Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?
--
Tim Lamb

On 12/04/17 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

I went to a firm of heating engineers who charged me a bit to prepare a
report that said that yes, I could meet standards with single glazing by
stuffing more rockwool and or celotex everywhere.


--
To ban Christmas, simply give turkeys the vote.

On 12/04/2017 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

Do Rockwool given any number for a different thickness?

Could you extrapolate accordingly?

On 12/04/2017 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

http://wiki.diyfaq.org.uk/index.php/Heat_loss

Any use?

--
Cheers,

John.

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

In message , Fredxxx
writes
On 12/04/2017 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

Do Rockwool given any number for a different thickness?

Could you extrapolate accordingly?

Probably. If I didn't find mathematics challenging:-)

--
Tim Lamb

In message , John
Rumm writes
On 12/04/2017 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

http://wiki.diyfaq.org.uk/index.php/Heat_loss

Any use?

Umm.. As TNP says, for the time spent, it might be better to use a
commercial site.

I am mixing PIR foam with Rockwool which complicates things. As Tim
Watts knows, attic dormers have lots of extraneous timber and hard to
reach corners over soffits.

I don't think this construction and *airtight* go together unless the
builder is onside from the outset.

I'll have a closer look over the weekend.

Current job is stapling up plastic sheet for vapour barrier.


--
Tim Lamb

In message , The Natural Philosopher
writes
On 12/04/17 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

I went to a firm of heating engineers who charged me a bit to prepare a
report that said that yes, I could meet standards with single glazing
by stuffing more rockwool and or celotex everywhere.

We have fitted current standard double glazed Argon filled units
throughout.

One trick for the Wiki.. use a sheet of Perspex or polycarbonate to mark
out shapes for cutting foam to fit angled/non parallel bits of studwork.
Felt tip pen and then rub off the marks for the next sheet.



--
Tim Lamb

On 12/04/17 23:25, John Rumm wrote:
On 12/04/2017 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

http://wiki.diyfaq.org.uk/index.php/Heat_loss

Any use?

Building inspectors wan to see a proper report that covers their arses
signed by someone who appears to be an expert.

The truth is not enough.


--
€œIt is hard to imagine a more stupid decision or more dangerous way of
making decisions than by putting those decisions in the hands of people
who pay no price for being wrong.€�

Thomas Sowell

The Natural Philosopher wrote:

Building inspectors wan to see a proper report that covers their arses
signed by someone who[...]

.... has got indemnity insurance.

On 13/04/17 08:48, Andy Burns wrote:
The Natural Philosopher wrote:

Building inspectors wan to see a proper report that covers their arses
signed by someone who[...]

.... has got indemnity insurance.

LOL!

That made me chuckle...


--
Future generations will wonder in bemused amazement that the early
twenty-first centurys developed world went into hysterical panic over a
globally average temperature increase of a few tenths of a degree, and,
on the basis of gross exaggerations of highly uncertain computer
projections combined into implausible chains of inference, proceeded to
contemplate a rollback of the industrial age.

Richard Lindzen

On 12/04/17 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

U-Value calcs are pretty simple. Do you want to do them yourself? In
which case much help will be forthcoming here (from me for a start as
I've done a lot - the only thing I cannot do is floors, but that sounds
like it's not a problem for you).

Rule of thumb based on my experience:

I "got away" with the BCO approving 100mm celotex on my roof, with 75mm
around the periphery where 100mm was not practical - but that was an
exiting dormer conversion and I was upgrading the insulation from the
75mm wool that used to be there, so my insulation is now twice as good
as before plus I have no draughts.

However, for a new dormer, they will want it to be upto current
standards. Without checking, I suspect that's more like 125-150mm
celotex or equivalent - BUT they will usually accept less if you can
upgrade other parts of the building.

Do you have any guidance as to what your BCO wants?

Tim Watts wrote:

I "got away" with the BCO approving 100mm celotex on my roof, with 75mm
around the periphery where 100mm was not practical - but that was an
exiting dormer conversion

Wonder if they'll start insisting on VIP instead of PIR for dormers and
other places where there's not much space available, rather than letting
you get away with it?

