Shed roof venting?

[LGaston]

I just bought a house and it came with a 12x20 shed. It's a nicer quality unit they built somewhere else and then delivered. Normal 2x4 construction, 16" on center with a big roll up door. (like you would find at a self storage place)

The entire thing is sealed, except for the ridge vent on the roof. There is about a 2" gap in the sheathing inside, and some kind of vent under the asphalt shingles. (not sure what it's called) There are no vents in the eaves or anywhere else.

I'm thinking about plugging this ridge vent with spray foam, which would let me then install a filtered power fan to use if the air is either too hot or too humid, along with a small controlled exit vent. It could easily be attached to a thermostat and humidistat. This way the shed isn't always "breathing", and the air could be run through a simple filter easily. Pollen is killer here for a few weeks/year. I could also run a dehumidifier this way.

Also, I want to install a through wall 25,000 BTU air conditioner (already have it) so I can cool the space quickly without always keeping it cool, and a small heater for the winter. (want to keep it above freezing on cold nights) I feel like both of these would work better without the current ridge vent.

Does this sound like a good idea? I'm not going to insulate anything, I just want it sealed.

 

[Bigbandguy]

I gather you do not have a ceiling in the shed but just open to the roof? If that is the case if it were mine I would leave the ridge vent, install soffit vents and those plastic channels from soffit to ridge and then put in a ceiling of some sort. The ceiling would hold in the heat and cool depending on the season and the soffit / ridge vent would allow circulation and prevent moisture buildup.

More experience folks will no doubt have more info. I expect the big AC unit might be overkill for the space, but it certainly would cool it quickly. Let us know how this turns out.

 

[LGaston]

Not really tall enough for a ceiling, maybe 8', and the rafters make for good storage. Even if it was a separate air space it wouldn't do much since the volume would be low. (roof doesn't have a very steep pitch)

I'd really like it to just be sealed up so I can use a dehumidifier for any moisture. So far it hasn't gotten too humid in there, but it's NC - the air is made of water! Weather has been unusually hot...

Also have a lot of problems in this area with bugs and things like carpenter bees and mud daubers. I think the more I can seal it up the less they will be an issue. The air intake would have to have some sort of cover or louvers on it to close it up when I don't need ventilation.

I might consider hanging up a layer of rigid foam insulation in the future, but that won't be for a while.

 

[readhead]

I sell sheds like what you have. If you want to seal the building the first thing to do is get rid of the coil door. They leak like a sieve. Brush seals will keep the bigger bugs out but that is it. The ridge vent works because the door provides make up air.

 

[LGaston]

I sell sheds like what you have. If you want to seal the building the first thing to do is get rid of the coil door. They leak like a sieve. Brush seals will keep the bigger bugs out but that is it. The ridge vent works because the door provides make up air.

Darnit...sealing that up was going to be my next question. It's a nice door, but like you say it doesn't seal. I also don't need to drive anything that big inside. I'm thinking about replacing it with a pair of steel man doors.

Also going to add a lean-to on one side, a concrete pad, and an overhang on the front to block water. It will be my money pit for a little bit.