Best tool to cut a slit in a wall?
 

Hi all,

I need to cut a vertical slit at least 4mm wide through a 100mm wall,
and up to a height of 3m from the ground (for a vertical DPC where a
new extension joins a house). What is the best tool for the job? I
have got a 230mm angle grinder, but that would only go to about 75mm
depth, and is a beast to use anyway (i.e., I'd rather not use it up a
ladder). I've seen a few hire shops can supply wall cutters (basically
a plunge saw with a diamond blade), but these only go to about 50mm
depth. Is there a tool specifically for this type of job?

thanks,

dan.

Best tool to cut a slit in a wall?
 

In article ,
dent writes:
Hi all,

I need to cut a vertical slit at least 4mm wide through a 100mm wall,
and up to a height of 3m from the ground (for a vertical DPC where a
new extension joins a house). What is the best tool for the job? I

I'd have to say this sounds rather misguided in the first place.
Who advised doing this, and for what purpose?
Has a structural engineer been consulted on the weakening of the wall?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Best tool to cut a slit in a wall?
 

On Mon, 21 Sep 2009 05:31:20 -0700, dent wrote:
I've seen a few hire shops can supply wall cutters (basically
a plunge saw with a diamond blade), but these only go to about 50mm
depth. Is there a tool specifically for this type of job?

I saw a wall cutter once on TV - walls were a good 2ft thick. Crew had to
make their own rig to support it and guide it, then attach it to the wall
with some serious concrete anchors. They do exist, but possibly outside
the realm of hire shops :-)

re. angle grinder, can you access both sides of the wall? If so, drill a
couple of guide holes so you can line everything up and then attack from
both sides (and maybe source/hire a scaffold platform - or at least make
sure your ladder's secure; maybe anchor it to the wall and patch up
afterwards?)

cheers

Jules

Best tool to cut a slit in a wall?
 

"dent" wrote in message
...
Hi all,

I need to cut a vertical slit at least 4mm wide through a 100mm wall,
and up to a height of 3m from the ground (for a vertical DPC where a
new extension joins a house). What is the best tool for the job? I
have got a 230mm angle grinder, but that would only go to about 75mm
depth, and is a beast to use anyway (i.e., I'd rather not use it up a
ladder). I've seen a few hire shops can supply wall cutters (basically
a plunge saw with a diamond blade), but these only go to about 50mm
depth. Is there a tool specifically for this type of job?

There is a subcontractor doing just that on a lot of Smiths houses near my
parents (to demolish one half without affecting the other half).
They have a jig they bolt on the wall and then cut it with a diamond saw.
Without the jig it would be difficult to do a straight cut.

With care a big angle grinder would work but you are going to want a jig of
some sort.

Best tool to cut a slit in a wall?
 

On 21 Sep, 13:41, (Andrew Gabriel) wrote:
In article ,
* * * * dent writes:

Hi all,

I need to cut a vertical slit at least 4mm wide through a 100mm wall,
and up to a height of 3m from the ground (for a vertical DPC where a
new extension joins a house). What is the best tool for the job? I

I'd have to say this sounds rather misguided in the first place.
Who advised doing this, and for what purpose?
Has a structural engineer been consulted on the weakening of the wall?

Local Building Control told me I had to do this. I omitted it on my
original plans, and they only passed the plans on the condition that
this was added. It doesn't seem to be unusual to do this (e.g., see
http://www.cavitytrays.co.uk/damp-pr...-dpc-cavitray).

dan.


--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Best tool to cut a slit in a wall?
 

Andrew Gabriel wrote:
In article ,
dent writes:
Hi all,

I need to cut a vertical slit at least 4mm wide through a 100mm wall,
and up to a height of 3m from the ground (for a vertical DPC where a
new extension joins a house). What is the best tool for the job? I

I'd have to say this sounds rather misguided in the first place.
Who advised doing this, and for what purpose?
Has a structural engineer been consulted on the weakening of the wall?


I'm sure he means "into" rather than "through" the wall :-)
Angle grinder is the norm but keeping the cut straight isn't that easy IME

Best tool to cut a slit in a wall?
 

On 21 Sep, 13:55, Jules
wrote:
On Mon, 21 Sep 2009 05:31:20 -0700, dent wrote:
I've seen a few hire shops can supply wall cutters (basically
a plunge saw with a diamond blade), but these only go to about 50mm
depth. Is there a tool specifically for this type of job?

I saw a wall cutter once on TV - walls were a good 2ft thick. Crew had to
make their own rig to support it and guide it, then attach it to the wall
with some serious concrete anchors. They do exist, but possibly outside
the realm of hire shops :-)

re. angle grinder, can you access both sides of the wall? If so, drill a
couple of guide holes so you can line everything up and then attack from
both sides (and maybe source/hire a scaffold platform - or at least make
sure your ladder's secure; maybe anchor it to the wall and patch up
afterwards?)

Unfortunately not. It's a cavity wall, and I only need to put the slit
through the outer cavity.

thanks,

dan.

Best tool to cut a slit in a wall?
 

On 21 Sep, 13:31, dent wrote:
Hi all,

I need to cut a vertical slit at least 4mm wide through a 100mm wall,
and up to a height of 3m from the ground (for a vertical DPC where a
new extension joins a house). What is the best tool for the job? I
have got a 230mm angle grinder, but that would only go to about 75mm
depth, and is a beast to use anyway (i.e., I'd rather not use it up a
ladder). I've seen a few hire shops can supply wall cutters (basically
a plunge saw with a diamond blade), but these only go to about 50mm
depth. Is there a tool specifically for this type of job?

thanks,

dan.

Diamond chainsaw. They are great fun, but it might be hard to avoid
the temptation to saw the rest of your house into small pieces. They
can be hired, but they are a little hard to find (the place I used was
just about to stop doing them, so I can't recommend anywhere).

Best tool to cut a slit in a wall?
 

On 21 Sep, 15:43, Bolted wrote:

Diamond chainsaw.

Diamond wiresaw, surely? I though diamonds didn't like chains as
there was too much shock loading. Even then, those are usually kept
for concrete with hard aggregates as brickwork will succumb to a far
cheap wheel.

I sometimes use a chain morticer with a carbide chain that costs an
indecent amount. I imagine these make even that look cheap.

Best tool to cut a slit in a wall?
 

On 21 Sep, 16:25, Andy Dingley wrote:
On 21 Sep, 15:43, Bolted wrote:

Diamond chainsaw.

Diamond wiresaw, surely? *I though diamonds didn't like chains as
there was too much shock loading. Even then, those are usually kept
for concrete with hard aggregates as brickwork will succumb to a far
cheap wheel.

Wire-saws need access from both sides, I think.

I said (and meant) chainsaw. The one I hired was an ICS 14 inch
petrol one but they do some truly impressive looking hydraulic ones
too http://www.redbanduk.co.uk/ICS-CONCR...NGE/C9-1-0.htm.

I was cutting concrete (extension with a raft foundation with walls
sitting on a cast concrete upstand to DPM level, builder cocked up and
set the gap in the upstand 300mm too narrow).

Much easier to control than a big disk cutter, especially if not
cutting along the ground.

I sometimes use a chain morticer with a carbide chain that costs an
indecent amount. I imagine these make even that look cheap.

I think they are around the £150 mark for a new chain. Chain wear was
a significant proportion of the total hire charge for me.