On 13/04/2017 08:45, The Natural Philosopher wrote:
On 12/04/17 23:25, John Rumm wrote:
On 12/04/2017 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

http://wiki.diyfaq.org.uk/index.php/Heat_loss

Any use?

Building inspectors wan to see a proper report that covers their arses
signed by someone who appears to be an expert.

The truth is not enough.

It seems to depend greatly on the BCO. I found the one I have had a
couple of times was quite content to take your word for it, once he felt
comfortable that you knew what you were doing. Although you may recall
tales of Mr B, the BCO and the cooker circuit which went completely the
other way.


--
Cheers,

John.

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

The Natural Philosopher wrote:
On 12/04/17 23:25, John Rumm wrote:
On 12/04/2017 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

http://wiki.diyfaq.org.uk/index.php/Heat_loss

Any use?

Building inspectors wan to see a proper report that covers their arses
signed by someone who appears to be an expert.

The truth is not enough.



Find someone with a civil engineering degree to sign off your
calculation. He/she doesn't have to have any real experience!

On 13/04/2017 08:22, Tim Lamb wrote:
In message , Fredxxx writes
On 12/04/2017 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

Do Rockwool given any number for a different thickness?

Could you extrapolate accordingly?

Probably. If I didn't find mathematics challenging:-)

That bit is actually quite easy. What you need is the "k" value - this
is a measure of the intrinsic heat conducting property of the material
itself, per watt and a standardised thickness. The U value is simply the
K value divided by the depth.

So say you have a spec for the material that says its U value is 0.4,
and its 100mm thick, that tells you that :

0.4 = K / 0.1

So you can work out that K must be 0.04

Once you have that for your chosen insulation material, you simply
divide that by the new thickness to get the revised U value.

So for the above material, the U value of 125mm thickness would be

0.04 / 0.125 = 0.32



--
Cheers,

John.

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

On Wed, 12 Apr 2017 21:07:09 +0100, Tim Lamb
wrote:

Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

Celotex for one have a free online calculator on their site where you can
select various wall/roof/floor options with varying construction types either
for new build or retrofit with options for joist/rafter spacing and various
brick/block manufacturers.

The end result is a pdf with the specifications and all the calculations,
unfortunately it can't accommodate existing insulation from other manufacturers
but you'd probably be ripping that out in any major refurb.

https://www.celotex.co.uk/member/u-value-calc

They also have whole raft of application datasheets

There should be no reason why you couldn't substitute your 150mm of Rockwool for
an equvalent (lower) thickness of PIR in the calcs and end up with a usable
result. Cut and paste and then edit the pdf for something buiilding control
would accept.

--

On 12/04/17 23:12, Fredxxx wrote:
On 12/04/2017 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

Do Rockwool given any number for a different thickness?

Could you extrapolate accordingly?

You can extrapolate.

U-Value of 1 means (in SI) 1 watt is passed for a section 1m2 in area,
1m thick with a temperature differential of 1 kelvin.

Double the area, double the power. Double the temperature differential,
double the power.

Now, for thickness variances: this is a little harder - like putting
resistors in parallel - it's a reciprocal formula, because U-values are
a measure of thermal *conductivity" (the reciprocal of resistivity which
is the more usual physics unit of thermal property).

1/U-value = R-value = thermal resistivity.

R-Values are additive for additional thicknesses, even of dissimilar
materials.

So if you switch to R-values, you can multiply the quoted R value
according to the thickness.

eg if they quote for 100mm rockwool, and you need 150mm, you can
multiply by 1.5.


You can further add the R-values for other layers, such as the 9.5mm
plasterboard facing and so on.


There's a trick for dealing with parallel paths too (eg rafters bridging
the insulation) - but I'll save that for now.

If you want to break your

On 13/04/17 10:01, Andy Burns wrote:
Tim Watts wrote:

I "got away" with the BCO approving 100mm celotex on my roof, with 75mm
around the periphery where 100mm was not practical - but that was an
exiting dormer conversion

Wonder if they'll start insisting on VIP instead of PIR for dormers and
other places where there's not much space available, rather than letting
you get away with it?



If that is a practical material, then probably - in the same way
stuffing 4" of wool in where there used to be 3" is both a bit pointless
and the BCO would probably not have agreed it.

Have you got any links to VIP pricing?

