I have two load bearing walls running down the centre of my detached bungalow, spaced apart at 3.3m for an overall building width of 8m. I want to use this central space in the attic for storage so need to have twenty 2x10 joists fiited spaced at 40cm. These walls are interior only and I can supply 3.6m lengths of 2x10 but they are too heavy for me to get up into the loft myself. Access is thru a hatch in the (long) hallway and the gable roof is very high so there should not be a problem getting them up there. There is insulation running over the current joists plus wiring so the new joists would need to sit proud of the interior walls by an inch or two. Being a 1946 house the current joists are a bit undersized so no real use except for holding up the ceiling though safe enough when spanned over the hallway which would have to be the starting point for putting the new joists in. You would basically have to build it up one joist at a time outwards from the centre of the house so it would be a one or two man job rather than a whole team.
Just wondering what the approx cost would be (I am in Devon not London BTW)