how to prepare and paint interior woodwork

How To Prepare and Paint Interior Woodwork (2 Easy Methods)

Preparation is the key to a professional finish. I learnt this the hard way, so now I invest time preparing woodwork before painting.

In this DIY guide, I’ll show you the steps to perfectly painted wood and offer hints and tips to make your life easier.

Tools and Materials

Ensure you have all the tools and materials below before preparing and painting woodwork.


  • Filling knife
  • Sponge
  • Sandpaper
  • Vacuum cleaner (with a hose)
  • Scraper tool
  • Paintbrush (2-inch/4-inch)
  • Step ladder (optional)
  • Dust sheets 
  • A clean stick (to stir the paint)


  • Sugar soap
  • Knotting solution
  • Primer
  • Undercoat (optional)
  • Topcoat
  • Masking tape

Safety Gear

  • Gloves 
  • Protective goggles
  • Face mask

Prep and Plan Like a Pro

Preparing and painting interior woodwork takes planning. Keep these things in mind:

  • The more effort you put into the preparation work, the better the result and the longer the paint will last.
  • The level of prep work depends on whether you’re painting old or new woodwork.
  • Always lay out dust sheets to protect surfaces and furniture.
  • Clear as much of the area as possible for uncluttered access.
  • Use a sanding block on flat surfaces to keep a level area.
  • Always work in the direction of the wood grain for the smoothest results.
  • Grade the sandpaper, starting with 60-grit and finishing with 220-grit.

Safety First

According to the Health and Safety Executive, some paints contain VOCs (volatile organic compounds) and solvents that release hazardous vapours as they dry.

Furthermore, when you sand paintwork, you kick dangerous dust particles into the atmosphere. Therefore, always wear protective goggles, gloves and a face mask when carrying out the steps below.

It could be lead-based if you’re stripping paintwork in an old house. Lead paint was banned in the UK in 1992 but was widely used in buildings and homes before that date.

How To Prepare and Paint Interior Woodwork — Step-by-Step Instructions

Once you’ve laid out your dust sheets, removed obstacles, and covered your furniture, you’re ready to get started:

There are two methods when prepping and painting woodwork, one for Old Woodwork and one for New Woodwork.

Method 1 — Preparing and Painting OLD Woodwork

Older woodwork can be challenging because it requires more attention. 

Cracked, flaking, and bubbled paint produces a poor finish, so you must remove it properly before going any further.

Preparing Old Woodwork

carpenter applying wood filler
1. Check for Imperfections

As white paint is excellent at masking faults, the best way to check for bubbling, cracks and peeling is to run your finger over the surface. 

2. Remove Imperfections

Use the scraper to remove loose, flaking paint to reveal the wood beneath. Use the sanding block with 60-grit sandpaper to remove stubborn paint spots. 

3. Fill Gaps and Holes

Use the filler to fill any gaps and holes in the woodwork. 

Smooth the filler into recesses with the filler knife and then wipe it smooth using the flat edge of the blade. 

Add more filler as needed. You don’t need to be a perfectionist here because you will sand it when it dries. 

4. Wait for the Filler to Dry

Follow the instructions on the packet to get the correct drying times. Don’t be tempted to skip the curing time, or you risk a weak bond with the woodwork, potentially damaging the finish.

5. Ventilate Room

Once the filler dries, open windows to allow air to circulate. This ventilation is crucial for the next step because paint dust particles can be hazardous.

6. Sand Filled Sections

Grab the sanding block and the 220-grit sandpaper and remove any excess dried filler. 

Once you’ve flattened and smoothed the filled sections, grab the vacuum cleaner with the hose and remove the dust. 

Safety Note: Keep your face mask on to avoid inhaling hazardous dust particles. 

7. Sand Woodwork

Carry on sanding with the block and 220-grit paper until you’ve removed all the excess filler and a top layer of the old paint. We call this “keying the paintwork.” 

A lightly scratched surface helps the paint bond and form a hard coating. Use the vacuum cleaner to extract the excess dust.