On 13/04/17 10:57, Tim Watts wrote:
On 12/04/17 23:12, Fredxxx wrote:
On 12/04/2017 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

Do Rockwool given any number for a different thickness?

Could you extrapolate accordingly?

You can extrapolate.

U-Value of 1 means (in SI) 1 watt is passed for a section 1m2 in area,
**1m thick** with a temperature differential of 1 kelvin.

Sorry ^^^ should read "of the quoted thickness" (eg 50mm or 100mm).

I was mentally jumping towards K-values.




Double the area, double the power. Double the temperature differential,
double the power.

Now, for thickness variances: this is a little harder - like putting
resistors in parallel - it's a reciprocal formula, because U-values are
a measure of thermal *conductivity" (the reciprocal of resistivity which
is the more usual physics unit of thermal property).

1/U-value = R-value = thermal resistivity.

R-Values are additive for additional thicknesses, even of dissimilar
materials.

So if you switch to R-values, you can multiply the quoted R value
according to the thickness.

eg if they quote for 100mm rockwool, and you need 150mm, you can
multiply by 1.5.


You can further add the R-values for other layers, such as the 9.5mm
plasterboard facing and so on.


There's a trick for dealing with parallel paths too (eg rafters bridging
the insulation) - but I'll save that for now.

If you want to break your

On 13/04/2017 10:01, Andy Burns wrote:
Tim Watts wrote:

I "got away" with the BCO approving 100mm celotex on my roof, with 75mm
around the periphery where 100mm was not practical - but that was an
exiting dormer conversion

Wonder if they'll start insisting on VIP instead of PIR for dormers and
other places where there's not much space available, rather than letting
you get away with it?

I was under the impression that VIP panels could not be shaped or cut,
would that not be difficult in many retrofit applications where you need
to fill irregular spaces?


--
Cheers,

John.

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

On Wednesday, 12 April 2017 21:07:20 UTC+1, Tim Lamb wrote:
Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.
I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

Surely :-) your architect must have done sufficient calculations to prove compliance with Building Regs anyway, before submitting drawings to Building Control? Otherwise his design might not be compliant and you'd be entitled to not pay him?

Owain

On 13/04/17 11:27, wrote:
On Wednesday, 12 April 2017 21:07:20 UTC+1, Tim Lamb wrote:
Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.
I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

Surely :-) your architect must have done sufficient calculations to prove compliance with Building Regs anyway, before submitting drawings to Building Control? Otherwise his design might not be compliant and you'd be entitled to not pay him?

Owain

Not necessarily.

The 'quick' way to compliance is simply to 'do it te way everyone else
does' and shove in x00mm of celotex, approved cold bridge avoidance
techniques etc etc.

If you go outside te box however, you have to prove that it meets actual
requirements. A bigger exercise.


--
How fortunate for governments that the people they administer don't think.

Adolf Hitler

On Thu, 13 Apr 2017 10:33:37 +0100, The Other Mike
wrote:

Forgot to add that from the last change in part L of the building regs about
three years ago you have to meet the following:

External walls 0.26 W/m2K
Floors 0.22 W/m2K
Roofs 0.18 W/m2K

We ended up with around 0.14 W/m2K for a 30 degree pitched roof, which requiring
a total of 170mm of PIR (120mm between the rafters and 50mm under) with 600mm
rafter spacing and 12.5mm plasterboard. Without the 50mm 'under' we were over
the 0.18W/m2K limit

150mm of rockwool by itself in one layer is certainly not going to be enough -
although you might be able to argue a dormer as being a wall not a roof
--

John Rumm wrote:

I was under the impression that VIP panels could not be shaped or cut,
would that not be difficult in many retrofit applications where you need
to fill irregular spaces?

They can't, I'd also worry about some oaf putting a new or screw in one.
Suppose you could cover the regular areas with their standard sized
panels, then stuff pir/rockwool in the odd corners, and the average
would still be much higher.

Tim Watts wrote:

Have you got any links to VIP pricing?

They seem a very coy about the prices ...

Andy Burns wrote:

John Rumm wrote:

I was under the impression that VIP panels could not be shaped or cut

They can't, I'd also worry about some oaf putting a new or screw in one.

Not sure how 'nail' turned into 'new' ...

