Hello everyone,

My semi detached house loft has a loose fill material and has been floored 
with normal woodchip flooring. I was thinking of upgrading the insulation 
but rather than lift the flooring I thought I would put the insulation onto 
the inside of the roof. Is this a good idea and what type of insulation 
should I use? I envisaged using glass fibre rolls but how would I keep it in 
place?
All suggestions welcome, Jackie

"Jackie"  wrote in message 
news:eamXe.111111$G8.54055@text.news.blueyonder.co.uk...

> Hello everyone,
>
> My semi detached house loft has a loose fill material and has been floored 
> with normal woodchip flooring. I was thinking of upgrading the insulation 
> but rather than lift the flooring I thought I would put the insulation 
> onto the inside of the roof. Is this a good idea and what type of 
> insulation should I use? I envisaged using glass fibre rolls but how would 
> I keep it in place?
> All suggestions welcome, Jackie


sorry I meant chipboard

Jackie wrote:


> My semi detached house loft has a loose fill material and has been floored 
> with normal woodchip flooring. I was thinking of upgrading the insulation 
> but rather than lift the flooring I thought I would put the insulation onto 
> the inside of the roof. Is this a good idea and what type of insulation 


Whether it is a good idea or not will depend on a few things...

The roof timbers need ventilation to ensure they stay dry and free from 
rot. If you stick a layer of insulation under them you can potentially 
cut off the air flow to them, and in time cause more serious problems.

The way round this is usually by arranging for some air flow behind the 
insulation using either a breathable under tile felt, or soffit and 
ridge vents.


> should I use? I envisaged using glass fibre rolls but how would I keep it in 
> place?


One way is with a rigid PIR foam insulation board. Well known trade 
names include Celotex and Kingspan, but there are plenty of other brands 
that make the same stuff - often cheaper. This can be wedged into place 
between rafters, and screwed to the underside of them.

There are some pictures here:

http://www.internode.co.uk/loft/insulating.htm


-- 
Cheers,

John.

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

John Rumm wrote:

> Jackie wrote:
> 
>> My semi detached house loft has a loose fill material and has been 
>> floored with normal woodchip flooring. I was thinking of upgrading the 
>> insulation but rather than lift the flooring I thought I would put the 
>> insulation onto the inside of the roof. Is this a good idea and what 
>> type of insulation 
> 
> Whether it is a good idea or not will depend on a few things...
> 
> The roof timbers need ventilation to ensure they stay dry and free from 
> rot. If you stick a layer of insulation under them you can potentially 
> cut off the air flow to them, and in time cause more serious problems.
> 
> The way round this is usually by arranging for some air flow behind the 
> insulation using either a breathable under tile felt, or soffit and 
> ridge vents.

> One way is with a rigid PIR foam insulation board. Well known trade 
> names include Celotex and Kingspan, but there are plenty of other brands 
> that make the same stuff - often cheaper. This can be wedged into place 
> between rafters, and screwed to the underside of them.
> 
> There are some pictures here:
> 
> http://www.internode.co.uk/loft/insulating.htm


Also have look at this Kingspan brochure, which has lots of diagrams 
related to what John wrote above:
http://www.insulation.kingspan.com/newdiv/pdf/extras/UG.pdf

And as I mentioned in a reply to another post a few hours ago, the place 
to buy cheap insulation board from is:
http://www.secondsandco.co.uk/

David

On 19 Sep,  
     Lobster  wrote:


> John Rumm wrote:

> > One way is with a rigid PIR foam insulation board. Well known trade 
> > names include Celotex and Kingspan, but there are plenty of other brands 
> > that make the same stuff - often cheaper. This can be wedged into place 
> > between rafters, and screwed to the underside of them.
> > 
> > There are some pictures here:
> > 
> > http://www.internode.co.uk/loft/insulating.htm
> 
> Also have look at this Kingspan brochure, which has lots of diagrams 
> related to what John wrote above:
> http://www.insulation.kingspan.com/newdiv/pdf/extras/UG.pdf
> 
> And as I mentioned in a reply to another post a few hours ago, the place 
> to buy cheap insulation board from is:
> http://www.secondsandco.co.uk/



I have a low pitched roof boarded out for storage. It only has 50mm of
fibreglass insulation. I don't want to insulate the rafters as it will reduce
the headroom, and will be difficult to ventilate. I could get 90mm kingspan
(or equivalent) under the boarding (floor) between the (ceiling) joists,
possibly supplemented with 50mm above the joists. Are there any pitfalls in
this approach?


