Hi,

I'm about to create a new window opening with a 900mm lintel into a
cavity wall.

Rather than start banging away I'm looking to use the 10mm mortar rake
bits from screwfix attached to a grinder to remove the top layer of
bricks and install the lintel first.

To make the cuts on the internal wall I'm going to use a 9 inch grinder
with diamond blade.

For the exterior brick work I'm looking to make it good by cutting half
bricks and mortaring them in the alternate courses.
That's presuming the the mortar comes cleanly off the full length
bricks and the courses are pretty regimental in the first place. An
alternative was to cut with a bricksaw and make good with a render coat
but not sure how to finish the render coat neatly around the opening
without some kind of frame..

Anyone got any other suggestions or advice I should take on board?

wrote:
Hi,

I'm about to create a new window opening with a 900mm lintel into a
cavity wall.

Rather than start banging away I'm looking to use the 10mm mortar rake
bits from screwfix attached to a grinder to remove the top layer of
bricks and install the lintel first.

To make the cuts on the internal wall I'm going to use a 9 inch grinder
with diamond blade.

For the exterior brick work I'm looking to make it good by cutting half
bricks and mortaring them in the alternate courses.
That's presuming the the mortar comes cleanly off the full length
bricks and the courses are pretty regimental in the first place. An
alternative was to cut with a bricksaw and make good with a render coat
but not sure how to finish the render coat neatly around the opening
without some kind of frame..

Anyone got any other suggestions or advice I should take on board?

I really am no expert here (Caveat DIYer)...

Why remove the single course of bricks first? Sure you'll have a nice
lintel shape aperture if it does /not/ collapse. But even a single
course removed will mean its unsupported above - may as well take the
whole lot out. You could support the above courses with a strong boy or
two to avoid collapse either way. Or let the bricks loose and rebuild
later.

For a lintel of 900mm won't you need to take more than one course out
and put some padstones on?

As for the mortar rake, why not just cut out a line in the mortar with
the grinder (less dust as the blade is thinner) or a stone cutter. Clean
the remaining mortar off with a bolster etc.

Why not use a petrol powered stone cutter/"stihl" saw to cut either side
and then bang bricks out with a club hammer as they will no longer be
attached ... feeding water onto the blade will reduce the dust and these
are much better for this sort of thing, IMO.

I seem to remember the new windows in our house (18" thick random stone)
walls being cut this way.

HTH,

Alex.

In article , "AlexW"
says...
wrote:
Hi,

I'm about to create a new window opening with a 900mm lintel into a
cavity wall.

Rather than start banging away I'm looking to use the 10mm mortar rake
bits from screwfix attached to a grinder to remove the top layer of
bricks and install the lintel first.

To make the cuts on the internal wall I'm going to use a 9 inch grinder
with diamond blade.

For the exterior brick work I'm looking to make it good by cutting half
bricks and mortaring them in the alternate courses.
That's presuming the the mortar comes cleanly off the full length
bricks and the courses are pretty regimental in the first place. An
alternative was to cut with a bricksaw and make good with a render coat
but not sure how to finish the render coat neatly around the opening
without some kind of frame..

Anyone got any other suggestions or advice I should take on board?

I really am no expert here (Caveat DIYer)...

Why remove the single course of bricks first? Sure you'll have a nice
lintel shape aperture if it does /not/ collapse. But even a single
course removed will mean its unsupported above - may as well take the
whole lot out.

But with only one course out it won't collapse very far :-)

AlexW wrote:

I really am no expert here (Caveat DIYer)...

Why remove the single course of bricks first? Sure you'll have a nice
lintel shape aperture if it does /not/ collapse. But even a single
course removed will mean its unsupported above - may as well take the
whole lot out. You could support the above courses with a strong boy or
two to avoid collapse either way. Or let the bricks loose and rebuild
later.

For a lintel of 900mm won't you need to take more than one course out
and put some padstones on?

Yes, I will need to take out more than one course, I know that, I
didn't word it very well. My main reason for using the mortar rake is
because I want to preserve as many good bricks as possible to make good
the sides and this seems necessary because the opening isn't
particularly large so I won't have that many left over. Plus it's less
likely to disturb the course above the lintel and save a bit of work.
I'll only take out as much as I need to install the lintel just to save
me having to secure a larger hole if I can't fix the window straight
away, that's all. I'm a DIY'er - we take our time ;-).


As for the mortar rake, why not just cut out a line in the mortar with
the grinder (less dust as the blade is thinner) or a stone cutter. Clean
the remaining mortar off with a bolster etc.

I was thinking of that but thought the depth may be limited on a
grinder and these mortar rakes may be more efficient and more
controllable.

Why not use a petrol powered stone cutter/"stihl" saw to cut either side
and then bang bricks out with a club hammer as they will no longer be
attached ... feeding water onto the blade will reduce the dust and these
are much better for this sort of thing, IMO.

That's still an option but I'm pretty sure the bricks are not going to
knock out that easily. It's quite a new house and the mortar is strong.

