Venting garage attic

[crazybrit]

I have a garage with a later added shop extension. See picture.

The 2x4 walls are insulated as is the ceiling of the extension.

The 2x6 attic floor above the original garage was partially insulated (by previous owners) with R19 in certain bays but not completely. Odd.

I just finished insulating it and completed the flooring also.

The pitch of the attic roof isnt insulated.

A while ago I added a gable exhaust fan to the rear of attic (so not visible in images) but there is no intake venting. No roof vents, no soffit vents, Nada. I just kept the attic folding ladder door open as a stop gap.

I know I need to create some proper form of intake venting and I believe its now code mandated since the floor is now insulated.

What's the best way? Vent in the gable at the front? Some form of roof vent through the shingle? Something else?

Thanks

 

[The Cobbler]

a vent in the gable end would be easy & effective . some roof vents would be good for when the fan is not on to get natural air flow

 

[crazybrit]

a vent in the gable end would be easy & effective . some roof vents would be good for when the fan is not on to get natural air flow

Thanks for reply.

What kind of roof vents? Something like: https://www.homedepot.com/p/Gibralt...q-in-Net-Free-Area-in-Black-RVG38BL/202092818

Or a ridge vent?

I'm also in process of adding a 12k btu mini split to shop area in case that's relevent.

 

[nadogail]

If Portland is as I remember it to be, your vents need to be "Rain Tight".

 

[crazybrit]

If Portland is as I remember it to be, your vents need to be "Rain Tight".

Yes winter is wet though not as much as it's reputation.

I'll put the gable vent in first. Its a 1915 house so I was planning on makimg something custom out of wood like this but I just noticed there is a structural 2x4 in the way (see image attached to first post).

I can either just put the vent in front of it and accept a slightly reduced airflow or make something like this instead.

I'm leaning towards the later.

Thanks for the replies.

 

[Bretny]

Ridge vents only work when you have air flow through the soffits. A gabel vent and a ridge vent will nor vent properly.

You alreaty have gabel vents so dont use a ridge vent. I found that a ridge vent wasn't enough for my house and had to go back to gabel vent/fan.

 

[crazybrit]

I found that a ridge vent wasn't enough for my house and had to go back to gabel vent/fan.

What about the earlier comment recommending roof vents (a couple? Four?) in addition to a gable vent, for when the gable fan isn't running?

 

[kbs2244]

soffit vents
they move the air all through the attic
and keep the rain out

 

[crazybrit]

soffit vents
they move the air all through the attic
and keep the rain out

I could only add on one side (not on extension side). I'd also have to add some form of vent to ply floor which now covers soffits.

I'm def adding gable vent .... Not sure what else yet.

 

[rayra]

soffit vents. Combined with your gable for good airflow and passive cooling when the gable vent is off. Let convection / hot air rising work for you. Seconding ridge and gable are a terrible combination, especially if you have a gable vent and are using the ridge as an intake, the very opposite of what a ridge vent is supposed to do.
If you have trouble with installing soffits, then put a gable vent on the opposing gable and put the exhaust fan on the downwind side. Side opposite your prevailing winds. Work WITH with the wind and with hot air rising, instead of fighting against it.