Soffit vents not actually vented

[bc.]

I am getting ready to insulate and drywall my garage ceiling and was planning on running r-13 kraft faced up my 2x6" studs to where it meets the ridge vent. Problem is, I do not have functioning soffit vents, they are blocked on both sides from the outside. So while the R-13 will leave about a 2" gap between roof and insulation for air to flow, I wont have any.

Ceiling:

Blockage:

On the door side it is this 2x6, which is easy enough to drill through for breather holes. On the opposite side it is a piece of plywood parallel with the aluminum soffit and is going to be a PITA to cut or drill breather holes.

How should I go about doing this? (I do need to have some air circulation right?) I am not in the mood to take down the aluminum soffit to remove these 'properly'.

Thanks

 

[The Cobbler]

is your soffit vented ?
you also need vents high on the roof or ridge to allow the air to flow

 

[Kaizen]

Instead of drilling through the 2x I think I would see if you can sawzall out the nail then pull it out. Holes drilled will give a little flow so better then nothing. Get the foam baffles to put up on the ceiling before the insulation. Think I would fir out those ceiling joists and use r40. Do it right or you might as well don't. Take off the aluminum


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[ddawg16]

Quick question.....will this be an open vaulted ceiling?

If so....you don't need vents. That's assuming you are also going to drywall the ceiling/roof.

 

[kbs2244]

I disagree on vaulted ceiling not needing venting.
I have 2 x 8 rafters and 4 inch insulation to provide a 4 inch air channel below the roof decking.
Moisture is going too find it's way in there and it needs a way to get out.

To the OP,
Remove your existing soffit on the outside of the wall.
This will allow you to get to the blocks.
A 4 or 5 inch hole saw will give you enough air flow in each rafter space.
You want at least 2 inches air space between the top of the insulation and the bottom of the roof decking.
And, of course, some way for the hot air to exhaust.
I went with a continuous peak vent.

Replace your soffits with vents installed.

 

[bc.]

It does have ridge vents, had some hail over a year ago and got a new roof. Are my pictures not working??

Instead of drilling through the 2x I think I would see if you can sawzall out the nail then pull it out. Holes drilled will give a little flow so better then nothing. Get the foam baffles to put up on the ceiling before the insulation. Think I would fir out those ceiling joists and use r40. Do it right or you might as well don't. Take off the aluminum


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I got advice not to do this and it seems to make sense to me. Instead of spending a bunch of extra money on a higher R rating insulation and then spending more money on Styrofoam air channels, then compressing the expensive insulation against the air channels turning the R-30 back into R-15, just buy R-13 and use the space it doesn't fill as an air channel.

Sawzall on the nails is a great idea though, I could pull that off easier than drilling 200 holes.

Quick question.....will this be an open vaulted ceiling?

If so....you don't need vents. That's assuming you are also going to drywall the ceiling/roof.

I thought about this after I saw the soffits were 'sealed', I could essentially drywall everything and leave a space to blow in insulation at the top. This would render the ridge vents useless, but would it be harmful? This is how two story houses are insulated sometimes, or attics.

I disagree on vaulted ceiling not needing venting.
I have 2 x 8 rafters and 4 inch insulation to provide a 4 inch air channel below the roof decking.
Moisture is going too find it's way in there and it needs a way to get out.

To the OP,
Remove your existing soffit on the outside of the wall.
This will allow you to get to the blocks.
A 4 or 5 inch hole saw will give you enough air flow in each rafter space.
You want at least 2 inches air space between the top of the insulation and the bottom of the roof decking.
And, of course, some way for the hot air to exhaust.
I went with a continuous peak vent.

Replace your soffits with vents installed.

This was basically my plan, create an airspace via thinner insulation. BTW, I have 16" on center for the rafters.

The existing soffits have vents but they left the original bird blocks installed when they did the job, probably because they thought nobody would be crazy enough to finish a garage...

 

[bc.]

