Attic Insulation?

Build4less.ie

cubix wrote: »

Looked this up on B&Q "Knauf Saver Value Triple Loft Insulation 200mm" for £3 but it mentions price is not applicable in the North, is this correct?

This promotion is not available in Northern Ireland, who do not participate in the CERT Scheme

Yes this is correct. The UK run a grant scheme which is quite controversial to say the least but it is there. You need to own a property in the UK to avail of this and in some cases it is not applicable to Northern Ireland due to no such schemes available here in Southern Ireland.

Build4less

paddy147

Build4less.ie wrote: »

Yes this is correct. The UK run a grant scheme which is quite controversial to say the least but it is there. You need to own a property in the UK to avail of this and in some cases it is not applicable to Northern Ireland due to no such schemes available here in Southern Ireland.

Build4less

I got a lorry load os the stuff for 3 quid a roll. I got 100,150,170 and 200mm insulation rolls

Homebase,BnQ,Focus DIY (now gone bust),Wickes,and many other UK mainland companies participated in the scheme.It was a UK goverment run scheme to make british homes more greener and energy effiecent.You could only buy 1 lot of insulation and you had to provide your address and also postecode before you got the deal from the shops involved.But there were and are many ways around this and getting lots of insulation rolls each time.

Oh happy days.:D

Beruthiel

I'm just back from B&Q. Was just looking at what different kinds of fiberglass there is out there.
You have your normal stuff and then you have fiberglass wrapped in a thin foil thermal film. That stuff goes at twice the price of normal stuff.
Is there a big difference in what it does to justify the price difference?

heinbloed

Check the product data sheets incl. the product safety data sheets. These should be available in the shop, if not try the manufacturer's homepages.

gman2k

Beruthiel wrote: »

I'm just back from B&Q. Was just looking at what different kinds of fiberglass there is out there.
You have your normal stuff and then you have fiberglass wrapped in a thin foil thermal film. That stuff goes at twice the price of normal stuff.
Is there a big difference in what it does to justify the price difference?

Will it perform twice as good as the product half it's price?
No.

cubix

B&Q have rolls of rockwool for €10 as per picture. Not sure if its 100mm thick as it has 2x below it, seems to do 6mtr sq. Whats the thinking of people here between fibre/rockwool.

gsxr1

build for a whole lot less.co.uk

CBYR1983

cubix wrote: »

B&Q have rolls of rockwool for €10 as per picture. Not sure if its 100mm thick as it has 2x below it, seems to do 6mtr sq. Whats the thinking of people here between fibre/rockwool.

Did anyone get this. Labels baffled me. Measurements suggested roll only 3.3 sq m so maybe there's 2 100mm rolls in it. Need something thicker anyhow, but it looks good value.

heinbloed

What is baffeling you, CBYR1883? The label is clear as far as I can see.

toshy321

Don't want to hijack thread but wondering what I should be insulating my attic with I'm using t and g for the ceiling its an A shaped ceiling so there is no joists would 100kingspan boards be okay cut between rafters??

heinbloed

Don't want to hijack thread but wondering what I should be insulating my attic with I'm using t and g for the ceiling its an A shaped ceiling so there is no joists would 100kingspan boards be okay cut between rafters??

"Kingspan" is a brand name. They sell a lot of different insulation materials.
Check the home page of the company and look for the installation advices.
Copy them,print them out. You might need them for later regresses.

CBYR1983

heinbloed wrote: »

What is baffeling you, CBYR1883? The label is clear as far as I can see.

You cheeky geek. What a pointless post. Others I've seen are always single roll, if I'm the target market, and it confuses people like me, then some boffin like yourself has made a pig's ear of it.

heinbloed

The label refers to rolled-up mats, CBYR1983.
Not to matted-out rolls (smiley).
These are different things for different purposes. Better read the product data sheet, ask for the installation instructions and safety data sheets as well.

As far as I can see the label is conform with the industrial standard, nothing unclear.
The European Mineral Wool Industry has a home page, check this for on explanation of the labels.

cubix

A buit confused myself, as any instalation I have been looking at would give you the sq area it covered and the thickness. So in this case the sq area given is 6.6 so in this pack is there 2x 100mm thick rolls that cover 3.3mtr sq each??

Thanks.

CBYR1983

heinbloed wrote: »

The label refers to rolled-up mats, CBYR1983.
Not to matted-out rolls (smiley).
These are different things for different purposes. Better read the product data sheet, ask for the installation instructions and safety data sheets as well.

As far as I can see the label is conform with the industrial standard, nothing unclear.
The European Mineral Wool Industry has a home page, check this for on explanation of the labels.

