On Jan 20, 9:26*pm, "Roger R"
wrote:
The illustration of a back boiler installation shows that is not
acting as structural support for any of the chimney brickwork.

From my mother's 1950s (ok 1947-1951) the chimneys are all U-shaped
self-supporting (and supporting joists of rooms above with walls &
ceilings additionally). Lintel may be angle iron, but I suspect it may
be concrete. Very small windows (a foot) use what looks like cast in
place concrete 8in high, larger windows use a smooth grey cement
lintel equally oversized into the room & span, both on slate
padstones. Note however the mortar may be utter crap so beware
cracking particularly if the lintel is above the fireplace opening
which is not unusual (big open fire reduced for gas fire either by
builder or later on).

Is that what I'm likely to find in this 1950's house enabling the boiler to
be taken out without risk of some of the chimney liner brickwork coming
down, or at least needing support ?

People here are referring to cast-iron backboiler, if yours merely
heats the HW tank you may find it is a simple box made of copper. I
assume copper going by the green verdigras all over it.

Drilling a big hole in the top of the front face and tubing very fine
sand in should be effective. When it has water in the temperature and
thus thermal expansion distance is limited. Without water the
temperature can become grossly elevated and thus thermal expansion
distance is much less limited - it could exert significant forces. By
filling it with sand you restrict the temperature it can heat to, thus
limit its thermal expansion distance - and provide a degree of heat
storage.

Sand filling matches the temperature, and better matches the thermal
expansion, of the surrounding brickwork.

If you find blue tiles they are a refractory lining and quite common
in that period. Coal is pretty nasty (acidic) and 1950s mortar pretty
crap really even without coal's onslaught. Wood was often burnt with
chimney fires treated with wild abandon as first attempts at central
heating. Watch out for gas poker taps hidden behind kitchen units,
they are invariably still live :-) I am also dubious that some gas
fires are supplied by what were originally pipes sized for gas pokers
and due to distance combined with small bore have historically been
"passed over" re pressure drop limits :-)

With backboilers of that era you will probably find the pipes into the
chimney are not well sealed - they should be sealed with fire cement
but rarely are, it's often polyfilla collecting together various
previous cracked attempts into a wallpaperable but non-sealed ensemble.