The outdoor soffit:

The plywood bird block:

The R-13 with 2" air gap:

Not sure if these photos are working, I just starting using Flickr because photophucket is trying to destroy their business, I am not used to it yet.

 

[Diesel Dan]

Seal off the ridge vent and spray foam directly to the roof deck.

 

[Kaizen]

I get what you are saying. I tried it that way in a 2x12 rafter and it got really dirty. I didn't say compress. Use the right size insulation. I know insulation does its job by insulating the air in it. Leaving the backside open I would think reduced the r value a lot. But we see open batts laid in attics all the time.


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[Infinia]

The existing soffits have vents but they left the original bird blocks installed when they did the job, probably because they thought nobody would be crazy enough to finish a garage...

Si Senor
The ridge vent is part of a roofing ventilation system, the soffit vents are the second half. A good roofer didn't recommend drilling them because you have an open space. By installing insulation you are now modifying the design to a heated / living space, it has moisture to get rid of> full stop You now need to drill holes to allow the soffit to work and leave a gap in the insulation to allow air to the ridge. A roofing supply house might have ideas on products, either wood battens or plastic corrugated sheeting. Talk to a reputable roofing contractor or esp. your old one if you expect the new work not to void any remaining warrantees..

 

[Spencer Was Here]

If memory serves, you need a minimum air gap below the roof sheathing of 1". There is a formula for how much soffit vent you need, but I don't remember it off my head. It should be easy enough to Google.

I would be wary of leaving the fiberglass insulation open to the vented space. As someone else mentioned, they make baffles that you install in the cavity first.

I believe the minimum R-value for ceilings is around R-38, but that is for residential homes and may not be applicable to your situation. You can get more R-value per inch by using rigid foam vs fiberglass, but even that maxes out at about R-5 per inch.

Someone else mentioned spray foam. Good ones have an even higher R-value than rigid foam, but I am not sure about not having an air gap as suggested. I know having no air gap is normal when using spray foam in wall cavities, but I think the requirements are different for roofs.

 

[CJ7VFR]

Question for my own curiosity.

Were the bird block wood pieces installed to keep birds out of the attic space while the house was being built? And before the soffit vents were installed, were the bird block pieces supposed to be removed?

I will Google it, but I have never heard of people doing this before.

Jim

 

[bc.]

I would be wary of leaving the fiberglass insulation open to the vented space. As someone else mentioned, they make baffles that you install in the cavity first.

I believe the minimum R-value for ceilings is around R-38, but that is for residential homes and may not be applicable to your situation. You can get more R-value per inch by using rigid foam vs fiberglass, but even that maxes out at about R-5 per inch.

Someone else mentioned spray foam. Good ones have an even higher R-value than rigid foam, but I am not sure about not having an air gap as suggested. I know having no air gap is normal when using spray foam in wall cavities, but I think the requirements are different for roofs.

There is open fiberglass in attics everywhere. Some people use unfaced batts as attic insulation, either between ceiling joists or laying on top of existing layers of blown insulation. My thought was the only reason baffles were used is for filling out that last bit of insulation for living spaces, but this is not a living space, I am not interested in spending an additional $600 to get my R-13 into a R-15. the garage used to be R-(-)5 (oven), lol.

Question for my own curiosity.

Were the bird block wood pieces installed to keep birds out of the attic space while the house was being built? And before the soffit vents were installed, were the bird block pieces supposed to be removed?

I will Google it, but I have never heard of people doing this before.

Jim

This house was built in '65, it's possible there never was intended to be aluminum soffits on the garage, so to keep critters out they just blocked it off with wood. It's not like they needed to vent the garage ceiling, it was all open.

 

[nh_yota]

Roof ventilation was handled differently in the old days - back then they would throw in a couple of gable-end vents and call it a day. Ridge vents and soffit vents are something that started in the 80's, so they may have intended those bird blocks to be permanent since it was an open garage.

 

[Infinia]

Roof ventilation was handled differently in the old days - back then they would throw in a couple of gable-end vents and call it a day. Ridge vents and soffit vents are something that started in the 80's, so they may have intended those bird blocks to be permanent since it was an open garage.

