Cutting hole through thick walls

[chocccie]

I need to cut a small hole through the very thick walls of a house for a waste pipe. 

I was planning using an angle grinder with stone cutting disc.  Does anyone have a better idea, or suggestion as to how I best approach it?  Is there a more suitable tool readily available for hire?

Cheers

[Pierre ZFP]

The best way is to hire a diamond cutter which fits into an SDS drill.  You can hire different diameter drills of course and they have extension rods to get great depth.  There are 2 types generally, those that are used wet with a special drill and those that are dry used in a normal SDS. What happens (in the UK) is that the cutting teeth are measured before and after the hire and you pay so much depending on what you use.  Be careful if there are any reinforcing rods in say concrete.  Diamond drills like stone but not metal.

[Quillan]

You can usually hire a hole boring drill for the right size hole for the pipe you want to put through the wall. You will also need to hire the drilling machine as well as it needs a big, powerful one. Just a word of warning, don't use ladders or a chair, make a decent base to stand on as the drill is VERY powerful and you need to hang on tight especially when it 'snags' on something a bit harder. I learnt this from first hand experience and being thrown across a kitchen.

[tj]

Hi

If we are talking about a traditional stone built house, stone on both sides and all the rubbish in the middle, with a little patience and a hammer and bolster, you should be able to remove the stone from both sides. It is preferable to using a heavy drill whose vibration in many cases also damages the bonds of the surrounding stonework.

I dont suggest its possible in every case, but would try it first.

regards

 

 

[Val_2]

That is exactly how my OH does it here in Brittany and has done for many years now as the stonework is v ery unpredictable and you can cause a lot of damage by going at it hammer and tongs with a powerful drill until you suss it out a fair bit. It takes longer but less damage means less to make good afterwards. We have a good selection of hammers and bolsters now.

[Gluestick]

Small hole......... sort of standard sink/basin waste pipe size?

Since it is very difficult to drill out many materials to a perfect size (as whatever drill is used it tends to find harder and softer bits and snag and jump laterally) unless the whole wall is a very uniform substance like insulation blocks - unlikely - I would tend to use a small very long SDS drill and "pilot" a hole through.

Thereafter the rest of the material can be removed by drilling a number of additional holes on the cusp of the diameter of the hole desired; or with a hammer action SDS drill; or manually.

All really a question of "Suck it and See" as different materials can behave in wildly different ways: facing bricks, for example, can be exceptionally hard and brittle.

Core drills are great for things like extractor fans: however, don't under-estimate the amount of electrical "Grunt" you need to drive a big 'un! Nor under-estimate the sheer physical effort. Nor the torque of the drill snags! Big drills tend to rev slowly (typically 800 rpm) but with massive rotational torque.

My big SDS is circa 1.5 Kw and if that snags...............................

 

 

[chocccie]

Thanks for the excellent advice everyone.  It is a 100mm waste pipe I'm looking to build a hole for in a stone farmhouse.  Plently for me to think about.

Cheers

[Ford Anglia]

100 mm is NOT particularly small.

I'd try it by removing stuff from both sides, maybe pilot it with a LONG, (mine are 1000mm) say 10mm drill fist, just to check you are in the right place on both sides.[;-)]

Remember that a lot of stone walling has rubble infill, and will be a pain to remove enough to get a pipe that size through without it all falling into the hole from above.[8-)]

You MIGHT get it through by gently knocking it after removing the bonded stuff from each side, but use a longish length so you can cut off any damaged areas at the ends.

[Framboise]

When our chauffage was being installed the plumber asked hubby to drill the overflow pipe through the outer wall "to save time.....", although we suspect he did not fancy the job himself as he knew what was lurking behind the old plaster.   Nor did he mention that doing so would blunt the drill bits in seconds and furthermore, what should have been a small hole ended up a cavernous one due to the huge boulders that comprise the entire wall.   We could have put another window in!    The job was eventually done with hammers and bolsters due to it being a futile effort with even a hammer drill.  The Sky tv man had just as much trouble drilling the cables through as well, so I guess its safe to say that the house will not blow down in a storm.

