Crawling on loft insulation?

[Agile]

I was thinking of adding 50mm insulation boards across the joists to supplement the 100 mm glass fibre between the joists.

The cheapest is just polystrene but that needs chipboard across the top for walking over. The designed loft flooring is quite expensive but the sheets would need a bit of work cutting.

Are there any stronger 50mm insulation boards which could be crawled over at a not too high price?

Or is polystrene and chipboard always going to end up being the cheapest option?

Tony

 

[PrenticeBoyofDerry]

If you have any electrical cable in this area, I would forget polystyrene, it reacts with the PVC on the cable.
If your current joist are full, I would run some more joist at right angles with them and fill the void with rockwool and the board on top of that.

 

[Agile]

I dont want to raise the height so much and I want to keep the weight down to a minimum.

Tony

 

[PrenticeBoyofDerry]

If you install 50mm joist, the height will be the same.
The difference in weight will depend on the area of the loft space.
I have seen loft boards with insulation fitted to the underside.
http://www.insulatedloftboard.co.uk/

 

[freddiemercurystwin]

Or is polystrene and chipboard always going to end up being the cheapest option?

Polystyrene is cheap because its cr*p!