Timber framed workshop, 5m by 3m, framing is 3 x 2 studs with
weatherboarding. What should I use for insulation - I'm planning to
line the walls with OSB board, with a polythene membrane under it.
The insulation level does not need to be high as I've lived for years
quite happily in the old one which has some thin poystyrene slabs
stuck to the walls.

Thanks for suggestions

Rob

On 14 Nov, 10:41, robgraham wrote:
What should I use for insulation

Rockwool roll between the studs and damn the cold bridging at the
studs (only a workshop). You've enough depth there to be useful and
it's cheaper than yellow foam slabs.

Watch out for water ingress though, as damp rockwool is unpleasant. If
it's leaky outside, consider the yellow PIR foam anyway (although even
that's no guarantee against a sustained leaky roof). Alternatively go
for double water barriers both inside and out. This is tricky though,
as the outer barrier needs to be 4 or 5 times more breathable than the
inside one, either by choosing different membrane materials, or by
provided a ventilated airgap under the outside membrane.

OSB is a better choice on the inside than plasterboard, as you won't
knock holes in it. Won't be so fire resistant though, which might be
an issue for you.

Andy Dingley wrote:
On 14 Nov, 10:41, robgraham wrote:
What should I use for insulation

Rockwool roll between the studs and damn the cold bridging at the
studs (only a workshop). You've enough depth there to be useful and
it's cheaper than yellow foam slabs.


It's cheaper because it's not been treated with a water repellant.

Watch out for water ingress though, as damp rockwool is unpleasant. If
it's leaky outside, consider the yellow PIR foam anyway (although even
that's no guarantee against a sustained leaky roof). Alternatively go
for double water barriers both inside and out. This is tricky though,
as the outer barrier needs to be 4 or 5 times more breathable than the
inside one, either by choosing different membrane materials, or by
provided a ventilated airgap under the outside membrane.

To the OP: - if it were mine, I would use the fibreglass batts used in new
build projects - they meet all the standards required for new homes and they
are, as I've already said, water repellant - that is to say, they won't soak
up any water like normal loft insulation type fibreglass (or rockwool) will


OSB is a better choice on the inside than plasterboard, as you won't
knock holes in it. Won't be so fire resistant though, which might be
an issue for you.

--
Phil L
RSRL Tipster Of The Year 2008

robgraham wrote:
Timber framed workshop, 5m by 3m, framing is 3 x 2 studs with
weatherboarding. What should I use for insulation - I'm planning to
line the walls with OSB board, with a polythene membrane under it.
The insulation level does not need to be high as I've lived for years
quite happily in the old one which has some thin poystyrene slabs
stuck to the walls.

A job I have just been doing in mine. I went for the foil faced PIR foam
slabs (50mm) this time. A place near us does seconds at about £10 each
which works out about the same price as polystyrene.


--
Cheers,

John.

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On 15 Nov, 23:12, John Rumm wrote:
robgraham wrote:
Timber framed workshop, 5m by 3m, framing is 3 x 2 studs with
weatherboarding. *What should I use for insulation - I'm planning to
line the walls with OSB board, with a polythene membrane under it.
The insulation level does not need to be high as I've lived for years
quite happily in the old one which has some thin poystyrene slabs
stuck to the walls.

A job I have just been doing in mine. I went for the foil faced PIR foam
slabs (50mm) this time. A place near us does seconds at about £10 each
which works out about the same price as polystyrene.

--
Cheers,

John.

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| * * * *John Rumm - john(at)internode(dot)co(dot)uk * * * * * * *|
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And where, John, is "near you" ? So that I can take advantage of your
source.

I was thinking along the lines of polystyrene as I've got 40mm slabs
in my present workshop - I'm sure the PIR is better but does ordinary
polystyrene have any disadvantages ?

Rob

robgraham wrote:

And where, John, is "near you" ? So that I can take advantage of your
source.

APCO Wholesale in Benfleet Essex - just off the A13 between Saddlers
Farm roundabout and the bottom of Bread and Cheese hill.

I was thinking along the lines of polystyrene as I've got 40mm slabs
in my present workshop - I'm sure the PIR is better but does ordinary
polystyrene have any disadvantages ?

PIR is about twice as effective IIRC. Ordinary poly is ok, although you
ideally want a fire retardant treated one - Jabfloor or Jablite would
probably be fine.

--
Cheers,

John.

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| Internode Ltd - http://www.internode.co.uk |
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| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 16 Nov, 00:14, John Rumm wrote:
robgraham wrote:
And where, John, is "near you" ? *So that I can take advantage of your
source.

APCO Wholesale in Benfleet Essex - just off the A13 between Saddlers
Farm roundabout and the bottom of Bread and Cheese hill.

I was thinking along the lines of polystyrene as I've got 40mm slabs
in my present workshop - I'm sure the PIR is better but does ordinary
polystyrene have any disadvantages ?

PIR is about twice as effective IIRC. Ordinary poly is ok, although you
ideally want a fire retardant treated one - Jabfloor or Jablite would
probably be fine.

--
Cheers,

John.

/================================================== ===============\
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Thanks John - bit far from Edinburgh then !!

Not sure that in a wooden shed, and behind OSB board, fire retardancy
is going to make much difference.

Rob

robgraham wrote:

Thanks John - bit far from Edinburgh then !!

Erm, yup! Don't think they do mail order!

Not sure that in a wooden shed, and behind OSB board, fire retardancy
is going to make much difference.

Probably not... having said that, most products designed for building
with will probably be treated anyway.


--
Cheers,

John.

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| Internode Ltd - http://www.internode.co.uk |
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\================================================= ================/

On 15 Nov, 23:51, robgraham wrote:

A place near us does seconds at about £10 each
which works out about the same price as polystyrene.

And where, John, is "near you" ? *So that I can take advantage of your
source.

All over the place - it seems relatively common to find "seconds
outlets" for insulation boards. I'm nowhere near John (or Edinburgh),
but we've a local one too.

On the whole, I think Phil L might be right and the glasswool batts
being about the right compromise between loose rolls and rigid foam.