Noisy waste stack...any ideas?

[Modokon]

We have an internal waste stack and the builders have been so there's been a bit of movement etc around the area of the stack.

Problem is that whenever we get a lot of hot water out (dishwasher, washing machine) the waste makes a pretty loud creaking sound for about a minute, like pipes expanding. Seeing as we use cheap rate night electric, this is loud enough to wake me up!

I know copper CH pipes can creak/expand like that, but a large bore plastic waste pipe?

Lord knows if it's that, and if it is, what is are my options? Hunt around for the interference (not easy) and shim it or a flexible coupling?

 

[Hugh Jaleak]

My guess is the hot water hitting the (cold) plastic is causing it to expand pretty sharply hence the noise. Stack is probably vented to atmosphere so will have a fairly constant cold draught through it. Maybe the joints are tight, recommended to insert pipe to stop then withdraw it slightly when fitting 110mm pipework. (Unless its solvent weld type, where expansion joints are available, not that i've seen many on household stacks.)

If any consolation, my parents house has the stack running internally (in the corner immediately inside the front door), that has always made a loud 'clicking' noise whenever W.C. is flushed or bath/basin discharged. We learned to live with it!

 

[tincup]

Hi

Put some loft insulation round it where possible.

HTH

 

[flameport]

Presumably this stack is secured to the wall with plastic brackets?
Try loosening the brackets slightly to allow movement - could be the plastic pipe expanding and moving against the brackets.

Joints should have rubber seals, so unlikely to make any noise.

 

[Nige F]

look where the stack penetrates the floor and roof ( ceiling ) It`s probably there - rubbing on a piece of timber - Millions are like it across the UK .

 

[Nige F]

, but a large bore plastic waste pipe?

Lord knows if it's that, ?

I just prayed , and got the answer