Stud wall Thickness

[danr86]

Trying to build a stud wall using 2 x 4 with a doorway and 12.5mm plasterboard.
So in theory 4" = 100mm
Therefore 100 + 12.5 + 12.5 + 6 (for skim) = 131mm and a door liner / casing is about this size. However i've noticed 2 x 4 wood is only about 95mm thick - how should I make up this difference - extra skim?
Also, what's the best type of 2 x 4 to use for a stud wall - sawn KD / CLS etc?
I'm looking in Selco at the moment but if anyone knows any better places for timber around Stratford / East London that would be appreciated.

Cheers

 

[noseall]

In t' olden days before cls finished timber was widely available we used rough sawn. This finished a couple of mm thicker than todays' cls.

Door casing widths were standardised according to the older graded timber sizes and were better suited regards skim thickness although the more recent cls offers a larger degree of alteration when uprighting the casing.

If you happened to have some real thick 4" x 2" back then you barely had room for skim at all!

Your best bet is to make up the difference with skim.

 

[joinerjohn]

Much easier to have someone run the door casing through a planer /thicknesser, thus reducing the casing to suit the width of the stud/p,board,skim.

 

[danr86]

Problem solved - Selco do 125mm (120mm) door casings to go specifically with 2 x 4 cls timber for stud walls. Thanks for the help guys.