Why is the water getting in? Is the wall rotted out?

How have they determined that the wall needs rebuilding? This requires selective demolition at the least.

Thanks! Maybe I will get a second opinion?

I think he said there is dry rot or risk for dry rot?

The glazed units don't have exterior sloped sills which should be corrected. Are they operable? The only way to know the extent of the damage in the walls is to remove some of the interior finish and take a look. I wouldn't sign a contract or let work start based on a guess.

Thanks JDS. The glass panels are fixed. I left a msg. with the ctr. who might be doing my addition. I'm hoping he can look at it or recommend someone else to get a second opinion. I'll pass on your recommendations.