Cracks and gaps can rear their ugly heads in any home, from new builds to Victorian houses, and everything in between. They can take many forms, too, whether a hairline crack across a wall, an ugly gap along a skirting board, or a crevice next to a window frame. So, it’s fair to say that learning how to fix cracks in walls is a must-have skill for homeowners.
Failure to do so can cause various issues in your property, from letting in the cold to ruining the finish of an otherwise perfectly decorated room. There may even be structural issues down the line, so it’s best to get them tackled early.
The good news is that with the right tools and a reliable crack filler, fixing these imperfections is a doddle. You don’t have to get in a professional, either, as most DIYers can get this kind of job done in no time at all.
This guide will cover the most common places you’ll find these sneaky cracks and gaps, step-by-step guides for fixing them, and why quality trade products give you the best chance of success.
But first, an important question.
Why Do Cracks Appear in the Home?
Temperature and humidity changes make wall materials move and put stress on plaster and joints. This can result in gaps and holes in your walls and is the most common reason for cracks appearing.
Vibrations are another major culprit, which happen if people slam a door once too often. These can result in hairline cracks or the beginnings of a hole. Poor workmanship is another issue we see a lot, with dodgy installations causing cracks to come around quicker than with a professional job.
How to Choose the Right Products for Filling Cracks in Walls
Generally speaking, there are three products for filling cracks in walls. Each of them has its own benefits, and one reigns supreme for most job types.
- The first product option is decorator’s caulk, which is best for flexible joints between skirting boards and walls, but isn’t ideal for deeper gaps.
- Expanding foam is a popular product that works well around pipes, external gaps, and cracks. Unfortunately, things can get messy if you use it for wall cracks inside your home.
- All-purpose fillers are the final option and top dog out of the three. Not only are they versatile and sandable, but they’re the most effective of the bunch for plaster, masonry, and wood.
Now, what about tools?
The Tools You’ll Definitely Need
You can take your pick of products, but some tools are simply too crucial to ignore.
First, you’ll need a filling knife and/or a plastering scraper wide enough to spread your filler smoothly, but flexible enough to give you control. Next, you’ll need medium and fine grade sandpaper, with medium used for shaping the dried filler and fine used for creating a seamless finish.
A dustpan and brush combo is also crucial, or a hoover, so you can clear dust and flaked paint and make sure the filler holds. Always keep a damp cloth handy, too, to wipe away excess filler before it sets. And of course, work with gloves to protect those hands.
This small but mighty set of tools makes the job quicker and more effective.
How to Fix Cracks in Walls
Ready to get answers to this million-pound question? Follow our step-by-step guide for dealing with all kinds of wall cracks:
- Start by slightly widening the crack to give your filler something to grip onto.
- Clean the area with a brush, and hoover any dust up so it doesn’t become messy or stop adhesion with the filler.
- Press your filler into the crack with your knife or scraper.
- Level the filler out with the knife and spread the edges into the surrounding wall as neatly and as flat as possible.
- Let it dry before sanding the area lightly until it’s smooth and flush to the wall.
- Repaint the area and the job’s a good ‘un.
Top Tip: Over-sanding damp filler is more likely to result in flaky repairs, so don’t skip the drying stage.
How to Fix Cracks in Window and Door Frames
Windows and doors are notorious for developing cracks, with hairline gaps the biggest perpetrator. Here’s how to get them sorted without calling in a professional:
- Get rid of flaky paint and dust from the area before you begin.
- Add masking to create neat, straight edges and avoid ugly smears.
- Apply your crack filler directly with a filler knife for narrow gaps, or use a caulk gun if you have one.
- Smooth the filler with your scraper or a damp finger.
- Let the filler dry before sanding it and repainting with a suitable topcoat.
How to Tackle Skirting Board Gaps
Nothing quite ruins a freshly decorated room like skirting board gaps, which can come about thanks to uneven plaster. Let’s sort this one for you:
- Apply your crack filler into the gap with a caulk gun or filling knife. Press it firmly to make sure that the gap is fully filled.
- If you’re adding multiple layers (advisable for deeper holes), make sure each one dries before adding another.
- Smooth it all over and make sure the joint line blends into the filler.
- When it’s dry, sand it, and paint the area to match the rest of the wall.
Seasonal movement is a common issue with skirting boards, so ensure you pick a versatile crack filler that flexes with the material it’s applied to. This stops cracks from reopening down the line.
How to Repair Holes in Masonry and Plaster
Whether it’s a huge dent or a little nail hole, masonry and plaster repairs are part and parcel of home ownership. Here’s how to tackle them so they don’t ruin your masonry and plaster.
- Clean the hole first and remove loose plaster and dust.
- Apply your crack filler with a filling knife, and get it right into that hole.
- Smooth the surface level with the surrounding plaster.
- Sand and finish when it’s dry, and paint it using the same colour as your wall.
For textured walls, a sponge pressed lightly on the filler can mimic the existing finish, but do this before the filler sets.
When to Consider Calling a Tradesman
DIY repairs are manageable, but sometimes, you have to admit the job needs the help of an expert. Large cracks that keep coming back and those linked to damp or structural movement, for example, usually require the help of a pro, and if you have a project where texture and blending are crucial, it’s probably best to call a painter and decorator.
Not only will they already own the right tools, but they’ll also know how to layer filler professionally and match finishes to make repairs invisible. This can save you a lot of time and hassle, and give you peace of mind that the job is done properly.
It’s also worth monitoring cracks that seem to be spreading or getting wider as time passes. These can be signs of something much more problematic, with structural issues no filler can fix.
Ready to Fill Cracks Like a Pro?
Many cracks and gaps aren’t something to be overly concerned about and just need the right approach, tools, and filler. Armed with this handy guide and a bit of patience, you’ll be filling holes like the best of them in no time.
But remember, if it seems more serious than a DIY job, it probably is! So, don’t be afraid to call in an actual professional if you’re feeling overwhelmed or the hole looks too large or deep to handle yourself.