Filler or caulk for skirting boards: still or moving

The shadow along the top of the skirting is the bit you notice once the wall is painted. Filler or caulk for skirting boards is decided by whether that gap moves. A nick that stays the same width can be filler. A line that opens in summer and closes in winter is a flexible sealant, not one of the eight pastes. UK skirting guides treat that perimeter as a caulk job. The rule here is movement.

Products Compared checked the surface-filler cards on amazon.co.uk on 15 October 2026. Palace's fine tub and Palace's 1 kg tub are the listings that name skirting. The comparison's top pick is Polycell Multi-Purpose Polyfilla 330 g, for a small static nick and the largest review file. That page does not name skirting, and the paste is not a flexible sealant. Gloss, dust, and damp bond poorly. Links to amazon.co.uk use the tag pcuk26-21. A qualifying purchase can earn a commission at no extra cost to you. There is no sealant price in this set. The rows sit on the surface filler comparison.

In short

If the shadow line along the skirting opens and closes, buy a flexible sealant, not one of the eight fillers. If the damage is a static chip or hairline in the skirting or the plaster, Palace's fine card or the 1 kg card are the listings that name that surface. Clean the joint first. Paint only after the product you chose has cured on its own clock.

A gap that moves is a sealant job

Run a finger along the top of the skirting and then along the floor. A gap that is wider by the radiator than by the door, or wider this month than last, is moving. Timber skirting, plaster, and a timber floor respond differently to heat and to the moisture in a British house. The joint works. A flexible sealant can stretch a little with that movement. Rigid filler hardens, then splits on the same line.

That sealant is not among the eight ready-mixed pastes. Calling one of them caulk because the tub is white does not make it flexible. Decorators' caulk is sold for the joint. Multi-purpose filler is sold for holes and static cracks. Polycell's multi-purpose page covers plaster, masonry, concrete, and brickwork, indoors or outdoors for that product. It does not, on that page, replace a flexible sealant.

If you have only looked once, you have not seen the season. Mark the width with a bit of tape and look again in a fortnight. A gap that changes goes to sealant. A one-off chip from a hoover stays in the filler conversation. Do not pack filler into a moving joint because the sealant is a second trip to the shop.

A still nick in timber or plaster can be filler

A knock that took a chip out of the skirting, or a hairline that has not opened since you marked it, can be filler. The surface has to be named on the tub, and the depth has to fit the layer the card allows. Sand the shine off a glossy board, brush the dust out, and leave a damp skirting until the leak or the condensation is dealt with.

Fine filler is the shallow version of that still nick. Palace's 600 g card, B07XGMLGRX, is interior and names skirting among timber and plasterwork, with deeper repairs in layers of no more than 3 mm. It was £1.25 on 15 October 2026. A gouge deeper than that layer wants a multi-purpose paste that states a greater depth, not three wet coats of fine paste piled on before the first has dried. The choice between those two pastes is on fine or multi-purpose filler.

A crack in the plaster just above the skirting is still a crack. If it is wider than about 5 mm, growing, or paired with damp, filler is the wrong first product, sealant included. The skirting decision on this page assumes the wall is stable and the only question is the joint or the chip.

Which compared tubs name skirting

Palace fine, 600 g, names interior masonry, timber-based structures, plasterwork, decorative beams, and skirting. Deeper repairs stay in layers of no more than 3 mm. The card does not state a dry time. The two-pack of the same fine line, at £2.50, states touch-dry in 1–2 hours and names plaster, wood, and masonry, without restating the 3 mm layer. Use the 600 g card for the depth, and do not assume the two-pack's clock applies to every fine tub.

Palace's 1 kg ready-mixed filler, B07XMM93KC, names plasterwork, render, masonry, skirting, architraves, beams, and window and door frames. Layers are no thicker than 10 mm. It excludes exposed exterior locations and continuous water immersion. It was £6.99, with 4.5 from 4,537 reviews. A static chip in a frame or skirting is inside that sentence. An outside timber cill in the rain is not. The data sheet of 28 October 2024 is the cure clock: skin about 30 minutes, surface-dry in 1–2 hours, full cure up to 24 hours at 20°C.

Polycell's multi-purpose page does not name skirting. It names plaster, masonry, concrete, and brickwork. The 330 g tube, at £3.49 with 4.6 from 14,595 reviews, is the top pick for a small static nick. A white tube is not a skirting specialist. Pack size and interior or exterior sit on the buying guide once the nick is static. Sinto does not state interior or exterior. Zawan's wood line is not a skirting sentence. Stay with the cards that print the word.

Why filler cracks again on a moving joint

Filler that has dried is a rigid patch. When the skirting moves against the plaster, or against the floor, the patch cannot stretch. The crack comes back in the filler or in the paint on top of it, often as a clean line exactly where you filled. That is shrinkage plus movement, not a sign you needed a more expensive tub of the same rigid paste. Another layer of the same filler repeats the failure.

The floor joint is the common one. A gap under the skirting, where boards or a laminate edge meet the timber, moves when the floor moves. UK how-to titles treat caulking that perimeter as the job. Those page bodies were not the source, so this page does not copy their steps. If that gap opens and closes, it is sealant. Filler along the floor cracks again because the joint was never still.

A still hairline in the face of the board is the opposite case. Nothing is asking the repair to stretch. Fine paste, kept to the layer on the card, can stay. If you are unsure, watch the gap for a fortnight. Ready-mixed paste can also shrink as water leaves it, so a deep static chip still wants layers, not one fat fill. Movement and shrinkage are two reasons a line reappears.

Paint comes after the right material has cured

Neither filler nor sealant is a same-day paint just because it looks dry on the surface. The clocks differ by product, and a skin is not a full cure. Palace's 1 kg sheet gives up to 24 hours at 20°C for full cure, against a skin in about 30 minutes. Polycell's page says 1–2 hours surface-dry, while the 330 g Amazon card says full cure 2 hours. Those are different sentences. The wait, and why a deep repair paints badly, is in how long to leave filler before painting.

Paintable, on a filler card, means the cured and sanded patch will take the paints the listing names. Palace fine says most domestic oil or water-based paints, once cured and sanded. It does not say the paste is ready when it turns dull. A sealant for a moving joint has its own paint line on its own cartridge. Do not copy a filler's two-hour claim onto that cartridge.

Dust from sanding has to come off before the paint, or the sheen shows every scratch. Keep the abrasive for a static fill that has gone hard. Choose the material, let that material cure, then decorate. The £1.25 fine tub and the £6.99 kilogram are both wasted if the gap was moving.