Bathroom sink leak

[stealthwolf]

The wife's noticed that there's water on the floor under the sink in the bathroom. At first we put it down to me being messy. But it persisted over the last two weeks and I've had today off so I investigated a bit further.

I cleaned the area dry, stuck newspaper under the sink and then slowly ran the taps so the bowl was full but didn't run up to the overflow hole. There was water slowly leaking (drop by drop) on to the newspaper. I can't feel any wetness from around the trap or waste pipe but the bottom of the sink is wet.

I've attached pictures. The red circled area is the bit of the sink that's wet. There's no cracks that I can see in the sink. Any ideas where the water's travelling through?

 

[muggles]

Got to be a hairline crack. Might seal with some Stixall/The Works/Sticks Like Sh!t but could need replacing.

PS it's a basin, sinks are found in kitchens

 

[Nige F]

Has the waste flange - in the top picture - been sealed with silicone ?

 

[nortonj]

My money is on cracked basin as long as you didnt splash around the seal to the worktop when filling?
That flexi though! Whats going on there?

 

[stealthwolf]

@muggles - I was wondering that since the leak is in such a strange area. I tried doing a dye test using food colouring (well I didn't have anything else to hand ) but that didn't help. I've looked closely with a torch at various angles but cannot spot a telltale mark of a hairline crack anywhere.

@Nige F - I don't know. I've worked out how to take off the plug thing (it's a click clack type plug and I just unscrewed the top) but I've no idea how to remove the waste flange. Having seen the liberal use of silicone around the house, it wouldn't surprise me! The wife has also admitted to using drain cleaner a couple of weeks ago, which ties in when this all started (although she tells me she used it down the plug and didn't let it sit in the sink).

@nortonj - I was very careful to run the tap slowly enough to fill the basin. My next plan is to try and pour water down the plug hole directly rather than letting it sit in bowl and see what happens. No idea about the flex. Very strange set up and I'm not sure how to go about making it right.

 

[stealthwolf]

I did a few tests but realistically I think I need the sink to dry out fully before trying again.

1. Used a plastic water bottle with the bottom cut off as a funnel. Took the top of the click-clack plug off and poured water directly down the drain. No leak.

2. Filled with cold water to overflow - leak (one drop every 10-13 secs)
3. Filled with cold water so level was below overflow - leak (as above)
4. Filled with hot water to overflow - leaking a bit quicker (one drop every 8-10 secs)
5. Filled with hot water so under overflow level - leaking a bit quicker (as above)
6. Opening the plug after steps 3 and 5 - leaked a bit more quickly (every 5 secs)

The trap/waste area is bone dry. I've been checking by running toilet paper around each section. The moisture is always from the red circled area.

To me, this means the trap/pipes are okay but either there's a leak around the plug hole, or there's a crack under the plughole that can't be seen from the outside.

Any suggestions how to proceed? I plan to leave the sink alone for a few hours to make sure there's no water dripping and then do the same tests as above.

 

[nortonj]

If there is no water running down the threads on the waste or around the trap. Then its your basin.

 

[Nige F]

To me, this means the trap/pipes are okay but either there's a leak around the plug hole, or there's a crack under the plughole that can't be seen from the outside.
.

That's why I asked about the silicone - it looks like there is none - and so the water is going into the void that should be for the overflow to run to waste . But somewhere in that void is a porous/split in the porcelain . I personally would remove the waste flange by unscrewing the large brass nut - and fill the void with a load of silicone - OK it will render the overflow redundant but I'll bet it stops the leak. Also change the chrome bottle trap for a plastic one - maybe still use the flexi in a better manner.

 

[Steelmasons]

Industry gone to the dogs FFS.

 

[HERTS P&D]

Fek me, who put that flexible waste in???



Andy

 

[stealthwolf]

That's why I asked about the silicone - it looks like there is none - and so the water is going into the void that should be for the overflow to run to waste . But somewhere in
that void is a porous/split in the porcelain . I personally would remove the waste flange by unscrewing the large brass nut - and fill the void with a load of silicone - OK it will render the overflow redundant but I'll bet it stops the leak.

I take it you're talking about the top bit of the waste that sits in the sink? I've unscrewed the plug bit and can see two slots either side like in the photo below:



Reading around, it looks like I should be able to unscrew the spindle with pliers. Will the waste flange just unscrew or is there something else I'm supposed to do?

Also change the chrome bottle trap for a plastic one - maybe still use the flexi in a better manner.

I was looking at getting a longer waste pipe and then have the horizontal pipe level with the drainpipe in the wall. Does this sound sensible? Means no ugly flexi.

Fek me, who put that flexible waste in???

TBH by the looks of things, a lot of stuff done around the house was done by the previous owner.

 

[Nige F]

You need to unscrew the large nut under the basin - inside the cupboard - and shown on your picture.

 

[stealthwolf]

Right guys, big update time.

I removed the waste trap. The basin wasn't secured down in any manner, so I just lifted it up.

This is the underside view:

You can see the overflow at the back.

And here's what I saw on closer inspection:

This is the area that's been wet all this time. The leak has been coming out from here for sure. I've closely examined the rest of the sink and can't find any other cracks.

I removed the large nut at the bottom:

There was some silicone there.

This is what was left when I removed the waste flange:

And after I cleaned it up:

I can't see any cracks anywhere in the basin. The overflow empties into the main drain. Is it possible that water is backtracking and enters the interior of the sink at some point and then leaks through the crack?

I plan to refit the waste flange and put everything back together.

1. How do remove the remnants of silicone? I've scraped what I can off with a stanley knife. Or should I just leave it?
2. Do I use new rubber washers?
3. There's a rubber washer that fits between the waste flange and the basin on the top side. I've seen a youtube video where the chap just uses silicone instead of a washer here.
4. Before I replace the bottom washer, should I use silicone here too?
5. Should I bung up the overflow spout with silicone?
6. What can I do with the crack? Leave it or silicone it or do something else?

Apologies for all the questions but I really need some help and advice on what to do next. Wasn't planning to do any bathroom renovations until 2018 and we were going to get the whole bathroom refurbished.

 

[nortonj]

I would find something similar and just change the basin.