Ridge venting a modular

[Cburg]

We are installing a new single roof on my son’s 35 year old modular home. We found a lot of deck rot near the gutters and are planning on just replacing the deck 4ft up along the whole roof. This will let us blow in more insulation at the same time. We found only 1 inch of insulation above the ceiling. We plan on using foam spacers and batten insulation at the lower ends of the roof (by the gutters) to both maintain the vented air space near the roof and keep the blowing insulation from blocking the sofit vents. We have also decide to use ice/snow shield under the whole roof since the roof is only 2/12 pitch.

That was the plan but here is the problems/questions.

First, we found there were NO sofit vents under the eves. Second: when we removed the old ridge vent we found it was not doing anything. This was because when the home was made they used plywood on the ends of the trusses so the attic air could never reach the ridge vent.

If we cut the roof open on down side of this plywood it will result is a vent being very close to edge of the new ridge vent cap. I am concerned that we may not be able to seal this ridge vent properly (there will be only about ¾ inch of wood)

We were planning on adding sofit vents (under the eves) once the roof was finished. But in when looking for information about wider ridge vent for modular homes I have come across research that suggest that this attic space my have been sealed by design.
There are four small vents. ( 2 on each section) one is located over each bathroom and the other 2 are just evenly spaced 2/3rds up the roof. But this is the only venting on the whole roof.

I am now at a loss just what to do at this point? The roof is stripped of the old shingles. We are about ready to begin to add insulation.

We live in western PA zip code 16214 if this helps you determine our climate.

What do you suggest we do (or not) do about Venting?
Any help suggest would be great! Thanks in advance!
Carl

[trmimo]

This roof was not sealed, but just poorly vented. It didn't need much venting because it didn't have much insulation. If you have a full height plywood ridge beam, your best bet is to use square roof vents rather than a ridge vent. You will need to put vents on both sides of the roof.