-- 
  B Thumbs
  Change lycos to yahoo to reply

me9@privacy.net wrote:


> I have a low pitched roof boarded out for storage. It only has 50mm of
> fibreglass insulation. I don't want to insulate the rafters as it will reduce
> the headroom, and will be difficult to ventilate. I could get 90mm kingspan
> (or equivalent) under the boarding (floor) between the (ceiling) joists,
> possibly supplemented with 50mm above the joists. Are there any pitfalls in
> this approach?


It will work... Remember that the better insulated it is, the colder it 
will get. That means you will need to take more care preventing any 
tanks/pipes from freezing (that will apply pretty much to any insulation 
you fit).

The solid panels obviously need to be cut to fit (which is the advantage 
of the fibreglass stuff - you can stick that in quite quickly), the ones 
over the joists however can just be screwed down in a few places and 
then the boards laid directly on them (it is quite tough in compression)


-- 
Cheers,

John.

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

In message <432ef045$0$17487$ed2e19e4@ptn-nntp-reader04.plus.net>, John 
Rumm  writes

>me9@privacy.net wrote:
>
>> I have a low pitched roof boarded out for storage. It only has 50mm of
>> fibreglass insulation. I don't want to insulate the rafters as it will reduce
>> the headroom, and will be difficult to ventilate. I could get 90mm kingspan
>> (or equivalent) under the boarding (floor) between the (ceiling) joists,
>> possibly supplemented with 50mm above the joists. Are there any pitfalls in
>> this approach?
>
>It will work... Remember that the better insulated it is, the colder it 
>will get. That means you will need to take more care preventing any 
>tanks/pipes from freezing (that will apply pretty much to any 
>insulation you fit).
>
>The solid panels obviously need to be cut to fit (which is the 
>advantage of the fibreglass stuff - you can stick that in quite 
>quickly), the ones over the joists however can just be screwed down in 
>a few places and then the boards laid directly on them (it is quite 
>tough in compression)
>
>


I only have one layer of (off the top of my head around 40-50mm) 
fibreglass loft insulation. I've boarded half the loft (screws, so can 
be moved), and I'm thinking about improving the insulation, both because 
the house gets bloody cold upstairs in winter and also because of fuel 
costs. Does anybody have any links that point to the relative efficiency 
of insulation methods. I will be going for the floor insulation as I 
also don't want to lose headroom, and would like to know how my rough 
and ready current fibreglass compares against the above boarding, and 
also how a floored loft (standard shed loft chipboard) compares against 
non-floored (hey even chipboard must insulate to some extent!). A quick 
google didn't find any straightforward links.

-- 
Mike Buckley
RD350LC2
http://www.toastyhamster.org
BONY#38

mike. buckley wrote:


> I only have one layer of (off the top of my head around 40-50mm) 
> fibreglass loft insulation. I've boarded half the loft (screws, so can 
> be moved), and I'm thinking about improving the insulation, both because 
> the house gets bloody cold upstairs in winter and also because of fuel 
> costs. Does anybody have any links that point to the relative efficiency 
> of insulation methods. I will be going for the floor insulation as I 


Good load of figures in this document:

http://www.sheffins.co.uk/building_regs/pdfs/FULL%20DOC.pdf

for the fibreglass stuff:

http://www.isowool.com/pdfs/Loft%20Insulation.pdf

(note they are showing figures for two layers of (thicker) wool that you 
have)


> also don't want to lose headroom, and would like to know how my rough 
> and ready current fibreglass compares against the above boarding, and 
> also how a floored loft (standard shed loft chipboard) compares against 
> non-floored (hey even chipboard must insulate to some extent!). A quick 
> google didn't find any straightforward links.


