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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.