Fitting extraction fan - how to cut hole in block wall?

rustynutz · 29-11-2009 08:16PM #1

I have a serious problem with mould in my ensuite so it's time to fit an extraction fan.I bought one today,it's designed to go through a block wall,so my question is,what is the easiest way to cut the 100mm diameter hole through the tiled block wall to allow the duct to fit through to outside?

Davy · 29-11-2009 08:46PM

You want a TCT core drill bit. Can get variious sizes, 100mm or a little bigger if you need room for cables

Sleipnir · 29-11-2009 08:50PM

Davy wrote: »

You want a TCT core drill bit. Can get variious sizes, 100mm or a little bigger if you need room for cables

Can you get those? I was looking for one a while ago but couldn't find one.
Do they work well on tile?

Davy · 29-11-2009 08:58PM

Sleipnir wrote: »

Can you get those? I was looking for one a while ago but couldn't find one.
Do they work well on tile?

Ye you can, they can be quite expensive. They are pretty tough tho, take some abuse. Need a decent drill to go with them. Makita have a good job, its a kango and a drill in one unit.

They will work on tile ye, just takes a bit of care and time. It can hard to hold it pefectly still as its quite heavy. It will take a little plaster off on the outside around the hole if you drilling inside to outside but nothing major. Defo a much better job than a hammer and chiesel

northsidedave · 29-11-2009 09:44PM

if you didnt want to buy a tct bit for just the one job you could go for the less expensive method.mark out the size of your hole ,then wit a 6/8mm masonary drill bit (long enough to suit the width of the wall) and drill a series of holes around the cicumference.it`s a bit boring but does the trick,then bang away with chisel.

rustynutz · 29-11-2009 09:45PM

Davy wrote: »

Ye you can, they can be quite expensive. They are pretty tough tho, take some abuse. Need a decent drill to go with them. Makita have a good job, its a kango and a drill in one unit.

They will work on tile ye, just takes a bit of care and time. It can hard to hold it pefectly still as its quite heavy. It will take a little plaster off on the outside around the hole if you drilling inside to outside but nothing major. Defo a much better job than a hammer and chiesel

Thanks,I wonder could I hire one?Wouldn't be worth buying one for a one off job.

Davy · 29-11-2009 09:51PM

rustynutz wrote: »

Thanks,I wonder could I hire one?Wouldn't be worth buying one for a one off job.

No it would be expensive for one job ofcourse. Im sure you could hire one, ive never got on hire tho so im not certain.

As northsidedave said, the more traditional way is an option.

quietsailor · 29-11-2009 09:56PM

rustynutz wrote: »

Thanks,I wonder could I hire one?Wouldn't be worth buying one for a one off job.

Two things to know

1. Yes you can hire hole saws for blocks, they are called core drills and cores. You'll need one slightly bigger than the pipe your using ie a 107mm core for a 100 mm pipe.

2. There are 2 types,

ones like this just grind their way through the wall and cut smoothly, they are less likely to break plaster off the outside of your wall. You never use the hammer function with this type of core
http://cgi.ebay.co.uk/Dtas-Duro-Plus-158mm-Dry-Diamond-Core-Drill-Bit_W0QQitemZ290197456768QQcmdZViewItemQQptZUK_Home_Garden_PowerTools_SM?hash=item43911dc780

I think this type is the one most commonly rented out, if you get one of these ask if you have to use the hammer function or not with it. It works by grinding/chipping the block away so it's a much rougher type of work.
http://cgi.ebay.co.uk/110mm-SDS-TCT-TUNGSTEN-CORE-DRILL-HOLE-CUTTER-M16_W0QQitemZ380100759873QQcmdZViewItemQQptZUK_Home_Garden_PowerTools_SM?hash=item587fc55141

Unless you have a big - sds max - drill already your going to need to hire a drill as well so this will nearly double the price. You should look up coring companies in your area, I don't know prices but it might work out cheaper for you.

intbn · 05-01-2010 04:14PM

quietsailor wrote: »

Two things to know

1. Yes you can hire hole saws for blocks, they are called core drills and cores. You'll need one slightly bigger than the pipe your using ie a 107mm core for a 100 mm pipe.

2. There are 2 types,

ones like this just grind their way through the wall and cut smoothly, they are less likely to break plaster off the outside of your wall. You never use the hammer function with this type of core
http://cgi.ebay.co.uk/Dtas-Duro-Plus-158mm-Dry-Diamond-Core-Drill-Bit_W0QQitemZ290197456768QQcmdZViewItemQQptZUK_Home_Garden_PowerTools_SM?hash=item43911dc780

I think this type is the one most commonly rented out, if you get one of these ask if you have to use the hammer function or not with it. It works by grinding/chipping the block away so it's a much rougher type of work.
http://cgi.ebay.co.uk/110mm-SDS-TCT-TUNGSTEN-CORE-DRILL-HOLE-CUTTER-M16_W0QQitemZ380100759873QQcmdZViewItemQQptZUK_Home_Garden_PowerTools_SM?hash=item587fc55141

Unless you have a big - sds max - drill already your going to need to hire a drill as well so this will nearly double the price. You should look up coring companies in your area, I don't know prices but it might work out cheaper for you.

Which do you reckon would be the quicker job quietsailor? cheers for the info

al2009 · 05-01-2010 07:49PM

Using one of these hole saws with the requisate drill is awkward if you've not used one before, they can be heavy and long (drill plus bit plus extension if needed could be 2 to 3 feet), they are great if you have good access and not recommended off ladders etc, have you thought of drilling ceiling and ducting out through the soffit? what part of the country are you in?

al

Joey the lips · 05-01-2010 08:26PM

You have all the advice you need above just be careful of the"Coming through" drilling a way can be sometimes like a bullit going through someone. It makes a bigger hole on the other side.

I usually on a cavity wall core on both sides to prevent this. Use a pilot drill first to guide you.

However if its slightly bigger on the outside you can just fill it. Chances are the bathroom wall is at the side or back of the house where it wont be noticed.

This might sound mad but it might acually work out cheaper for you to get someone to core it as you wont ever need the gear again.

eoghan.geraghty · 05-01-2010 10:29PM

I've had to do this a couple of times in houses, and I've always gone up through the roof once the wall is tiled.
Replace a roof tile with an aluminium flashing c/w 4" pipe and vent cover, run flexible ducting from your fan to this. The flashing kit will cost about 50 to 60 euro.
I wouldn't risk drilling a 4" hole through tiles.

Let us know how you get on and good luck with it.

items · 05-01-2010 11:31PM

Core drill's are a pain, unless they are water cooled bolt to wall wall type. The ones you get from hire shops are lethal, they hop and kick, many a sore head, leg, arm etc after using one.

I've spent a life time drilling out holes from 1/2" up to 6", best way I find is to use a combi drill breaker, drill a series of holes then break out hole. I've drilled tiles in this way also, just have to start with a small bit, mark out hole, drill loads of 8mm holes, knock of tile, then drill more holes through wall with long 1/2 or 3/4 bit.

Venting an extract by use of roof tile / attic might have condensation troubles, vent pipe has to go straight up, no dips or bends etc, insulated vent pipe also.

I'd drill it out.

Fitting extraction fan - how to cut hole in block wall?

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