thinest external wall to meet building regs

[RobertL]

Can anyone suggest how to make the thinnest wall that will meet
building regulations (especially part L) for an external wall?

I am building a oen ground floor side extension along part of the
gable end of my terraced house, but the available plot is only 700mm
wide at its narrowest. I want to lose as little internal width as
possible.

any suggestions?

Robert

[Bob Minchin]

Presumably you can virtually do away with the inner skin if you have
arrange for all load bearing needs to be catered for about head height.
So from the inside. Plasterboard, vapour barrier/insulation in a metal
studding system, minimal damp gap cavity with the stud supported on the
exterior brickwork skin. Might get you to 200mm overall with skim coat?

Provide the length of this wall construction is kept to a couple metres
only then you should get away without piers.

Will poss be a job for an architect though I guess to prove to the BCO
that all requirements are met.

Bob

[Owain]

On Sep 10, 10:28 am, RobertL wrote:
> Can anyone suggest how to make the thinnest wall that will meet
> building regulations (especially part L) for an external wall?

You can use a double glazed window wall system, similar to that used
for shop fronts, if you can support the roof above (cantilever slab?)
and use compensatory insulation elsewhere to meet Part L. Should get
you down to about 100mm for the framework and the thickness of the
glass for the infill. Glass can be frosted/etched for privacy.

Owain

[js.b1]

Render over Expermet (metal mesh) attached to Knauf cement panel,
celotex on inside.

I think it is Knauf cement panel, there are many, they come in planks
for cladding to sheets. The only note is they are very heavy,
something like 1.2 tons per metre-cubed. I think insulation-direct or
somewhere similar has several of them, they range from about £25 per
sheet up to something ridiculous if you go for very fancy advanced
materials.

I recall there are 2 figures for BR, #1 is the overall figure, #2 is
the minimum figure. You just need to meet the minimum figure with a
little extra elsewhere to compensate.

Any architect should be able to solve this one off the top of their
head. Glass is the other suggestion, and a floor to ceiling window is
quite attractive if that area inside can be used as a play area for
children to sit and watch the rain outside.

[Lee Nowell]

I seem to remember that when I had a similar issue, working with BC,
we agreed on...

100mm stud wall filled with Cellotex
Insulated plasterboard on the inside (25mm)

I guess overall thickness would then depend on your prefered exterior
finish. We did 18mm ply then EML and render so probably around 150/
160mm in total.

[harry]

Studding with external skin planks of feather edge boarding on vapour
permeable roofing felt. (Timber or suchlike.)
Between the studding ridgid insulation board.
Inner skin, vapour barrier & foil backed plasterboard.
Studding would probably need to be 150mm to meet insulation
requirements.

[Tabby]

Vacuum insulation panels have by far the greatest insualtion per inch,
so might be of interest. They don't come cheap though.

NT

[The Natural Philosopher]

Con the bco by making that part a double glazed window.

[Paul R]

I am working on the same problem. My verbal discussions with BCO (not
been on site) suggest that I can use plasterboard, vapour barrier, 120mm
stud (with 100mm Celotex or equivalent infill)external board, breather
membrane and am planning to use Delta-PT membrane with screed to finish.

I await to hear other suggestions.

Paul R

[Martin Bonner]

On Sep 10, 10:28 am, RobertL <robertml...@yahoo.com> wrote:

You might be able to make things thinner with aerogel insulation
rather than Celotex. http://thermablok.co.uk/Thermablokintro.php
suggests you only need half the thickness.

Of course, you probably need to budget for twice the bank balance ...