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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> New drains in mill conversion https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1292343851 Message started by SHBS on Dec 14^th, 2010, 4:24pm

Title: New drains in mill conversion
Post by SHBS on Dec 14^th, 2010, 4:24pm

I am about to start conversion of a small mill and the only thing that worries me is the drains. Is it standard practice to concrete in a hub? Should I connect the WC, shower and sink drains to the hub/vent stack then concrete them in before laying insulation and underfloor heating?

Stuart

Title: Re: New drains in mill conversion
Post by thescruff on Dec 14^th, 2010, 6:02pm

Download approved document H, it contains everything the building inspector will want to see and check.

Title: Re: New drains in mill conversion
Post by SHBS on Dec 15^th, 2010, 9:52pm

I have part H but it doesn't mention drains under floors. I suppose if I just follow the rules I will figure out what is possible.

Title: Re: New drains in mill conversion
Post by CWatters on Dec 15^th, 2010, 11:13pm

If you must have a junction indoors consider the implications of 2.49d which may mean you may need a (sealed) inspection/access hatch in the floor.

Normally you avoid this by either running pipes..

a) Above floor to a stack or stub stack (Diagram 2, 5 and 7)
or
b) To the outside and then join them up out there (Diagram 1, 7 and others).

Note also the minimium/large bend radius at the bottom of a stack and the minimium height of a connection.

Title: Re: New drains in mill conversion
Post by SHBS on Dec 23^rd, 2010, 8:52am

Thanks for directing me to 2.49 but it's not usual to provide access to junctions into the soil stack is it? They must be talking about the main drains not branches. In my house built in 1993 there are rodding points outside to clear the main drain but if a sink was blocked and couldn't be unblocked with a plunger then floors would have to be lifted and boxed-in bits opened up. I suppose I should just wait until I apply for a building warrant and ask the inspector.

Title: Re: New drains in mill conversion
Post by CWatters on Dec 23^rd, 2010, 11:56am

Quote:

it's not usual to provide access to junctions into the soil stack is it?

No, they are frequently boxed in. Not sure if that counts as "access" but you don't often see proper hatches. I was really refering to junctions in the floor/ground. Perhaps I missunderstood what you meant by..

Quote:

Is it standard practice to concrete in a hub?