Odd;" the wall is around 9-10 inches deep" Thick?
2X8 and or 8" block?

Was this an in-frame style change out, where the windows and their frames were removed without removing or breaking any stucco and the windows were just set and caulked.

Tell the whole story, none of us have been to your house.

Luke:

With all due respect, by the questions you're asking you sound like you're in over your head.

The Andersen specs you're reading are for new construction. It takes a great deal of skill and knowledge to bridge the gap between old and new.

Unless they are simply too far gone to repair, the original windows are nearly always a better option than replacement ones. In situations like this with an out-of-the- ordinary wall configuration, it's doubly true. Replacement windows have been over promoted, to put it mildly, and almost never live up to there claims of energy savings for very long. If it's possible to return the new windows and concentrate on the original ones, you'd be better off doing so.

Trade them in for energy efficient storm windows (available in eglass) and repair/maintain/weatherstrip original sashes, get insulation and air sealing in attic to eliminate updraft effect which may be pulling cold air into your house.

And have money left over.

take photos and measurements of your existing openings and windown and contact anderson technical help, you will get a human on the other side and they will give you an email address to send your pictures and specs to. they also have an online form you can fill out for technical questions.

anderson has been very helpful and responsive to me, we did our entire home in their products, as well have anderson in our rental property, they stand behind their products.

Post this in the "window forum" here at GW, there are many pro's there who will be happy to point you in the proper direction.

Hi , thanks for all ideas. The old windows were double hung and I replaced with casements.Since the interior walls were not insulated I framed the whole inside with 2x4 (or 2x6) wall. That new interior wall has the rough openings.When I place the window into R/Opening then how to fill the gap between the interior 2x4 wall, and the existing cinder block wall and properly flash it?
Attached please find the pictures of the opening and wall

Another picture:

A couple of choices.
Bring the framing to the same plane as the block and use wood, drywall or MDF to jamb the openings.

OUCH, my eyes! Just kidding.... window forum or remodeling forum would be helpful with pro's in those areas. Old House forum was started by request a few yrs back from those of us with more preservationist sensibilities. HTH.

You will need a good sill pan flashing under the window and extending to the outside of the exterior wall. You can use pre-formed ones--if you can find one deep enough--or make your own from a cold applied self adhering membrane or aluminum coil stock. I've had aluminum eaves cos. fabricate pans on site.

You might want to add a backdam, simply a vertical board at the bottom interior of the window frame, as in the drawings below.

The purpose of the sill flashing is to gather any water that might leak in around the window, or through the window, and direct it to the exterior drainage plane or exterior of the house in this instance.

Sill Pan Flashing

This post was edited by worthy on Sat, Jan 18, 14 at 18:20

Thanks worthy for a good solution: this helps since I can get aluminum or copper in sheets and fabricate wide drip pans to size.
How would I seal the sides though? I can't housewrap right now, since stucco will get done later , maybe in a year or two and the membrane hates UV.In other words : I need a solution for the sides and tops, that will work with future stucco mesh/coat.Maybe just wide aluminium angles just like the drip pan , or is it overkill?

Metal, pre-formed products or cold-applied will all work. Just check their maximum sun exposure time. Considering the damage that can occur from leaking windows, it's hard to "overkill" this detail.

The closer you keep the new units to the exterior, obviously the less flashing you have to do. But that's an aesthetic matter.

Inadequate window installation invites water damage.
Source: National Research Council of Canada

This post was edited by worthy on Mon, Jan 20, 14 at 20:47

All good suggestions. I would set the new Windows to the original position of old and create a large interior sil.

As for the gap created between the old outside wall and your newly furred out wall that would depend on how you intend to insulate that interior wall. Batt insulation or closed cell spray?

Looks like you can get 5.5 inch Roxul in that new wall, then 6 or 8 mil poly and Tuck tape. No pink please.

Depending on budget spraying is the best option in my opinion. Fills all those nooks and crannies and provides a vapour barrier as well.

Do that sil connection correctly or just burn the money and more that you are spending now.

Not a bad idea to get a few installers in for quotes and pick their brains.