The video below by Natasha Dickens shows you how to load and hold a basic sanding block:

YouTube player

Painting Old Woodwork

decorator painting window frame
1. Clean Sanded Paintwork

Use a sponge soaked in sugar soap to wipe down the sanded paintwork. 

Sugar soap is a mild detergent that comes in crystal form, resembling sugar, hence the name. It de-greases the surface and removes any remnants of debris.

Pro Tip: Keep a bucket of soapy water handy to rinse off the sugar soap when done. It helps to remove debris particles.  

2. Let Woodwork Dry

Allow the woodwork to air dry before applying the primer. 

The video below by Wickes shows you the process of preparing woodwork from start to finish:

YouTube player

Now that you’ve prepped the woodwork, it’s time to paint. Use masking tape to protect the edges and corners that must remain paint-free. 

3. Apply Undercoat

Always work with the wood grain because it makes the covering more even, and the paint spreads further. 

If you’re using a solvent-based undercoat, wear a face mask to avoid the fumes, and keep windows and doors open for airflow.

For window and door frames, use a 2-inch brush for detailed work and a 4-inch brush for flatter, more expansive areas. 

4. Sand Between Coats

Don’t be tempted to skip this bit because sanding between layers of paint gives you a mirror-like finish and removes drips and brush marks. 

Use 220-grit sandpaper and lightly scuff the surface. You’re not trying to remove paint; just rough up the woodwork for the next paint layer to bind.

5. Apply the Second Undercoat Layer 

Apply the second layer of undercoat by repeating step 3. Check the instructions on the tin for drying times.

Pro Tip: When working on previously painted woodwork, there is no need for a primer, as the wood already has a layer of paint for the undercoat to adhere to. 

6. Topcoat Time

Remove the lid of the topcoat and stir the contents with a stick. Stirring mixes the paint, distributing the pigments evenly.

Dip your brush into the paint and work with the wood grain. 

Pro Tip: Only dip the bristles about a third into the paint to stop it from becoming overloaded. Too much paint increases the risk of runs and drips, ruining the finish. 

7. Second Coat

Once the paint dries for the recommended time, apply the second topcoat, repeating the previous step. 

You can sand between each topcoat layer if you want a glass-like finish, but it isn’t necessary unless you have brush marks or imperfections. Wait while the paint dries. 

The video below by Wickes demonstrates wood painting techniques perfectly:

YouTube player

Method 2 — Preparing and Painting NEW Woodwork

New woodwork can be porous and leak sap or resin, especially around knots. This leakage can ruin your new paintwork, so follow ALL the steps below.

Preparing New Woodwork

empty wood kitchen countertop
1. Clean Woodwork

You can use sugar soap diluted in water or soapy water and a sponge to clean the surfaces of your new woodwork.

Ensure the woodwork is dry before moving on to the next step.

2. Prepare Knots

Apply the knotting solution to the woodwork using a small paintbrush (some products have a built-in brush). 

The knotting solution seals the knots where wood resin or sap leaks. Follow the manufacturer’s guidelines on drying times before moving to the next step.

Pro Tip: Sanding the knots with 220-grit sandpaper helps the knotting solution bind to the wood surface.

3. Sand Woodwork

While your woodwork may be new, lightly sanding it to help the paint bind is still a good idea. 

Use 220-grit sandpaper and a sanding block for the smoothest results. Vacuum up the dust when done, and wipe the surface with soapy water. Wait for the wood to dry.

The video below by CharlieShooters KnowHow shows you how to apply a knotting solution:

YouTube player

Painting New Woodwork

decorator painting skirting boards
1. Time to Prime 

Detailed work is more efficient with smaller, more manageable brushes. 

If you’re painting window and door frames, use a 2-inch or 4-inch paintbrush for the best results. 

For doors and other large areas of woodwork, bigger brushes give better coverage and a smoother finish. 

Once you’ve applied this first coat of primer, wait for it to dry completely. 

Pro Tip: Tape off edges and corners with masking tape to prevent paint from spreading onto unwanted surfaces. 

2. Sand Primer

If you want the smoothest results, sand between both layers of primer. 