Actually the infill problem is not confined to France.  My parents bungalow was built by my Grandfather in the early 1930s and whilst it looks all brick this was most definately not the case. At one stage there as a roofing job to be done which exposed the top of the wall, and there in clear view was the top of a brass bedstead, an old bicycle and solid concrete.   Who knows what other horrors lurk beneath, making it just as well there are no plans to add more windows.

[Frederick]

Please forgive me if I am stating the ovious here ....but if you use a heavy drill and core cutter dont grip it like a pistol .........keep your thumb same side as your fingers as you push through ....if you hit a stone and it kicks it then wont disslocate your thumb ......

[Gluestick]

Oh what fun reminiscense is.........................................

Bought a garage in 1969 which needed a total update from the 1930s decor and facilities.

Well remember my ex partner of the time, perched, dangerously, at the very top of some tall decorator's trestles, determined to drill a half inch hole through an "H" section girder with a web of about nine inches. We were re-wiring and he was feeding 7-21 cable for the workshop ring main. Me? I would have gone under and along; him, no way, determined to take the shortcut.

He was using an old drill of half inch capacity, which normally resided in a drill press frame and was probably about one horse power and revved at about 850 rpm. Massive, massive torque.

Old girders tended to have hidden pockets of carbon and thus tough bits; like flint in walls!

Of course, the bit snagged: of course the side handle smacked him firmly under his left eye. Luckily for him, I managed to turn the mains off and rescue him.[blink]

 

[friend of stouby]

Hello chocccie.

I have drilled (3) 125mm holes through a 500mm sandstone wall this year and  have to do more of these later too plus some smaller sizes.

On the first hole I cut I used a long 10mm drill bit then a hammer and chisel. The result although successful was very messy so decided to make the job easier. As I have so many holes to cut through I bought a Makita diamond drill bit set (for dry cutting with an SDS+ drill) and now have the 4 sizes that I will need.

The drill that is used has a torque limiter so that when, not if, it snaggs the drill bit stops turning so no broken wrists etc. I also decided not to use the hammer action as the diamond bit cuts sandstone quite well, although the build up of dust has to be removed regularly as does the cut material that fills the bit. It has taken on average about 20 minutes per hole of very hard work but the result is fabulous. No loose stones and a really smooth hole of the exact diameter required. 

There is a short pilot drill bit with the kit but I decided to drill all the way through the wall with a different longer 10mm bit first, just to get the angle and direction, then found that the shorter pilot bit with the cutter follows the first hole easliy.

Hope this is of help to you, I am not a professional (as probably shows) and not even a very keen DIYer, but with a little thought and a little money this time it has worked out great.

ps: The diamond bit set cost around £115 which I will sell on when I'm finished with it. I don't know what a drill bit hire cost is but as all our internal and external walls are 500mm thick, I have a lot to do so the initial outlay is to my mind worth it, plus it is always available at the moment it's required.

Jamie

 

 

 

[stewart]

Firstly, don't worry about causing any damage to the stonework, if you use an SDS diamond core bit to cut through the masonry, DONT USE IT ON HAMMER, it only wrecks the diamond.

Secondly, a 100mm core bit, or any other size for that matter should only be used with an apropriate drill, one with a clutch!!! so when it snaggs, as it will, it doesn't snap your wrist

Thirdly, the pilot bit that is located in the centre of the core bit is only used to get the core bit started, once the core bit has made an indentation, the pilot bit is removed as this snaggs the the core bit.

It's a slow process, but much easier than using a hammer and bolster and will cause less disturbance to any rubble infill within the wall. The secret to using them is to keep the same angle when going in as a few degrees will cause the bit to snagg. Also remove dust and debris frequently.