Adding flooring to an uninsulated loft will help (more by virtue of ther 
trapped layer of air than the chipboard itself), however compared to a 
real insualting product the chipboard iteself is relatively insignificant.

-- 
Cheers,

John.

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

In message <4330089b$0$22913$ed2619ec@ptn-nntp-reader01.plus.net>, John 
Rumm  writes

>
>Good load of figures in this document:
>
>http://www.sheffins.co.uk/building_regs/pdfs/FULL%20DOC.pdf
>
>for the fibreglass stuff:
>
>http://www.isowool.com/pdfs/Loft%20Insulation.pdf
>
>(note they are showing figures for two layers of (thicker) wool that 
>you have)
>


That's interesting thanks.

I've had a look in my loft and I seem to have variable joist widths 
(3400->3700mm), but I reckon I'll be able to cram better insulation in 
than I currently have. The property (1938 semi) has been re-roofed at 
some point, and a lot of debri has been left over the plaster which the 
current fibreglass rolls are sitting on.

I had a look in one of the sheds at lunch and they had 150mm, 170mm and 
200mm rolls, but when they are wrapped up they feel nothing like that 
size! I think I'll probably get a couple of rolls and see how it goes, 
the site above assumes double layer over the joists, but I want to put 
chipboard down, so that's not an option for me. Hopefully with the more 
modern foil backed fibreglass I'll get better insulation than the 
current fairly haphazard fibreglass.

-- 
Mike Buckley

Mike Buckley wrote:


> I had a look in one of the sheds at lunch and they had 150mm, 170mm and 
> 200mm rolls, but when they are wrapped up they feel nothing like that 
> size! I think I'll probably get a couple of rolls and see how it goes, 
> the site above assumes double layer over the joists, but I want to put 
> chipboard down, so that's not an option for me. Hopefully with the more 


You could fill between the joists with the fibreglass, but then lay a 
ridgid panel right over the joists and put the chipboard down on that. 
(a bit like you make flat roofs these days).


> modern foil backed fibreglass I'll get better insulation than the 
> current fairly haphazard fibreglass.


Much of the stuff is not foil backed (unless you explicitly go looking 
fot it!). There not not much point compressing more into the joist space 
than fits normally, since it is the trapped air that does a fair amount 
of the insulating)


-- 
Cheers,

John.

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

In message <43304411$0$97098$ed2619ec@ptn-nntp-reader03.plus.net>, John 
Rumm  writes

>Mike Buckley wrote:
>
>> I had a look in one of the sheds at lunch and they had 150mm, 170mm 
>>and  200mm rolls, but when they are wrapped up they feel nothing like 
>>that  size! I think I'll probably get a couple of rolls and see how it 
>>goes,  the site above assumes double layer over the joists, but I want 
>>to put  chipboard down, so that's not an option for me. Hopefully with 
>>
>
>You could fill between the joists with the fibreglass, but then lay a 
>ridgid panel right over the joists and put the chipboard down on that. 
>(a bit like you make flat roofs these days).

Hmm, need some long screws to secure it all - but that sounds a good 
idea.

>
>> modern foil backed fibreglass I'll get better insulation than the 
>>current fairly haphazard fibreglass.
>
>Much of the stuff is not foil backed (unless you explicitly go looking 
>fot it!). There not not much point compressing more into the joist 
>space than fits normally, since it is the trapped air that does a fair 
>amount of the insulating)

I just randomly looked at the first stuff I came to in the shed, it was 
foil backed and plastic wrapped, which you just lay down in the joist 
space and cut the ends as necessary. The rest of the stuff was about 3 
miles up on the top shelf, so I could see neither price nor quality. 
Trip to a builders merchant methinks.

Thanks for the advice.

-- 
Mike Buckley