Loft conversion insulation

We're having a loft conversion done - work starts tomorrow - and I'm wondering about upgrading the roof insulation they've specified. They use TriIso9 as standard, and it could be upgraded by adding 50mm of cellotex between the rafters . This would reduce the U-value of the roof from 0.25 to

0.15 according to the engineer. Cost of the upgrade would be £630 - ouch!

Can anyone hazard an educated guess as to what the likely pay-back time will be? It's a 3-bed semi, and we're miserly with our heating! Or is a compromise worth considering? Eg. only upgrading over the new landing, or only the north-facing side of the roof.

Thanks, Dave

Reply to
Dave Rowell
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Get them to put "only" high perfroming cellotex in all around. Triso9 is a con.

The Advertising Standards Authority got them claiming their reflective insulation is 'Equivalent to 200mm of traditional thick insulation'. A complaint has been upheld after ASA went to independent technical experts.

The judgement can be seen at:

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NOT let them put this stuff in.

Tell them to reassess without the Tiso9 and all cellotex.

Go for the most you can get. Fuel keep on rising in price. Payback is quick.

Reply to
Doctor Drivel

I did my entire loft in PIR foam (celotex being one example of such).

The total cost of all my insulation was about £750, so your upgrade sounds a bit pricey. (I used 100mm in the walls, 85mm on the flat roof,

50+35 on the sloped roof, and 90+10mm cork in all the internal walls).

imposaible to say really, but it certainly going to be several years. This is also one of those situations where the payback is not only measured in cost terms, but it could also make a noticiable diffference to the comfort level of the new rooms.

If you are planing to stay in the house then I would suggest going for the full monty since you will only do this once, and will probably not get a realistic chance to retro fit anything better later.

Reply to
John Rumm

On Mon, 03 Jul 2006 20:46:05 GMT, a particular chimpanzee named "Dave Rowell" randomly hit the keyboard and produced:

Check with your local Building Control about Tri-Iso 9 or 10 (& other 'multi-foil' insulation). There's been a lot of chatter in the last few weeks about whether they have anywhere near the insulation value they claim. As a result, my Council has stopped accepting it until something is resolved.

Reply to
Hugo Nebula

This sounds very expensive I have just had 70 mm Kingspan tp10 for 19.99+VAT for a sheet 1200*2400 ( althougt I think =A323.00 + VAT is nearer the mark.

What I think has probably happened was that your builder went to sheffield insulations and has quoted retail price which is =A346.00+VAT per sheet. He will get 50% discount on this

Ring Minster Insulations for a proper price for the area you need

HTH Phil

Reply to
nimbusjunk

Ask the architect/builder how many 8' x 4' sheets of Xtratherm or Kingspan or Celotex (all same product near enough) are required. To do this properly you need 6" of flexible/on a roll type insulation between the rafters, then 50 mm celotex under the rafters. You may not have the depth of rafters or headroom to do this so you will have to go 50mm celotex between the rafters and 35mm under the rafters. I would advise to get a breathable roof membrane installed as then you can get away with a 50mm gap between the insulation and this membrane. I get 8' x 4' sheets of 50mm celotex for =A320 incl vat incl del from my local builders merchant - had to haggle a bit. Or, look on ebay (search for insulation). It the conversion has flat roofing near the roof apex (i.e. a small loft area) then fill this void with flexible insulation to save money, or rigid if you want a storage area.

Reply to
nafuk

See this:

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Reply to
Doctor Drivel

Reading the adjudication shows that it provides no new information. It is already known that basic u-Values are much worse for it, as it takes no account of the method of heat transfer resistance used by Triiso type insulation. This has never been in dispute.

The Tri-iso Super 9/10 insulation works using a completely different method to Celotex/Kingspan/Rockwool. Methods used to measure conduction of traditional insulation are not applicable to tri-iso insulation. This is why BM Trada designed an "as used" type of methodology that measured actual performance as installed which is valid for any type of insulation, no matter how it works. The ASA adjudication reads in a very suspect manner.

i.e..

"We acknowledged that BM TRADA Certification was a leading multi-sector certification body accredited by the United Kingdom Accreditation Service. We considered that the BM TRADA report did not provide enough detail to support their methodology instead of the methodology employed by the internationally recognised ISO industry standards."

It is very clear to me why the ISO industry standards are not applicable and why a different methodology was required. I can't see why the ASA thought otherwise. A methodology that actually involves sticking it on a house and seeing how much heat is required to keep it warm would appear to me very superior to measuring one aspect of a material's construction in the hope that there is a linear relationship to energy use. The main reasons that such a methodology is not normally used is obviously one of cost.

