Do I need ridge or soffit vents?

[edcantu9]

I am going to side my garage and insulate it. Do I need a ridge vent? I ask because I will be putting in insulation and then covering it and would that not cover up the vent in the ceiling hole for the ridge vent?

Or would i be fine just installing soffit vent and not covering up the area where wall meets trusses to let it vent?

Or Could i do fine without both?

 

[FullRaceMerc]

Take a minute & go to the User CP & fill in your approximate location.
<----- It will show up over there on every post. Some of the answers to these type questions vary by region.

 

[404]

Depends on your climate.
Up here in MA one would need both to prevent ice dams.
Here it is mandatory to have a continuous prop a vent or better air passage between the soffit and the ridge if there is a cathedral ceiling.

Air must flow without restriction to keep the ENTIRE roof deck below freezing to prevent the melting that causes ice dams.

I am the only person within miles without any ice dams. Jeebus it is not that hard people. People around me are on their roof with axes and rock salt every winter. Then they need new shingles in the summer. Go figure.

This info is in DIY home repair books going back to the 1940s at least.

 

[FullRaceMerc]

Yeah, no ice dams on my house either. But my roof hasn't seen snow but once or twice since it was built in the 40s.

Location, location, location. This stuff varies. Even around here some ventilation is important, but not nearly a vital as it is in other ares.

 

[gasgas17]

Ventilation is important no matter where you live. If you don't want your sheathing to rot from the inside out. Leave at least a 1-2 inch airspace above your insulation and provide venting at the soffit and the peak. Either ridge vent, gable vents or other depending on construction and where you live.

 

[edcantu9]

I apologize for that!! I am located in Southeastern Iowa.

 

[csp]

Will the insulation be just under the roof sheathing? Or will the garage have a ceiling with insulation laying on top of the ceiling?

You need ventilation of some sort whether it's a ridge vent, or roof vents, or gable vents along with vent intakes in the soffit.

 

[kbs2244]

What you need is air movement from the soffit up to the ridge.
So your ceiling insulation should allow for at least 2 inch between it and the top of rafter sheathing.
So you need both high and low vents.
Air in and air out.

 

[volleyball]

High density foam is the only thing that changes the rules. I got rid of all my venting and I don't get any ice dams either.

 

[pablo94sc]

I just have gable vents, but I live in Hell, err, Memphis.

 

[Leaflessshadetree]

Upper and lower vents work together. Just doing one or the other isn't very effective.
Proper ventilation will extend the life of shingles, avoid moisture buildup (and mold) and it will help with cooling in the summer.

 

[pattenp]

Vent like this ......

 

[IlliniJeeper]

I put soffit and ridge vents in my shed and I think it keeps it noticeably cooler inside it during the summer months. Doesn't let the sun turn it into a big oven, and that's just with an unfinished stick built interior and wood decking floor.

 

[edcantu9]

Ok great information here! Will definitely do both. I have a crazy question. Instead of doing house wrap can I do fan fold insulation and tape it? Or should I do both? Or just stick with house wrap? Any advantage of one over the other?

 

[mypov]

This helps a lot with shingle life too - if there is no ventilation the roof actually bakes the shingles and their life is drastically reduced. (as per leaflessshadetree)
The previous owner of our hose had installed new shingles about a year and a half before we bought the house, I went on the roof to add proper ventilation for our bathroom fan (they had it vented directly into the attic/not outside) and add stove vent. Long story longer, the shingles look like they are 5-10 years old, they are so baked and brittle.

 

[cva1993]

Soffit vents help with air intake into the attic while the ridge vent will help ventilate the air to the exterior. You will get air flow with both vents and will avoid ice dams. Hope this helps.

 

[edcantu9]

Ok guys so I installed the soffit and ridge vent in the garage. I understand that it will allow heat to escape during the hot days, which I have noticed already.

I will be insulating it, my concern is will the heat be escaping out the soffit and ridge vent during the winter months when I run the heater? Or it is so little loss that I will not notice?

 

[Falcon67]

Make sure your walls are sealed to the ceiling at the edges and that any penetrations are also sealed to prevent air leaking into the attic space. I used OSB on the ceiling and caulked all the seams to stop air migration. Did the same thing in the house - all can lights sealed to the drywall, all the AC vents sealed to the drywall, even door strike holes sealed to keep air from leaking up the door frames into the attic. You'd like the attic space to "breathe" on it's own.

 

[reader2580]

Only heat that makes it into the attic would get lost through the vents. Any heat that gets into the attic is lost anyhow. You should have continuous vapor barrier on the ceiling and attic insulation to minimize heat loss into the attic.

