A thin gap under the skirting is one of the most common small faults in any home. It collects dust, lets in draughts from under the floor and looks untidy. In kitchens and bathrooms it can also let water reach the floor edge. Most gaps are harmless and easy to seal with the right product. A few are a sign of something more. This guide covers both.
Why gaps open up
- Timber shrinking. Skirting boards and floorboards dry out over time, especially in new or newly heated homes.
- Seasonal movement. Timber floors swell in damp months and shrink in dry, heated ones, so gaps open and close.
- Floor settling. Suspended timber floors can flex slightly underfoot.
- New flooring. A new floor at a different height can leave a gap under existing skirting.
Matching the sealant to the floor
| Situation | Usually suits |
|---|---|
| Painted skirting in a dry room, small gap | Flexible decorators’ caulk, painted over |
| Tiled or vinyl floor in a kitchen or bathroom | Sanitary silicone, colour-matched |
| Wet room or shower area floor joint | Anti-fungal sanitary silicone |
| Laminate or engineered wood floor | Check the floor maker’s instructions |
Our guide to caulk vs silicone explains why the two aren’t interchangeable.
Laminate and wooden floors
Floating laminate and engineered wood floors are usually laid with an expansion gap around the edge, so the floor can move. That gap should not be filled with a rigid material, or the floor can buckle when it expands. It is normally hidden by the skirting or by a beading strip.
Some floor makers allow a flexible sealant at the edge in kitchens and bathrooms, to keep water out. Others don’t. Always check the instructions for your floor before sealing it to the skirting.
Need it done properly? Mr Mastic covers the South East, London and Scotland, with a one-year guarantee on every job. Call or email for a quick quote.
Tiled floors and commercial floors
On tiled floors, the joint between floor and wall, and around thresholds, should be flexible sealant rather than grout. Larger tiled floors also need movement joints, which are part of the floor design. In commercial and industrial units, concrete floors have their own joints that need a sealant suited to traffic. Our guide to movement joints explains why.
Our floor joint sealing service covers skirting, threshold, tiled floor and concrete floor joints.
When a gap means something bigger
Most skirting gaps are cosmetic. But get advice from a builder or surveyor if:
- The gap keeps growing over months, rather than opening and closing with the seasons
- The floor feels springy, soft or uneven near the gap
- Doors start sticking or cracks appear in walls at the same time
- There is damp, a musty smell or staining at the floor edge
Sealing over these problems only hides them.
Thresholds and doorways
Doorways are a common weak spot. Where a tiled bathroom floor meets the landing carpet or boards, there is usually a threshold strip. The joint between the tiles and the strip, and between the strip and the door frame, can let water reach the floorboards. A flexible sealant in those joints helps, especially in bathrooms and wet rooms.
In kitchens, the joint between the floor and the plinths under the units is another place where mop water can get in.
Quick answers
Can I fill a big skirting gap with sealant?
Very wide gaps may need a backing rod or a timber fillet first. Sealant works best in joints of a sensible size.
Should I seal laminate flooring to the skirting?
Only if the floor maker allows it. Laminate needs room to expand, so rigid fillers must not go in the expansion gap.
Why has my skirting gap come back?
Timber moves with the seasons. A flexible product copes better than a rigid filler.
Related services
More advice
- Decorator’s Caulk vs Silicone: Which and Where
- Expansion and Movement Joints Explained
- Coloured Sealant and Colour Matching
- All advice
This guide is general information about sealant work. It isn’t legal, fire-safety or structural advice; for those, speak to a qualified professional.