Timber windows do not need the same kind of clearance that placcy ones do and Joe is correct on this.
Let's not forget, wooden windows were at one time built in, so there would be almost no gap.
When i were a lad and virtually ALL widows were wood, the local joinery firm had axes (yes axes) in their tool bag when fitting wooden window frames.
The axes were as sharp as razors though and they would trim the sides with the axe and fine tune with planers if necessary. Some of the skilled guys did not need a planer.
We are fitting some stunning oak frames at the mo' and all require a firm tapping into place. There is about 5mm to 10mm clearance under the sills and a hairs width up the sides.
We are fitting them all with concrete screws so no need for permanent side packers in any case.
Let's not forget, wooden windows were at one time built in, so there would be almost no gap.
When i were a lad and virtually ALL widows were wood, the local joinery firm had axes (yes axes) in their tool bag when fitting wooden window frames.
The axes were as sharp as razors though and they would trim the sides with the axe and fine tune with planers if necessary. Some of the skilled guys did not need a planer.
We are fitting some stunning oak frames at the mo' and all require a firm tapping into place. There is about 5mm to 10mm clearance under the sills and a hairs width up the sides.
We are fitting them all with concrete screws so no need for permanent side packers in any case.