How to repair cracks in exterior render

If you find a crack or cracks in your exterior render, it is unsightly and off-putting. However, you also know a small crack today can become a massive hole, and problem, in no time at all. This is why you need to know how to repair cracks in your exterior render.

Being able to spot cracks in exterior render, knowing the tools and materials you need to resolve the problem, and understanding when you should call on an experienced house rendering company is vital information for homeowners. This guide helps you maintain your property, and repair cracked render, no matter the size of crack in your existing render.

Can you fix the cracked render?

The good news is yes, you can fix cracks in render, and in some cases, repairing rendering is a quick and simple job.

Render crack repair covers a lot of problems

However, cracks come in all shapes and sizes, and depending on the condition of the render, and wall beneath, there are times when it might be best to replace the old render.

If the crack is small, and the rest of the wall coating looks in good condition, follow the render repair steps below to fix the crack, but if you have concerns about the process, take steps to protect the house and surface.

Are cracks in render common?

According to We Do Render, yes, it is common for hairline cracks to appear in existing render. In most cases, cracks are harmless, and will not cause your problems in the long-term. Of course, not every crack is the same, they aren’t aesthetically pleasing, and more cracks might follow.

Is a crack in render serious?

As said, most cracks are harmless, but this doesn’t mean small hairline cracks are always harmless. Cracks are due to movements in the foundation, brickwork or building, and will sometimes indicate a significant structural problem.

Try to repair cracks quickly

With old render, cracks in render can be a sign of structural damage, and this heightens the need for render crack repair. Sometimes, you’ll need new render on your wall coating, but if you can repair a rendered wall, you should.

What is the best filler for render repair?

Some of the leading options include:

  • Masonry filler
  • Silicone render
  • Repair mortar

These are all good options and short-term solutions for filling cracks and effective crack repair.

The steps for render crack repair

Please follow this step by step guide to repair a crack in external rendered walls.

Thoroughly clean the area

One of the most important stages in repairing cracked render is the first step, thoroughly cleaning the gap. Be prepared to thoroughly clean through the brickwork and leave it to try for up to two days. To feel confident you have removed all algae, use a specialist cleaner, but failing that, a pressure washer and a scrubbing brush with warm, soapy water should suffice.

Create a crack big enough to use filler

While you want to remove cracks, the process requires filling the gap, so you need to ensure the crack is wide enough for you to enter and add filler. A bolster chisel, angle grinder or even a sharp knife should allow you to widen the crack to be large enough for you to comfortably fill and block the gap.

Mix the filler products

There is a broad range of filling products to choose from, so please follow the stated instructions on whatever package you buy. Pay close attention to the substance to water ratio, as if the dilution mix is wrong, the colour or impact of the filler will be impaired.

Filling the crack of the render surface

If you use a cartridge gun, fill the gun with your mixture, ensure the nozzle is the appropriate size for the crack, and then feed the mixture into the crack in small patches. You want to avoid overlaying or overlapping the original render. Instead, you want the new filler to sit in front of the previous render.

If you aren’t using a cartridge gun, be sure to use a suitable implement, with a knife or trowel options to consider.

Allow sufficient drying time

Simply filling the new cracks isn’t the end, you need to allow enough time for the filler to harden, and this will usually take around 20 minutes to 40 minutes, although the time will vary depending on a range of factors. When exterior wall coatings are dry, remove the protruding section with a filling knife.

You can now paint the whole wall

If the filler isn’t the colour you want, or you are keen to change the colour of this section, now is the ideal time to paint the wall coating.

Do you have solid walls or cavity walls?

As cavity walls started to become standard in the UK between the two World Wars, there is every chance that the property you work on have cavity walls. However, if you are working on an older property, it might have a solid wall. It is important to know the type of wall you are working on, as this impacts the steps you must take.

Dealing with damp in external walls

There are many signs of render problems and damp to look out for, including:

  • Nasty smells
  • Blistering plasterwork and emulsion
  • Wallpaper peeling from walls
  • Black mould
  • White salt stains
  • The wall might sound hollow

While many damp patches look worse than what they are, it is always best to minimise and deal with damp when it arises. If you have a dampness problem, and there are cracks in your walls, you are more likely to suffer significant issues. If you have damp and cracks around junctions and mortar joints, it is of a greater concern, and you should make resolving this issue a priority.

If you have a cavity wall, it is more likely to deal with this problem, as the gap helps to resist moisture.

Render repair is simple when you know how

Understanding render crack repair and knowing how to repair existing render and exterior wall coatings is vital for homeowners. These tips help your rendered walls last longer, will lower repair costs and ensure you are confident in undertaking render repair work with exterior walls and surrounding render.

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