The method that you have suggested for boarding out the loft is good and will enable you to ensure insulation is maintained to a reasonable depth.
All lofts have a residual capacity and you should be able to store materials within your boarded loft.
We would advise if you do have very heavy items or a combined group of heavy items that these should be placed near support walls or be distributed around the loft.
Look forward to seeing some photos of your finished project.
Jeremy Wedge MIstrutE CEng on behalf of Loft Conversion UK
