Converting ventilation for insulation

[akpingel]

Hi everyone,
My wife and I recently bought a new-to-us home that included a 30x50(!!!) shop. It is older construction, probably built around the time of the house which was 1975. It has exposed 2x4 2' OC fink trusses across the 30' span, and it has a relatively new shingle roof on it. I would like to insulate the shop with a few stages over the next few years. My question is in regards to ventilating the attic space after I have sheetrocked & insulated the ceiling. Right now there are two vents at each end of the roof, just plastic vents, probably 1'x1'. There is no ridge vent or soffit vents. I imagine this is going to be inadequate once the sheetrock is up. My plan would be to vent the soffits between every truss, and add turtle vents near the ridge. Will I risk over-ventilating the roof, if that is even a problem?

Any other comments, suggestions on ventilation?

Thanks,
Alex

 

[The Cobbler]

you can never over ventilate an attic space
more is better

 

[Diesel Dan]

Vented soffit, ridge vent and seal the gable vents.

 

[akpingel]

Vented soffit, ridge vent and seal the gable vents.

Didn't consider a ridge vent, but after reading a little about them it seems the install is simple. Thanks!

 

[matt_i]

I'd recommend same, saw open the roof peak about 1-1/4" each side, don't cut too deep.

Depending on how the last course is nailed, you might have to pre-nail the partial-tab that's still up there.

Ridge goes on very fast after this, and then some cap shingles.

The ridge vent will have a "net free area in square inches per linear foot" rating published. Ideally you want to match that same area per foot on the soffit end for the best flow.

 

[yeldogt]

Location?

I have not built with a ventilated attic .. lets see .....25 years .. Have never built with a ventilated crawl space.

The worst thing you can do is install a powered roof vent.

The only time its needed (ventilated attic) is if you have a whole house fan exhausting to the attic.

If you seal up the floor under the attic and insulate properly -- no need to ventilate

 

[akpingel]

Thanks for the feedback all!
I'm in North Carolina. I am planning to do a ridge vent and soffit vent. I just got a couple of temperature controllers and am going to take some before/after data to see what happens.

It will probably be some time before I get to this, so I am planning on putting in an exhaust fan to the existing ridge vent in the mean time.