DIY Home Improvement Forum banner

Should I use an Edge/Smart Vent Intake OR Rework it somehow (just gable vents, power fan vent?)

  • Guy was right: Don't need Intakes. Not the best, but it will work with just Gable Vents, etc.

    Votes: 0 0.0%
1 - 19 of 19 Posts

·
Registered
Joined
·
25 Posts
Discussion Starter · #1 ·
Need some help. My contractors disagree and my research does too.

PROBLEM: I have a 1940s house in N. Illinois with no eaves and no soffits (see image below of how it is NOW) and ventilation problems. Owned for last 10 months.
  • Soffits aren't possible.
  • I have no intake now, and its causing condensation issues (one contractor said one of the rafters is on stage 1/10 of mold.
  • It used to have just cross ventilation with gables (as I understand it). Last roofers put in static vents, and then a power vent--seems this was ill-advised?
POSSIBLE SOLUTION:
  • Put in an intake, it seems. Seems I have the options of smart or edge vents as an intake. However, one contractor who I liked contested the safety of a edge or smart vent from ice dams.
  • He made a compelling case that the house was built with just gable vents, and though less than ideal it could be configured to not use an intake.
I'm at a loss. What configuration do I opt for here? I don't want to screw this up like the previous homeowner and have non-stop issues for 20 more years.



651217
 

·
Naildriver
Joined
·
12,350 Posts
Obviously the single point venting at the top is redundant and it should be a passive ridge vent. The power vent will eventually fail and become a liability.

Two things as I see it could help. Reinstall the gable vents to allow air to be introduced and evacuated via the ridge vent. Not ideal, but solves the problem of ice dams. Secondly, many cape cod houses are fitted with low intakes since they are built without soffits. Not the prettiest from the street view, but they do allow air intake LOW where you need it.
 

·
Registered
Joined
·
191 Posts
Air seal your attic floor & other penetrations to stop moisture from getting in... Air Sealing: Sealing those Attic Penetrations (thehtrc.com)
Then your gable & turtle vents will have a chance to do what they are supposed to - expel excess heat & moisture
PAV have no business being in most homes RIP: Solar Powered Attic Ventilator’s (thehtrc.com) especially as it was just pulling conditioned moist air into the attic during the winter & air conditioned air our during the summer months possibly creating hidden points to allow for condensation to form from the nice humid air
 

·
Registered
Joined
·
6,791 Posts
What started this? How much mold and do you have ice dam problem? Condition of insulation up there? Ventilation will not help if insulation is stuffed in ways that doesn't allow drying. Soffit venting will not help if insulation doesn't dry out. If low slope, probably not enough insulation along eave. Best is, I think, stay with venting you have and use ice barrier sheets on roof and facia, drip edges and gutters so water drains quickly as possible. This means layers of flashing and gutters that slope enough to see. Drape the ice sheet down to facia, don't just end it at the edge. If drip edge, seal the drip edge and ice barrier joint with eternabond tape. Do the layers look like they are building up too much thickness? It's better that way. Don't just focus on flat and level.


Searched with words : facia detail for house roof without soffit. Go to images.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #5 ·
What started this? How much mold and do you have ice dam problem? Condition of insulation up there? Ventilation will not help if insulation is stuffed in ways that doesn't allow drying.
-Bathroom and area right outside the bathroom, the paint was delaminating and plaster cracking from moisture. Fan is venting out and other issues ruled out. It only started/got worse in the winter and its thought this is due to condensation/ventilation issues.
- Well insulated with blown in. Insulation appears dry. One roofing contractor said that a couple of the rafters had very early stage mold that would clear out with good ventilation
 

·
Registered
Joined
·
12,398 Posts
Your diagram shows no baffles so I will assume your insulation is filling the eaves with no space left for air flow. Can you detail what the insulation looks like over the bathroom?

Any vapor barrier under the ceiling drywall, especially in bathroom area?

