Mutiara Posted June 24, 2008 Share Posted June 24, 2008 Has anyone actually ever had this installed ON TOP of their rafters, ie; under the roofing slates ?Our roofer has proposed this to us as an alternative to normal breathable felt. He proposes to fix it on with battens on top of the rafters and then counter batten to leave an air gap. I have used it inside a loft before and would seem a lot less hassle to have it above before I board my loft with plasterboard. I know that the jury is still out on it's efficiency, but I think that if I complemented it with some normal insulation when I plasterboard it would be a really well insulated roof.It is a considerable cost so I would welcome any thoughts, comments from you pro's Link to comment Share on other sites More sharing options...
Nick Trollope Posted June 24, 2008 Share Posted June 24, 2008 I'm no roofer, but in what sense is foil insulation "breathable"?I've never seen a French roofer add anything under tiles. Link to comment Share on other sites More sharing options...
Val_2 Posted June 24, 2008 Share Posted June 24, 2008 We do not put anything under tiles here in Brittany apart from the wooden volige. Felt is not used because there is no point and the wood cannot breathe naturally thus decaying would start. You insulate UNDER the volige with rockwool etc and then plasterboard on suspended railing. This is for Brittany region, don't kow where the OP lives. Link to comment Share on other sites More sharing options...
WJT Posted June 24, 2008 Share Posted June 24, 2008 We are about to have a new roof and have been quoted the same. Triso super 9 insulation under the tiles and then plaque de placo marine sur chevronnage, I assume translation is waterproof plasterboard fixed on (below the chevrons). We would have no other insulation and no felt was quoted. I have noticed recently new builds in our area ( S.E. Dordogne) using this method for insulation.I would be interested to know if anyone would recommend that a felt should be used in this situation or if it would be the same as in Val_2. I am embarrassed to admit that I don't know what volige is. [:$] Link to comment Share on other sites More sharing options...
Clair Posted June 24, 2008 Share Posted June 24, 2008 [quote user="WJT"]I don't know what volige is. [:$][/quote]Volige is the French name for the thin wooden batten onto which you nail roof slates. Link to comment Share on other sites More sharing options...
WJT Posted June 24, 2008 Share Posted June 24, 2008 Thank you Clair.[:)] Link to comment Share on other sites More sharing options...
Clair Posted June 24, 2008 Share Posted June 24, 2008 I had to find out by necessity, not by desire... [:)] Link to comment Share on other sites More sharing options...
Mutiara Posted June 25, 2008 Author Share Posted June 25, 2008 Nick - I have spoken to the roofer today and apparently the foil stuff is completely waterproof and not breathable at all, but what is imperative is that the roofer has to install roof ventilation outlets top and bottom in the roof slates to vent the area between the foil and the underside of the slates; In fact he showed me a document today from tri iso showing this exact method of installation, so we are quite pleased and happy to proceed.Apparently "voliges" are wider boards and "liteau" are are standard narrow roofing battens. Link to comment Share on other sites More sharing options...
Kittycat Posted June 28, 2008 Share Posted June 28, 2008 If you have the available headroom, I would recommend sticking with a more traditional insulating material inside the building. The multi-layer foil 'insulation' is nowhere near as efficient, despite what the manufacturers would have you believe. Factor in also that to work at it's optimum it must be installed very precisely, ie suitable overlaps between layers and all joints tightly sealed with tapes. You'd be better off asking your roofer to install a breathable roofing membrane, if the point is to exclude water ingress (again counter-battened and vented to protect the structure). If you're in any doubt, and it's not too late? I'd suggest asking to visit previous installations & speaking with the owners to get their opinions. Link to comment Share on other sites More sharing options...
WJT Posted June 29, 2008 Share Posted June 29, 2008 Before I sign the devis and give the roofer a hard time, I would like to know what you think Multiara about the below and of course what Chezchatts said and if you are still going ahead? I am getting very worried now. [8-)] http://www.totalfrance.com/france/forum/viewtopic.php?t=46165 Link to comment Share on other sites More sharing options...
Mutiara Posted June 30, 2008 Author Share Posted June 30, 2008 I have done extensive research and even been to see a job in progress. I have no problems with the product and as long as it is installed properly I think it is an excellent method of insulation. I have signed the devis. Link to comment Share on other sites More sharing options...
WJT Posted June 30, 2008 Share Posted June 30, 2008 [quote user="Mutiara"]I have done extensive research and even been to see a job in progress. I have no problems with the product and as long as it is installed properly I think it is an excellent method of insulation. I have signed the devis.[/quote]I really know nothing about it so when I read such negative things, I must admit they make me worry. I haven't signed the devis yet because he has changed a few things in it and I should receive it tomorrow. I actually sent him the link I posted and the very negative French one mentioned in the post and the below was his response:Pour moi, la toiture sentie comme vous l'appelez ou menbrane ne serre a rien il y a le triso (isolant) il est aussi un pare pluie. Alors ne vous inquiétez pas nous connaissons notre travaille et nous sommes dans les bons prix. To be honest that response doesn't fill me with confidence. However, your confidence does make me feel better.[:)] Link to comment Share on other sites More sharing options...
cooperlola Posted July 1, 2008 Share Posted July 1, 2008 I assume this is what you're talking about:[IMG]http://i134.photobucket.com/albums/q103/cooperlola/ceilingshome005.jpg[/IMG]No complaints about ours - works a treat! EDIT : Ooops, sorry - forgot to resize the pic! I'll try again.Edit 2 : I re-sized the pic but it's still coming up huge. Sorry.[:$] Link to comment Share on other sites More sharing options...
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