Questions: Interior Surface Preparation and Painting

Question 1

You want to repaint a kitchen wall that has small nail holes, some greasy smudges, and currently has a bright red color. In what order should you prepare the surface before rolling the new paint?

• A. Sand the entire wall first, then wash it, then fill holes
• B. Apply primer directly over the smudges to seal them, then fill holes and sand
• C. Wash the wall, fill holes with spackle and sand smooth, then apply primer
• D. Fill the holes and sand, then paint directly — washing is only needed if the wall is visibly dirty

Answer: (C)

The correct sequence is: clean first (paint over grease will peel), then patch (fill and sand holes), then prime (essential here for two reasons: bare spackle patches need primer to accept paint evenly, and going from red to a lighter color without primer means the red bleeds through and requires many more coats). Sanding before washing deposits dust in the grease; priming before patching leaves raw patches to bleed through.

Question 2

You are painting a bathroom. Which paint sheen is most appropriate, and why?

• A. Flat/matte — it hides imperfections best and gives a clean, uniform look
• B. Semi-gloss or satin — these sheens resist moisture and can be wiped clean
• C. Eggshell — it is the standard for all interior rooms regardless of use
• D. Oil-based flat — it provides the best moisture barrier in humid spaces

Answer: (B)

Bathrooms require a higher-sheen paint (satin or semi-gloss) because moisture and frequent cleaning make washability and moisture resistance essential. Flat/matte paint absorbs moisture and cannot be wiped clean — it would peel and grow mold. Oil-based flat combines the worst properties: durable but non-washable in a way flat latex is not. Semi-gloss/satin balance durability, moisture resistance, and appearance for wet rooms.

Question 3

Interior painting professionals typically spend more time on surface preparation than on applying paint.

• T. True
• F. False

Answer: True

Preparation — washing, patching, sanding, and priming — commonly accounts for roughly 80% of a quality paint job's time. The final appearance is largely determined before a drop of paint is applied: paint over dirty surfaces peels, paint over unfilled holes shows imperfections, paint without primer on bare drywall produces uneven sheen. The painting step itself is relatively fast once the surface is properly prepared.

Question 4

Applying one thick coat of paint produces a better result than two thin coats because it reduces the number of times you have to paint the wall.

• T. True
• F. False

Answer: False

One thick coat tends to drip, sag, and dry unevenly, while two thin coats produce a smoother, more durable finish. Thick paint doesn't cure correctly — the surface dries while the interior stays wet, leading to wrinkling or cracking. Two thin coats allow each layer to dry fully, and light sanding between coats further improves the final surface quality. The extra pass is faster than correcting a sagging thick coat.

Question 5

Why do professionals say 'preparation is the job' when it comes to interior painting? What happens specifically when preparation steps are skipped?

Model answer: Preparation determines adhesion — whether the paint bonds to the surface and stays there. Skipping cleaning means paint is applied over grease or soap film, which prevents bonding and causes peeling within months. Skipping patching leaves holes and cracks visible under the new surface. Skipping primer on bare drywall or drastic color changes causes uneven sheen (bleed-through) and requires many more expensive topcoats to achieve coverage. Each skipped step creates a defect that shows up after the paint dries and is difficult or impossible to fix without stripping back to the surface.

The paint itself is the easy part; its quality depends entirely on what it's adhering to. Preparation creates the clean, smooth, uniform substrate that allows paint to perform as designed. Rushing through prep to save time typically results in rework that costs far more time than the preparation would have taken.