Flood Control

With Sydney and much of Australia’s eastern seaboard suffering from unprecedented rain in 2022, it’s not surprising that homes up and down the coast have been affected by water damage.

These effects range from mould and mildew to superficial damage, right through to flooding, with homes in northern NSW and southern Queensland the worst affected.

So what do you do if your CSR Gyprock® plasterboard walls are affected by water? There’s a lot to consider, but here’s where to start.

First steps

It’s important to recognise that water is one of the main ingredients in plasterboard, which makes it quite vulnerable to flood damage. It can be adversely affected by prolonged exposure to water and may need to be replaced if badly damaged.

However, plasterer John Paul Brancato, of M.E. Brancato and Sons, says that if you catch it in time, you can prevent water-affected plasterboard being replaced or minimise the scope of damage.

John Paul has worked with and replaced a lot of water-damaged ceilings over years, mostly caused by rains and storms, but occasionally from faulty plumbing work or leaking showers.

He says that if you see signs of water in the ceiling, he says it can be a good idea to pop small holes in the plaster to let the water fall out as the first step.

Image: Imperial Interior Linings

“Sometimes letting the water out is the best thing you can do,” he explains. “Cutting a small hole, or a few small holes, can be really handy because that stops the water pooling on top of the board and ultimately sagging the board.”

By limiting the damage to a smaller area, repairs will be much easier, he says.

‘You’re better off making some small holes and then the repair costs and mess are going to be a lot less than leaving it.”

A small hole is easily repairable by a home handyman, using Gypock’s convenient Rapid Repair Kit, available from Bunnings.

Find the source

Before you repair the damage, it’s important to find out the source of the water, so that can be fixed.

“I’ve had people say, ‘Oh look, just repair it now, I’ll get the roof fixed later’,” says John Paul. “But it doesn’t work that way.”

He adds that if the source of the water is a plumbing issue, a builder or plumber might have to cut bigger holes to fix the leak. “That’s not ideal, but if it’s a roof leak, which is probably the most common, then they don’t normally have to cut the plasterboard because they can go in the roof space and have a look without cutting too much more of the plasterboard.”

Image: Phillip Flores Unsplash

Flood damage

CSR has prepared a comprehensive guide on dealing with flood damage that covers all the building materials it sells, including Gyprock®, Bradford Insulation, Cemintel® and Hebel®.

Assessment of the damage may need a professional, says John Paul, adding that there are a lot of factors that need to be taken into consideration when looking at water damage on plasterboard.

“It depends on how deep the water was, how far up the wall it’s gone, and how quickly it’s dried out,” he says. “If it’s been sitting in water 30cm deep for a week, or even a couple of days, but there was still a lot of damp and moisture around, I’d say you’d have to probably cut that out eventually because it’s just going to get full of mould.”

If the plasterboard (or plasterboard tile) is flat and shows no sign of the paper delaminating from the plaster core, is flat, shows no signs of distortion and that its strength does not appear to be affected, the board can be retained. When fully dry, plasterboard (or plasterboard tile) can maintain its properties and strength and not be permanently affected. However, if there is any doubt, it should be replaced.

However, John Paul points out that even if the plasterboard needs to be removed, you may not have to replace the whole wall, you might be able to just remove the lower part of the wall, where the damage has occurred. He says he has often just replaced parts of affected ceilings or walls, limiting the costs involved.

Removing mould or mildew

Plasterboard affected by mould, particularly on the unpainted back surface, should be removed. Mould on the painted surface of plasterboard can usually be removed by washing with a bleach solution (sodium hypochlorite) mixed 1 part bleach to three parts water. Allow to stand for 15 – 20 minutes before washing off with clean water.

Care must be taken to protect hands, skin and eyes when using bleach solutions. If the mould cannot be removed by this method then the Plasterboard (or plasterboard tile) should be removed.

It is important that the substrate (such as timber frame or masonry) is fully dry before replacing any plasterboard. Use fans and open windows (when low humidity outside) to assist in the drying process. Moisture measurement tools are available to test walls and timber frames before commencing any work if required.

Check also that the stud adhesive is holding the board firmly to the frame and that any nails or screw fixings have not been compromised. Additional nails or screws may be used.

Need more help?

Contact your local CSR Gyprock® Customer Service Centre for more information or for a list of recommended plasterboard contractors in your area.

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