At the moment I have regular ceiling joists ( 75mm ?) in the loft of my 1930s semi. The roof joists are supported on purlings. I have just had eaves ventialtors fitted along with ventilator tiles fitted near the ridge to avoid condensation problems. I now intend to update the insulation from the old thin insulation currently fitted to 200mm-300mm
The ceiling joists run from the front to the rear and a section is boarded over for storage. This section occupies half the width of the loft spacebetween the party wall and the load-bearing dividing wall running down the centre of the house from front to back. The boarding sits astride another wall running across half the width of the house (ie the dividing wall between the front and rear bedrooms - also a proper brick wall rather than a partition ). The loft boarding extends 5 - 6 feet either side of this wall.
I want to get a decent thickness of insulation and improve the load bearing of the boarded area. I was considering running a few joists across the existing ceiling joists at 90 degrees and supporting the ends on joist hangers at the party wall end and sitting on the front-to-back wall at the other end. Then I would put nice fat insulation between the joists and board over.
In addition, I was thinking of laying a vapour barrier below all the insulation that would end up under the boaring to prevent any condensation under the loft boards.
Does this seem reasonable?
Thanx in advance for any advice