Interior: Paint, Drywall & Trim

Learn how to patch drywall, choose the right paint, and update your interior trim.

Interior: Paint, Drywall & Trim
On this page
  1. The Bones of Your Walls
  2. Common Wall Problems
  3. Prepping to Paint
  4. Choosing the Right Paint
  5. Trim and Molding
  6. Water Damage and Stains
  7. What Does It Cost?

The Bones of Your Walls

Drywall is the skin of your house. It is made of chalky gypsum rock pressed between two thick sheets of paper. Builders screw large panels of it directly to your wooden wall studs. They cover the seams between the panels with paper tape and a wet paste called joint compound. Once it dries, they sand it smooth so the wall looks like one solid piece.

Drywall is cheap and easy to fix. But it is also soft. It dents when you bump it with a couch. It crumbles if it gets wet. Most of the cosmetic work you do inside your house will involve fixing small drywall bumps and bruises.

Drywall panels are taped and mudded together to create a smooth, continuous wall.
Drywall panels are taped and mudded together to create a smooth, continuous wall.

Common Wall Problems

Houses move. Wood dries out and shrinks. Because of this, your drywall will eventually show some wear and tear.

Nail pops are very common. This happens when a drywall screw or nail backs out of the wood stud. It pushes a small, round bump of paint out of the wall. To fix it, you drive a new screw into the wall right next to the old one. Then you pull the old fastener out and patch the hole.

Hairline cracks often show up above doors and windows. This happens because the framing shifts slightly. You can scrape the loose paint away, apply new drywall tape, and cover it with joint compound. If cracks keep coming back or get wider than a pencil, your house might be settling. You can read more about what causes this in our Foundation & Structure guide.

For small nail holes from hanging pictures, you just need a tiny dab of spackle. Spackle dries fast and does not shrink much. For holes larger than a golf ball, you need a sticky mesh patch. You put the patch over the hole and spread joint compound over it. The mesh gives the wet mud something to hold onto.

A mesh patch gives joint compound something to grab onto when fixing medium holes.
A mesh patch gives joint compound something to grab onto when fixing medium holes.

Prepping to Paint

Painting is 80 percent prep work and 20 percent actually painting. If you rush the prep, your walls will look terrible.

First, wash the walls. Paint will not stick to greasy fingerprints or thick dust. A damp sponge with a little dish soap works fine. Next, fill all your nail holes and sand them smooth. Run your hand over the wall. If you feel a bump, you will see it through the new paint.

Pro Tip: Shine a bright flashlight parallel to the wall before you paint. The harsh light casts long shadows on tiny dents and bad patch jobs you would normally miss. Fix them now before the new paint locks them in forever.

Finally, tape off your baseboards, window frames, and door frames. Use high quality painter tape. Press the edge of the tape down hard with a putty knife so paint cannot bleed underneath it. Drop a canvas tarp on the floor to catch drips.

Choosing the Right Paint

Walk into any hardware store and you will see hundreds of paint cans. The most important choice you make is not the color. It is the sheen. Sheen means how shiny the paint dries.

Shiny paint reflects light and is very easy to wipe clean. But because it reflects light, it highlights every single dent and flaw in your wall. Flat paint absorbs light. It hides terrible drywall work beautifully, but it is very hard to clean. If you scrub flat paint with a wet rag, the paint might rub right off.

Paint SheenBest Room or SurfaceDurability and Cleaning
Flat or MatteCeilings, low traffic bedroomsLow. Hard to clean. Hides wall damage well.
EggshellLiving rooms, dining roomsMedium. Wipes clean easily with a damp cloth.
SatinKitchens, bathrooms, hallwaysHigh. Resists moisture and takes light scrubbing.
Semi-GlossTrim, doors, baseboards, cabinetsVery High. Highly scrubbable but shows every dent.

You also need to think about primer. Primer is a base coat. It sticks to bare drywall better than paint does. It also blocks old stains from showing through. If your walls smell like old cigarette smoke, a regular coat of paint will not fix it. You need a special stain blocking primer. Check out our Smells & Odors guide for more details on trapping bad smells.

Trim and Molding

Trim covers the ugly gaps where different materials meet. Baseboards cover the gap between the wall and the floor. Casing covers the gap between the wall and a door frame. Crown molding sits up high between the wall and the ceiling.

Trim takes a lot of abuse. Vacuum cleaners smash into baseboards. Dogs scratch window casings. Upgrading your trim is a fast way to make an old room look modern. If you just put in new floors, you will probably need to remove and replace your baseboards anyway. Read our Flooring guide to see how floors and trim fit together.

When you install or repair trim, you need two different fillers. You need wood filler for the nail holes in the wood itself. Wood filler dries hard and you can sand it smooth. You need caulk for the long gap between the trim and the drywall. Caulk is flexible. It stretches when the house moves so the gap stays hidden.

Caulk fills the gaps between trim and drywall to create a smooth, finished look.
Caulk fills the gaps between trim and drywall to create a smooth, finished look.

Water Damage and Stains

Water is the enemy of drywall. If a pipe leaks behind your wall, the drywall turns to mush. Even after it dries out, it leaves a dark yellow or brown ring on your ceiling or wall.

Warning: Never just paint over a yellow water stain. The stain will bleed right through your new paint in a matter of days. You have to fix the leak first, then seal the old stain with an oil base primer.

If the drywall is soft to the touch, or if it crumbles when you poke it with a screwdriver, it is dead. You cannot save it. You have to cut the damaged square out with a utility knife and screw a new piece of drywall into the studs. Always make sure you actually fixed the source of the water first. If you have a hidden leak, check your Plumbing before you close the wall back up.

What Does It Cost?

Painting is the most popular DIY project in America because the labor is expensive but the materials are cheap. A gallon of good interior paint costs $40 to $80. A professional painter will charge hundreds of dollars for that same room because of the time it takes to prep and clean up.

Drywall repair costs depend on the size of the hole. A handyman can patch a doorknob hole in an hour. Replacing an entire ceiling ruined by a burst pipe takes a crew several days.

DIY Paint & Supplies (1 Room)$150 to $300
Pro Painter (1 Room)$400 to $800
Pro Drywall Repair (Small Hole)$100 to $250
Pro Painter (Entire House Interior)$4,000 to $8,000

Keep in mind that prices vary widely based on your region, the age of your home, and the exact scope of work. If you want to hire this out, our guide on Hiring Contractors & What Things Cost is a great place to start.

Frequently asked

How do I fix a nail pop in my drywall?

Do not just hammer the nail back in. Drive a new drywall screw a few inches above the popped nail to secure the board tight to the stud. Then pull the old nail out, patch both holes with joint compound, sand it smooth, and paint.

Do I always need to use primer before painting?

Not always. If you are painting over a similar color and the old paint is in good shape, a paint and primer in one works fine. You need a dedicated primer if you are painting bare drywall, covering very dark colors, or sealing water stains.

Why is my new paint peeling off the baseboards like a rubber skin?

You probably painted latex paint straight over old oil base paint. Latex paint will not stick to a glossy oil finish. You have to scuff the trim with sandpaper and use a bonding primer first.

What is the difference between spackle and joint compound?

Spackle is thick, dries fast, and hardly shrinks. It is great for tiny nail holes. Joint compound is thinner, takes much longer to dry, and is better for taping seams or skimming large patches.

How many coats of paint do I need?

Plan on two coats for almost every project. The first coat rarely covers perfectly and often looks streaky. The second coat provides the true color and an even, durable finish.

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