How To Fit Skirting Boards On Uneven Walls
Posted by Lee Watkinson on 14th Aug 2025
Uneven walls turn what should be a simple skirting board installation into an exercise in problem-solving. The wall looks fine until you hold a piece of skirting against it and discover gaps you could post letters through.
Note: Perfect walls are rare. Even new builds often have walls that lean slightly or plaster that's been applied unevenly. The techniques here help you work with what you've got.
Assessing the problem
Before you start cutting or bodging, spend five minutes understanding what you're dealing with. Hold a piece of skirting against the wall and look for gaps.
Common problems include walls that lean forward or backward (out of plumb), walls that bow inward or outward along their length, and irregular bumps or hollows from poor plastering.
Use a spirit level to check if the wall is plumb, and a straight edge to reveal any bow. Mark problem areas with a pencil - this planning saves time later.
Gaps up to 3mm are barely noticeable once painted. 3-8mm need attention but are manageable. Over 10mm and you're into alteration territory.
Small gaps and quick fixes
For gaps under about 5mm, you often don't need to get fancy. Good caulk work and strategic sanding can solve most minor issues.
Caulk to bridge gaps
A flexible decorators' caulk can bridge gaps up to about 5mm effectively. Apply it with a cartridge gun after the skirting is fixed, then smooth with your finger or a caulk shaper.
Use white caulk that matches your wall colour rather than the skirting colour. This makes any remaining gap less obvious to the eye.
Reducing high spots
Sometimes a small bulge in the plaster is all that's stopping the skirting from sitting properly. If it's below the skirting height, you can often chip it away with a bolster chisel.
Work carefully and check for cables first. You only need to remove enough to let the skirting contact the wall - don't go mad with the hammer.
"Use a decent caulk to fill the gap and let it dry for a few days. You may need to repeat. When finally dry, paint the caulk the same colour as the walls to keep the straight line of the skirting."
— Practical advice from the forums
Scribing for a better fit
When gaps are too big for caulk but the wall follows a fairly consistent curve, scribing can give you a much better fit. It's the technique the professionals use and charge more for.
How scribing works
Hold the skirting against the wall where it naturally wants to sit. Use a compass or scribing tool to trace the wall's shape onto the back of the skirting, then cut along that line.
Set your compass to the widest gap you need to bridge. Keep the compass level as you run the point along the wall - the pencil will mark the exact cutting line on your skirting.
Cut carefully with a coping saw or jigsaw. You're removing material from the back, so any small mistakes won't show from the front.
When scribing works best
Scribing is ideal for walls that are consistently out of plumb or have a gentle bow. It's less effective for walls with random bumps and hollows, where you might end up with a very wavy cutting line.
This technique works better with thinner skirting (15mm-18mm) that's easier to cut accurately. Thicker boards can be scripted, but require more patience.
"This stage can be tricky to get right, so practice on some offcuts first. Check the fit and make adjustments if necessary, using the coping saw and some sandpaper."
— Experienced carpenter
Forcing with screws
Sometimes the most practical approach is to force the skirting to follow the wall using screws. This works particularly well with flexible materials like MDF and for moderate curves.
The technique
Drill through the skirting into the wall every 250-300mm. Use good wall plugs and gradually tighten the screws to pull the skirting against the wall. The key word is gradually - don't try to close big gaps in one go.
Work along the length, tightening each screw a bit at a time. This spreads the stress and reduces the chance of pulling plugs from the wall or splitting the skirting.
Let new skirting boards acclimatise in your house for 24 - 48 hours to ensure they don't change shape after you fit them.
If plugs keep pulling out, try longer screws, add matchsticks to the holes, or use resin fixings. Sometimes the wall just isn't solid enough for this approach.
Packing out hollows
For hollow spots behind the skirting, cut small pieces of wood to act as packers. This gives you something solid to screw into and prevents the skirting from flexing when it gets knocked.
You don't need to fill the entire void - just create fixing points every 400-600mm. Fix the packers with adhesive before offering up the skirting.
"I have tried plug and screwing to bend the skirting to the wall but the tension just pulls the plugs from the brick. 6mm bit, 6mm plug when it has ripped out, I tried 8mm bit and plug but the same issue occurs."
— Common frustration
Severe problems
When you're dealing with gaps over 15mm or very tight curves, standard techniques may not work.
Kerfing for flexibility
Kerfing involves making cuts partway through the back of the skirting to make it more flexible. Start conservatively - cuts every 20-25mm, about half the thickness of the board.
Test as you go, and deepen or add more cuts if needed. This technique significantly weakens the skirting, so be very careful where you place screws - never close to a cut line. This works better with wooden skirting, but can be performed on MDF if done carefully.
When to give up
Sometimes it's better to accept defeat and try a different approach:
- Consider having the wall replastered
- Use quadrant moulding to bridge large gaps
- Install battens first, then fix skirting to those
- Get a professional to assess whether the wall problems indicate structural issues
Finishing touches
Even with careful fitting, you'll probably have some gaps to hide. The finishing work often makes the difference between a job that looks professional and one that obviously struggled with problem walls.
Multiple caulk passes
For gaps up to about 8mm, apply caulk in two or three passes rather than trying to fill everything at once. Let each layer dry completely before adding the next.
This gives a much neater finish than one thick bead that sags or cracks as it dries.
Screw holes and touch-ups
Countersink all screws below the surface and fill with wood filler. For MDF, use a flexible filler that moves with the material rather than hard wood filler that might crack.
Sand everything smooth once dry, then prime and paint. A good paint job can hide a surprising amount of imperfection.
Remember that once furniture is in place, small imperfections become much less noticeable. Don't aim for perfection if good enough will do the job.
Making peace with imperfect walls
Uneven walls are part of most properties, especially in older houses, almost everyone has them. The techniques above give you options for dealing with different severities of problem, from simple caulk work to more involved scribing.
Start with the simplest approach that might work, and only move to more complex solutions if you need to. Sometimes good caulk work and careful painting can achieve results that look perfectly professional.
If you're facing severe wall problems - gaps over 15mm or structural issues - don't hesitate to get professional advice. Some problems are beyond DIY solutions, and recognising when you need help is part of being a smart home improver.