How to waterproof below terrace home?

[miraperry]

Hi there, we have a 200 year terrace. External Walls are combination of rendered brick and hardi plank. We had some rain water seep in from outside ground.  The back yard is grave. What the best way to stop water seeping in? waterproof this area? 

[JacobZ]

Hi @miraperry,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

Do you have any photos that you can share? Seeing what you are working with is certainly going to help us give the most relevant advice possible. Let me know if you need a hand uploading images. I am happy to help if required.

Waterproofing is all about locating and sealing gaps and porous materials. Is the issue that water is seeping in through a subterranean block wall or a concrete slab, or something similar to that?

If so, then sealing that wall with a waterproofing membrane that is suitable for use below ground is likely the best option. This Crommelin Exterior Grade Brushable Waterproofer is a UV-stable, exterior-grade waterproofing membrane that is suitable for use below ground.

This is a positive side waterproofing membrane, meaning it needs to be applied to the outside of the wall, so you would need to expose the outside of the wall, clean it, then apply the waterproofing membrane, allow it to fully cure and then rebury it.

Let me know what you think. If you don't think this is going to solve your issue, please provide some further details so I can assist further.

Jacob

[miraperry]

Hi there

Thankyou for your quick response.  Here are some photos.

One wall is brick and render and other is sometimes of board that has deteriorated. 

Kind regards

Mira

[MitchellMc]

Hi @miraperry, 

In the first image, it looks like the gutter is overflowing quite heavily. Water is spilling over the edge and landing both on the windowsill and directly down the face of the wall. That amount of water being dumped onto the exterior surface will almost always lead to some form of moisture penetration inside. Before anything else, I would have that guttering checked. It could simply be full of debris, or the downpipe may be blocked. Once the gutter is flowing properly, you will have removed the main source of water that is saturating the wall.

In the second photo, you have cement sheet cladding that is completely unsealed in sections. Cement sheet is not designed to be left exposed. When it gets wet, it allows moisture to wick through and eventually show up inside the house. It looks like someone has started painting but stopped partway through, and even the painted board on the left has only had a thin coat. Once the area has dried out, I would give all of the cladding a proper wash down and then apply a full coat or two of exterior paint so the boards are fully sealed.

If your moisture issue is only light weeping, fixing the gutter overflow and fully painting the cladding may be enough to resolve it. If you are still seeing a significant amount of water coming through after those steps, you might then need to expose the lower section of the outside wall and apply a below-ground, brushable waterproofing membrane, as Jacob mentioned. That membrane needs to go on the outside surface, so addressing the above-ground issues first is the most sensible starting point.

Please let me know if you have any questions.

Mitchell

[miraperry]

Thankyou. We will most definitely ensure this is done as the you have have suggested. We bought the property looking like this.  We replaced the gutter over the wall in picture that you see with rain. We are installing a new gutter to the other wall that is half painted. Now we are up to making sure the walls are prepped properly. Can anyone recommend a good waterproofer in sydney that could help with this?

[MitchellMc]

Hi @miraperry,

If you've already replaced the gutter, it would be worth having a drainage plumber check to see whether the downpipe is blocked. You shouldn't see that amount of water overflowing from a gutter unless it's a torrential downfall or the gutter is overloaded due to collecting from a huge roofspace.

Since you're in Sydney, you might like to check out our Services Marketplace to find a professional for your job.

Mitchell

[miraperry]

Thankyou. I didnt know about the services marketplace.  The downpipe was replaced and tested when the plumber did the gutter. We only use insured and licenced trades that warrenty their work. Been a slow process finding licenced and insured trades for each step. Nearly there. This group has been fantastic.  Thankyou all.