On 13/04/2017 09:53, Tim Watts wrote:
On 12/04/17 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

http://www.changeplan.co.uk/u_value_calculator.php


U-Value calcs are pretty simple. Do you want to do them yourself? In
which case much help will be forthcoming here (from me for a start as
I've done a lot - the only thing I cannot do is floors, but that sounds
like it's not a problem for you).

I did all my own 35 years ago when dimensioning the CH.
Not really needed but it was easy.

In message ,
writes
On Wednesday, 12 April 2017 21:07:20 UTC+1, Tim Lamb wrote:
Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.
I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

Surely :-) your architect must have done sufficient calculations to
prove compliance with Building Regs anyway, before submitting drawings
to Building Control? Otherwise his design might not be compliant and
you'd be entitled to not pay him?

Exactly and why I asked him to produce a set of calculations. The
drawings accepted by Building Control offer a selection of solutions and
I am choosing to use the most practical for the circumstances.

I think BC would like to have seen PIR foam throughout. In hindsight the
next thickness of insulated plasterboard might have given a safer
margin.

I look at this when time permits. 300mm Rockwool over attic floor is
easy enough and might allow for a tighter margin elsewhere.

Owain


--
Tim Lamb

On 13/04/2017 11:53, Andy Burns wrote:
Tim Watts wrote:

Have you got any links to VIP pricing?

They seem a very coy about the prices ...

From http://www.vacuum-panels.co.uk/faqs/

"VACUPOR® is not the cheapest insulation material on the market. However
in numerous cases its use will pay back because:

Space is saved – allowing a project to be realised
Time scales are reduced – alleviating expensive site site set up
costs and prelims."


Sounds rather like, if you need to ask.... etc.




--
Cheers,

John.

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

On 4/13/2017 8:45 AM, The Natural Philosopher wrote:
On 12/04/17 23:25, John Rumm wrote:
On 12/04/2017 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

http://wiki.diyfaq.org.uk/index.php/Heat_loss

Any use?

Building inspectors wan to see a proper report that covers their arses
signed by someone who appears to be an expert.

The truth is not enough.


My mate the brewer once had an HSE type trying to insist he put in CO2
detectors (worth saying it is a small draughty Victorian brewery and
geometry is in his favour). I wrote him a little report based on
production rates and air changes, and that did the trick.

And yes, I do know there's a fatality a year in breweries and similar.
We worry quite a lot about CO2 leaks in nuclear power stations because
these have quite nice enclosed basement type spaces.

On Thu, 13 Apr 2017 11:53:41 +0100, Andy Burns wrote:

Tim Watts wrote:

Have you got any links to VIP pricing?

They seem a very coy about the prices ...

Seems a bit like cutting your feet to fit the shoes! OK, perhaps, from
design stage onwards but no good for retrofit. I can imagine trying to lay
them between existing joists (mine vary from about 14" to about 18" and
aren't really parallel in most places).
VIPs are also failure-critical - damage PIR and it doesn't leak; damage a
VIP and all the vacuum escapes and the panel is an expensive conductor.
--
Peter.
The gods will stay away
whilst religions hold sway

On 13/04/17 15:15, John Rumm wrote:
On 13/04/2017 11:53, Andy Burns wrote:
Tim Watts wrote:

Have you got any links to VIP pricing?

They seem a very coy about the prices ...

From http://www.vacuum-panels.co.uk/faqs/

"VACUPOR® is not the cheapest insulation material on the market. However
in numerous cases its use will pay back because:

Space is saved – allowing a project to be realised
Time scales are reduced – alleviating expensive site site set up
costs and prelims."



Oh - it's a vacuum panel... I've only heard of those in double glazing
(vacuum between two panes of glass - Pilkinton IIRC).

Yep - vacuum panels in embedded insulation sounds like a hiding to
nothing - one misplaced drill and your insulation goes from great to ****e.

What happened to aerogel?

In message , Tim Watts
writes
On 12/04/17 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

U-Value calcs are pretty simple. Do you want to do them yourself? In
which case much help will be forthcoming here (from me for a start as
I've done a lot - the only thing I cannot do is floors, but that sounds
like it's not a problem for you).

