Sealing shower screen - why the outside?

[wedge69]

While dozing in the shower I noticed the join where the shower screen meets the wall isn't sealed on the inside, but it is on the outside. I thought this might be a mistake, but looking on the net I have seen this installation guide (this isn't the screen I have, but it's the only one I could find!) that says to only seal the outside:

http://www.lakesbathrooms.co.uk/downloads/Shower-Screen.pdf

Why would you seal the outside and not the inside?

 

[seco services]

so that any water that gets in to the shower screen wall channels can drain out the bottom into the tray

 

[wedge69]

That's fair enough, but surely if you sealed the inside as well, then water couldn't get in at all, or am I missing something?

 

[swbjackson]

The full force of the spray hits the inside so it's possible for it to find it's way through a pin prick hole. On the outside this is unlikely to happen. If both in and out are sealed this water will sit and stagnate.

 

[TicklyT]

I was told to seal the verticals on the inside, and continue part way along the bottom, and seal the horizontals on the outside at the bottom.
That lets the odd drop of water passing the vertical seals run back into the tray instead of getting trapped there and eating through the fixing screws.

Sealing the outside of the verticals does little to keep the water in, but it sure can hide a multitude of sins!

 

[wedge69]

Is that the same on shower screens that go over a bath? I've resealed my bath, and though this seams to have stopped the majority of the water leaking, I am still getting a little. I can only imagine that the water is leaking from the shower screen. It's not sealed on the inside edge, so I think water is getting in, and then down the back of the bath.

 

[bogbasher]

I fitted an enclosure which the instructions said to seal only the outside, which i thought was strange too. But the enclosure had a gasket down the verticals to seal against the wall. So i looked into it and it seemed to make sense. I fitted it as per instructions and 3 years later it hasnt leaked.

 

[jrsmk1]

Here is an update to the correct url for the .pdf quoted in the initial post.

http://www.lakesbathrooms.co.uk/downloads/instructions/enclosures/Shower-Screen.pdf

Sealant is only applied to the outside so that any potentially trapped water can drain out of the structure and back into the shower tray.