Loud Banging Noise When Upstairs Toilet is Flushed?

[AOIS]

Hi all,

I have noticed recently when we flush our upstairs toilet sometimes you can hear what sounds like a loud banging almost matalic noise from the loft? It only lasts a split second.

It doesn't happen all the time and only seems to occur when the upstairs toilet is flushed.

Any help much have appreciated.

 

[Scott_D]

Do you have tanks in the loft?

 

[AOIS]

Hi Scott,

No I don't.

 

[townfanjon]

I know you dont have tanks in your loft but are there any unsecured pipes , they could "bang" as the toilet fill valve closes

 

[Christopher buzzard]

Trying changing the washer in the ballvalve. Prob making the noise when the valve is shutting off. Had that happen before.

 

[AOIS]

We have an ongoing problem with the soil stack pipe contracting against a joist which produces a tapping and minor knocking noise.

This new noice sounds very much like trapped air, almost like an airlock type noise that occurs a second or so after the toilet is flushed. It sounds like it's coming from the top of the soil stack. Could it be the AAV?

We did accidentally flush a cardboard toilet role down the toilet 2 weeks but have seen no evidence of a blockage since and only noticed this noise since yesterday. Could this be related and a possible cause?

Thanks

 

[AOIS]

In addition, the noise does only seem to be related to the toilet in the main bathroom. The en suite is not effected.

Any advice very much appreciated.

 

[Harvest Fields]

It is probably the inlet valve inside the cistern of the toilet.