noisy flush on toilet

[simon1]

We have a two-storey home and our toilet makes a terrible loud noice aa soon as flushing STARTS. It sounds like the pipes are noisey. The walls are shaking...
If you turn on the downstairs cold sink tap the noise stops.
anyone know how to stop this?

[pgtek]

hi
sound like ther a venting problem
check if the roof as a vent for the toilet pipe stack also check if there a pressure pipe extender on your water pipe at the top of the toilet supply pipe sounds like air trap

[simon1]

there is a roof pipe but not too sure about the other
when the water is re filling the cystern and you put your finger over the pipe to stop the water the sound stops , so sounds like air?
but not being a DIy expert dont know how to cure this

[majakdragon]

I would guess that your fill-valve is bad. You can buy a Fluidmaster fill-valve for about $6 at home centers and hardware stores. They come with excellent instructions for installation. Good luck.