Paint outside window sills and frames

Clean, fill, prime and paint your window sills and frames in one weekend session, working safely on a dry, mild day.

PW-01Check the weather and plan your sessionPick a dry spell with no rain forecast for at least 24 hours after your last coat, and a temperature above 10°C. Exterior paint needs time to cure, and damp or cold weather stops it drying properly and can cause bloom or peeling. Check the whole job — prep, priming and two coats — fits into the daylight and weather window you've got, or split it over a few dry days.

PW-02Protect the area below and around the windowLay a dust sheet on the ground or patio below the window to catch scrapings and drips. If you're working from a ladder, set it up on firm, level ground away from the window swing. Close the window while you work so you don't paint it shut.

1 each · Dust sheet

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PW-03Scrape and sand away loose or flaking paintUse a paint scraper to lift any loose, cracked or peeling paint back to a sound edge, then key the surface with medium sandpaper. If your home was built or last painted before 1970, old paint on the frame may contain lead — wet-sand it instead of dry-sanding to keep dust down, wear a dust mask, and bag up scrapings for the household waste recycling centre rather than the general bin.

RULES

1 each · Paint scraper

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1 pack · Sandpaper, assorted grades

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1 each · Disposable dust mask

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KNOW THE RULES

This is practical safety advice, not a legal requirement for homeowners. HSE guidance says older exterior paint can contain lead — avoid dry sanding or burning it off, and dispose of scrapings as hazardous waste rather than in normal rubbish.

PW-04Fill cracks, holes and gapsPush exterior wood filler into any cracks, screw holes or gaps in the sill or frame with a filling knife. Overfill slightly, since it shrinks a little as it dries. Leave it to cure fully — check the tin for timing, usually a few hours.

1 tube · Exterior wood filler

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PW-05Sand the filler smoothOnce the filler is hard, sand it flush with the surrounding wood using medium then fine sandpaper. Feather the edges so there's no visible ridge once painted. Brush off the dust.

PW-06Wash down and let dryWash the sill and frame with sugar soap and water to remove dirt, algae and grease, then rinse with clean water. Let it dry completely — painting over a damp surface traps moisture and ruins the finish. This usually takes a few hours in decent weather.

1 bottle · Sugar soap

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PW-07Mask off glass, brickwork and ironmongeryRun masking tape along the glass edges, any brick or render meeting the frame, and handles or hinges you don't want painted. Press the tape down firmly so paint can't creep underneath. Take your time here — it saves scraping paint off glass later.

1 roll · Masking tape

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PW-08Spot-prime any bare woodAnywhere you've sanded back to bare wood, or filled, needs a coat of wood primer or undercoat before the top coat goes on. Let it dry fully, following the tin's timing. Skipping this on bare patches leads to patchy, uneven colour and poor adhesion.

1 litre tin · Exterior wood primer/undercoat

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PW-09Apply the first full coatBrush on a full coat of exterior gloss or satin paint, working in the direction of the wood grain. Cut in carefully along the masking tape edges. Let it dry fully according to the tin before touching it again.

1 litre tin · Exterior gloss or satin paint

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1 set · Paintbrush set

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PW-10Apply the second coatOnce the first coat is fully dry, apply a second coat the same way for even colour and better weather protection. Check for any missed patches or thin spots, especially on sill edges that catch the weather. Let it dry fully before moving on.

PW-11Remove masking tape and check the finishPeel off the masking tape carefully while the paint is still slightly soft, pulling away at a shallow angle so you don't tear the fresh paint. Check the edges are crisp and touch up any thin patches with a small brush.

PW-12Clean up and dispose of wasteWash brushes in water or brush cleaner, depending on the paint type, and let them dry flat. Fold up the dust sheet and bag any scrapings or filler waste for the bin, or the household waste recycling centre if you suspect lead paint. Store leftover paint with the lid tight for touch-ups later.

1 pair · Disposable gloves

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