Indeed roofing / insulation materials and techniques have evolved as well. Remember cedar shake roofs etc. lots of really old homes had little to no insulation E.g. ventilation was built in.

 

[yeldogt]

I never vent ... fill in with insulation. use a batt insulation with a VB -- I like the encapsulated.

People have trouble when thy use plastic VB -- you don't want plastic. Moisture is not a problem if it can dry form the inside or outside.

I don't get this roof vent stuff -- we don't vent walls? What are we venting?

With proper insulation -- especially on a cathedral ceiling you will not get any ice dames.

 

[Infinia]

.
I don't get this roof vent stuff .

local roofing contractors contacts & info can be found via GAF website.
sheesh you have a compute device connected.. http://www.homeadvisor.com/r/5-myths-about-attic-ventilation/#.WYIzOLqcFhE

 

[LX-Markham]

Seal off the ridge vent and spray foam [closed cell] directly to the roof deck.

This is what I did with my vaulted ceiling. Expensive, but it was much easier in the end. So worth it IMO.

 

[yeldogt]

local roofing contractors contacts & info can be found via GAF website.
sheesh you have a compute device connected.. http://www.homeadvisor.com/r/5-myths-about-attic-ventilation/#.WYIzOLqcFhE

Your point ? Most of the manufactures have now agreed that foam and batts against the roof deck don't have much effect on the life of a roof. Simple color changes can make a greater difference.

 

[Kaizen]

With proper insulation -- especially on a cathedral ceiling you will not get any ice dames.

Ummm straight out wrong. With an overhang up here everyone gets them no matter what. It all the time but when it happens you either shovel it or use heat wires or you flood


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[Infinia]

Your point ? Most of the manufactures have now agreed that foam and batts against the roof deck don't have much effect on the life of a roof. Simple color changes can make a greater difference.

I was just pointing the way to knowledge on-line or from trained contractors, but somehow you've become an expert in-between 2 posts. Color is related to heat not ventilation.

 

[Diesel Dan]

ISomeone else mentioned spray foam. Good ones have an even higher R-value than rigid foam, but I am not sure about not having an air gap as suggested. I know having no air gap is normal when using spray foam in wall cavities, but I think the requirements are different for roofs.

This is what I did with my vaulted ceiling. Expensive, but it was much easier in the end. So worth it IMO.

On the house portion I was going to use the baffles in the eaves and full length ridge vent. I have since spray foamed the deck(CLOSED CELL) so it required ripping out the baffles, closing the cavities off from the outside with some thin ply material and stapling tyvek over the ridge vent. Now my attic space is conditioned and I can install some HVAC stuff up there without the crazy temps normally seen in an attic.

 

[yeldogt]

Ummm straight out wrong. With an overhang up here everyone gets them no matter what. It all the time but when it happens you either shovel it or use heat wires or you flood


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I lived in New England --- everybody does not get them??

 

[finn]

On the house portion I was going to use the baffles in the eaves and full length ridge vent. I have since spray foamed the deck(CLOSED CELL) so it required ripping out the baffles, closing the cavities off from the outside with some thin ply material and stapling tyvek over the ridge vent. Now my attic space is conditioned and I can install some HVAC stuff up there without the crazy temps normally seen in an attic.

If you did that here, you'd have the biggest ice dams in town.

When we spray foamed the underside of the roof of the new addition to the house, the insulation contractor insisted that "proper vent" baffles be installed in each cavity. Closed cell foam is no miracle product. If the underside of the roof isn't always cold enough to prevent remelt, you'll end up with snow melt and ice formation, given enough snowfall and time.

 

[yeldogt]

I was just pointing the way to knowledge on-line or from trained contractors, but somehow you've become an expert in-between 2 posts. Color is related to heat not ventilation.

Lots of common building practices that don't work -- Don't know where they start .. but venting roofs is big business. Lost of products sold for doing it.The fact that you don't have to do it --- well that's something else. Same with crawl spaces -- why vent them? Make them part of the conditioned space -- solves all the problems.

