We have a client with a Ranch home 42’x32′ located in Climate Zone 5 that has the following existing conditions:
– 2 layers of asphalt shingles over 1/2″ plywood sheathing on top of 2×8 rafters @ 24″ OC
– The roof has a continuous ridge vent + Gable vents at each end wall + a thermostat controlled vent fan on one gable end. There appear to be NO soffit vents
– (3) skylites that need replacing
– Attic insulation consisting of R-19 fiberglass batts installed on top of drywall ceiling that is 2×6 joists @ 16″ OC
– Attic access folding ladder with no sealing or insulation

Client wants to:
– Tear off and replace existing shingles with new asphalt shinges
– Replace the (3) skylites and re-do the drywalled light wells and insulate those light wells to eliminate condensation issues
– Upgrade the insulation in the attic
– Create an insulated cover box for the ladder to stop drafts and energy loss

Questions are:
– Replacing the shingles is easy enough….but do you keep or eliminate the ridge vent? and/or the gable vents? 
– We will reframe the skylite light wells and add 2″ rigid foam around the entire assembly on the attic side to eliminate condensation
– Improving the attic insulation?
—Remove all of the existing fiberglass so that we can get to and seal all of the air leaks/penetrations in the existing ceiling and than add r-49 of blown in cellulose on top?
—OR just install 12″ of blown-in cellulose on top of the existing fiberglass. I have a quote for this of $ 1350
—OR spray foam the underside of the roof deck and the end walls with closed cell at 4″ thick…wrapping the rafters at the same time…I have a quote for this of
$ 6500

Thanks in advance!
Jonathan