Does your Perth property have hairline cracks in the render? It’s a common problem. The exterior of a property must contend with a range of climate variations throughout the year. In Perth, that means periods of mid to high humidity, hot, dry summers, and wet, mild winters. Combine that with the soft, sandy soil that Perth properties are built on, and the reality is that hairline cracks will eventually be a problem for your rendered property.
What Causes Hairline Cracks in Render?
The main culprits responsible for cracking render are fluctuating temperatures and weathering. As the seasons change, cement render will shrink and swell. This expanding and contracting causes hairline cracks to appear over time. If moisture gets between render and the external wall it’s covering, cracking is inevitable.
Additionally, the sandy foundations Perth properties are built on can cause structural movement. Even minimal shifting and settling in a building can cause hairline cracks to form in the render coating.
And let’s not forget the “Freo Doctor.” Yes, this sea breeze may be a relief on hot days, but it can quickly turn into nature’s sandblaster on high-wind days. All of this is rough on a render coating, and over time, the cracks will begin to show – literally!
The good news is that hairline cracks in render are usually superficial and, therefore, easily repaired. However, it’s worth having the cracks assessed by a professional who can determine whether a more serious structural issue could be to blame.
How To Repair Hairline Cracks in Render
In many cases, repairing hairline cracks in render is simple and can be completed in a weekend. Follow these step-by-step instructions to repair small cracks in your rendered walls.
What You’ll Need
- Outdoor masonry cleaner with mould-killing properties
- Scraper blade
- Sandpaper
- Exterior primer
- Paintbrush + roller
- Exterior patch filler
- Trowel for applying filler
- Texture finish paint
Step One: Clean the surface
To achieve a smooth, even finish, it’s important to clean the surface around the crack before you apply filler. Remove dust, dirt and mould. Use a masonry cleaner that kills mould spores. Allow to dry.
Step Two: Enlarge the crack
Using the edge of a scraper blade, dig out the crack a couple of millimetres. It may seem odd to make the crack bigger but this will give the filler a larger surface to bond with. Now drag the blade over the crack from left to right to remove any sharp or protruding render. You can use a wire brush to clear out any loose render. Use the scraper blade to bevel the edges of the crack.
Step Three: Sand the surface
Give the surface around the crack a very light sand. This roughs the surface and removes any paint that could prevent the primer from bonding to the surface.
Step Four: Apply primer
Apply a primer to the surrounding render and any exposed surface around the crack. This will provide the foundation for a solid bond. Using a paintbrush, apply the primer inside the crack first. Next, use a flat roller to apply primer over the crack and about 10cm on either side of it. This will ensure the repair will blend into the original render.
Step Five: Fill the crack
Once the primer has dried, apply the filler. Using a metal trowel, scrape the filler over the crack to ensure a flat and even surface. You may need to go over larger cracks again to ensure they’re completely filled. Allow to dry, and then lightly sand.
Step Six: Prime again
Once you’ve achieved a flat, consistent surface, prime over the filler with a roller, again allowing for a generous border to ensure complete coverage. Allow to dry.
Step Seven: Apply texture finish
Using a product like Dulux AcraSand, apply the texture with a roller. Work quickly to avoid the product thickening and causing an uneven finish. To achieve a uniform finish, roll the product on in one direction only – either bottom to top or top to bottom. If you use a combination of both, you’ll find the texture will appear uneven from stroke to stroke. Allow to dry.
Step Eight: Final paint
Now you’re ready to repaint your rendered wall in its existing colour.
Need Help Repairing and Repainting Render?
If you’re not keen to try this DIY, call in professional house painters to get the job done right.
AJ Cochrane & Sons have been painting and repairing render on Perth properties for nearly a century. Contact us today for a quote.
