Recomend Rockwool, Triso-Super10 or Kooltherm K7/ThermaAero ?

mendo

Hi All,

I've got someone to insulate my roof and he sugested to use Rockwool and fill all the space between the rafters and then nail thin playwood on top of them to hold it in place.
The house is 50 years old, apex roof and concrete slates and under the slates, felt.

I am concern a little bit about the insulation (the rafters are 13 cm in depth and 31 cm apart) and the fact that I won't have any space between the rockwool and the felt, for ventilation.

My neighbour used Actis Triso-Super 10 (it is a 19 layer sandwich, 350 euro for 20 sqm - I need 45sqm =770 euro ) stapled on top of the rafters, nailed wooden battens on top af that, and then nailed palsture board (in this case he has ventilation between the felt and the trio-super and then between that and the plasture board, but he lost a couple of inches inside the attic space, one inch the Triso foil and one inch the wooden batten, 2 inches in total).

I want to stay away from the Kingspan due to the fact that it can't be fitted without gaps between the rafters and it needs supplementary filling for the gaps.

My main concern in using Rockwool is the lack of ventilation between the felt and the rockwool.
The Actis Trio-super 10 wasn't mentioned here at all on the forum, if it is good solution.

I have to give the man an answer if I want to go ahead Monday, with the rockwool, the Actis Trio or Kingspan.

Any suggestions?

Regards,

Mendo

mendo

Some info about the Actis:

NEW TRISO-SUPER 10

ACTIS has led the way in thin thermo-reflective insulation for the past 25 years. In order to comply with increasingly stringent building regulations, the ACTIS research team has developed a new, improved, version of the popular TRI-ISO SUPER 9.

TRISO-SUPER 10 is a complex arrangement of 19 insulating layers - suitable for over and under rafter applications - which is only 30mm thick and equivalent to 210mm of mineral wool (U-value = 0.19W/m².K) as certified by BM TRADA Certification Ltd.
TRISO-SUPER 10 has been tested under real conditions by the independent test body, TRADA Technology Ltd following their rigorous test protocol.

INSTALLATION GUIDELINES

1. Ensure an air gap on either side of the insulation.
2. Ventilation:
* BREATHER MEMBRANE: Ensure a minimum air gap of 25mm between the insulation and the breather membrane. The membrane should have a vapour resistance of < 0.25MNs/g.
* FELTED ROOF: Ensure a minimum air gap of 50mm between the insulation and the felt with ventilation from eaves to ridge according to British Standards.
3. Pull the insulation taut and staple to the rafters using galvanised staples, 14mm min.
20 mm Stainless Steel staples are recommended
4. Overlap the insulation from 50-100mm at each joint and staple every 50mm onto the rafter.
5. Cover all the joints with ACTIS ISODHESIF tape to give an air tight finish.
6. Fold all finishing edges under by a minimum of 50mm and staple every 50mm, or trap with a final batten.

dixiefly

I was considering the TRISO-SUPER 10 but have had some negative comments from people in the industry that their figures are unproven. At this stage I am planning to go with the Metac glass wool in the roof rafters and will leave a gap for airing. I will probably use Gyproc Thermal board or similar.

Viking House

TRADA Technology, a UK research and consultancy body specialising in the assessment of timber and timber related products in construction, witnessed a 2-month trial carried out by ACTIS during the winter of 1997 on their R&D site. The purpose of the trial was to compare the insulating properties of TRI-ISO SUPER 9® with mineral wool of 200mm in thickness under full scale and real internal/external conditions.

TRADA Technology verified the reliability of the methods used for measuring and recording ACTIS test data. During the trial it was demonstrated that the TRI-ISO SUPER 9® had insulating properties equivalent to mineral wool 200mm in thickness (R=5).

An extract of the testing gave the following results.

The two buildings tested had an internal temperature maintained at 23°C and the external temperature range was 6°C to 16°C. The relative humidity range was 45% to 90%.


Total uninsulated surface area for each building: 80.08m²
Total surface area of Building 1 insulated with ACTIS TRI-ISO SUPER 9® insulation: 78.7m²
Total surface area of Building 2 insulated with 200mm mineral wool: 65.3m²

ardara1

Building Control in the UK have with drawn approval for all multi foils other than those tested in accordance with BR442 (AS IS CASEI N IRELAND)stating that they're claims were exagerated, meeting around 0.60 U value in a typical roof (0.20 required) and had the equivalence of 20mm Kingspan on a wall - with a cavity either side! - Many builders merchants have quit stocking them

This stuff works best at reflecting heat, best used in addition to thermal insulation INHO and not in it's own right.

ircoha

was at the building show today and came across more "silver paper" insulation from a company called DPS ltd http://www.dpspackaging.net/Our%20products.htm

it has a u value of 0.35 but is fire rated, I gather the super9 or 10 is not

ardara1

the guys on the stand todya made a claim of 0.35 - the product when measured under all European convention measures 0.60 W/m2K - this is why the UK authorities have put their foot down - Don't listen to sales guys on stands.

Personally I would only use this material if I was building an attic room to keep the summer heat OUT and rely on kingspan or similar to keep the heat IN for the remaining 11 months:D of the year.

Redjeep!

