HOUSE IN MALLORCA - HOW TO INSULATE CEILING/ROOF?

[Lisa T]

I have purchased a little stone house in Mallorca and need to insulate the roof as it is like an oven in the summertime and very cold in winter. The walls are 600mm thick stone so no issues with those! The roof has been renovated with concrete beams (horrible!), terracotta rectangular flat tiles on top of the beams and then typical red arab tiles overlapped on top to form the outer roof. I am thinking of using polystyrene panels covered in aluminium foil to reflect the heat and then building a wooden framework over the beams internally to attach thermal plasterboards to. Would this provide a really good level of insulation?

 

[^woody^]

NOT REALLY.

 

[Lisa T]

Hey Woody - thanks for the useful comment!

 

[motorbiking]

be careful about using fire/toxic materials. You could use a standard loft roll and then use a tonge and grove covering. Or you could use something like celotex.

Are you heating via aircon?

 

[Lisa T]

It says the polystyrene is fire retardent. I will be doing a plasterboard ceiling and fitting led lights into it. I will probably have to get reverse cycle air con for cold & hot but do have a wood burning stove and may be fitting underfloor heating alsoas the winters can be VERY cold!

 

[motorbiking]

Do you have a link to what you are talking about? Have you done any calculations to determine heat loss and energy required? Your stove should be good for at least 3kw, depending on type, fuel and size.

 

[Lisa T]

No I haven't but I just need to insulate the roof. The stove is 4.5kw and the space in question is only 24 sq m so sufficient amount of heat generated. Anyway, back to my original question of aluminium backed polystyrene and thermal plasterboard - do you think this will work well enough?

 

[motorbiking]

It's entirely dependent on the product you use and your installation of it - sorry but without knowing the specific product you are considering - nobody can say.

is it like this :

If you are able to get something like this in a 70mm+ thickness then I think you should plan for about 10-15kw of heat needed based on your comments on the walls and no knowledge of the floor and windows. So a decent 10kw aircon unit and your log burner should be good to get you 18-20 degrees from zero

 

[Lisa T]

Yes it will be similar - but more keeping te heat out in the summer is th biggest issue. I'm pretty certain that using the 2 methods I should be fine. Thanks.

 

[David Frank]

I have a similar issue with a house in Andalucia. First floor ceiling is terracotta type blocks in concrete beams under a shallow tiled roof. It's a fridge in winter and an oven in summer. I am considering pretending it's a wall and using celotex PIR with bonded plasterboard and vapour control layer fixed direct to the ceiling. Link below.
https://www.celotex.co.uk/products/gd5000
Can anyone see any problems with this?