Airtightness at cavity closers

[WWilts]

New build in progress. Brick or stone outer. Block inner (carefully pointed, blocks themselves have independent test of very low air permeability). Plasterboard on adhesive frame & skim finish internally.

Cavity closers at windows/doors pose challenge. Uneven masonry finish. Builder used some silicon between closer and masonry. (pic)

Inclined to try putting a bead of Orcon F along that join. 

Sensible? Worth doing to assist with airtightness?

How long to allow for a test bead of Orcon F to dry?

[Mr Punter]

You can get all sorts of airtightness tapes where you stick between the window or door frame and the substrate - in your case the blockwork.  I would not try to use the cavity closer as part of the airtight layer.

 

You will do this after the windows are fitted and before you dry line.

[SimonD]

+ 1 to airtightness tape or similar. For masonry to other materials I've recently become a fan of the Soudatight LQ liquid membrane that also uses a goetextile tape to seal larger gaps.