Air infiltrating into the attic is a big cause of ice dams. The house I bought last year did not have a continuous vapor barrier on the ceiling in the original 1980 portion of the house. I had all of the attic insulation removed and a thin layer of spray foam installed to stop any air leaks. The attic was then filled with loose fill fiberglass insulation. No ice dams this winter, but snow was half of normal. (No idea if the house had ice dams previously.)

 

[csp]

The purpose of the insulation is to keep the heat in the house. The attic isn't supposed to hold the heat in for you.

 

[fotoflojoe]

Make sure your walls are sealed to the ceiling at the edges and that any penetrations are also sealed to prevent air leaking into the attic space. I used OSB on the ceiling and caulked all the seams to stop air migration. Did the same thing in the house - all can lights sealed to the drywall, all the AC vents sealed to the drywall, even door strike holes sealed to keep air from leaking up the door frames into the attic. You'd like the attic space to "breathe" on it's own.

Wow, that's some good information. Thank you.
Despite having both soffit and ridge vents, we had ice damns this past winter. Attic insulation is good everywhere except one obvious spot: the space over the pull-down stairs. My solution is to build a movable insulated cover. I know they can be purchased, but I'm cheap, and have the materials laying around to build it.

All that said, maybe I need to dig a little deeper in search of more air leaks.

 

[edcantu9]

The Garage has no attic. Did I make a mistake? Will this make insulating and heating impossible?

 

[jwhcars]

Look at the picture in post 12. The left side is how you would insulate and have an air gap to the ridge vent.

 

[edcantu9]

Look at the picture in post 12. The left side is how you would insulate and have an air gap to the ridge vent.

Thanks for the reply! So by looks of it I gave to make a small channel for air that leads from soffitt to ridge vent. Would a good way to do this without having time to research yet but the jist of it would be to lay sheathing on it that is a bit elevated then insulation then sheet rock?

 

[kbs2244]

You have the idea.
2 inches is good enough.
But more i better.

Just remember it is a shop, not a house, leaks are OK.

 

[jwhcars]

Thanks for the reply! So by looks of it I gave to make a small channel for air that leads from soffitt to ridge vent. Would a good way to do this without having time to research yet but the jist of it would be to lay sheathing on it that is a bit elevated then insulation then sheet rock?

You have it figured out

 

[csp]

So by looks of it I gave to make a small channel for air that leads from soffitt to ridge vent.

Use commercially available insulation baffles. Your local big box hardware/lumberyard has them.

 

[edcantu9]

Thanks for all the help guys! I have definitely learned a lot about insulation. Now I am wondering what insulation to use. I will be buying baffles like the ones pictures above.

http://www.lowes.com/ProductDisplay...gId=10051&cmRelshp=rel&rel=nofollow&cId=PDIO1

Now I am wondering, the trusses are 2x6. If I install the baffles, will i have space for 2x6 R19 insulation? Or will I have to use the 2x4 R13 since the baffle will take up space in the cavity?

I also noticed in the specs of the R19 insulation that the thickness is 6.5" despite it stating that it is for 2x6 ceilings. Here is the link:

http://www.lowes.com/pd_10584-1722-K1251_1z0vjj3Z1z135rz__?productId=3006194&pl=1

If the above insulation does not work I am planning on this R13 2x4 insulation.

http://www.lowes.com/pd_108995-1722-K292_1z0vjj3Z1z135rz__?productId=3006486&pl=1

 

[GYPSY400]

Thanks for all the help guys! I have definitely learned a lot about insulation. Now I am wondering what insulation to use. I will be buying baffles like the ones pictures above.

http://www.lowes.com/ProductDisplay...gId=10051&cmRelshp=rel&rel=nofollow&cId=PDIO1

Now I am wondering, the trusses are 2x6. If I install the baffles, will i have space for 2x6 R19 insulation? Or will I have to use the 2x4 R13 since the baffle will take up space in the cavity?

I also noticed in the specs of the R19 insulation that the thickness is 6.5" despite it stating that it is for 2x6 ceilings. Here is the link:

http://www.lowes.com/pd_10584-1722-K1251_1z0vjj3Z1z135rz__?productId=3006194&pl=1

If the above insulation does not work I am planning on this R13 2x4 insulation.

http://www.lowes.com/pd_108995-1722-K292_1z0vjj3Z1z135rz__?productId=3006486&pl=1

I used 2 layers of batt insulation in the ceiling.. one layer thick near the Styrofoam vents, then 2 layers with the seams offset as soon as space would allow.

 

[jask]

The bottom edge of those baffles should extend past the outside of the wall top plate- this is especially important with blown in or loose fill insulation as it can obstruct the bottom opening and render them useless. If you are retrofitting the baffles, bring along a "pizza paddle" of thin plywood 14" x 14" with a long stick handle - you can slip it in and press back the insulation to make room while you slip in the baffle and use it to re position the insulation when you are done. do it early in the morning, attics get hot quick after the sun comes up.