Use 220-grit sandpaper and lightly rub the surface. The goal isn’t to sand off the primer you’ve just applied but to remove paint splatters or drips and erase brush marks.

When you’ve finished sanding, use the vacuum cleaner to remove the dust and wipe it down with a damp cloth. Wait while the wood dries.

Pro Tip: Always work with the grain when applying the primer to ensure an even spread and the smoothest covering. 

3. Second Primer Coat

Following the grain line, apply a second primer coat and wait for it to dry.

4. Sand Again!

Follow the same sanding procedure between coats (step 2) using 220-grit sandpaper. Remember to sand lightly because you only want to remove brush marks. 

Clean the surface with a vacuum cleaner and a damp cloth, and wait while the surface dries. 

5. Apply Topcoat

Remove the lid of your topcoat and stir it with a stick to evenly distribute the pigments in the paint.

Apply the paint in the same way as the primer, working with the grain. Remember not to overload your brush, as this encourages drips and runs (dip the brush a third of the way into the paint). 

When done, leave the first coat to dry for the recommended time.

Note: Solvent-based paints take 4 to 6 hours to touch dry and 24 hours before you can apply the second coat. Water-based paints are ready for a second coat in 4 to 6 hours.

6. Apply Second Coat

Repeat the instructions in step 5 and wait for the recommended drying time. If you want to be ultra-fussy, you can also sand between each layer of topcoat. 

Undercoat or Primer: What’s the Difference?

When do you use an undercoat, and when do you use a primer? Or do you use both? 


Undercoats create a flat surface for the topcoat, so always use an undercoat on previously painted woodwork. It also helps the topcoat adhere, but you don’t need a primer because the existing paint layer seals the wood and allows the undercoat to bond.


Think of primer as a foundation for the topcoat. 

Always use a primer on new woodwork because it seals the wood and helps the topcoat adhere. Furthermore, it masks the wood grain, creating a smoother surface. 

Note: You don’t need an undercoat if you use a primer on new woodwork. 

Which Paint is the Best — Water or Solvent-Based?

You have two paint options for interior woodwork — Water-Based Paint and Solvent-Based Paint.

Each has its merits, but which should you use?

Water-Based Paints

Water-based paint is ideal for interior surfaces. It has fewer VOCs (volatile organic compounds), which harm the environment and give off potent fumes. And because it’s water-based, it’s safe to wash your brushes without fear of polluting the environment. 

Drying times are also quicker, meaning you can finish the project faster. However, water-based paints aren’t as hard-wearing as solvent and oil paint, making them less useful in areas with high footfall. 

Water-Based Paint ProsWater-Based Paint Cons
Faster drying timesLess hard-wearing
Fewer VOCsNot suitable for all wooden surfaces
Lower fumes
Safer for the Environment

Solvent-Based Paints

Using solvent-based paint indoors can pose risks, as strong fumes and high VOC levels can harm your health. Always open windows and doors and wear a face mask to prevent health issues. 

Solvent-based paints are suitable for exterior woodwork because they are harder-wearing than water-based alternatives. They also have greater longevity in areas with high footfall, like skirting boards and door frames.

However, solvent paints take 16 to 24 hours to dry between coats, making the project longer. They also damage the environment by poisoning the water supply when cleaning brushes and releasing low-level ozone as the paint dries. 

Solvent-Based Paint ProsSolvent-Based Paint Cons
Hard-wearingHarmful to the environment
Great for high-footfall areasHarmful to health
Suitable for exterior woodIt gives off strong fumes
Lasts longerTake 16 to 24 hours to dry between coats

If you’re still unsure which paint you should use, our complete paint guide examines the subject in more detail.

Final Thoughts

Proper prep work is the secret to a professional paint finish, but you’d be amazed how many people skip these crucial steps.

So when preparing and painting interior woodwork, take your time and carefully follow all the steps. If you do, you’ll get a professional quality finish.

Pro Tip: If you’re short on time or lack the confidence to paint your woodwork, find trusted local experts through Rated People.