I also don't believe in the non-breathing sheathing products popular today-- any plastic VB's ... OSB. I have always built a rain screen into all my building behind the siding.

 

[yeldogt]

If you did that here, you'd have the biggest ice dams in town.

When we spray foamed the underside of the roof of the new addition to the house, the insulation contractor insisted that "proper vent" baffles be installed in each cavity. Closed cell foam is no miracle product. If the underside of the roof isn't always cold enough to prevent remelt, you'll end up with snow melt and ice formation, given enough snowfall and time.

4" of foam will give you over R25 with no air leaking -- air leaking is the big dam producer. My house in concord MA was sealed up tighter then a clam ... never a problem.

Nothing will stop snow buildup -- that's why the old houses had steep metal roofing.

 

[Infinia]

Lots of common building practices that don't work -- Don't know where they start .. but venting roofs is big business. Lost of products sold for doing it.The fact that you don't have to do it --- well that's something else. Same with crawl spaces -- why vent them? Make them part of the conditioned space -- solves all the problems.

I also don't believe in the non-breathing sheathing products popular today-- any plastic VB's ... OSB. I have always built a rain screen into all my building behind the siding.

Why vent a roof? Same reasons for using a vapor barrier on walls , stops rain but allows moisture in vapor to escape.
The OP has a newish roof with ridge vents he wants to cut down on temperature extremes in his space using DIY labor & tools. Folks are advising changing roof color and spray on foam on backside of roof deck. Both aren't reasonable solutions for many reasons.

I'm just advising the OP where to go for professional advise, free internet advise is worth exactly what you paid for it E.g. nada. Also reminding him that any changes underneath the roof decking may impact his new roof warrantee. It's good advise to check 1st right?.
Fiberglass insulation with 1 or 2" spacing and venting to soffits by drilling the wood between seems reasonable way for him to proceed. An additional option to consider is a radiant barrier.

 

[yeldogt]

Why vent? Same reasons for using a vapor barrier on walls , allows moisture to escape.
The OP has a newish roof with ridge vents he wants to cut down on temperature extremes in his space using DIY labor & tools. Folks are advising changing roof color and spray on foam on backside of roof deck aren't IMO reasonable solutions for many reasons.

I'm just advising the OP where to go for professional advise, free internet advise is worth what you paid for it E.g. nada. Also reminding him that any changes underneath the roof decking may impact his new roof warrantee. It's good advise to check 1st right?.
Fiberglass insulation with 1 or 2" spacing and venting to soffits by drilling the wood between seems reasonable way for him to proceed. An additional option to consider is a radiant barrier.

VB is to slow transfer of moisture -- mostly from internal (human) sources .. OP has a cathedral ceiling w/ ridge beam. The danger with vented buildings -- they bring in more moisture. The negative pressure along the wall of a house brings air up along the wall from the ground -- the wettest area. It's why more and more buildings are being built without them -- same with vented crawl spaces.

 

[Diesel Dan]

If you did that here, you'd have the biggest ice dams in town

At my brothers camp NW of Marquette his neighbor had 3' of snow sitting on a vented metal roof with no gutters or snow jacks and a 6/12 pitch. With 300" per year a conveyor is your best friend!

 

[Infinia]

VB is to slow transfer of moisture -- mostly from internal (human) sources .. OP has a cathedral ceiling w/ ridge beam. The danger with vented buildings -- they bring in more moisture. The negative pressure along the wall of a house brings air up along the wall from the ground -- the wettest area. It's why more and more buildings are being built without them -- same with vented crawl spaces.

False, please do some research or cite references for one or two of those statements. "The Danger it brings in more moisture"? The intuition of folks is often dead wrong by mixing old building practices with new building materials. Where does it say using proper roof ventilation brings danger in adding moisture? Most roofing warrantees insist on having it!
I dont know what goes on his space but humans sweat breathing, combustion, heating, cooking etc. add plenty of water vapor inside a "living space".

