Hello all. I'm looking for advice or re-assurance that I'm not an idiot 
My wife and I have just purchased a 1972 house.
Our existing loft is 48.16m2 (5.6m x 8.6m) with joists at 450 centres using 4"x1" timber. The insulation is currently about 15mm thick, which is a joke. The current loft hatch sits between two joists (380mm x 580mm after enclosure) and is directly above the balustrades making it hard to access with a small opening.
My plan is:
1. Counter-batten the joists with 3"x2" Timber. I'd lay it flat (2" high, 3" wide) and use either 2 1/2" x 12mm screws, 3" x 10mm screws, or 4" x 10mm screws (thinking 4" best, just for that little extra bite). I'll leave 400m between battens (450mm centres)
2. Remove a section of the joist to the inside (over the landing) of the loft hatch and install one of these bad boys (http://www.diy.com/nav/build/ladders/loft-ladders/loft_ladders/Abru-Blue-Seal-Complete-Loft-Access-Kit-35002-L-111-x-W-55cm-9273865)
3. Throw away old insulation (I found a dead bird in the loft this week, I either want to disinfect the area, or bin insulation. Bin insulation seems cheapest and easiest).
4. Lay new insulation at 170mm depth (yes, only 150mm to top of counter battens, but I can't find 150mm depth insulation - not including £12 space blankets for less than 2m2 coverage).
5. Stick some 18mm T&G chipboard on the counter battens. I may screw this down using the 2 1/2 x 12mm screws, but probably not. I plan to leave 50mm - 100mm at all edges for ventilation
The new floor will be used for walking on and for storing light items (empty suitcases, empty boxes, christmas decorations, etc...). I might also hide up there on occasion if I can't stand the company downstairs.
Am I being an idiot? Appreciate your input.
N.B. I know the artex on the landing ceiling is asbestos. I will be soaking and cutting with a sharp blade to remove the texture before cutting out the ceiling for the loft hatch.
My wife and I have just purchased a 1972 house.
Our existing loft is 48.16m2 (5.6m x 8.6m) with joists at 450 centres using 4"x1" timber. The insulation is currently about 15mm thick, which is a joke. The current loft hatch sits between two joists (380mm x 580mm after enclosure) and is directly above the balustrades making it hard to access with a small opening.
My plan is:
1. Counter-batten the joists with 3"x2" Timber. I'd lay it flat (2" high, 3" wide) and use either 2 1/2" x 12mm screws, 3" x 10mm screws, or 4" x 10mm screws (thinking 4" best, just for that little extra bite). I'll leave 400m between battens (450mm centres)
2. Remove a section of the joist to the inside (over the landing) of the loft hatch and install one of these bad boys (http://www.diy.com/nav/build/ladders/loft-ladders/loft_ladders/Abru-Blue-Seal-Complete-Loft-Access-Kit-35002-L-111-x-W-55cm-9273865)
3. Throw away old insulation (I found a dead bird in the loft this week, I either want to disinfect the area, or bin insulation. Bin insulation seems cheapest and easiest).
4. Lay new insulation at 170mm depth (yes, only 150mm to top of counter battens, but I can't find 150mm depth insulation - not including £12 space blankets for less than 2m2 coverage).
5. Stick some 18mm T&G chipboard on the counter battens. I may screw this down using the 2 1/2 x 12mm screws, but probably not. I plan to leave 50mm - 100mm at all edges for ventilation
The new floor will be used for walking on and for storing light items (empty suitcases, empty boxes, christmas decorations, etc...). I might also hide up there on occasion if I can't stand the company downstairs.
Am I being an idiot? Appreciate your input.
N.B. I know the artex on the landing ceiling is asbestos. I will be soaking and cutting with a sharp blade to remove the texture before cutting out the ceiling for the loft hatch.