Preliminary internal drainage / pipework…
April 2, 2015
This week we began the first fix for the internal foul drainage pipe work. Where the pipes pass through or within the intermediate floor they sit below the insulation layer and are clipped at regular intervals to prevent noise. We also added a secondary layer of insulation below these pipes for acoustic separation from the storey below.
At this point we also made sure we
had full depth insulation over the wall head to help with the acoustic
separation between rooms. These photos show the steps we took...
The main soil stack is ventilated externally via an 82mm diameter pipe (depending on certain parameters the standard stack diameter of 110mm can be reduced to 82mm diameter for the venting part only).
In our case this passes in front of the
service cavity and we weren't ready to construct this in entirety yet, so in order to restrain the pipe we fitted a small section of
service cavity insulation and sheeting at this stage only where we needed to. This pipe will then be
boxed in later as it is above our wardrobe in the master bedroom. The venting part of the pipe must be a specified distance away from openable windows, so this is why it extends along the wall internally before popping out through to the outside. As usual there is an airtightness grommet around the pipe where it passes through the spano durelis board, which you can just see the bottom of below the insulation in this next photo.
To connect the venting section of pipe to the main stack we have to pass over a floor to ceiling door opening (with no wall head above) so we created an airtight box within the ceiling zone by wrapping the membrane up into a joist space (to the far right in the above photo). The pipe can then pass up into this zone and over the wall head into the en-suite in the ‘inner box’ where there is a lowered ceiling to conceal it as it connects to the vertical portion of the stack. This is one of the potential complications of such a high level of airtightness: all of the service routes need to be planned in advance so as to prevent any unnecessary or 'difficult to fix' penetrations in the membrane / airtightness layer later.