toddmanqa1

I'd like to deepen my existing window wells to accomodate larger windows.

I've read that 'If the bottom of the window well is less than 1,800 mm (6 ft) above the footing, consult a geotechnical engineer about protecting the footing from frost action.'

and (this refers to stairs, but I think it would apply to window wells as well):

'When an exterior basement stairwell is added, the stairwell opening effectively lowers the exterior grade level, and also lowers the depth to which frost can penetrate. After the stairwell is in place, the frost can theoretically go down as much as four feet below the bottom of the stairwell opening. This can lead to localized frost heaving of the footings and the foundations.'

What would I need to do to avoid these type of problems? 2" of exterior foam on the whole wall?

I live in upstate NY.

Wuzzat?

Somebody may have software that can do an exact analysis of thermal problems like this.
Getting this answer by experimenting is probably out of the question for most people.

So. . .

First, try your local permitting dept. for info of this type.

My copy of the International Residential Code talks about insulation for this purpose; you might take a peek at the latest version of this book in a tech. bookstore.

Lastly, Border's may have a copy of the fat little handbook that Civil Engineers use to solve problems like these. Take a peek.

Here's a link that brings up several factors affecting this problem
http://oikos.com/esb/43/foundations.html