"BigWallop" wrote in message
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"Tony Bryer" wrote in message
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In article ,
BigWallop wrote:
Leaving a gap between the lintel and the masonry will mean the
bricks are not supported properly and will drop onto the lintel.
Dropping bricks, even by a slight amount, is not what you want.
The lintel is put there to hold the bricks in one place so
should actually be resting on the lintel with nothing between
them.

I'd prefer to see a gap of 15-25mm between the top of the lintel
and wall over which is then dry-packed: 1:1 cement and sand with
just enough water to hold it together when you squeeze it. This
needs to be rammed into the gap with a suitable piece of wood and
hammer.


And if the mortar crumbles ? Down comes the lot above it. No Thanks.

BW, dry packing as Tony describes really is the proper way to do things. Any
structural engineer would recommend it. It is also the method used for packing
between old foundations and new underpinning. The big benefit is it that the
mortar moulds itself to the bottom surface of the brickwork above, giving a
solid overall bearing, rather than bearing on just a few high spots.

The mix has to be strong (I would say 1 cement to 2 sharp sand by volume), and
fairly dry - just wet enough to give proper hydration of the cement. This would
form a cohesive ball in your hand if you squeezed it. And you must kill any
suction from the brickwork by wetting it first. The props should be left in
position for at least 3 days, a week is better. If you have experienced
crumbling mortar then something was obviously wrong.

Peter