humid conditions. If the paint sags as you apply it, immediately brush it out or reroll it evenly.
Blistering can be caused by:
-- Applying oil-base paint over a damp or wet surface
-- Outside moisture seeping in through the interior walls
-- Exposing latex paint to high humidity or moisture shortly after paint has dried
-- Remove any source of moisture, if possible. Repair loose caulking. Remove blisters by scraping and sanding, prime bare spots, and repaint with a quality acrylic latex interior paint.
Burnishing can be caused by:
-- Using flat paint in high-traffic areas
-- Frequent washing and spot cleaning
-- Objects rubbing against the walls
-- Low-grade paint
-- Paint heavy-wear areas that require regular cleaning with a scrubbable latex wall paint. In high-traffic areas, choose a semigloss or gloss rather than a flat sheen. Clean painted surfaces with a soft cloth or sponge and nonabrasive cleansers.
Cracking and flaking can be caused by:
-- Low-quality paint with inadequate adhesion and flexibility
-- Over thinning or overspreading the paint
-- Improper surface preparation, or failure to prime the surface
-- Excessive hardening and embrittlement of alkyd paint as the paint ages
-- Remove loose and flaking paint with a scraper, sand and feather the edges. Fill deep cracks in multiple layers of paint. Prime bare wood with a top-quality primer and paint with a high-quality finish coat.
Roller marks or stipple can be caused by:
-- Using a low-quality roller cover or one with the wrong nap
-- Low-grade paint
-- Incorrect rolling technique
-- Use a high-quality short-nap roller cover and high-quality paint whose higher solids content rolls on and levels more evenly.
-- Dampen roller covers before loading with latex paint; shake out excess water.
-- Don't let paint build up at roller ends. Begin rolling at a corner near the ceiling and work down the wall in 3-foot-square sections. Spread the paint, beginning with an upward stroke to minimize spatter; then, without lifting the roller from the surface, bring the roller back with a downstroke. Finish the section with light, parallel strokes.