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cutting hole in kitchen wall for fan flue
locoboy - 29/1/12 at 12:00 PM

I am looking at getting a cooker hood / extract that vents outside and I will need to cut a 5 inch diameter hole in the wall from inside to outside.

any tips on what is the best way to do this?
Cheers

SausageArm - 29/1/12 at 12:08 PM

If you don't already have one, hire an SDS drill and a 5" masonry hole saw, it'll make the neatest hole in the shortest time.

Or you could just chain drill and chisel out the hole, but it'll take a lot longer and make a lot more mess and no doubt not look as nice.

fullpint - 29/1/12 at 12:13 PM

Does it have to be round? I'm sure the ones Ive seen you just knock a brick or two out, pop the hose thru the hole and then use a filler/foam. On the outside/inside I would have thought you could get a plastic vent cover and that will cover up the filler..
You can hire a hole tool..
http://www.pistonheads.com/gassing/topic.asp?h=0&t=601959&i=0

mad4x4 - 29/1/12 at 12:14 PM

quote:
Originally posted by locoboy
I am looking at getting a cooker hood / extract that vents outside and I will need to cut a 5 inch diameter hole in the wall from inside to outside.

any tips on what is the best way to do this?
Cheers


Drill from the Outside in so you get a nice cut on the outside ( on the inside you will patch and hide with drywall)

dhutch - 29/1/12 at 12:15 PM

Hiring a hole saw for the win.
- Unless you have a really big one i would hire the drill too as its not much more and even though the supplied drill wasnt any better than mine its then not your drill getting the abuse. They dont use hammer action but take a fair bit of turning.


Daniel

adam1985 - 29/1/12 at 12:21 PM

Stitch drill it round and a few holes in the middle then hammer and chisel
I do 3-4 a week this way quicker than diamond cores and a lot less dust.

SausageArm - 29/1/12 at 12:24 PM

Forgot to mention, i'd drill a pilot hole right through the wall first, then drill with the hole saw from outside and inside towards the centre, so you have a neat hole on both the inside and outside.

MakeEverything - 29/1/12 at 12:33 PM

quote:
Originally posted by SausageArm
Forgot to mention, i'd drill a pilot hole right through the wall first, then drill with the hole saw from outside and inside towards the centre, so you have a neat hole on both the inside and outside.


Thats what i would do, only masonry holecutters dont have an arbour / pilot (well, the ones ive used didnt).

Proby - 29/1/12 at 12:41 PM

I borrowed a core drill to do mine, but it took around 3 times longer than I expected. Arm ache and lot of dust!

SausageArm - 29/1/12 at 12:53 PM

quote:
Originally posted by MakeEverything
Thats what i would do, only masonry holecutters dont have an arbour / pilot (well, the ones ive used didnt).


Oh, didn't realise that!

MikeR - 29/1/12 at 01:11 PM

make sure you drill the hole for the middle from the inside to act as a guide. When you make the hole also make sure the outside is lower than inside so everything drains out / nothing can drain in. I stressed about making sure the hole warm't too close to the roof so as not to upset the floor joist mounting. Unless you run the fan to a plug / replace existing damaged wiring you'll need a part p spark to wire it in - may still need part p due to being in the kitchen if damaged wiring.

Agriv8 - 29/1/12 at 01:27 PM

I did mine by pilot all the way through from inside ( proper SDS drill ) mark arround pipe drill every 15 mm with a SDS 8mm.

then chisseled through with hammer drill on Chissel and an SDS shissel set took arround an hour or two ( not skimping on the Brew breaks ).

regards

Agriv8

mark chandler - 29/1/12 at 01:36 PM

A decent core drill is the way forward, you need a proper SDS drill with clutch, should cost around £15 to hire.

Stitch drill is okay, if on an old house you could disturb the mortar and end up pushing out a brick if not careful

Regards Mark

adam1985 - 29/1/12 at 01:51 PM

quote:
Originally posted by mark chandler
A decent core drill is the way forward, you need a proper SDS drill with clutch, should cost around £15 to hire.

Stitch drill is okay, if on an old house you could disturb the mortar and end up pushing out a brick if not careful

Regards Mark


The proper core drills dont use sds they slip they just have a Threaded chuck

r1_pete - 29/1/12 at 04:27 PM

I've a 5" core drill with a centre pilot, fits in a normal drill, I bought it to do my combi boiler flue, have a 1000w Makita drill I used to drive it.

Can't see me needing it again, cover the post and its yours.....

Confused but excited. - 29/1/12 at 05:47 PM

quote:
Originally posted by adam1985
Stitch drill it round and a few holes in the middle then hammer and chisel
I do 3-4 a week this way quicker than diamond cores and a lot less dust.


+1
A hole saw leaves a nice neat hole and a ton of really fine dust that is still settling out of the air days/a week later and no matter if you tape up the kitchen doorway, it still gets all over the house.
Ask me how I know.
Having tried both methods, I'm definately with Adam on this one.
You can get nice plastic sheilds to slip over the pipe and hide the rough edge of the hole. Just done the sister-in-laws.
Proper job!

JoelP - 29/1/12 at 06:32 PM

I drill out from inside to mark the correct spot, then slightly lower i predrill the pilot hole (all my core drills have a pilot bit), then a few turns with the core drill to mark, then stitch drill it to pieces, use the drill to chisel it out, then coredrill through the middle to remove any bumps that will tear your pipe. This is by far the fastest way.

You can get away with a lot of mess outside since the vent covers a fair bit of overshoot. I usually pull the pipe through, fasten on the vent, then pull the pipe back inside to hold the vent snug. Then tidily silicone the top and sides, leave bottom unsealed incase it needs to drain for any reason.

It can be very hard to drill the screwhole without it chipping the bricks off - if you can, do this before you cut the full hole when the bricks will be stronger.

Make sure you pad the worktops inside when you do it, invariably fragments will end up on the far side of the kitchen!

locoboy - 30/1/12 at 09:30 PM

Good advice Guys thanks,

I will get the flue pipe and fitting kit and then tackle it, Pete I may be in touch if its definately a 5 inch flue, thanks for the offer.

Colin

BenB - 30/1/12 at 09:57 PM

I've done shed loads of these over the last few years. Cheap and cheerful screwfix SDS drill and a £10 TCT core drill off ebay and job's a good 'un. Does make some mess though