I wish to board my already insulated loft in which existing insulation is just above the top of the joits. Can I board directly onto the joists or do I need ventilation/air flow space under the boarding.
... But, bear in mind that the insulation works by trapping air within the fibre-glass. If the insulation stands proud of the joists, by squashing it down to install the boarding you will reduce the amount of air in the insulation and therefore its effectivness.
Hugo Slim, December 2009
Hi George.
No air space needed, if you leave and air space condensation could build up on the under side of the boards.
Hope This Helps