For me, the jury is still out. My loft has been insulated with it (I had read all the controversy and the BM Trada methodology BEFORE installation). Right now, the loft temperature is acceptable, especially compared with my MOL's loft which was insulated conventionally and is currently uninhabitable due to heat.

When the insulation originally went in (about March), the loft room immediately became the warmest room in the house despite having no heating system.

Christian.

Reply to
Christian McArdle

Read it again!!!! "We considered that the BM TRADA report did not provide enough detail to support their methodology". Trada did devise a separate testing method and they don't agree that it is adequate.

It doesn't work until proved it does. They claim equiv to 200mm of Rockwool. Not proven at all.

It is bubble wrap with a layer of foil in a covering of poly. If taped, it tends to make the place more air-tight giving the impression of superior insulation. There is no testing model to explain, which is good enough. After all this time you would have thought they could have done tests on an Actis Triso9 house and an identical house without Actis with 200mm of insulatiion in the walls. If there was a clear difference I'm sure they would be crowing from the rooftops with all data printed and freely given out.

Many people have seen an improvement, although I think more to the air- tightness the plastic sheeting gives.

There is NO proper independent tests for this stuff. It is not the same as Rockwool that is clear and reacts differently. So, two identical houses both air-tight to the same levels, one with 200mm of Rockwool one with Triso9. Then test the houses using meangfull recorded data. Simple isn't it? Not one test has been performed.

So, far it is a case of it doesn't work until reliable meaningful independent test data is produced on houses in cold climates. Triso9 is "very expensive" bubble wrap, nothing else...until proven otherwise.

Reply to
Doctor Drivel

How did you insulated the loft? Put this stuff on the rafters? Above the floor joists with 25mm air gap?

Reply to
Doctor Drivel

It is under rafters with 25mm cross battening and plasterboard, as recommended.

Christian.

Reply to
Christian McArdle

The message from "Doctor Drivel" contains these words:

So for all those years that it was unclear how bumblebees fly[1] they actually weren't?

[1] Now rather better understood.
Reply to
Guy King

On Tue, 4 Jul 2006 14:52:12 +0100, a particular chimpanzee named "Christian McArdle" randomly hit the keyboard and produced:

There is nothing to say what the external conditions where during the test to maintain the temperature at 23°C. It could have been during a hot, southern French summer. Likewise the date of the testing in the UK isn't given, nor is the external weather conditions.

It's probably very easy to maintain a minimal temperature difference due to the better radiation properties of the material, but I suspect at greater differences the conductivity has a much more dramatic effect.

TRADA apparently don't have UKAS certification to test insulation products, so their test doesn't count.

Reply to
Hugo Nebula

The only way to test this stuff is over a period of time with as I have said, two identical houses next to each other, both air-tight to the same levels, one with 200mm of Rockwool one with Triso9. Then see how much fuel they use and measure temperatures at various points around the house either side of the insulation.

It may do what they are saying, but until proper meaningful tests are carried out is not the equivalent to 200mm of Riockwool. And it is not exactly cheap either.

Reply to
Doctor Drivel

Thanks for the info guys.

I'll call Devon CC tomorrow and see if they're accepting Tri-Iso9 at the mo.

The cost of the upgrade includes materials, installation and VAT - they're charging about £230+VAT for the celotex alone (seems reasonable from ebay etc), and then 2 man-days labour (seemed a lot, but maybe if it's gotta be cut careful with no gaps etc .... ??).

Anyway, any thoughts on how to work out a pay-back time for the celotex addition? 10-20 yrs would do me, but not 30+

Cheers, Dave

Reply to
Dave Rowell

Funny how this bothers you here, and yet is of no concern when you are promoting quack descaling devices.

No, it either works or it doesn't - whether it has been "proven" yet will not change what it does in reality.

And you are a waste of usenet space until proven otherwise.

Reply to
John Rumm

You can do that without a breathable membrane so long as you have sufficient ventilation of the 50mm gap. IIUC you can reduce the gap further if you do have breathable sarking.

Reply to
John Rumm

On Tue, 04 Jul 2006 20:42:13 GMT, a particular chimpanzee named "Dave Rowell" randomly hit the keyboard and produced:

And they'll go, "huh?!"

Building Control is looked after by your district council.

Reply to
Hugo Nebula

They were flying. We could see them flying.

They say equiv to 200mm of rockwool. That should cascade into energy used/saved. Not difficult to measure.

Reply to
Doctor Drivel

Chav, what devices might they be?

Any figures? How does this cascade into energy used or saved?

What does it do in reality?

Boy you are thick! Chavs usually are. He had never heard of the stuff until he read this thread.

Reply to
Doctor Drivel

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