another from me

[noserhodes]

hi all this time its onto roof insulation.
i am probably going to plasterboard the ceiling just under the roof and i wanted to know, which would be the best way to add some insulation inbetween the plasterboard and roof tiles?
i do know on new builds they use a spray on type insulation but i need something i can put in off my own back.
any thoughts, help?
thankyou

[canoeman]

I don't believe you can get roof spray foam insulation done here , although it is used to insulate between internal skins and external below covering.
I wouldn't recommend it here, you really need to keep some air circulation to roof for the hot months, plus maintenance the clay tiles do crack are are not designed for a lifetimes use, plus woodworm is pretty rampant here so you reaaly want if necassery to get a roof spaces, unless of course you have a concrete roof of one type or another .
I would seriously suggest that you should strip tiles and fit external insulation as a long term effective method, they are products specifically designed for that here.
If you don't want to do that, there are 2 products that you could staple in place before plasterboarding
1. a silver bubble wrap in various thickness (developed from Space Shuttle)
2. a similar reflective sandwich used in UK to back radiators
With either you need to layer joints so any water will run down, but the problem is not running it directly into wall.
I would favor T&G against a roof, purely because of the expansion and contraction during day & night, plasterboard I'd mount on a suspended frame.

[noserhodes]

hi canoeman yes we have seen alot of t&g in lofts in portugal and for me that would certainly be the easiest option.
would that not be prone to woodworm or infestation though?
also would you have a rough idea as to prices on t&g? maybe it wouldnt be any more expensive than me plasterboarding and then skimming which as youve explained isnt really the best option.
the house has been built as a concrete spider with all floors concrete but not the roof
many thanks to you, you are really helping me out here

[canoeman]

Treat it first, local product clear around €8/5lts to cuprinol €40odd/5ltr, treat then first coat stain/varnish both sides before fixing. Most local woodyards produce T&G too long since I last used it for my prices to be current. B&Q type sheds around €12 m2,

Are the roof rafters wooden with wooden battens or concrete with concrete battens?

Plasterboard isn't exactly cheap here, but there are some very good specialists around, where abouts in Central Portugal will you be.

[noserhodes]

the roof rafters are timber with concrete tiles above and the loft does have three windows in it so i suppose the wood wouldnt make it feel too closed in. the area is near to proenca a nova,castelo branco.
having said that we still have another three properties near to the top of our list, but the one we really want is the one i have described near to proenca

[canoeman]

My plasterboard contact/contractors are way out of your area then.
The contrast between day and night temperature is enormous, so if you intend using the roof space insulation is extremely important, you should also check that roof space is included in rateable value, as you might have to declare it you make it inhabitable.

[noserhodes]

i agree it will definately need some form of insulation we only really intend to use the space for when family and friends come over to visit.
so i do need to check then that the space has already been declared habitable? the house is about 30years old and like i say the loft does have windows and does have a concrete staircase leading up to it
thanks again

[canoeman]

Rates are to a formula, so the loft as a room as opposed to an empty space? regardless of staircase.
We recently viewed a new build on Silver Coast, with a fully fitted bathroom and 2 bedrooms in loft/attic, but no staircase, which would have been added once all licences had been granted!