Another point is, do I need to place a DPC above the cavity lintel?
Some sites advise you need to, others don't even mention it. As it's
only 900mm I thought I might be able to get away with it.

Thanks for your input.

If you are living in the house when you do it, you will regret 'til the
day you die that you used a diamond disc indoors to cut through
brickwork! Any dust found by your wife in the next 10 years will be
your fault, all your friends will be told, in detail, about the amount
of dust you made,and your children and your children's children will
annually be told the story of the day when Daddy cut through the wall.
DAMHIKT.

wrote:

AlexW wrote:


I really am no expert here (Caveat DIYer)...

Why remove the single course of bricks first? Sure you'll have a nice
lintel shape aperture if it does /not/ collapse. But even a single
course removed will mean its unsupported above - may as well take the
whole lot out. You could support the above courses with a strong boy or
two to avoid collapse either way. Or let the bricks loose and rebuild
later.

For a lintel of 900mm won't you need to take more than one course out
and put some padstones on?


Yes, I will need to take out more than one course, I know that, I
didn't word it very well. My main reason for using the mortar rake is
because I want to preserve as many good bricks as possible to make good
the sides and this seems necessary because the opening isn't
particularly large so I won't have that many left over. Plus it's less
likely to disturb the course above the lintel and save a bit of work.
I'll only take out as much as I need to install the lintel just to save
me having to secure a larger hole if I can't fix the window straight
away, that's all. I'm a DIY'er - we take our time ;-).


I would have thought that with any approach there would be plenty of
bricks to clean up and make good the sides etc, even having used quite a
bit of welly with a club hammer to extract. The bricks will probably
come out in 'clumps' which can be split down and cleaned on the floor.

Also, sure knocking the mortar off from below may bring some of the
bricks in the course (to be) above the lintel off but they can go back
on once cleaned - you've got a mix on to make good the sides right? Or
if they are intact once the horizontal upper cut is made with say the
grinder, you could just grind the mortar off carefully so none is
visible at the front face.


As for the mortar rake, why not just cut out a line in the mortar with
the grinder (less dust as the blade is thinner) or a stone cutter. Clean
the remaining mortar off with a bolster etc.


I was thinking of that but thought the depth may be limited on a
grinder and these mortar rakes may be more efficient and more
controllable.

IIRC the mortar rakes I have seen are only a couple of inches long and
8-10mm thick, I can't see how they would cut any deeper than your 9"
diamond grinder blade.

I, perhaps wrongly, have always thought that the application for these
tools was raking out before re-pointing. I can't see them being more
efficient than a diamond blade for deep cutting applications or even
controllable as you would be basically using a hand mortar milling
machine with a long bit.

Never tried a mortar rake so maybe I am talking rubbish here!



Why not use a petrol powered stone cutter/"stihl" saw to cut either side
and then bang bricks out with a club hammer as they will no longer be
attached ... feeding water onto the blade will reduce the dust and these
are much better for this sort of thing, IMO.


That's still an option but I'm pretty sure the bricks are not going to
knock out that easily. It's quite a new house and the mortar is strong.

If you hit 'em hard enough they will come out ;-)


Another point is, do I need to place a DPC above the cavity lintel?
Some sites advise you need to, others don't even mention it. As it's
only 900mm I thought I might be able to get away with it.

Don't know about this, sorry. I have seen buildingswith DPC's above the
lintels, mainly stone IIRC, although I can't remember the exact
circumstances.

If by cavity lintel you mean the galvanised hat profile __|\__ type then
the galavanised steel is water impermeable anyway so putting an DPC on
the outer leaf does not make any sense to me ... but I'm just a punter
and am just guessing!

HTH,

Alex.


Thanks for your input.

AlexW wrote:
wrote:
Hi,

I'm about to create a new window opening with a 900mm lintel into a
cavity wall.

Rather than start banging away I'm looking to use the 10mm mortar
rake bits from screwfix attached to a grinder to remove the top
layer of bricks and install the lintel first.

To make the cuts on the internal wall I'm going to use a 9 inch
grinder with diamond blade.

For the exterior brick work I'm looking to make it good by cutting
half bricks and mortaring them in the alternate courses.
That's presuming the the mortar comes cleanly off the full length
bricks and the courses are pretty regimental in the first place. An
alternative was to cut with a bricksaw and make good with a render
coat but not sure how to finish the render coat neatly around the
opening without some kind of frame..

Anyone got any other suggestions or advice I should take on board?

I really am no expert here (Caveat DIYer)...

Very ditto for me..


Why remove the single course of bricks first? Sure you'll have a nice
lintel shape aperture if it does /not/ collapse. But even a single
course removed will mean its unsupported above - may as well take the
whole lot out. You could support the above courses with a strong boy
or two to avoid collapse either way. Or let the bricks loose and
rebuild later.

That row of bricks are only effectively supporting a triangle of bricks
above them. I would remove a single row (and others below if they want to
come too..) and get the lintel in, to minimise the time they are unsupported
for. Especially since the rest of the opening will be being bludgeoned about
and the shocks could loosen the mortar.

