Richard Conway wrote:

I was originally thinking of some sort of angle-iron support, but how
about instead using two or three 4x2" vertical battens secured to the
wall (would plugs and screws be sufficient or would I need some kind of
rawlbolt type things?) and then a horizontal piece across the top.

If you make the uprights long enough then you can spread the load...

Some of it will be taken in shear on the screws (very strong), and some
will be in tension on them - not as strong, but still good for 25kg at
least per fixing. So I would be tempted to go for:

(side view))

#
# | |
# | Tank |
# | |
# | |
############### - plinth
# //
# //
# // - bracing
#//
# - batten fixed to wall in four places
#


That sort of arrangemment should mean most of the load is carried in
shear on the screws, with not too much attempting to pull them from the
wall.

The higher you stick it up the wall, the more head and the better the
shower performance. (I would keep at least a couple of courses down from
the top of the gable however - since there is no load above the bricks
they can be quite weak)

--
Cheers,

John.

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