In message
,
Andy Dingley writes
From a recent thread on rendering:

On 16 Nov, 09:30, Tim Lamb wrote:

When the farmhouse was *done up*, the exterior was re-rendered over 25mm
of insulation.

I'm facing a bunch of this for refurbs over the next couple of years.
The main house isn't going to be changed, but I've thin-walled
extensions to the rear (pantry etc.) and various sheds that are
certainly candidates for adding wall insulation. The rendering,
particularly one shed, isn't impressive at present anyway.

So what are my pros and cons for adding insulation to either the
inside or outside of the wall?

Having paid the gas bills for the last 13 years, I don't think 25mm was
anywhere near enough!

The technique used was to sand/water blast off the exterior water proof
paint, secure 25mm Kingspan at 18" centres with vertical battens and
re-cover with feather edge boarding (upper part). The lower part was
similar except sheets of galvanised expanded metal were nailed to the
battens and then rendered.

I don't know where/if a vapour barrier was installed.

The nice thing from your POV is that external render over insulation
will give you a drip well clear of the bricks.

regards
--
Tim Lamb