Rockwool V Expanded Polysytrene

Janrey

Hi,
Do any of the contributors have any opinions/suggestions as to which is better to use for external insulation,rock wool/mineral wool or expanded polystyrene? A house built in 1970's,cavity block.Thank you

BryanF

rockwool would have you believe that their product is recyclable at end of its lifespan, so that would be my choice.
please look around this forum at some of the External Wall Insulation (EWI) threads.

both materials are grand, its how they are detailed and installed is the issue!

will your guy
wrap and overlap the window opes properly, whats the detail around at the cills?
install vents in each room or just cover over your outside tap?
carry the insulation to the footpath/foundation or just stop at the plinth?
warp the insulation in above the soffit or just butt it up against it?

see the other threads the list goes on.. this is not intended to put you off, just so that you aware that there are good and bad contractors out there

Janrey

Thanks ByranF.Will do that.Can I ask what you mean by "wrap the insulation in above the soffit?

BryanF

there is a tendency for installs to stop the EWI at the eaves and not do their best to overlap the insulation with the attic insulation (ensuring ventilation of course) - something like this: http://www.energyquarter.ie/pages/house-b-upgrade/

Janrey

Thanks BryanF.I see what you mean.I gather that this would mean removing the soffit in order to let the insulation up and then re working the soffit? I see in the article that there is a qualification mentioned regarding pebbledash with expanded polystyrene being mentioned as acceptable.We have serious pebbledash on our house and that is why I was opting for the mineral wool with the 'soft' side being used on the dash.Thanks again

beyondpassive

Hi Janray,

I've experience of a project using Rockwool and Pebbledash on a nursing home, very robust. PM for installer.