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How can I protect my garage cabinets from floodwater?

Bluetooth
Having an Impact

How can I protect my garage cabinets from floodwater?

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This week I got this great set of cabinets off Gumtree to help organise my workbench. Unfortunately a few times per year my garage floods with about an inch of water, and I want to protect these cabinets. My initial plan was to build a timber frame for underneath and attach casters to give it to height to keep out of any potential flooding. But I'm open to any other suggestions!

What wood and what casters would.you recommend?

EricL
Bunnings Team Member
Bunnings Team Member

Re: How can I protect my garage cabinets from floodwater

Hi @Bluetooth

 

I suggest putting in a Holman 90mm 90° Female And Female PVC Stormwater Junction with a Holman 90mm Threaded PVC Storm Cap. The important part of this assembly is that the O-ring sits firmly on the inside of the cap. This is to prevent air from entering the charged area. A good position for them would be one on each end after the turn and one in the middle of the run. 

 

However, before you proceed with your proposed project, I encourage you to have a look at the water tank overflow discharge regulations in your local area. It sounds like a fantastic project, any updates you can provide would be much appreciated.

 

If you need further assistance, please let us know.

 

Eric

 

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Re: How can I protect my garage cabinets from floodwater

@Bluetooth,

 

What's the elevation change between the street and the front of the property? From your image, there appears to be none or such a slight difference that correct installation of stormwater pipes with an adequate fall could easily transfer water to the front of the property without the need for pumps or a charged system. Charged systems are usually only considered if an elevation difference is more than what can be countered with a fall in the pipe.

 

I'd imagine it would be just a case of measuring the distance from the street to the rainwater tank. Say it is 20m, you'll need to bring the pipe down from the tank to 20cm's above the ground and add a Holman 90mm 45° F-F PVC Stormwater Elbow and Holman 90mm 22.5° M-F PVC Stormwater Elbow to get a bend of 67.5 degrees (or thereabouts). Then you'd run the pipe to the street at a gradual fall of 1:100. So, for each of the 20 metres, you'll drop 1cm in height.

 

Please be advised that in most locations around Australia, you'll need to employ the services of a qualified stormwater/drainage professional to change this pipework. I'd encourage you to seek out their services, especially for the charged system, as that is something you'd really want to get right.

 

Suppose there is no particular difference in elevation between the street connection and the house. In that case, I wonder whether the stormwater pit is actually the cause of not having a standard setup. Is the pit dropping the water so low that a standard fall can not then be achieved? Perhaps without the pit, you could have the whole house's pipes run directly to the street.

 

Mitchell

 

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Re: How can I protect my garage cabinets from floodwater

Option 1 - DryOption 1 - DryOption 2 -WetOption 2 -Wet

 

The drawings above are the two best options in my opinion. They're not exactly to scale, but give a decent idea of whats going on. 90mm pvc pipe.

 

A friend prefers to put a hole half way up the irrigation tank, and use 50mm black slotted draincoil. He argues that the hydraulic head from half of the tank will be enough to push the water out and up to the pit at the top of the driveway. I'm not sure if I could cut the tank and install the fixture to take the draincoil myself, and it risks the irrrigation tank to puncture it, if something goes wrong. The 50mm coil has the advantage of being cheaper than pvc, since i have about a 20m run.

Re: How can I protect my garage cabinets from floodwater

There are some interesting points to consider in @Bluetooth 's suggestions. I am not sure that I'd be putting holes in an existing tank, nor do I see water "pushing" water uphill. It just falls until the levels at each end of a pipe are even (if levels allow that to happen, else it drains away).  I don't think there's a need to be making extra holes in the tank. The existing outlet at the bottom can be cut into and a T piece inserted. That way a Standpipe can be put up the outside, which will contain water at the same level as the inside of the tank.  Then you place a T connection in that pipe, at the height of the tank that you want to draw water down to.  (If using this method, make sure that the top of the standpipe is open to air or the water could be siphoned from the tank instead.)

Re: How can I protect my garage cabinets from floodwater

Thanks @@TedBear , @MitchellMc @EricL @Jason 

I managed to finish the project over the holidays with the help of my FIL. I'm happy with the results, and the water now drains to the street with gravity. The pit by the driveway is still necessary, as I found that some water still ends up there, but much less now.

 

 new 90mm gravity feed next to the old 40mm pumped out water

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 new irrigation tank overflow

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 gradual fall along fence

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 mostly hidden by bushes

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Re: How can I protect my garage cabinets from floodwater

Great work @Bluetooth! A simple solution that sounds like it's solved your issue for now.

 

Keep us updated. I'll be keen to hear how it goes after the next big downpour.

 

Mitchell

 

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