Interior Paint
Updated: September 10, 2010
Location – Our segment featured an older house filled with a lot of detailed wood trim that had been stripped & readied to repaint. Some of the wood had a layer of latex painted improperly over a layer of oil-based paint, so it was peeling and separating. We’ll explain in a minute why this was such a bad move, and what steps were needed to correct the mistake
Proper prep is essential – Surfaces need to be clean and dry before painting. New walls (drywall) need to be primed before painting. Primer looks like white paint, and it’s applied just like paint. Primer “seals” the original surface to create a good dry flat adhesive surface for the paint to grab onto. Old wall surfaces that you want to repaint need to be cleaned thoroughly. Wood surfaces that you want to repaint need to be cleaned and stripped of as much old paint as possible. The house in our segment featured surfaces that had been stripped to the bare wood with professional rotary sanders, but the Do-It-Yourselfer doesn’t need to go that far.
Detailed wood trim that’s been painted repeatedly, like we saw in the house in our segment, is nearly impossible to strip completely before repainting. Our contractors got around that challenge this way: First they hand-sanded the wood trim as much as possible. Then they applied a coat of primer to this freshly-sanded wood. Next, they lightly sanded the wood again, after this coat of primer dried, to create the best possible surface for new paint to adhere to.
If you want a shortcut, consider buying or renting a heat gun. The heat gun looks like a hand-held hair drier; it heats air up to 175 degrees and blows that hot air onto painted surfaces, “melting” the paint so you can peel it off easily to get down to bare wood with little effort.
Apply the Paint – Paint can be sprayed on, rolled on, or brushed on – Rollers save a lot of time on large surfaces like walls, but you need to be careful not to leave globs of paint or “hairlines” (lines created by the fibers in the roller). Thick rollers (rollers with a large “nap”) apply paint more evenly. Brushes are essential for detail work like the trim we’ve mentioned. Make sure you get a brush that’s sized right for the job at hand. A thinner brush allows more finesse when it come to detailed trim work.
Be very careful if you use a sprayer to apply paint indoors. Proper ventilation is crucial to your health and safety. Check local ordinances. Some areas outlaw sprayers altogether.
Variety of Paint Bases – Oil vs/ Latex (water-based):
Oil-based paints are becoming increasingly rare; in some places they’re outlawed for environmental reasons. Water-based (or latex) paints are the most common nowadays. Oil may offer a slightly richer finish and a slightly higher durability in some applications, but latex paint is easier to clean and maintain. Our location had some spots where latex was applied to an old coat of oil-based paint a few months before we taped our segment. The latex coat quickly started to peel away from the oil-based coat.
This happened because the previous painter did not take the time to properly prep the old (oil-based) coat for the new (water-based) coat of paint. This is a common situation in a lot of older homes where you’re most likely to find layers of oil paint.
Here’s the solution: Oil-based paint has to be de-glossed before it can receive a new coat of paint. De-glosser is an inexpensive liquid treatment readily available in any hardware or paint store. De-glossing removes the shine from the oil paint. Once it’s de-glossed, the old layer of paint should be cleaned (it doesn’t hurt to sand it too, if you want), so the new latex paint has a clean flat surface to adhere to.
Variety of Finishes – flat, satin (or semi-gloss) & gloss –
Paints start as a flat-finished product, then a plastic material is added to increase the level of gloss. Glossy paints offer durability and longer life in general, and they’re easier to clean. Flat paints tend to hide surface imperfections better. The choice of finish is entirely a matter of taste. Most people tend to use flat finishes for large surfaces like walls. Glossier finishes are usually chosen for detail work like trim or window frames. Glossy paints prove their durability in high-traffic areas, like doorjambs or the railings on stairs.
There is no limit to the variety of paint colors. Consult with a paint professional for help with any questions about base, finish, color, method of application, or the prep work required before you paint inside your house.





