RichardS wrote:
"RichardS" wrote in message
...
"Christian McArdle" wrote in message
. net...
Does anyone see any fault with this plan, and do I need to install any
additional vents (if so, how - I really don't fancy climbing on the
roof)?
If there is plenty of soffit ventilation, I think you may just get away
with
it, although I suspect some BCOs might want to see ridge vents.
Shame you've got sarking, though! Without it, you could fully fill the
rafters and just put in breathable membrane next time the tiles/slates
need
changing.
hmm, I may have completely the wrong term for this - I can't see the
underside of tiles, there's a plastic membrane underneath them (& over all
the rafters) - the kind that is reinforced with an internal mesh.
There's no requirement for BCO involvement in this is there? It isn't a
loft conversion, just a boarded loft. Well, at the moment, but if it does
get converted that'll obviously require the whole Building Control
enchilada.
Actually, I've just had another thought.
I'd been wondering how I would hold the insulation between the rafters.
Cut it a mill oversize, wedge or use nails, and cover the rafters and
the kingpsan with aluminium tape that the kingspan supplier will sell
you for this very purpose. Obnec bioarded it can't fall down anyway.
You may car3 to fill any small gapos with an acrylic style sealer as well.
It
strikes me that if I get another lot of kingspan/celotex of about 20mm
thickness (if the cost doesnt prove prohibitive), then I can install that
over the top of the rafters (well, on the underside - ie on the loft-space
side) and that would hold the between-rafter stuff in place. As well as
giving me a nice ledge near the apex that the top horizontal insulation can
sit on & a nice smooth internal finish to the whole loft. Are there any
vapour-condensation issues for cold roof rafters so-covered?
The kingspan is foil coated.
That'd also give me 40% extra insulation (there will only be space for 50mm
of insulation between the rafters - I've just measured it).
Do it.
I'm sure they won't be, but insulation products such as this damned well
ought to be VAT zero rated.
--
Richard Sampson
email me at
richard at olifant d-ot co do-t uk
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