In message , John
Rumm writes
On 02/09/2019 16:45, sm_jamieson wrote:
On Monday, September 2, 2019 at 3:05:28 PM UTC+1, Jim GM4DHJ ...
wrote:
Why can't they just move gas supply pipes in external insulation
projects rather than just boxing them in vented ducts...looks
pathetic and cheap...even seen them do it with rainwater
downpipes.....
Has anyone DIY'ed external insulation ? The cost was far too high
when I got a quote.

I have dabbled with the numbers and looked at some options for cladding.
I was considering battening over the insulation, then weather boarding
in either real wood, or a modern composite cement fibre board. I found
that the insulation itself can be quite cheap, and even the cladding not
too bad, but its often the sundry extras that add up; such as all the
trim parts for corners and window reveals.

The farmhouse was *externally* insulated here in 1995. The original
construction was largely 4" timber frame with nice pargetted render on
expanded metal. Probably itself a replacement for tarred board.
25mm PIR foam was inserted between treated vertical battens and then
painted sawn feather edge on top. The lower section has the same system
but with metal lath rendered over. Window reveals and corners emphasised
with slightly projecting board.
I expect current building regs. will require more than 25mm foam.

Drawbacks to cheap treated feather edge... you must paint both sides
before fitting otherwise it will curl also some knots will fall out.

They always say the thin coat / resin render is a specialist
treatment. I was looking for some DIY cladding system to do my gable
wall, which has no windows at all (it faces an entry) - a system that
was approved for building regs of course. I did not find anything -
was a few years ago.

ISTR the main requirement for building regs when making a substantial
change to a thermal element was to achieve a certain U value, which was
not particularly onerous.



--
Tim Lamb