With only 3 days notice, the carpenter that was going to fit my kitchen has
hit me with a 6 week postponement. Unfortunately it's too late for B&Q to
re-schedule the delivery, so from Saturday morn every room in my house is
going to be stacked with kitchen components and appliances.

So I've decided to do it myself!
Don't forsee any problem with the cabinets. I'm flat-pack capable, and
proficient in electrics and plumbing, but rather novice carpenter.

Main problem is my existing kitchen floor has about a 75mm fall in one
corner (over a 3.8m x 3.1 floor). The (1900's) house was gutted and fully
renovated 10 years ago including roof, internal walls, stairs, electrics and
plumbing, but for some reason they didn't level this floor, which leads me
to think it may be a bigger job than I could do. It is on the 1st floor, so
fully suspended. The ceiling of my office below has a similar matching
slope. There's been no cracking since the renovation so I guess it's old
movement.

So we have resolved it by designing a 'split-level' kitchen to sit on a
raised, level, false floor section covering 3/4 of the room on top of the
existing floor. I have 6" x 3/4" laquered pine floorboards to go on top. The
breakfast bar area and doorway stay on the existing floor at the more level
end. (bit hard to explain this - sort of walk in and sit at breakfast bar,
or step up into cooking area).

So I need to build a 150-200mm high, or so, 'false' floor over the existing
one, except level!

What I don't know is the dimensions and spacing of the frame members I need
to construct this raised section from. Any suggestions?
Should I remove the existing floorboards and build it onto the joists or
just put it on top of them, nailed through?

I'm guessing 2 x 4s spaced about 600mm apart, blocked up at similar
distances along them to level. Is there a building regulation covering
this?

Also should the staove gas & electric that have to be relocated be run under
the false floor , or above it ander the cabinet units?

Any hints, tips and suggestions appreciated.

Steve