Frosty sills on new patio doors
To any pro installers,
I have three brand new Andersen Frenchwood gliders recently installed by a licensed contractor. I get condensation on the metal sills at 15-20 degrees outside and frost starts to form on them at around 10 degrees and less. When it gets below zero, the frost gets really thick. Andersen tells me that this can occur when there is no "thermal barrier" installed under the sill. My old Marvin patio doors never had any frost on the sills.
My questions are:
- What exactly do they mean by a thermal barrier?
- What is the proper method of prepping the sill for installation?
- If my contractor did not install these doors correctly, that is, without a thermal barrier, is he on the hook for removing the door frames and reinstalling them correctly? What recourse would I have?