Ah sure, it's been a long day! Nevermind the rant. Enlighten me so. What confused me was that it said 6.6 sq m coverage at 200 mm, in brackets, whereas obviously the thickness is 100mm, which nearly implies coverage of 13.2 at 100mm.

heinbloed

Here my purely speculative opinion:

The mineral wool label linked at cubix' post is suposed to be used for an upright positioning.

This means it has to be jammed, otherwise it will sag. With a standard room height of 2.45 meter and a loss of length of about 5% due to jamming and sagging under it's own weight the given length (when unpacked) is about the standard length for a standard room. 2.75 meters unpacked versus 2.45 meters installed.
The same goes for the width.

So the INSTALLED coverage is per mat 3m2.

And there are 2 mats per packet.

Note that mats and rolls aren't the same, they show different characteristics despite being made from the same basic material.

The mats are more stiff, are heavier(when installed) and show a different water vapour transmission - due to their higher content of oil, resin, glue.

I'haven't looked at the PRODUCT DATA SHEET, maybe someone of the interested parties will link it and we can THEN discuss the suitability of the product.

darrenheaphy

Hi chaps. Our relatively new house has one layer of fibre glass installation laid onto the floor and walls (around two attic rooms). It has only one layer of fibre glass though and I wonder if another laid down on top would lessen heat loss? What do you think?

Some pics, you can see it's just the eaves that go all around the house that I need to do.

BryanF

is there an air-tightness/vapour barrier layer Darren?
your 'relatively' new house doesn't seem to have its pipes insulated

http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/

you should deal with the air-tightness before installing more insulation, once that's A1, (that includes light fittings, hatch and if its a dormer that could be major work if not already done properly:eek:), then you can go ahead and install another foot. (don't forget all pipework and water tank + retaining adequate ventilation at the eaves)

heinbloed

Shocking but Irish standard.

Yes, you should correct this, straighten out existing insulation and top it up.
Your extractor pipes are badly laid, expect condensation puddles and mould growth in them. Rip them out and re-install these. They're a health risk.
Use a downward slope (2%) with a straight rigid pipe, not the flex-pipe. Support the straight pipe similar as it should be done with the electric cables. Never hang them free floating in the air.

Get a civil engineer/building inspector in, they will point you towards the basic standards.

heinbloed

Be carefull when walking there: your planks are sitting on stiffeners, these are not load bearing.

Esel

This deal any good? 360 sq ft 150mm fibreglass installed for €275 extra €0.71 per sq ft over.

I realise from reading here that 150mm is low, but in comparison to nothing?

darrenheaphy

Wow, great responses, thank you. heinbloed - thanks for pointing out the stiffeners, I never noticed before and I've been stomping around catching rodents and installing ceiling speakers! I'll lay wood across the load bearers instead.

How can I deal with airtightness on light fittings and what not, there's always a few mm around each circular hole (of which there are 30!) for spot lights.

What's an air tightness/vapour barrier? Is that the material on the underside of the tiles?

Finally, if I may, presuming I sort the other stuff out, what type of insulation should I place over the existing? More of the same?

BryanF

darrenheaphy wrote: »

Wow, great responses, thank you. heinbloed - thanks for pointing out the stiffeners, I never noticed before and I've been stomping around catching rodents and installing ceiling speakers! I'll lay wood across the load bearers instead.

How can I deal with airtightness on light fittings and what not, there's always a few mm around each circular hole (of which there are 30!) for spot lights.

What's an air tightness/vapour barrier? Is that the material on the underside of the tiles?

Finally, if I may, presuming I sort the other stuff out, what type of insulation should I place over the existing? More of the same?

this 'relatively new house' what building regulations did it comply with?

massive amounts of heat loss in a home are through unregulated air-leakage, the most common place is in dormer spaces where unsupervised trades did not install a VB correctly or at all!

As per the attic details I sent you (Heinbloed, they are crap but them's the Regs we got:rolleyes:) , do you see that blue line? that should be a continuous uninterrupted/unbroken air-tightness/vapour barrier that is this or something similar ,and it should have been installed above your plaster board ceiling.

although you may have foil-backed plasterboards, they were designed in an age before people started poking holes for large number of down-lighters and speakers etc. you need to install something like these Loft%20Covers

heinbloed

Darrenheaphy asks:

How can I deal with airtightness on light fittings and what not, there's always a few mm around each circular hole (of which there are 30!) for spot lights.

There are a lot of lamp holders available for this purpose. Note that mineral wool fibres are carcinogenic. So you should really separate the habitated space from the attic.

