Good-quality render is very durable indeed; in fact, you can expect it to last for at least 20 years, maybe even 40 or more. In Europe and the UK there are some buildings with centuries-old render still clinging to the walls…
However, eventually, due to the action of sun, rain, winds and general wear and tear, all renders will start to fail. They will develop small cracks that let in water and expand and contract with temperature changes. Over time, these cracks grow larger and the lower levels or under layers of the render can become loose and crumble, leading to a hollow layer that can cover up the damage going on underneath.
How to spot failing render
If you’re seeing cracks appearing, or there are areas of render that look blistered, discoloured or loose – even absent altogether – then it’s time to get someone in to have a closer look. It’s not a small outlay, getting your house re-rendered, so if you find out you have another couple of years until it becomes serious, then you can budget. On the other hand, if you find it’s already serious, then you can take action before your walls and brickwork are too badly affected.
Another problem is that over time render will lose its “key”, or its grip on the brickwork underneath it. This is problematic because chunks can start to fall off, or hollowed-out gaps can form underneath the surface that can collect water, which starts to wash out more of the render.
If there’s no waterproofing other than the render, then damp will penetrate into the house, with disastrous consequences.
Be on the look-out
If you see signs like this, or if you’ve recently bought a rendered house and you know it was last covered sometime back in the 1980s, then it’s probably time for a whole new coat. Thankfully, modern renders have acrylic compounds added to the mix, so not only are they less vulnerable to cracking, they’re also more waterproof and durable than older mix-types.
If you’re in any doubt, call in a surveyor for a professional opinion – secure rendering is a very worthy investment.