Rubber tiles on a flat roof for Insulation

[DaveSheps]

Hi - newby - be gentle!

I have a small (16m2) GRP flat roof- it’s in good order and perfectly serviceable - 100% waterproof and is a “cold roof” design - the problem is it’s very cold as the insulation in it is pretty crap.

I don’t want to pull down the ceiling to add insulation (long story!) so I could strip of the exiting good roof and add insulation or overlay etc ... but I was wondering if anyone had any thoughts on just laying a couple off layers of these on the existing layers ? Would it add any appreciable amount of insulation and/or cause any problems ? https://www.ebay.co.uk/itm/263374890129

 

[Alastairreid]

Wouldn't be much more to overlay with kingspan, plywood and epdm....warm roof.

 

[Notch7]

Hi welcome to the forum.

if your roof is a cold roof construction, then the roof void will be vented to the outside...so anything you put on top of the existing roof externally wont do anything.

you best option is as Alastairreid says: convert to a warm roof.

 

[JP_]

How tall are the ceilings? You could always put insulated plasterboard over (under) existing and skim/paint. Would probably be the least disruptive option.

 

[DaveSheps]

Hi welcome to the forum.

if your roof is a cold roof construction, then the roof void will be vented to the outside...so anything you put on top of the existing roof externally wont do anything.

you best option is as Alastairreid says: convert to a warm roof.

Thanks for the feedback folks

Update on this - have been and had a look and can't find any ventilation of the roof void ! so it looks like I have an unventilated cold roof! All looks very dry (surprising in a kitchen?) so no obvious condensation problem but then its a very old house (17th century) so "ventilation" is rarefy an issue as the wind howls through the place !

Anyway I get what you guys say about overlaying with a warm roof is actually the best/correct solution but there are a few other issues with that (to do with upstands on roof lanterns and listed building consents etc )that make it quite difficult/expensive - so ......

... given it appears I don't *actually* have a proper cold roof would say 60mm of these tiles have any appreciable insulation effect on an unventilated roof void and ... more importantly .... would I be making an already bad situation of an unventilated and badly insulated roof void any worse if it did improve the insulation

I'm guessing it either has no thermal effect (so I've just wasted some money - not the end of the world) or it does it make the existing roof structure a bit warmer which (I'm guessing here!?) should make any condensation issues I can't (yet) see a bit better - or do I not understand the thermodynamics here (highly likely!)?