Rainwater strap boss?

[fabgav]

Hi all, I'm sure they must exists but I'm dammed if I can find one to buy anywhere.

I need to connect my bath waste to rainwater down pipe which is to a combined foul and surface water system.

Where the waste exits the wall there is no rooom for a hopper head and need a strap boss or any other way?
Maybe a branch section and drop the bath waste into the branch with a rubber adaptor.....if that exists?

OR can anyone tell me where I can buy a 3 inch strap boss?

cheers

 

[JimCrow]

http://www.mcalpineplumbing.com/waste-pipe-fittings/boss-connectors.html?p=2

 

[Charnwood]

Err, when I was a lad rainwater downpipe was 21/2" (68mm in new money) not 3" (82mm)

 

[Hugh Jaleak]

As Charnwood has said, Rainwater is usually 2 1/2"/68mm, and no fitting exists to my knowledge to join waste pipe to it. (Even the miniline guttering that uses 2" downpipe is not compatible with 2" (50mm) waste pipe.)

If you do have 3" (82mm) downpipes, (unusual but not impossible) the joints should be obviously different from standard downpipe which simply fits together, the 82mm will have the collars locating the seals.

 

[Charnwood]

In Jim's McAlpine link there is a mechanical boss which is supposed to fit RW pipe, but it is for condensate pipe - 11/4".

 

[fabgav]

Sorry yes, the rainwater pipe is standard size, I'm not sure why I stated 3 inch! (blonde moment)

IS there a reason why this does not seem to exists? As I said in o/p I can not fit a standard hopper as the area it would foul the folding doors

 

[Hugh Jaleak]

Not sure why they dont exist, but may be to discourage people from connecting wastes to rainwater downpipes to prevent waste water from being discharged into the surface water drains. Hoppers are unsanitary affairs, and for that reason are now banned under Building Regs for waste pipe discharges, unless as a direct replacement for an existing hopper.

If you have no other option, all I can suggest is maybe upsizing the last section of the waste to 50mm, fit that into a 68mm branch and seal with silicon. Bodge, but cannot think of a better solution.

 

[Charnwood]

Rainwater pipe often has an open outlet - rainwater shoe:

I think nowadays waste water has to go direct to a closed drain. (Open to correction.)

 

[Hugh Jaleak]

Soil appliances must be directly connected to the drain, wastes can go to an open gulley if required.

 

[Charnwood]

Tut, wrong again.
Well, sort of, some rainwater shoes discharge straight onto paths, patios, gardens etc.

 

[fabgav]

Thanks for the info all,

My dad did say about just runnign 32mm waste pipe down the wall and into bottle trap......but I think that will look really naff.

It does seem that Hugh's 'bodge' is going to be the only way, unless I just drill a 32mm hole in the side of downpipe, stick waste into it and silly it up?
Still a bit of a bodge

 

[Hugh Jaleak]

Rainwater is ok to discharge onto the ground although it may not do the foundations of the building any favours... Wastes must (should!) be connected to the foul sewer, either directly or indirectly!

Fabgav, a bath waste should be 40mm, putting a hole that size in the side of a 68mm pipe may prove awkward, and without 'shaping' the end of the waste it may protude into the downpipe sufficiently to allow detritus to collect on top and possibly block the downpipe.

You could replace the bottom section of downpipe with 110mm, connect downpipe into the top of that then fit a strap boss for the waste, but aesthetically the waste and rainwater running in parallel may actually be less obtrusive!

 

[fabgav]

Well currently the rainwater is around the side, I was going to move it to accom. the bath waste. But yes your right it may be more aesthetic.

 

[Hugh Jaleak]

Beware of too long a run in 40mm, if that is your preferred option, it can cause syphonage issues. Although with a bath there is plenty of surface area for the final runoff when emptied to refill the trap, if the basin is also connected it could 'pull' the basin trap. An AAV on the waste run or an anti syphon trap on basin maybe needed.

 

[Charnwood]

You could replace the bottom section of downpipe with 110mm, connect downpipe into the top of that

Or 82mm/3".