Roof/Attic insulation

[dragonrouge]

This is a black art as far as I am concerned but briefly we have some quotes and the figures are somewhat high. Our friend who is a good all round DIY guy in the UK has offered to come across strip out existing stuff and replace and re-board for us. Please what is the best insulation wool to use and does anyone have a brand name please.

[Sunday Driver]

Check out this useful website.  Gives lots of information about the different types of insulation material, thermal values, fire resistance, sample prices, etc.

 

[dragonrouge]

Thanks Sunday Driver

[Chancer]

If your friend is bringing over a decent size van get him to buy it in the UK, it is usually on promo in B&Q and dependant on the week you can get 2 or even 3 rolls for a tenner, it is identical to the Knauf stuff sold by my local grossiste except it lacks the pare vapeur, has 5.44m on a roll instead of 5m and of course doesnt cost €52.60 per roll [:-))]

It also doesnt irritate the skin in use which is the reason the grossiste uses to justify it costing more than the already expensive Isover insulation.

Even using the highest price I have paid it works out at 85 pence per m2 compared to the cheapest (and inferior) in France at €4.91 per m2, the cheapest cost 61 pence per m2 and the Knauf stuff from the local grossiste works out at an eye watering €10.52 per m2. All prices based on 200mm.

I recently heard of a devi for laying insulation in a 100m2 grenier, nothing to move out, just pass up the rolls and lay, it was close to  €3000 euros

[Théière]

Pinched from another forum:

"found that a product called "Eurotoit" manufactured and supplied by Recticel is very similar if not identical, it also has the advantage of being available in France".

[dragonrouge]

Thanks to everyone for their responses. Without wishing to bore everyone to death and in an attempt both to get it 'right' and to save pennies I do hope you will not mind if I post the devis (it is not too long) My French is good enough to understand most of the devis so the posting is for comments essentially on pricing and alternatives please?

Fourniture et pose de 74m2 de laine de verre en 200mm R=5 en rampant sous toiture @ 12.84 = 950.16 euros

Fourniture et pose de 74m2 de plafond placoplatre sur rails entre les poutres @ 31.01 = 2294.74 euros

Fourniture et pose de 40ml de lambourdes(?) pour dressage de support d'ossature (?) plafond.

I am so grateful to everyone and seeing the cost of almost 3500 euros I am now on notice!

rdgs

[Peter]

The Kraft paper that comes with the insulation is a vapour barrier and should be installed with the paper to the warm side (i.e. in your loft, down). As long as it is you main residence there are significant grants available for insulating a house.

If doing it yourself be careful about trapping moisture in so don’t block the eaves, don’t stuff it between the rafters etc – you still need loads of ventilation over the, cold side of the insulation

[dragonrouge]

Thanks Peter I see that credit for Impot has dropped this year from 40% to 25% so I suppose taking that into account its not too bad. However I am a cynic and believe that artisans hike prices knowing that Impot credits are around?

Is it me or is this site slow today?

[Northender]

There does seem to be problems on the site this morning , I may be posting this again.

You devis Dragon includes a large part for plasterboarding.

Is/Will your attic space be used for habitation?

There must be cheaper/better alternatives than pb for "holding up" insulation to the underside of roofs , unless its for aesthetics.

[dragonrouge]

No sorry I did not mention it is not for habitation simply for thermique reasons. It is and will only be for storage.

With plasterboard to hold it up what does one do please. I do not within reason care what it looks like. If future buyers want to convert the attic it is for them.

[Stan Streason]

I had a quote of nearly €4,000 to put insulation between beams and platerboard over (ie the insulation was the downstairs side of the ceiling/floor).  We were told much of the cost was the plaserboard.

We eventually decided that if I ever felt rich enough to convert upstairs I would be rich enough to re-do the insulation.  We ended up just laying insulation on the floor upstairs and locking the door to the attic.  Significantly cheaper.

[dragonrouge]

What an absolutely logical approach. Thanks for that.

[Northender]

The problem with using Plasterboard on the underside of roofs is water damage.

You may think your roof is sound but there are occasions when driving snow/rain can get under tiles and when you don't have underfelt , which is the norm in France, you can get problems.

Why not use simple slating battens to hold the insulation.These can be fixed on the underside of the rafters at say 400mm apart.

You can then still access the tiles for inspection purposes.

[dragonrouge]

thanks now over to my good friend!

[Chancer]

Knowing more from your subsequent postings I reckon that you would be better off just having battens or fourures screwed across your chevrons to hold the insulation, if you do buy it in France the pare vapeur will stop any fibres from falling, Isover also do one that has the glass fibres encased in a cling film like voile, or you could decide to buy it in the UK and save money.

I completely agree with the comment about not boxing in your roof with plasterboard especially as I bet you dont have roofing felt under the tiles, you will just hide any leaks untill the placo come crashing down.

The material costs with to do the job with UK insulation (this carries a carbon credit discount from EDF) would be between £45 and £100 add to that €20 to €30 for une botte de lattes and you are someowhat short of your devi price but of course you wont get a credit d'impôt just a subjonction on the price of the insulation.

Were the prices you quoted HT or TTC? The devi should also have seperated the material price from the labour which would have been an eyeopener instead of reading "supply and fit.........." although if I were a tradesman that is one regulation that I would not be keen to follow.

[dragonrouge]

Hi tax was not included and comes in at 5.5%. Every quotation we get from this guy does not separate labour from costs. His next door neighbour who is the plumber save for small jobs again does not separate out the price. I do know they hourly charge is about 37 euros. I am so grateful for all of the inputs it has helped a lot and concentrated one's mind. I am now not signing the devis and we will do it ourselves.