Do I need baffles if I have no soffit?

[getfamiliar]

My single stall is attached, but there is no heat coming in from the house - and I won't likely be going that route soon, if ever.

What do you guys think for a ventilation strategy in absence of having soffits? Do I need baffles if I put up batt insulation in the ceiling?

Currently there is nothing for vents but i am putting a ridge vent in as soon as the weather warms up (in MN). Here's what I'm working with...

There is no rear or front soffit. I added the foam just because i had some extra in a can and there was a small gap between the wood and the tar paper covering the rear (under vinyl siding).



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There's an opening above the front door, but no soffit or ventilation of any sort - just some wiring running to the door light outside.





Here's the ridge line and you can see the door/above door cavity too.

 

[Gary S]

Baffles keep the insulation from blocking the vents in the soffit. If you don't have vents there, baffles would be useless. In your situation, it would be easiest to install vents in the peak walls at the ends of the building. They work just as well as vents in the soffit.

 

[james_444]

I'm not an expert on this but I don't think soffits will do any good in the garage since it is open and does not have a ceiling. It is my understanding that soffits and ridge vents are used when to ventilate the crawl space. You don't have a ceiling so you don't have a crawl space.

If you are dealing with cold I would think insulation in the eaves would do the trick without soffits or a ridge vent. I don't see how those would help. All they would do is let cold air in which would simply freeze the rest of the garage. If you had a ceiling then you could have an insulation blanket on top of it between it and the rest of the garage. Soffits and a ridge vent would then help ventilate the crawl space while the insulation blanket on top of ceiling would keep the garage warm. Without a ceiling though I would would think you next best bet is to insulate the eaves.

 

[getfamiliar]

Baffles keep the insulation from blocking the vents in the soffit. If you don't have vents there, baffles would be useless. In your situation, it would be easiest to install vents in the peak walls at the ends of the building. They work just as well as vents in the soffit.

OK, i wasn't sure of there were benefits from keeping the hottest/coldest air apart from the batt or not.

I think I will run batts up near the ridge line and put some "end cap" boards between the rafters to stop the batts there and leave the ridge line exposed.

Thanks Gary!

 

[rburke65]

The soffits are there to allow air into the attic area.the cooler soffit air pushes the hot attic air out the ridge vents, thus coolly the attic and this also further the life of your shingled roof.

 

[theoldwizard1]

The soffits are there to allow air into the attic area.the cooler soffit air pushes the hot attic air out the ridge vents, thus coolly the attic and this also further the life of your shingled roof.

CORRECT !

If you plan on "traditional" insulating, you will need to add vents in that board just above the top plate. You will need a ceiling or a lot of strapping to hold the insulation. A full ceiling would be required for loose fill insulation. In either case, the baffles are necessary to prevent unobstructed air flow from the bottom of the roof to the ridge vent.

Of course, you could just spray foam the underside of the roof deck boards.

 

[pattenp]

The soffits are there to allow air into the attic area.the cooler soffit air pushes the hot attic air out the ridge vents, thus coolly the attic and this also further the life of your shingled roof.

A soffit is no more than the underside of a roof overhang. They are not there for the purpose to allow air into the attic. Vents in the soffit are for that purpose.

 

[JakeKohl]

If you are putting fiberglass bats along the roof sheathing, I ~think~ you still need to maintain some air flow between the bat and the sheathing.

 

[getfamiliar]

Appreciate all the responses. To clarify, I am not putting up a ceiling - this garage will be used exclusively as my home gym and for storage of lawn care equipment, etc. and a "hangout" of sorts during the summer months.

I am worried about shingle/roof implications as this is in direct sun all day and during the winter I heat it via a propane heater so i want to keep the warm air away from the roof also so the snow on it doesnt melt and refreeze.

Does this help? I feel like i'm getting some conflicting opinions on this.

 

[bd8134]

Your garage looks like it was designed for no insulation or ceiling, now it is a matter of how much you want to pay, how much work, etc.
If you spray foam the rafters like theoldwizard1 said, it will be the quickest, possibly the most effective but the most costly. You will then not need any ventilation to be added at the soffit or ridge. You do need to fireproof the insulation if you do not put a ceiling up, sheetrock can be the fireproof or you can spray on a fireproofer.

The traditional method is with a ceiling with insulation on top. You will need ventilation at the ridge and soffit. If you are putting in a cathedral ceiling in you might need an air channel against the inside of the roof sheeting. This will cut down on the depth of insulation you could use so may still get hot in the garage etc... Remember you need to fireproof glass fiber, batts insulation, etc, also.

Get a couple of quotes and see what they say.

 

[theoldwizard1]

If you just shove some fiberglass between the rafters, you are going to get moisture on the inside of the roof deck. Moisture will cause mold and can cause you roof deck to rot.

With any insulation that is not bonded to the roof deck (spray foam is), you need to provide outside air flow from bottom to top.

Another not cheap alternative is XPS foam board attached across the inside of the rafters. Seal the joints with the appropriate tape. Venting at top an bottom is still required.

 

[getfamiliar]

If you just shove some fiberglass between the rafters, you are going to get moisture on the inside of the roof deck. Moisture will cause mold and can cause you roof deck to rot.

With any insulation that is not bonded to the roof deck (spray foam is), you need to provide outside air flow from bottom to top.

Another not cheap alternative is XPS foam board attached across the inside of the rafters. Seal the joints with the appropriate tape. Venting at top an bottom is still required.

if I put up the poly sheeting over the kraft faced batts and seal tape the seams is that enough to mitigate the moisture issue?

All this is making me reconsider my approach. perhaps i'm better off stapling up some of those reflective insulation sheets, leaving a 1-2" space between the sheet and the roof deck, leaving the "ends" at the top and bottom of the rafters open (like a pseudo soffit inside the garage) and adding the ridge vent. does that sound more reasonable than the batt approach?

 

[theoldwizard1]

What ever you do, you have to have air flow ! You need vents at the bottom and vents at the top.