A Guide on Repairing Render

If your rendered wall is deteriorating or you attempted to render the wall but you didn’t get the results you wanted, it’s probably time to repair the render. Render may crack over time. In this case, you’ll need to know how to fix the cracks.

Most construction materials deteriorate over time due to weather elements. Poor application can also cause the materials to deteriorate. If you’ve just applied render on a wall and it has cracked sooner than normal, it might be as a result of reasons such as:

  • The newly applied render was exposed to direct sunlight. It should be shaded after application to avoid cracking.
  • The amount of lime added when mixing the render wasn’t sufficient.
  • The underlying material isn’t suitable for applying render. For instance, blockwork isn’t suitable for rendering. Bricks are more suitable for rendering.
  • Poor edges and joints that permit water seepage.
  • The render material wasn’t given enough time to cure or it didn’t cure properly.

Tips for Fixing Cracked Render

Before repairing render, you have to remove the cracked or damaged render. The area you want to fix will determine whether you have to remove the entire render or just a small part of the render. If you’re to remove the damaged section only, clean the rest of the surface and paint it to make the entire surface look redone and new.

Remove any loose material after removing the damaged render. Then allow the wall to dry for 2 days for any moisture trapped in the wall to come out. Our Sydney rendering company suggests that, in case there’s rain during the waiting period, allow the wall time to dry. Don’t proceed with the repair before the wall dries.

Replacing Render

Upon removing the cracked or damaged render and allowing it to dry, start doing the repairs. In this case, you’ll have to apply new render over the surface you’ve prepared. You can mix render or buy premixed render for a perfect mix. You can find premixed render from your local hardware. The render includes sand, lime, and cement in the mix. Just ensure you buy the correct sand texture depending on the finish you want such as fine, medium, or coarse.

Most premixed renders come in a 20-kilogram bag. This render amount is typically mixed with 4 liters of water. However, check the label on the product for any special instructions on mixing. If spread in a thickness of 5mm, it’ll cover a surface of about 2.5 square meters.

If you’re only rendering a small section rather than the entire wall, use render with a similar sand coarseness as the render that was applied on the rest of the wall. Also, apply the render in a similar finish as the rest of the rendered wall.

You can apply masking tape on the good render surface to prevent it from extra thickness when repairing a small section.

Applying Render

Upon mixing the render as instructed, it’s time to apply it. It should have a consistency similar to that of toothpaste to know that it’s properly mixed. Since render dries quickly, ensure you apply it within half an hour after mixing.

Use a trowel to apply the render. Spread it in a smooth and large action. Ensure the entire area is evenly rendered. Once done, remove the tape you applied. Use the desired finishing tool, like a sponge, to apply the finish you want. Preferably, finish the new render in such a way that it’ll blend with the rest of the area.

Render Maintenance

Allow the render to cure for a day. Then spray it lightly with water. Do this once daily for 7 days. This will make sure that the surface doesn’t dry too fast and start cracking again.

In case you’d like to paint the render with water-based paint, give it 14 days to cure. If you’d like to paint it with oil-based paint, then give it 28 days to cure.


FAQs on Render Repair

Is it possible to apply render over an already rendered surface?

Yes, you can apply a new render material over an already rendered surface. However, if the old render is damaged, remove it before applying new render. Applying new render over damaged render may also damage the new render, especially if the old render was damaged by water seepage.

How can you repair a small section of render?

You should start with removing the cracked or damaged render. Once done, apply the new render on the hole, just the way you would do for a new rendering job.

What causes render to crack?

Render may crack for several reasons. The most common causes include aging and exposure to direct sunlight after application or poor application.

How are hairline cracks on render fixed?

The best fix for hairline cracks is to completely remove the cracked section before it worsens and spreads further. Then patch the hole with new render.


Also read: A Guide on Rendering Blueboard