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How to stop water from entering through the back door?

Finding My Feet

How to stop water from entering through the back door?

The backdoor to my house has been giving me the a lot of trouble since I moved in and I'm a little unsure what to do about it. Heavy rain causes water to hit the backdoor and runs down it which pools at the bottom, this water then runs back into the house under the door pooling inside. There's a weird plate of some kind and a separate piece of rubber that I presume are from a old door that's no longer there that I think I can pry off so its less of a inward ramp towards the house but that'll still leave a place for things to pool. I'm not confident in the door seals I've been able to find fixing the issue either because the tiles go slightly under the door including the grout so even if the seal sits flush to the tile it leaves a small gap via the grout that water can come through, Bunnings was selling water proof seals but they list 23mm-25mm gaps only and the gap under this door is only about 10mm. The door also does not sit flush against the frame, I can pull it shut from the outside and hold it in the right position but when I let go it falls back a cm or 2.

Installing a cover above the door seems to also be off the table because the surrounding area is stucco (cement sheeting) and I've been told it won't hold the weight required.

Any advice on how to tackle this?


Bunnings Team Member
Bunnings Team Member

Re: Preventing water coming in the backdoor

Welcome to the Bunnings Workshop community @Gerby. It's wonderful to have you join us, and many thanks for your question about preventing water from entering under your door.


Traditionally a door threshold should be sloped away from the door, so any rain that hits it can't pool and runs off away from the door. That plate was likely part of a system when a mechanical door seal was attached to the door. It's a strip of aluminium on a spring that would have extended from the door right across and sat on top of the threshold plate. I would remove the plate as without the upper door seal, it wouldn't be helping your issue and could be the cause of it. If the threshold was sloped correctly and with that plate removed, the water would have somewhere to go other than under your door. 


With that plate removed and if the threshold is sloped correctly, a Raven 920mm Clear Anodised Automatic Weather Door Seal might be all that is necessary to prevent water from entering the door. As you have rightly pointed out, if the threshold is sloped incorrectly, the water will still find its way through the sunken grout joints. A simple solution to this might be to raise the grout joints under the door so they are flush with the tile. This can be done by carefully adding additional grouting to those sections.


Another option, though it does add a bit of a trip hazard, would be to install a traditional door sill, which is a timber strip that includes the sloped angle. I've created a rendering below of the door's side profile to illustrate.


I'd recommend you remove that plate and pour some water on the threshold to see if it runs off or under the door. Currently, it has no other option than to fill up the gap between the door and the plate and then run under the door.


Please let me know how you go and if you have any questions.





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Re: Preventing water coming in the backdoor

Thank you so much for the advice @MitchellMc, the door isn't used very often so I think the door sill idea is a good thing to give a try and shouldn't be too inconvenient.

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