I am designing openings in a concrete basement wall to receive operable vinyl windows measuring 24×24 RO. There is no concrete header over top, the window RO extends to the underside of the mud sill. The wall above has its housewrap flush with the exterior of the concrete wall. The 3/4″(?) rainscreen battons and cement siding clapboard extend about 1″ beyond the concrete. Therefore the windows above in the framed portion would be mounted to the battons (or heavier trim flush with the outer surface of the nearby battons). The windows below in the concrete wall would then be mounted more or less flush with the concrete surface and the trim applied over the nailing flange and adjacent concrete wall.
Is this fairly normal?
How do I size the concrete opening? Is it simply the normal window RO plus 3″ for 2×6 mounted to the concrete opening?
Thanks
John
Replies
RO
The concrete rough opening should be sized 3" to 3 1/2" larger than the the rough opening required for the window. This allows treated wood bucks to be fastened to the concrete that the window fins can be naile to.
To add to the above.
I'd apply sill sealer to the backside of the 2x6 window rap, adjust the opening as necessary. Provides a seal while giviing you a moisture block. Orient the wrap and fasten to prevent cupping of the wood.
That sounds like it'd work fine. The only detail is the trim/finish above the window and below the wall finish above. Maybe you need more head jamb material for the finish work? Also what's the interior finish to be?