Thick wall bore hole advice

[mcmook]

I have a waste water pipe to route, the best way to go would be through a wall... however the wall is 20" thick whin stone (probably with looser/rubble centre).

Should i attempt to bore a hole through this wall? (say 6" diameter) - and what would i need to do it (from a hire place). How long will it take? How much mess? (I'd be doing it from a cupboard under the stairs)

The other alternative is to go around the wall, this is the way the

15mm flow and return from the boiler has been routed in the past, this would introduce 2 extra 90 deg bends in the waste water pipe - if i did this would 2" pipe be more suitable than 1.5".

Thanks

[Lurch]

On Tue, 14 Aug 2007 07:11:44 -0000, [e-mail] mused:

I'd use a decent core drill, not a dry diamond core. Sleeving the hole with something that will protect the pipe from damage from the loose fill would be preferable.

Could you semi-recess it in the wall, make it a bit lower profile if it's on show? Could also bury the CH pipes as well.

[Roger]

The message from [e-mail] contains these words:

I have in the past put pipes through rubble filled walls by knocking a hole right through the wall and building back round the installed pipe. For a small pipe you may need to take out no more than one stone either side of the wall and if it is a wall built with lime mortar they should come out quite easily. (Too easily and the whole wall might start to collapse and you wouldn't want that to happen).

A small amount of rubble infill might fall down as you excavate the centre. If there is any chance of a further fall onto the installed pipe put in a substantial sleeve or a through stone above the pipe. If you are lucky there will already be a convenient through in place. If you are unlucky the stone you first try to remove will be a through. (It seems to have been a common practice to use through stones as wall ties in rubble filled walls).

The scariest task I have ever had to do was to make good the partially collapsed wall above a doorway knocked through a 2' wall (once an outside wall) without using adequate support. Luckily for the perpetrator one side of the wall had a cupboard (with lintel above) built in directly above the new opening so only one skin of the wall gave way and not completely but the wall sagged to such an extent that one of the original corner quoins was left at an angle of some 30 degrees to the horizontal and several throughs pulled out of the largely intact other skin. Remedial work (several decades earlier) had been confined to giving the bulge a thick cement overcoat which may have had only a cosmetic effect.

[TMC]

Not sure if this is relevant as I have never used a core drill

Whinstone is very similar to granite so is a hard close grained rock

Will a hand held core drill cope with this?

Tony

[mcmook]

one stone either side would be nice - but i've already made a hole in one of hese walls for an SVP pipe (to the outside) and i know this wont happen - i would end up removing a very large amount of stone. so i think a core drill is my only option - what i would like to know in advance is whether a hired core drill would do the job, and what exactly to ask for.

[dom]

Although HSS are outrageously expensive - I've found that they do listen carefully to what I need to do and make good recommendations from their products. Phone them.

[TMC]

This appears to be the system

even this kit with extension tube only goes to 400 mm although you may be able to fit more extensions

However I would not want to be sitting in an understairs cupboard whilst using it

In fact I don't think that I would want to use it at all

Drilling the pilot hole would be a challenge in whinstone and the rubble infill could throw it off line

I can also foresee problems with the rubble when using the core drill

The few times I have done this sort of work I have used the stone from each side method already described

Tony