ISO super 9 foil/fleece used again

[sm_jamieson]

They used ISO super 9 style foil/fleece insulation in a loft conversion on DIY SOS last week. It appeared to be stretched over the loft rafters leaving 50mm-ish gap behind, Then battens (38mm looked like) nailed through it onto the rafters, and plasterboard over the battens. Thus leaving suitable air gaps etc, but where it's squashed by the battens the insulation must be poor. But you get a much thinner roof than with celotex. Seeing a neighbours loft conversion where you could hardly stand up a while ago, made me think. And what about using it in normal roofs. If it's evquivalant to 75mm celotex, my extension roof design could be a lot thinner. Is this stuff proven, and would the BCO pass it ? Simon.

[fred]

In article , sm_jamieson writes

IMNSHO the chances of this stuff meeting the insulation level of 75mm Celotex in a real life situation is some where between zero and a a very small thing.

Even if you believe the spiel, you need static air in the (uniform) gaps to meet the claims so if you vent the outer air space, next to the roof, as you should then there is no chance whatsoever of meeting the claimed performance.

I have seen it used and passed by a BCO but that's not to say it is a performance insulation system. If you want it effective use Celotex, if you just want a box ticked then use whatever you can get away with.

HTH

[Christian McArdle]

Although sceptical for the same reasons, there are some genuine reasons why it might be superior. The main one is that celotex leaves uneven gaps where it is wedged between rafters, leading to draughts within the insulation which reduces its actual effectiveness. Tri-iso Super 9 is rolled on in a single sheet, so there can be no gaps for draughts to develop.

I'll know if the stuff works properly soon. My not yet finished loft conversion has it. I will say that in February, the room became the warmest in the house, despite not having installed the heating in it and having hardboard for one window and roofing felt for another. Previously, the roof had about 25mm of expanded polystyrene behind hardboard and was slightly cold, but not excessively so.

There is a new version out called Tri-iso Super 10. This has been independently tested to confirm that it provides the equivalent of 210mm of glass fibre wool in actual installed conditions. I don't know if similar testing was carried out on the Super 9, but they claim 200mm equivalence. It has a similar construction, but the Super 9 is nominally 25mm thick, rather than the 30mm of Super 10.

Christian.

[Christian McArdle]

Actually, it appears that they did.

[sm_jamieson]

It's where it is squashed between battens and the rafters that I am especially sceptical, and if that does not work, there is quite a bit of cold bridging. Simon.

[Christian McArdle]

It works a lot better for cold bridging than celotex only between rafters, which is a very common method.

Obviously, the Super 9 will be a lot worse performing in those areas than in free areas. However, they won't be too bad. Remember also, that these bridging spots are just that, spots. They aren't entire lines, as the battening runs perpendicular to the rafters and the bridging spots only occur where they cross. The lines from the joist and battens will be slightly compressed on one side, but will reach the majority of their full performance.

Christian.

[PeTe33]

To jump on the thread...

I am on the verge of getting the entire loft insulated, but the dilemma is that I want to use the loft space for PC equipment, a server or 2 and other things, so.... If I were to use this iso-10 stuff rolled over the rafters presumably I would have significant benefit from heat reduction in the loft during summer, but would the insulation in the living areas below be compromised?

What I mean is, would having the roof insulated rather than the ceiling require a greater heat input to warm the room below or shouldn't the difference be significant (once the loft achieved an elevated temp)

The whole of the living area below is heated by UFH (4 zones)

Oh, and..... :¬)

The living area gets extremely hot in the summer as it has a fairly high glass area and gets masses of reflected light from the Estuary as well as direct sun, so theoretically would insulating the rafters rather than the ceiling make the loft hotter as more heat would get through the ceiling? I suppose Insulation of rafters AND ceiling would cover both concerns but seems excessive.

Sorry to burden you with my ponderings, but I have been head scratching for a long while trying to work this one out.

Cheers Pete

[Hugo Nebula]

On 18 May 2006 02:42:15 -0700, a particular chimpanzee named "sm_jamieson" randomly hit the keyboard and produced:

The jury's still out on that one. The company claim (or used to claim) that the test rig with Tri-Iso Super 9 they set up in the south of France used no more energy to heat than one with 200mm Rockwool. The rumour is that the test was carried out in the middle of the summer, so the test was meaningless. The certificate for this material was withdrawn in February.

The certificate for Tri-Iso Super 10

appears to be a bit more explicit, and as it's been issued by TRADA, it should be accepted by Building Control.

[Pete C]

Hi,

Long discussion of it here:

Looking at p21(!) it appears the super 10 stuff has a TRADA cert for roof construction, so that /should/ keep BCO happy, though it would be well worth asking.

cheers, Pete.

[fred]

In article , Hugo Nebula writes

A very carefully formed response :-)

My concern is that the average punter puts this stuff in without really understanding the constraints that (may) enable it to achieve its quoted spec, particularly without understanding what air movement can do to their claims. The difference with Celotex et al is that you can achieve the specified results with the minimum of fuss, a tight fit with gaps sealed is all that should be required.

[Christian McArdle]

Tri-iso insulation works in a different way to conventional insulation. In practice, it means that it has some strengths and weaknesses in comparison. One of its strengths is reflecting solar gain from the roof, which can be a significant contribution to summer overheating.

Christian.