How to fix leaking in garage?

Hi everyone,

I have an old garage that I want to convert to a music room with lots of equipment. It has hardiplank on the outside and I plan to add acoustic insulation it and then add thick soundchek plasterboard for sound proofing.

My problem is that some water gets in at the bottom of the walls in heavy rain and I wanted to make sure this was fixed before starting work on the room.

On the advice for a local plumbing store I installed a down pipe and a stormwater pit which goes to a pit of blue metal…but this overflows in heavy rain. (please see pics)

My question is should I install some type of drain around the garage before doing the project and if so what type.

Also should I try to waterproof around the bottom of the walls?

As you should be able to see I. The fourth photo the fence is higher than the bottom the shed and the land slopes down.

I would be grateful for any help/ suggestions.

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Accepted answers

JacobZ

Hi @ChrisA,

A french drain would be great for this situation but they can mean a lot of digging. You should aim for the french drain to be around 100-200mm wide and around 200mm deep with slotted agi-pipe at the bottom and gravel on top. You should also ensure the agi pipe gently falls towards the drainage pit.

Have a look at this helpful article, How to install garden drainage, for some guidance.

If you are planning to dig a french drain, it will also be beneficial to install Corflute up against the slab to cover the gap between the bottom plate and the concrete and extending down below the slab. You could then seal the top edge of the corflute using the beforementioned Sikaflex 11FC, creating a solid physical barrier preventing water from getting in.

Let me know what you think.

Jacob

All comments

JacobZ

Hi @ChrisA,

Firstly, welcome to the Bunnings Workshop community, it's great to have you join us.

From your provided photos, there are a few things you can do to promote better drainage and stop the water ingress.

You should look to have some agi pipe installed around the perimeter of the garage to capture any water flowing into the area from the surrounds. This is likely something you should employ the services of a professional plumber for as they could connect the agi pipe into your drainage pit and your drainage pit into a stormwater pipe so the water flows away to the street.

You should also bring the height of soil around the garage down by around 100mm and backfill with 10-20mm Drainage Gravel which can also be ordered in bulk bags from your local stores Special Orders desk . This, in combination with the agi pipe, will allow the water to flow away from the concrete slab more effectively.

Finally, you should use Sikaflex 11FC Plus Polyurethane Adhesive Sealant to seal between the concrete slab and the bottom plate of the garage. This will create a physical barrier preventing the waters entry to the garage.

Please feel free to get in touch if you would like more advice or product recommendations.

Jacob