Rule of thumb based on my experience:

I "got away" with the BCO approving 100mm celotex on my roof, with 75mm
around the periphery where 100mm was not practical - but that was an
exiting dormer conversion and I was upgrading the insulation from the
75mm wool that used to be there, so my insulation is now twice as
good as before plus I have no draughts.

However, for a new dormer, they will want it to be upto current
standards. Without checking, I suspect that's more like 125-150mm
celotex or equivalent - BUT they will usually accept less if you can
upgrade other parts of the building.

Do you have any guidance as to what your BCO wants?

The figures intended to be achieved from the submitted drawings are :-

0.16W/m2K over new ceilings.

Sloping soffits under rafters 0.2W/m2K

Dormer cheeks not specified but design calls for 75mm raftersqueeze
between studs and 36/9.5 polyfoam liner board. I am actually using 80mm
PIR foam and 25/12.5 liner board.

The cavity walls should be 0.29W/m2K

New floor not specified but 80mm Celotex suggested. I will use 100mm for
other reasons.

Exterior glass specified as 1.6W/m2K

One thing of note.. BC was insistent on at least 30mm air gap under the
felt. Someone needs to tell the building trade because they are
convinced that permeable underlay avoids the need for ventilation!



--
Tim Lamb

On 13/04/17 21:30, Tim Lamb wrote:
In message , Tim Watts
writes
On 12/04/17 21:07, Tim Lamb wrote:
Yes. I do know it has been covered before.

Building Control seemed a bit doubtful about the options for attic,
dormer walls, and sloping soffit suggested by the drawings submitted by
my architect and wants a set of calculations for his records.

I requested this from the architect but got the distinct impression it
was not something he wanted to do and that there would be a significant
charge!

I have had a quick scan round the Kingspan/Rockwool/ whoever sites and
decided they will only help in exchange for an opportunity to market
something. (Rockwool don't actually list the 150mm insulation they sold
me!)

Any suggestions?

U-Value calcs are pretty simple. Do you want to do them yourself? In
which case much help will be forthcoming here (from me for a start as
I've done a lot - the only thing I cannot do is floors, but that
sounds like it's not a problem for you).

Rule of thumb based on my experience:

I "got away" with the BCO approving 100mm celotex on my roof, with
75mm around the periphery where 100mm was not practical - but that was
an exiting dormer conversion and I was upgrading the insulation from
the 75mm wool that used to be there, so my insulation is now twice
as good as before plus I have no draughts.

However, for a new dormer, they will want it to be upto current
standards. Without checking, I suspect that's more like 125-150mm
celotex or equivalent - BUT they will usually accept less if you can
upgrade other parts of the building.

Do you have any guidance as to what your BCO wants?

The figures intended to be achieved from the submitted drawings are :-

This:

https://www.celotex.co.uk/member/u-value-calc

Will sort you out. You have to register but it took me 1 minute.

0.16W/m2K over new ceilings.

Sloping soffits under rafters 0.2W/m2K

75mm celotex between 100mm deep rafters at 400mm spacings, plus 50mm
under the rafters, all final joints taped (actual U=0.18W/Km2)

The ceiling *may* just manage with the same plus the plasterboard which
does have some insulation value - but you'll have double check this.

I feel quite pleased as I managed 75mm between and 25mm under (except
for last 2' into eaves) - so my old but reinsulated roof is not that far
off modern standards.

Dormer cheeks not specified but design calls for 75mm raftersqueeze
between studs and 36/9.5 polyfoam liner board. I am actually using 80mm
PIR foam and 25/12.5 liner board.

The cavity walls should be 0.29W/m2K

New walls?

New floor not specified but 80mm Celotex suggested. I will use 100mm for
other reasons.

That should be more than enough - I'm using 50mm as I don't have the
space for more.


Exterior glass specified as 1.6W/m2K

That's bog standard modern double glazing with K-glass or equivalent.

One thing of note.. BC was insistent on at least 30mm air gap under the
felt. Someone needs to tell the building trade because they are
convinced that permeable underlay avoids the need for ventilation!

I was given 25mm as a target (aka 1") but my BCO essentially agrees with
yours.

Instruct the builders accordingly and WATCH THEM. I'd be inclined to
give the roofing work over to an actual roofer, not a generic builder. A
proper roofer would know this as it is a totally standard construction
method.