Drainage installation - advise on layout & components

[macadonald]

Hi Guys,

Hoping someone can advise on drainage. Apologies if this should be in the plumbing forum, but seemed more building related. I need to install the new foul and surface drains for my rear extension next week and have been researching and planning for a while now. I also have the foundations poured this week, but feel I have a good idea what and where i need to shutter. This will mainly affect the existing pipe at the boundary with the neighbours.

I know what I want, but am a little unsure of the best components to make this up from. I've been using very helpful websites like pavingexpert (http://www.pavingexpert.com/drain10.html), but again, a little confused with the options. Eg, Yard Gully, P-trap and hopper, Rest Bend and hopper or bottle gullies.

I have attached the image that best tries to explain what I propose. We are head of run and have an alley on the left side of the picture. I want to have rodding access from the head of these runs. The little dotted line is the existing connection of the foul to a manhole. Everything left of this does not currently exist. I want to replace the lot with plastic, connecting at the boundary with the neighbous (yellow). The new foul, I want to divert from the upstairs exit from the wall and take it horizontally to the alley and then straight down.

Where would I go about knowing what the best components are. There seem to be a few options for the same job. Just want to get this right first time.

Many thanks if anyone can spare some time to advise.

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• macadonald
• 23 Oct 2012
• 1

 

[Hugh Jaleak]

Looking at the picture, you're going to need the chamber (manhole) where the pipes converge, otherwise the run to downstairs W.C. isn't accessible for rodding. If this is going to be internal then fit a sealed cover. Not ideal, but should it ever block then you'll need to get to it.

Rest bends are needed at the foot of a stack, bottle gulley would be my preference, easier to clean out. Will need a stack open to vent at the head of the run.

 

[macadonald]

Hi guys,

Firstly, Hugh I'm not ignoring your previous response, just keen to know more before ordering my hunter drainage.

When is it best to use a p-trap gully and when a bottle gully? I would have thought a p-trap would be better to stop any potential sediment ever making its way down the drain and with water sitting in the bend, no risk of smells?

Is there not a risk of bottle gullies simply filling to the point where the sediment will just go down the pipe and potentially block further down? Saying this can you get a rod down the pipe out of a bottle gully to clean? I would imagine there is no chance of that with a p-trap?

I've also read on some sites that bottle gullies can be suitable for taking both rain water and waste water for downstairs appliances. I thought all appliances were considered grey water and needed to go down foul? So can kitchen sink, washing machine etc all go down surface water drains?

Cheers