See here for the WHO report/guideline:

http://www.euro.who.int/__data/assets/pdf_file/0005/74732/E71922.pdf

From point 8 onwards about mineral wool.
Be happy you don't have the shredded-and-pumped material up there!

The airtightness between heated space and attic is most import for energy conservation as well. With 30 lights you have a big hole alltogether. So check with the light manufacturer what solution they have for offer.

What's an air tightness/vapour barrier? Is that the material on the underside of the tiles?

An airtightness barrier is for example a sheet of paper, Kraft paper etc...
A vapour barrier not only stops air movements but also water vapour.
I don't know what type of felt you have installed between the attic and the tiles.
These roof felts are usually wind breaks and water barriers, stopping rain and snow being blown in and act as well as a last barrier in case a roof tile fails, breaks.
There are diffusion-open felts used nowadays, but these aren't mandatory.
Is there any brand name visible, any numbers, symbols?

Finally, if I may, presuming I sort the other stuff out, what type of insulation should I place over the existing? More of the same?

Well, yes.
Top up to the level of the timber beams with an insulant with similar qualities to the existing one.
Diffusing water vapour coming from the habitated space should be allowed to escape through the insulation layer, otherwise there is a risk of build-up of moisture within the insulant. And consequently rot.
Therefore the (Greek) my-Value should be similar or better, read the material data sheet, the label on the packet.
Make sure you buy rolls, not loose material and not bats. Read the label, the material should be designed for the very purpose.

Get a good dust mask (class two or three designed for carcinogenic small particles), a disposabel boiler suit and goggles and gloves first!

In the second step lay the new rolls of insulant paralel to the loadbearing timber, overlapping the existing strips of insulant at about center. Use rolls as wide as possible, they are available to up to 2 meters width, even wider if specially ordered.

Work-in up to 40 cm of total thickness, more would be a waste. 30 cm are acceptable as well. But the material is relative cheap and once you're at it finish the job.

Don't forget the proper installation of the ducts and cables.

Do not install the new insulant rolls cross-wise over the existing ones! You would create hundreds of air gaps (where they cross), similar to a fishing net's negative.
The advise-picture given by the SEAI on their home page is wrong in this case.
If you can push a pencil or stick through where the rolls/mats meet down to the plasterboard anywhere then you know you made a mistake. Otherwise you can use the recommendations of the SEAI, check their home page.

Good luck!

heinbloed

Esel asks:

This deal any good? 360 sq ft 150mm fibreglass installed for €275 extra €0.71 per sq ft over.

I realise from reading here that 150mm is low, but in comparison to nothing?

150mm is indeed very poor, propably not even enough to meet the building regulations. Which are pretty poor themself.
And they don't give a price per m2, this would make me wary. And not mentioning anxilliar works like closing holes (light fittings), preparing hatches, water tanks etc...

BryanF

heinbloed wrote: »

An airtightness barrier is for example a sheet of paper, Kraft paper etc...
A vapour barrier not only stops air movements but also water vapour.
I don't know what type of felt you have installed between the attic and the tiles.
These roof felts are usually wind breaks and water barriers, stopping rain and snow being blown in and act as well as a last barrier in case a roof tile fails, breaks.
There are diffusion-open felts used nowadays, but these aren't mandatory.
Is there any brand name visible, any numbers, symbols?

are we talking about air-leakage? then why switch to talking about roofing felt?, its definitely a relevant question, with regards to retaining adequate ventilation in the crawl space, but i think this will confuse the poster, discussing the ceiling air-tightness barrier and roofing/sarking felt in this way..

heinbloed

BrianF asks:

are we talking about air-leakage? then why switch to talking about roofing felt?

Because the poster asked the question.
Quote from Darrenheaphy:

What's an air tightness/vapour barrier? Is that the material on the underside of the tiles?,...

BrianF goes on further:

.....its definitely a relevant question, with regards to retaining adequate ventilation in the crawl space, but i think this will confuse the poster, discussing the ceiling air-tightness barrier and roofing/sarking felt in this way..

It is up to the reader what she/he does with the information provided. Adults need no nanny nor censorship, BrianF. They can decide what is important for them. And keep asking if something isn't clear.

darrenheaphy

Thanks chaps, all your comments have been very useful in understanding how to approach this. The house was constructed in ~2006 or so, can't recall the exact year but it was around then, and receives a BER of B3. I have standard felt underneath the tiles, when I initially posted my questions I didn't know what its purpose was but I do now Everywhere else is insulated well except the eaves as per my pics but at least I now understand what to do!