Drill 40mm hole in internal CI soil stack for new shower?

[Ralph2DIY]

Hi. Just moving into 'new' house with internal CI soil stack and doing bathroom (and kitchen below). All waste connections OK except bathroom sink and bath connections which run up hill to threaded connections (soil stack has 1 1/2" holes, threaded and screwed in short iron pipes (then plastic) above and below loo connection).

Plan to make new connections for bath and shower to go through ceiling into kitchen below (just below celing height) to get required fall for shower and bath waste.

So, how to make 40mm holes and connections to a CI soil stack - ask a plumber? Buy a hole saw (or a few hole saws)? Drill a ring of holes and file smooth?

All this assumes that the pipe won't crack, that I can find a rubber seal and strap boss that will suit cast iron.

By the way, all this talk of angle grinders on soil stacks makes me wonder if there's a risk of sewer gas explosion ? !

Thanks all,

Ralph

 

[Paul Barker]

go to engineering supplier, buy 10 hard 4mm drill bits. Stitch drill a circle, chisel between holes, file. You may go through all 10.

Veryt sensible to go through ceiling, if you don't do it now, the water hanging in the uphill pipes will bring it down eventually.

 

[Steady]

Can you not run the waste pipes outside to a hopper head or gulley? This would be a better solution. Cutting and bossing into cast iron soil stacks is never easy and not always successful . Plastic is the way to go if you want to do this.

 

[ChrisR]

Heavens to Betsy, that's hard work Paul. A hole saw will would be fine; something like the HSS ones from Screwfix go through pretty quickly.
Best lubricant is paraffin iirc, which nobody ever has..

Don't be tempted to try to use a plastic strap round a cast iron pipe though, they always leak eventually. Use one designed for CI.

 

[Paul Barker]

OH

 

[Agile]

Interesting question raised by Steady above!

Does anyone know if its still permitted to use an open hopper for drainage on new work any more?

Perhaps it is but its just cheaper/more fasionable not to use them?

I will say that they are virtually maintenance free whereas closed pipes sometimes block!

Tony

 

[Ralph2DIY]

Thank you all. Just for reference, there's no hopper - it's an internal cast iron soil stack.

If a plastic strap boss is not recommended, does anyone know of a metal one? Don't fancy threading the hole as has been done before.

Thanks, Ralph

 

[Steady]

Interesting question raised by Steady above!

Does anyone know if its still permitted to use an open hopper for drainage on new work any more?

Perhaps it is but its just cheaper/more fasionable not to use them?

I will say that they are virtually maintenance free whereas closed pipes sometimes block! (quote=Tony
)

Above rang a bell with me too so have looked at Part H Building Regs, quoted below :

Branch discharge pipes
1.7 Branch pipes should discharge into another branch pipe or a discharge stack unless the appliances discharge to a gully. Gullies are generally at ground floor level, but may be at basement level. Branch pipes should not discharge into open hoppers.

1.8 If the appliances are on the ground floor the pipe(s) may discharge to a stub stack or discharge stack, directly to a drain, or (if the pipe carries only wastewater) to a gully. (See paragraphs 1.11 and 1.30.)

First paragraph suggests not to use hoppers but allows waste pipes to discharge into gullies. Am a bit surprised by this as the hopper head invariably discharges lower down into a gully ,so it sounds a bit contradictory.

 

[chrishutt]

If a plastic strap boss is not recommended, does anyone know of a metal one?

Multikwik do a plastic boss that appears to clamp on. Might this work with CI? http://www.multikwik.com/products.php?cat=8&procat=Easy+Boss

 

[ChrisR]

I've used those but only on plastic. Best ask them.
There is an all-rubber unequal tee with 3 jubilee clips... forgotten the name.

 

[doitall]

http://www.hargreavesfoundry.co.uk/leveltwopages/pdf1.html

click on strapon bosses, there are other makes as well if you do a search or just go to BSS or Pipecenter