Insulating Roof From Outside
 

I have an older home that I want to renovate. I’d like to keep the bulk of the ceiling, with its beams and beadboard intact. So, I am contemplating insulating the roof from the outside. I realize this is not a novel concept and that it essentially calls for building a roof over the existing roof (after stripping the existing roof tiles).

Has anyone done this? If so, is there anyone you would recommend to do it? It seems like this would be a specialty that combines roofing and insulation expertise.

I would think a roofer could do it.
It may be a lot more detailed with the eaves and trim details, but an experienced roofer should be able to handle that.

They did this on the rehab of the A frame across the street from me. They stripped off the existing roof shingles and used 2" foam insulated 4x8 sheathing right over the old roof sheathing.
I'm not sure what the R value is but they also wanted to keep the original beamed ceiling. The original sheathing was 2" tongue and groove pine boards, so they ended up with a 4" thick roof.
It passed the building code inspection so it must have been enough of an R value?

Will you be considering using metal roofing? if yes the solution is simple. Have your roofer install 2x4s 2 feet apart as the purlins and place 1.5 inch foam board in between. Tyvek or similar vapor shield would also provide an even bigger improvement but may not be a good idea on an older home because it will trap too much moisture. The purlin/foamboard solution on it's own should provide a huge improvement in both heat retention and sound control while still allowing for sufficient ventilation. Older home? talk to a seasoned local expert!

Thanks for the comments.

I don’t know if there is any advantage, but, although it may not be the look here, I like metal roofs. I’d definitely go with a cool roof.

Tyvek (a roof would be Epilay or Triflex) shouldn't trap moisture.
They are designed to allow water vapor to move from the inside to the outside.

I did some reading and, aside from longer life expectancy, it seems that there are some heating and cooling benefits associated with a metal roof.