in most of our projects, achieving an specific internal area is an important part of the brief and can eventually be bound into 'employer's requirements' and contract docs. in this case having the reference line of the wall on the inside is good practice in more ways than one - if, (read: when
), the wall construction changes, the internal face will always remain where it was preserving the area requirements.
in other cases, a 'building line' may be set so stringently by planning that it would make sense for the external face to carry the wall reference line and be set in stone.
as matthew says, it is a matter of choice for the user - depending on the way you work and factors from the project . . .
~/archiben
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