Spray foam

Ive been roofing for years.Over the last 10 years or so have studied,learned and up graded many home ventilation problems because of people not getting full performance out of their roofs
My next door neighbor’s century home had a old uninsulated "shed"type room on the back.A couple years ago I helped him do the roof on it,installed ply wood over the plank deck and all because he wanted it right to last,and thought trained him about the importance of ventilation.It has no soffit and to ventilate it and he was on a tight budget,I installed some leak proof pot vents at the bottom for intake.I KNOW IT NOT IDEAL,but it works.I suggested that if he ever insulates it to put moore vents under the vents to get the airflow up over the insulation.

He recently got the room spray foamed.The insulator told him you don’t need intake or exhaust,so sealed it up.Called it a “hot roof system”,he says no moist air coming up into the attic no vents required to get rid of it.In my opinion the new shingles are now gonna bake because of no air space,air flow,it goes against everything Ive learned and preach.
Now for my question.
Whats everyones opinion on a hot roof system?

[quote=“ontario shingle wizzard”]Ive been roofing for years.Over the last 10 years or so have studied,learned and up graded many home ventilation problems because of people not getting full performance out of their roofs
My next door neighbor’s century home had a old uninsulated "shed"type room on the back.A couple years ago I helped him do the roof on it,installed ply wood over the plank deck and all because he wanted it right to last,and thought trained him about the importance of ventilation.It has no soffit and to ventilate it and he was on a tight budget,I installed some leak proof pot vents at the bottom for intake.I KNOW IT NOT IDEAL,but it works.I suggested that if he ever insulates it to put moore vents under the vents to get the airflow up over the insulation.

He recently got the room spray foamed.The insulator told him you don’t need intake or exhaust,so sealed it up.Called it a “hot roof system”,he says no moist air coming up into the attic no vents required to get rid of it.In my opinion the new shingles are now gonna bake because of no air space,air flow,it goes against everything Ive learned and preach.
Now for my question.
Whats everyones opinion on a hot roof system?[/quote]

Some think that the whole “baked shingle” thing is just the manufacturers trying to cover up & deny liability for bad organic shingles.

I have limited knowledge of spray foam, it’s more a question for an applicator.

From what I understand there are 2 main ways of insulating the attic with spray foam.

  1. Spray the attic floor and vent as normal. (ie cold roof)
  2. Completely encapsulate the roof from the underside making sure there is no air movement at all. I’ve had issues on several houses
    that had this type of system because if any air/moisture gets into the system for any reason at all it has nowhere to go and will cause mold.
    IF you need to change a piece of roof decking, soffit, fascia…whatever that has the spray foam stuck to the back side you’re breaking the "seal"
    and the entire system is now compromised.

Personally I think it’s crap; if for no other reason than it makes future roof repair impossible with regard to wood replacement. I would never have
it on my house. As I stated though, this isn’t my area of expertise, you’d need to talk to a knowledgeable insulator to get a full understanding of
the system. I’m calling shenanigans on the spray foam though.

Hot roof has satisfied thousands of customers who have chosen this system. This is by far one of the most energy efficient method to insulate any structure. So i think this type of roof can be preferred by people whenever they need house roof repair service as it satisfies the customers requirement.

It also acts as a vapor barrier that if not done correctly can lead to massive mold issues.

It is also approved by shingle manufacturer. CertainTeed sent out a memo regarding this (Technical Bulletin #R-201B)

“…coverage will remain in force…shingles (that) meet ASTM D3462 are applied to roof deck assemblies (with)…nail-board insulation,…insulation is installed beneath…roof deck, or where radiant barriers are installed, with or without ventilation directly below the deck.” (Some restrictions apply)