For a lintel of 900mm won't you need to take more than one course out
and put some padstones on?

As for the mortar rake, why not just cut out a line in the mortar with
the grinder (less dust as the blade is thinner) or a stone cutter.
Clean the remaining mortar off with a bolster etc.

'less' being very loose here. I'd use a grinder. Either way will make more
dust than you have ever seen...

Does the mortar rake reach right through? I thought it was only a couple of
inches, meant to get it ready for repointing...

Why not use a petrol powered stone cutter/"stihl" saw to cut either
side and then bang bricks out with a club hammer as they will no
longer be attached ... feeding water onto the blade will reduce the
dust and these are much better for this sort of thing, IMO.

I seem to remember the new windows in our house (18" thick random
stone) walls being cut this way.

The problem doing this with bricks is that they aren't solid all the way
through, so you'd end up with voids and holes. Sadly you do have to take out
the full bricks and replace them with halves, with all the attendant mortar
matching etc.

Good luck!

PC Paul wrote:
AlexW wrote:

wrote:

Hi,

I'm about to create a new window opening with a 900mm lintel into a
cavity wall.

Rather than start banging away I'm looking to use the 10mm mortar
rake bits from screwfix attached to a grinder to remove the top
layer of bricks and install the lintel first.

To make the cuts on the internal wall I'm going to use a 9 inch
grinder with diamond blade.

For the exterior brick work I'm looking to make it good by cutting
half bricks and mortaring them in the alternate courses.
That's presuming the the mortar comes cleanly off the full length
bricks and the courses are pretty regimental in the first place. An
alternative was to cut with a bricksaw and make good with a render
coat but not sure how to finish the render coat neatly around the
opening without some kind of frame..

Anyone got any other suggestions or advice I should take on board?


I really am no expert here (Caveat DIYer)...


Very ditto for me..


Why remove the single course of bricks first? Sure you'll have a nice
lintel shape aperture if it does /not/ collapse. But even a single
course removed will mean its unsupported above - may as well take the
whole lot out. You could support the above courses with a strong boy
or two to avoid collapse either way. Or let the bricks loose and
rebuild later.


That row of bricks are only effectively supporting a triangle of bricks
above them. I would remove a single row (and others below if they want to
come too..) and get the lintel in, to minimise the time they are unsupported
for. Especially since the rest of the opening will be being bludgeoned about
and the shocks could loosen the mortar.

If lucky the above bricks might not come down, if they corbell well.

You have essentially cut the mortar above and at the sides, I would have
thought that very little shock will be transmitted to the courses above
I think, nor will it take long to get the bricks out. No harm in doing
it this way though.



For a lintel of 900mm won't you need to take more than one course out
and put some padstones on?

As for the mortar rake, why not just cut out a line in the mortar with
the grinder (less dust as the blade is thinner) or a stone cutter.
Clean the remaining mortar off with a bolster etc.


'less' being very loose here. I'd use a grinder. Either way will make more
dust than you have ever seen...

Indeed and if its red brick then you might end up with permanent stains
on things like carpet etc.


Does the mortar rake reach right through? I thought it was only a couple of
inches, meant to get it ready for repointing...


Why not use a petrol powered stone cutter/"stihl" saw to cut either
side and then bang bricks out with a club hammer as they will no
longer be attached ... feeding water onto the blade will reduce the
dust and these are much better for this sort of thing, IMO.

I seem to remember the new windows in our house (18" thick random
stone) walls being cut this way.


The problem doing this with bricks is that they aren't solid all the way
through, so you'd end up with voids and holes. Sadly you do have to take out
the full bricks and replace them with halves, with all the attendant mortar
matching etc.

Depends on the brick, I think, even modern ones. Trimmed up a door
opening (single brick) this way ... no holes in mine!

I think from the OP that the OP was replacing alternate half brick
alternate courses, so I was assuming he would be slicing down a mortar
joint on alternat courses to acheive this. If this is the case the cut
half bricks will be easier to remove than just taking is out brick by
brick from below the lintel.


Good luck!



Yes this sounds like a bit of fun anyway.

Mr Fuxit wrote:
If you are living in the house when you do it, you will regret 'til the
day you die that you used a diamond disc indoors to cut through
brickwork! Any dust found by your wife in the next 10 years will be
your fault, all your friends will be told, in detail, about the amount
of dust you made,and your children and your children's children will
annually be told the story of the day when Daddy cut through the wall.
DAMHIKT.

The house is empty so no problems there.

Thanks to all for your input. I'll let you know how it goes.

Okay, just to update.

Got the opening sorted, lintel installed and all re-bricked in 2 days.
I ended up just drilling the mortar to get the first few bricks out and
then took the rest out.

Everything went fine and the two courses just below the prop all stayed
put. The biggest problem I had was working a straight level edge with
the course of bricks. The brickie used to build this house was either
crap or a real lazy barsteward as all the full bricks were totally out
of line and the pointing thicknesses varied like hell, so I had to take
more than just the half bricks out to get it sorted. But it's all good
now!