Flooring attic for storage

[hfp]

Have decided to get flooring down in my loft solely for storage purposes and it seems that the best option is going to be to lay a raised floor to allow for the mountain of insulation and cabling. At the moment there is a single timber support beam bracing the width of the roof which I can currently duck under easily enough but I fear that once I raise the floor doing the limbo will be required!! Does anyone have any idea of how big a job it would be to have the beam removed and replaced with an alternative support away from head height and the likely cost?

 

[Drakon]

I did something not dissimilar last year. I divided the attic into two, half for insulation only, and the other for reduced insulation and storage.
For the former I used the standard rolled insulation. Topped up the joists and maybe 300mm of insulation on top of this.
For the storage area I topped up the insulation to the top of the joists then put down XtraTherm Walk-R loft boards. These are just shy of 100mm in thickness, so should not overly worsen your ducking situation.
I was lucky that the electrical cables had plenty of slack so I was able to route these along the external extremities of the attic and cut channels in the insulation where they come across for sockets, lighting, etc.
Obviously I've only got a third of the thickness of insulation on top of the joists compared with the other half of the attic, but that's the trade off if you're to use your attic for storage.
In terms of cost I can't remember. I could have saved money by using insulation (only) PIR boards then putting my own chipboard on top. But there are advantages to having the pre-bonded version.
There's some sort of grant available at the moment for insulation your house but obviously it'll cost you more to go the grant route than do it yourself.