Correction .. Floor to “almost ceiling” windows . They are 10 ft height.

Vishal:

Of course it can be done. You and your contractor have to agree on flashing details.

In commercial storefront an extruded base flashing with a vertical interior leg is used.

Vishal,

Your contractor could consider using the 5/8" flooring depth to create a traditional backdam, subsequently installing a self-adhered flexible flashing vertically up the face of exterior sheathing, horizontally across the floor sheathing, and turning up vertically against the 5/8" backdam.

Building Science has a step-by-step guide that uses self-adhered flashing to create a sill plan. It shows a typical window installation in the diagram, but the sill flashing principles could still be applied for your application: https://www.buildingscience.com/documents/reports/rr-0407-installing-a-window-with-building-paper-on-osb-over-wood-frame-wall/view

Hope this helps!

Thanks,

If your window installer does not know how to detail this properly I would seriously look for another installer. Sill pans and flashing units this was is done all the time, everyday in fact. And the fact that he is unsure leads me to believe he is over his head, especially letting you know the fact that he doesn't know.

More consultation with window manufacturer/supplier/installer needed if one is involved.

These install similar to a sliding glass door. If you are on a slab, it might work better is there is a pressure treated sleeper to install fasteners on the bottom. Have two going, one with Fleetwood aluminum and the other with Anderson composite.

How to do this? Hire a more knowledgeable contractor.

Yeah, just from a basic homeowner's perspective, these aren't much different from a sliding glass door install where there are some fixed panels.

Do you have an architect? She may be able to assist.

These should be installed with sill pans with an upturned back leg between the window and the flooring as well as thorough use of proper window flashing around all sides and heavy polyurethane caulk sealant. It can be done. Your GC needs to consult with a window installer and a water proofer. Best of luck.

Thank you everyone for your help on this ! I really appreciate it. I will
Post some after pics

Hi Vishal,

We are doing our renovation in the SF Bay Area and our primary bedroom is very similar to your rendering and we are considering the Modern line as well. Can you please share if you ended up with the Marvin Modern line and if you were happy with how the install turned out ? Would love to get your recommendation on the dealer if so.

Thank you.