7 hours ago, cliveshep said:

 

Blockages now a thing of the past!

The clogging problem will return over time if grease and oil continue to go down the drain. I suspect the clogging was amplified by the collapsing fibre drain line but certainly the grease and oil alone coat the interior of the pipes and slowly close off flow as well as catching debris that travels long the drain line  

 

Also cutting in vent line in the vertical drain line will add venting and is better than no vent but add the potential of clogging over time at the point of cut in due to debris catching and accumulating at that opening. If draining issues occur in the future one area to remember to check and clean out would be that vent line. Normal venting, properly installed, is done at the top of the waste line going up from the point the drain connection enters the waste line.

3 hours ago, Dan O said:

The clogging problem will return over time if grease and oil continue to go down the drain. I suspect the clogging was amplified by the collapsing fibre drain line but certainly the grease and oil alone coat the interior of the pipes and slowly close off flow as well as catching debris that travels long the drain line  

 

Also cutting in vent line in the vertical drain line will add venting and is better than no vent but add the potential of clogging over time at the point of cut in due to debris catching and accumulating at that opening. If draining issues occur in the future one area to remember to check and clean out would be that vent line. Normal venting, properly installed, is done at the top of the waste line going up from the point the drain connection enters the waste line.

 No potential for clogging with fats and oils - possibly in the grey water pipes, in fact certain in the waste pipes going out to the manhole, but in the sewage pipes no chance, all that goes down those has been eaten or drunk first! And we no longer have any cement fibre pipes anywhere, all UPVC underground drainage as I replaced the lot after problems. 

3 hours ago, cliveshep said:

 No potential for clogging with fats and oils - possibly in the grey water pipes, in fact certain in the waste pipes going out to the manhole, but in the sewage pipes no chance, all that goes down those has been eaten or drunk first! And we no longer have any cement fibre pipes anywhere, all UPVC underground drainage as I replaced the lot after problems. 

Thats what I was referring to based on your explanation of what you had.  

 

20 hours ago, Dan O said:

The clogging problem will return over time if grease and oil continue to go down the drain. I suspect the clogging was amplified by the collapsing fibre drain line but certainly the grease and oil alone coat the interior of the pipes and slowly close off flow as well as catching debris that travels long the drain line

That is why I plan to have a separate grey water tank just for the western kitchen, Thai kitchen, and washing machine.