Ventilation space.

I was concerned about having to put a ventilation space behind the rockwool when I did the same thing in my attic last winter and I did a lot of searching around the net for advice.

It seems that although building regs require it, it's actual value is questionable. The USA Department of Energy website actually state that they feel the value of the gap is insignificant, as you won't get condensation anyway, however they continue to recommend it, saying that you'll still need it to comply with building codes in most States.

So there you have it, I'm absolutely not claiming that you don't need it (don't want you sueing me when your rafters rot) but I don't think it's that clear cut. I didn't leave a gap, but I plan to check it frequently this winter for damp.

I'll try and get the relevent reference and post it later.

Insulating my loft has become somewhat of an obsession - I live in a dormer (purpose built, 5 bed, 4 years old) and it's about 5C cooler upstairs in the winter than the summer ! (and the opposite in the summer). If anybody has any advice I'd be very willing to listen.

ircoha

ardara1 wrote:

the guys on the stand today made a claim of 0.35 - the product when measured under all European convention measures 0.60 W/m2K - this is why the UK authorities have put their foot down - Don't listen to sales guys on stands.

Interesting comment.

Does that mean that our measurement standards are out of sync with "all European convention measures" by a factor of c 1.7

In other words the projected U value for windows of 2.2 is in fact 3.74

In passing, "Don't listen to sales guys on stands", they have a brochure which claims the 0.35 per 202 building regs.

If I was a MOD on this site I would like some backup on the 0.6

ardara1

A number of insulation companies in the UK have posted a link to the Local Authority Building Control notification dated Aug 06. It was formulated after a working group meeting in July between the manufacturers, the BRE and the CPA - Foil manufacturers were promising alternative testing method approval from CEN - looks like its not going to happen -

Here's the link
www.waverley.gov.uk/buildingcontrol/multifoilinsulation.pdf

Basically all foil radiant barriers need to be tested in the same manner as every other insulation - hotbox test.

ircoha

ardara1 wrote:

A number of insulation companies in the UK have posted a link to the Local Authority Building Control notification dated Aug 06. It was formulated after a working group meeting in July between the manufacturers, the BRE and the CPA - Foil manufacturers were promising alternative testing method approval from CEN - looks like its not going to happen -

Here's the link
www.waverley.gov.uk/buildingcontrol/multifoilinsulation.pdf

Basically all foil radiant barriers need to be tested in the same manner as every other insulation - hotbox test.

ardara1, you are "the man"

Many thanks.

for those who want to see the only properly approved multifoil see http://www.webdynamics.co.uk/

Carlow52

This 2 year old thread seems to cast some doubt on the claims made for multi-foiled insulation, for example the TRI-ISO SUPER 9.

I have now come across a new 'release' from a different stable and it is quoting an R value [as per BR 443 Part L for foil insulation, using the hotbox test], of 2.218.

It further claims to be be certified by ILAC accredited laboratory.
[All of our testing has been carried out by ILAC Accredited Labs (International Laboratories Accreditation Cooperation). UKAS are the British representative for ILAC.]

http://www.bre.co.uk/filelibrary/rpts/uvalue/BR_443_(2006_Edition).pdf

suggests at page 6 that they are best used with an airspace either side.

3.10.2 Multi-foil insulation
Multi-foil insulation comprises products that consist of several layers of foil
separated by other materials. They are intended for applications with an
airspace on either side and the overall thermal performance includes the
effect of low-emissivity surfaces facing these airspaces.

Is the jury still out on foil insulations and if not where are they best used?
Thanks.

martin46585

hi there, if you can manage to get a full sized sheet in to the attic then an insulated plasterboard is an option.
The Kingspan tw52 are paperback insulation and the tw56 are foilback insulation bonded to plasterboard, the latter being used in timberframe for this purpose.
Priced in the region of around 9 euro m2 to 11m2 for 38mm tw56, they have the added advantage of vapour barrier included.
The boards can be nailed with 3" galv clout nails or screwed with drywall screws c/w washer to suit.
You could also place a kingspan foil insulation board between the rafter cut to size and tape down the seams with duct tape to maintain airtightness.

bibibobo

Redjeep! wrote: »

Ventilation space.

I was concerned about having to put a ventilation space behind the rockwool when I did the same thing in my attic last winter and I did a lot of searching around the net for advice.

It seems that although building regs require it, it's actual value is questionable. The USA Department of Energy website actually state that they feel the value of the gap is insignificant, as you won't get condensation anyway, however they continue to recommend it, saying that you'll still need it to comply with building codes in most States.

So there you have it, I'm absolutely not claiming that you don't need it (don't want you sueing me when your rafters rot) but I don't think it's that clear cut. I didn't leave a gap, but I plan to check it frequently this winter for damp.

I'll try and get the relevent reference and post it later.

Insulating my loft has become somewhat of an obsession - I live in a dormer (purpose built, 5 bed, 4 years old) and it's about 5C cooler upstairs in the winter than the summer ! (and the opposite in the summer). If anybody has any advice I'd be very willing to listen.

Tend to agree here. There is alot of this theory versus practice stuff in building regs much of it results in nothing but driving costs up. chances are you may move home within next 15 years. if so then its unlikely to be a problem.