DIY Doctor UK DIY Forums

Hi all,

First post here so please be patient.

We recently had our ensuite remodelled and were initially really happy with the result. However, there is now sometimes a smell of raw sewage which I have tracked to the back-to-wall toilet (it could have been the shower or the sink).

It's not always present and I can't discover what triggers it (whether it's another toilet in the house being flushed or something).

Anyway, I removed the front panel of the toilet unit and apart from the rubble which was left in the cavity, I was surprised to see that the contractor had used a flexi pipe which actually runs uphill from the toilet to the waste. I'm no expert but from where I'm sitting that doesn't seem like a good idea. Could this be the source of the smell?I wanted to attach some pictures to the post. Unfortunately, they're too big :(

Please give your honest opinions including how you would have solved the uphill waste issue (according to the specification, the toilet waste is 180mm from the floor, the main waste is higher but it's hard to say how much higher). Before I call the contractor back, I'd like some concrete facts to put in front of him.

Many thanks in advance!

Hi lionelbl,
It is not good practice to have the invert level of the pan outlet lower than that of the waste connection, sadly it’s quite a common thing.
It is unlikely that this will cause sewage smells but if an air admittance valve has been fitted this is probably the source of the smell.
You could get the soil pipe work modified so the connection is lower or find a pan with a higher outlet. Neither solution will be cheap.
Regards S