How do I cut a 4 inch dryer vent in an external cavity wall.

batman1

Can anyone advise if this is a DIY job or get a builder in.

I understand a core drill is needed, which can be hired.

My question is do I need to drill straight through both blocks and then cut inside core from inside and outside core from outside, or can a core drill run all the way through from one side. Just wondering about correct alignment etc.

bauderline

You shouldn't really need a core drill for this, I would just use a Kango to chisel out the hole either side. You can rent one for about 20 euro a day. Should not take any more than an hours work...

P.

fergal.b

The SDS core bits are quite long and you should be able to get one that will go all the way.



You can also get an extension bar if you need it.

DublinDilbert

I've done this a few times and never used a core drill. Lots of people just use a long SDS bit and trill out lots of holes, then knock them together with a chisel.

I would choose the location carefully so that you are near the edge of the brick, the cement is very easy to drill knock out ;-)

I would then cement in some 4 inch pipe from the outside to the inside and run the dryer hose into that.

aujopimur

A core drill is the tidiest way to do this, make sure you have a good work platform if it's high level, I've seen guys fall from ladders doing this.
Work from the outside in as it's easier to patch inside plasterwork.
Keep the outside a little lower to prevent the ingress of moisture.

heffo500

I'd definately hire a core and a sds max drill. Its makes it so easy to do and its the perfect job when finished. Since its a dryer vent I'm going to presume its near the ground you will be drilling so wont have to worry about a stable platform. I'd drill a long sds bit through first the diameter of the pilot bit and start the holke from both sides and then complete it from the outside to minimise damage.

You could tape the nozzle of a wet/dry vaccum near the hole underneath and the vaccum will catch most of the dust when your working inside.

paddy147

100mm core drill bit for the win here.

red sean

heffo500 wrote: »

I'd definately hire a core and a sds max drill. Its makes it so easy to do and its the perfect job when finished. Since its a dryer vent I'm going to presume its near the ground you will be drilling so wont have to worry about a stable platform. I'd drill a long sds bit through first the diameter of the pilot bit and start the holke from both sides and then complete it from the outside to minimise damage.

You could tape the nozzle of a wet/dry vaccum near the hole underneath and the vaccum will catch most of the dust when your working inside.

+1
You end up with a nice clean hole on both sides with no damage to repair.

tfitzgerald

DublinDilbert wrote: »

I've done this a few times and never used a core drill. Lots of people just use a long SDS bit and trill out lots of holes, then knock them together with a chisel.

I would choose the location carefully so that you are near the edge of the brick, the cement is very easy to drill knock out ;-)

I would then cement in some 4 inch pipe from the outside to the inside and run the dryer hose into that.

This is the way I have done it as well.

Kevwoody

bauderline wrote: »

You shouldn't really need a core drill for this, I would just use a Kango to chisel out the hole either side. You can rent one for about 20 euro a day. Should not take any more than an hours work...

P.

This sounds like a lot of extra work, you would get a much cleaner finish with a core drill.

I done this exact job at home and it only took 10 mins. Just make sure you insert a piece of 4inch plastic pipe between the 2 walls,otherwise if you have any uninvited guests in your cavity they will chew through your dryer hose

Also make sure you hold on tight to the drill as it breaks through, if it doesn't break through evenly, the drill will spin out of your hand!
Good luck

yllw.ldbttr

+1 on the core drill,
rented one (+the bit) in Cork last year, think it was 30-40 euro for the day.

One for a kitchen hood vent, and another for a dryer vent. Simple clean job and had both done in 30 mins.

paddy147

No real work involved.

Just apply steady pressure and let the core drill do the hard work for you.:)

Joey the lips

Make sure you fit a liner into the hole sounds obvious but a lot dont. Some fans come with liners. Some people have offcuts of 4" pipe.

If it were me i would use a core bit. Make sure you drill the pilot hole first. Its easier to guide the corer.

If it were my choice i would drill into the house not out. That way no fear of big lump coming away.