Loft hatch combined step ladder pre assembled

[riklee2003]

Hi Guys,
Can you advise???
I'm about to embark on a project of installing a pre assembled loft hatch and ladder kit, the sort that have a larger door with folding steps on the door.
I'm relocating the hatch into the landing ceiling from the bathroom.
I have a house that was built around 1900.
I think i have to strengthen the loft joists around the proposed opening/loft door before i do any cutting? i'e build up the frame work before.
Should i be aware of anything else structurally before committing myself to cutting the access hole for the loft hatch assembly.
I'm an aircraft engineer and have done some building work in he past, I have a good knowledge of engineering and have pretty much gutted the house and refitted it in the past 4 years. Should of thought about this before in the reconstruction process but i didn't.
Thanks for any support would grateful.
Best regards
rik.

 

[Symptoms]

rik - these things are very heavy, so once you've resolved the structural issues above, you need to have help with the installation (lifting & holding in position whilst fixing). Otherwise, if it's going to be a 'one-man-job', rig a block & tackle to lift it up and hold in position; some props would also be useful.