worried about install

hello, after finally choosing sunrise replacement windows, i was happy to hear that my windows were ready and made arraingements for the install, i noticed that the alluminum trim on one of my present windows looked loose, and was and was pulled away from the window. upon further inspection, i was horrified to find out that the trim under the alluminum was rotted. not only was the trim damaged, but the sill, and sheathing under the window, had water damage. to repair correctly, the vinyl siding has to be removed, and the damaged sheathing has to be cut out and replaced.i was totaly unaware of this and am sure that the company that is installing the windows are unaware of this also. they are coming out thursday to install. how should i handle this? im sure that they run into this alot, but am worried sick about it. need some help and insight. thanks.

i always make sure that my contract states we will replace/repair a certain number of rotted sills ; any additional will be x amount.
if you did not have that stated in the contract, it may not be included. i would obviously bring it to the installers attention. it may simply be a case where they automatically replace a certian number by default and that was taken into consideration when the pricing was determined. however, if it wasnt and its not stated in the contract, work out something between you and the installer.
not sure about the sheathing under the siding being an issue for a window installer, thats a different issue all together.

thanks for your response. yeah, i realize its not the installers responsibility for the sheathing. im hoping to work something out with him. but the windows cant be installed in a rotted sill, and the sheathing is nailed to the sill .

I'd contact the company prior to install. Have them come take a look, and give a bid on the additional work if necessary. It will be much smoother than if you just pop it on the installers when they show up. This way, they will have the necessary materials on-hand, know what to expect, etc.