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Andrew Mawson Andrew Mawson is offline
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Default Mortar setting time


"Tim Lamb" wrote in message
...
In message
,
Osprey writes
On 29 Oct, 11:19, Tim Lamb wrote:
I am lifting the roof on an old pig farrowing barn to accommodate

a
furniture restorer.

The roof is heavy but can be moved in one piece. So far I have

raised
one side on Acrows and intend to lay two courses of brick to gain

the
height needed.

What is a reasonable time to wait before heavily loading fresh
brickwork? I am particularly nervous of any side thrust

encountered as I
start to jack up the other side.

regards
--
Tim Lamb


I would leave it 48Hrs ... 24 Hrs is no problem if a simple daed

load,
but as you point out there is side thrust, and bricks not

particularly
strong in that direction.

use a good 3:1 mix and suitable bricks, deep frog frettons as a
minimum, laid frog up, and fully filled ... or engineering if you

have
them.


OK. The brickwork will be Flettons for the first course and
semi-engineering for the top. Basically because that is what I have
lying about the farm:-) I can easily wait 3 days as I also have to

fit a
wider door and re-plumb the electrical conduit.

regards
--
Tim Lamb


Tim,

Very temperature dependant: I've just laid 8 cu m of RC40 concrete and
it took two days in the current cold snap to 'not' take a finger
impression. Earlier in the year I laid a batch of the very same stuff
on a blazing hot day and we couldn't finish tamping before it set
solid (perhaps 1.5 hours from delivery)

Cement re-hydradtion (ie setting) is a chemical reaction and thus very
dependent on the temp. When it starts to go off though it is
exothermic - ie gives off heat.

AWEM