Air admittance valve

quad_red

Hi folks,

Bought a house a few weeks ago and few surprises have shown up in the attic. Was shocked last night to find the tank overflow pipe was hanging, separated in the middle. Also found that the sewer system vent pipe just comes up in the attic around two feet and then is connected to.... nothing.

Which explains the methane smell which we thought was caused by something else.

Anyway, grateful for advice on the following:

The stack of pipes at the side of the house is vented out the top. So would I be correct in saying that this will sufficiently vent the system and the main purpose of the vent in the attic is to allow air in the system when a toilet is flushed?

In this case, would one of these do?

http://www.goodwins.ie/p-1597-110mm-air-admittance-valve.aspx

The pipe is the same size of pipe on the side of the house. If this is too small, what sort of fitting would I need to fit on?

Celtic Tiger bulding standards

Cheers,
Quad

donedl1

Soil stack is generally 4 inch. Durco valve should do the job.