Fill gaps where skirting and architrave meet the wall with caulk for a neat, draught-free finish in one afternoon.
CS-01Clear the room and protect floorsMove furniture away from the skirting and architrave you're working on. Lay a dust sheet along the floor to catch scrapings and drips. Open a window — caulk and some cleaning products have a strong smell while wet.
CS-02Strip out old, cracked caulkRun a filler knife or scraper along any gap where old caulk has cracked, shrunk or come away. Pull out loose bits by hand where you can. Don't try to caulk over failed caulk — it won't stick properly and will crack again within weeks.
CS-03Clean and dry the gapVacuum out dust, cobwebs and old paint flakes from every gap you plan to fill. Wipe the skirting and wall edge with a cloth dampened in sugar soap solution to remove grease, then let it dry fully — caulk won't bond to a dusty or damp surface.
CS-04Mask up for a crisp line (optional)If you want razor-sharp edges, run a strip of low-tack masking tape along the wall side and another along the skirting or architrave side, leaving the gap exposed between them. This step takes longer but gives the neatest finish, especially on dark skirting or wallpaper.
CS-05Load the gun and cut the nozzleFit the caulk tube into the sealant gun. Cut the nozzle tip at a 45° angle — cut small first, since a bigger hole gives a bigger bead than most gaps need. Pierce the inner seal with a long nail or the gun's built-in piercer before you start.
CS-06Run the bead along the gapSqueeze the trigger steadily and draw the gun along the gap in one continuous pull, keeping even pressure. Work in short sections of 1-1.5m if your hand tires, overlapping slightly where you stop and start.
CS-07Smooth the bead before it skinsWet your finger with a little water and run it along the bead in one smooth stroke to press it into the gap and remove the excess. Wipe your finger clean between strokes. Do this within a couple of minutes of applying the caulk, before it starts to form a skin.
CS-08Pull the masking tape while still wetIf you masked up, peel the tape away slowly at a 45° angle immediately after smoothing, while the caulk is still wet. Leaving it until the caulk skins over will pull the edge with it and spoil the line.
CS-09Leave to cure and tidy upCheck the tube for the curing time — most decorators caulk is touch-dry in an hour but needs 24 hours before painting. Wipe the nozzle clean and cap the tube for reuse, and rinse tools before the caulk sets hard on them.
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