There are various air/ventilation holes in the eaves, which will be partially or wholly covered if the 200mm topper goes up to the edge. Am I to leave a gap to allow the loft to continue to breath? Thank you
Thank you, yes certainly not breathable. I am planning for the 50mm air gap to be between this sarking and the Celotex, then insulated plasterboard over the celotex. Is this correct as I read elsewhere the air gap should be the warm side, I.e the celotex direct against the sarking??
No you ventilate over the top of the insulation. Ventilation in your case is particularly important as you have Monarfol plastic sarking which will really cause your roof to sweat, fortunately it didn't last very long on the market.
Good to know. Planning to add some felt lap vents in but i really don't feel any airflow beneath the plastic sarking when creating the gap. Still likely worth doing.
Hi, Make sure your loft has ventilation gaps at the eaves or is fitted with loft ventilation. Be sure to maintain this ventilation gap during and after installation