During inspection of a 100-year old home we discovered that there is water damage to the interior drywall under some of the Pella hand-crank casement windows installed in ~2014. Mold tests revealed the presence of mold which we will be mitigating. On the exterior windows are slightly recessed inside stucco. Photos of the interior and exterior are below.
Does anyone know based on these photos what the installation technique was. What is the likely cause of the leaks?
What is the best way to diagnose/repair them to prevent further leaks?
Note:
1) You can see there is some vintage wood framing visible.
2) There are gaps at the corner joints in the exterior vinyl frame. It appears someone has smeared sealant on the gaps but the gaps have re-opened.
Replies
It looks to me like replacement windows were set from the outside into existing older frames.
plastic trim added to the outside to cover the space.
Just guessing, you may need to remove the plastic exterior trim, see what is going on. Perhaps remove the replacement windows, and make sure flashing is installed to divert any water around the replacement window, and at the bottom, over the original sill, to the outside of the stucco. (then re-seat the replacement window and seal it up.)
With the replacement window removed, you may decide the old frame has to go and be replaced due to mold and rot.
Thank you, UncleMike42. We have hired a window contractor to inspect the windows and he replied already based on the photos:
"I could see the gaps these windows were installed with an exterior applied flange my recommendation would be to re-order windows so we can be able to install them as new construction since the original framing is beyond repair."
Do you think such a full window replacement is necessary to repair these windows?
My guess is it may be more economical. (and end up with a cleaner result)
With the original frames beyond simple repair, and the existing windows sized to fit the original frames, you would have to gut and replace the old framing, then re-install the window.
While sized-to-fit custom replacement window installation is done every day by the window crew, rebuilding a 100 year old window frame is not.
Ordering new windows may also get you a little more window area.
I've seen Pellas leak at the inside corners before and while you can caulk them the long-term prognosis isn't good. The trouble is you can't see them leak until your baseboard is stained. I'd be thinking about new windows, not replacements.