Shop fan ventilation specs

[olytdi]

My shop is 36x36 with the peak at 18 ft and 12 ft side walls. No roof insulation -- 2 inch blanket insulation on the walls.

Ridge has a vent full length and about a 2 inch gap in the sheathing at the peak for that entire 36 ft length.

Things get hot in the summer and I'm considering installing an air intake fan at the floor on the north (coolest) side.

My question is will the intake air create enough head pressure for the hot air at the roof to adequately ventilate out that ridge vent? This, opposed to putting a fan up high to **** the hot air out -- which would necessitate an additional air intake at the floor anyway.

So my reasoning is that there is a convection ventilation dynamic already in place but pulling in a good amount of cooler air at the floor would facilitate forcing air out the ridge vent.

Am I on the right track?

 

[jack stand]

Is there any ventilation at a soffit? I might lean towards a gable end louver on each gable.
Something just above the wall height would be ideal.
You're on the right track if there's no venting "intake" to supply the ridge vent "exhaust", I just prefer to provide natural convection.

https://midamericacomponents.com/exterior-gable-and-roof-vents/

These folks make a very nice functioning louver in many shapes, sizes and colors. The trouble might be finding them in a retail situation. They're generally at a contractor supply house like ABC Supply or a siding distributor.

 

[olytdi]

No, I don't have soffit vents -- there are two trusses internal to the walls and the purlins cross the roof's slope. Just a wide open under-roof with the full-length ridge vent.

I have clear polycarb siding at the gables for light. I just figured it I pulled in cool are at the floor, it would pressurize the room and force air out the path of least resistance which would be the ridge vent.

 

[racecougar]

I'm baffled as to why it was built with a ridge vent and no soffit or gable venting, but forcing air in at ground level should work.

 

[dfiler2]

Open the door and inch or so and see how well it vents. If it gets hot I would think that you will move air through pretty well with an incoming vent.

 

[olytdi]

I'm baffled as to why it was built with a ridge vent and no soffit or gable venting, but forcing air in at ground level should work.

Well, the purlins are crossways to the slope so there is no way air let in at a soffit would follow the roof line to the ridge.

 

[olytdi]

Open the door and inch or so and see how well it vents. If it gets hot I would think that you will move air through pretty well with an incoming vent.

Yep -- that's going to be the way it works, I figure.
It does okay until the days get really hot, then there is so much radiant heat coming through the roof sheathing that it becomes oven-like (Steel over tar paper over plywood -- the other side of the plywood is the interior.

 

[racecougar]

Well, the purlins are crossways to the slope so there is no way air let in at a soffit would follow the roof line to the ridge.

That is common. Provided you're not attaching sheathing to the bottom of the purlins, air flows through the attic cavity from the soffits to the ridge.

 

[olytdi]

That is common. Provided you're not attaching sheathing to the bottom of the purlins, air flows through the attic cavity from the soffits to the ridge.

Yeah, the whole inside is wide open trusses/purlins -- no ceiling.

 

[racecougar]

Yeah, the whole inside is wide open trusses/purlins -- no ceiling.

Soffit venting would absolutely work then.