 

[finn]

4" of foam will give you over R25 with no air leaking -- air leaking is the big dam producer. My house in concord MA was sealed up tighter then a clam ... never a problem.

Nothing will stop snow buildup -- that's why the old houses had steep metal roofing.

Attic insulation Should be R49, per current thinking, not R25.

R25 may work if the underside of the roof is vented to keep it at the outside temperature, or close to it, but without venting, the snow against the roof will melt from the bottom, and refreeze at the eaves.

Water then backs up under the shingles, and the top of the snow and water guard and drips down the walls.

May not be a problem in mild climates like yours.

Steel roofs have their own issues with ice.

 

[Infinia]

Ice damning at the eaves.
Next time it starts to get freezing look at frost collecting on roof tops. Compare a ridged vent to one with a roof that's completely sealed up. The one with ridge vent will show a layer of frost on the eaves but will be clean at the very top. It's from the fresh cold air being drawn in which is keeping the eaves the same temp as the outside, this will prevent melting and then refreezing down there low forming ice damns. The one that is sealed up will have frost all over but not lower down nearest the structures wall and celings. This tends to promote ice damning at the eaves from nearby heat radiating, being closest to source, and then quickly refreezing due to low mass of the roofs overhang.

 

[bc.]

I talked to my roofer, he said there is no issue with running the kraft faced on the roof as long as I have an air gap. If I use thicker insulation I need to use baffles all the way up to the ridge vent.

As far as venting the soffits goes, he said to cut or drill the bird blocks as much as I can, too much venting is not going to be an issue, not enough would be.

Thanks for the help fellas.
-Brad

 

[yeldogt]

Ice damning at the eaves.
Next time it starts to get freezing look at frost collecting on roof tops. Compare a ridged vent to one with a roof that's completely sealed up. The one with ridge vent will show a layer of frost on the eaves but will be clean at the very top. It's from the fresh cold air being drawn in which is keeping the eaves the same temp as the outside, this will prevent melting and then refreezing down there low forming ice damns. The one that is sealed up will have frost all over but not lower down nearest the structures wall and celings. This tends to promote ice damning at the eaves from nearby heat radiating, being closest to source, and then quickly refreezing due to low mass of the roofs overhang.

Most ice damming is cause by leaking -- the roof at the top is warm -- from leaks. the roof down low is cold because heat rises ... most roofs with vents .. really don't vent .. that's the problem.

 

[yeldogt]

False, please do some research or cite references for one or two of those statements. "The Danger it brings in more moisture"? The intuition of folks is often dead wrong by mixing old building practices with new building materials. Where does it say using proper roof ventilation brings danger in adding moisture? Most roofing warrantees insist on having it!
I dont know what goes on his space but humans sweat breathing, combustion, heating, cooking etc. add plenty of water vapor inside a "living space".

Do some research -- they have all changed. Read up on sun driven moisture.

The warmest area outside in the winter is at the wall of your house -- this creates an upward draft .. the upward draft brings moisture into the attic through the vents ,,,,, since most vents don't really work that well .. the attic gets higher humidity. It's why there is so much mold in many attics.

 

[yeldogt]

Attic insulation Should be R49, per current thinking, not R25.

R25 may work if the underside of the roof is vented to keep it at the outside temperature, or close to it, but without venting, the snow against the roof will melt from the bottom, and refreeze at the eaves.

Water then backs up under the shingles, and the top of the snow and water guard and drips down the walls.

May not be a problem in mild climates like yours.

Steel roofs have their own issues with ice.

I lived in New England and we had a house in Maine -- Ice damming and R value .... misunderstood. It's why all those early high R value houses failed.

Fiberglass insulation leaks -- when no wind is around or building stack effect .. maybe you get the R value .. I only think so. Foam -- you get the R value and no air movement .. when the point of an R value when heated air can get through ?

 

[flan]

Those blocks will make the difference weather a fire will stay on the outside of your garage or burn through vinyl and run all up through your roofline. Hopefully that day never comes but also food for thought.