Quick question about opening size

[SparrowHawk99]

Hi all,

Just wanted to know how much of an opening width should I allow for from floor to header?

Average door height is 1981mm

So from the FFL + 6mm underlay + 12mm laminate timber + door lining 32mm + 3mm gap top and bottom = 2037mm?

Or is it better to undersize the opening and plane the door?

When I fit the header does it need to be spot on level or can it be there about level and the opening squared off by fitting the lining?

Thanks

P.S Studwork is 2x4

 

[pinenot]

If you're building stud walls, allow 2100 if you don't know the final size requirement, you can put a packer in to suit if and when required.
It's always better to hang doors with no planing at all, if possible, but then that's a old piecemeal joiner for you, counting the pennies earn t.
Your calculations are spot on except for an allowance for out of trueness, I would always factor in about 1/8" (or 3.5 mm in modern terminology) i.e. floor not absolutely level, or a bit of warp in the door slap studs (always look out the straightest, least out of wind studs for your post slaps) You can pack any spaces and cover these with the wall board or the door architraves, as long as you're post legs are bang on straight/plumb and your header rail is at 45 deg. precisely, door hanging couldn't be simpler...pinenot