With the difficult location likely the soil stack is not sir sealed and is providing a path for inside air to transport moisture and heat into the attic and insulation.

Not sure what you mean here "Don’t seal anything, allow to remain drafty-ish like original 1940s design."

Ridge vent would be good but it must have a low intake source.

Option #2 air seal what?

Option #3 the gable vents would stay, always. They only get sealed if rain or snow are getting in.

On a gable attic I like to see low venting on both front and back slopes.

When and how long do you run the bath fan. And what is there for intake air for that fan?

Bud
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #10 ·
So the insulation is blown in the main attic. To my knowledge there isn't anything besides insulation blown in? I'm not sure what they would do to prep the insulation being blown in, like a vapor barrier below--it was done 10 years ago (I bought 9 months ago).

Now, here's the difficult part: if you look at the diagram the bathroom juts out several feet. The plaster ceiling is arced/coved at the end to follow the slope of the roof as seen in this image. So I'm not sure what's up above it. When built in 1942 I don't know if they used vapor barriers. Air-sealing in my mind would be sealing whatever is above it with vapor barrier or whatever makes sense. Alternatively, one contractor said he preferred not to add intakes with the rationale that besides the previous owner who installed static vents and this power fan, the roof system was probably working well enough. Granted the 1942 way isn't the best but it was sufficient. I guess if you don't intake vent than it would be good to keep it drafty rather than sealed but a poster above said that is not the case.

We run the fan every time we have a shower. I wonder if it works well enough but it is new in the last 3-4 years I believe. We stop it once we get out of the shower. Hope this helps explain things.




651304
 

·
Registered
Joined
·
12,398 Posts
They make "delayed off" switches to keep that fan running for a selected amount of time after it is turned off, I suggest 20 or 30 minutes of additional run to be sure excess moisture is exhausted out.

The advice that is has always worked in the past is counter to the results you are seeing. Maybe they took short cold showers (ouch) but now moisture IS a problem. How does air get into that bathroom to replace exhausted air, undercut door or door left open?

All we have on the solution side are suggestions you have ruled out. Those suggestions follow time tested examples that air seal house to attic and ventilate soffit to ridge and/or gables.

Sorry nothing else in the recommended bag of tricks.

Bud
 
  • Like
Reactions: RollonRolloff

·
Registered
Joined
·
191 Posts
The biggest issue I see is you are trying to solve an issue without knowing the why. You need to solve the moisture problem first (cut it down, block it from moving, exhaust it) - more ventilation rarely solves the issue & in some cases can exacerbate the situation by pulling it into the attic. Bathroom timers as Bud pointed out are one good thing, but also is it vented properly outside. Do you have baffles & if not you will need to install them especially where ice-dams can be an issue - I can't begin to tell you how many houses I have seen where the insulation is frozen directly to the sheathing because it is touching it. You should find links to many of these items in the piece I gave you & if not a quick search can help or just ask
 

·
Registered
Joined
·
6,791 Posts
The photo. It looks like leak damage where drywall is damaged and the paint film bulged with water. When the bulge broke the paint film curled as it dried. This should have been obvious. If it is moisture damage, the problem looks like from the ridge, maybe leaking through the vents, then missing passive venting. Fan will not help.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #14 · (Edited)
The photo. It looks like leak damage where drywall is damaged and the paint film bulged with water. When the bulge broke the paint film curled as it dried. This should have been obvious. If it is moisture damage, the problem looks like from the ridge, maybe leaking through the vents, then missing passive venting. Fan will not help.
So, no trace of actual water. The balloons were empty and when I pulled them aside the cracked plaster was bone dry. I called all sorts of folks out: attic, plaster, roofers, and they kind of shrugged and said they didn't know for sure, looked like moisture. Apparently, water on the other side of the base coat of plaster in any amount can cause the plaster to crack. The cracking causes the delamination.


To recap:
  • Attic ventilation can help. Gables and Ridge Vent at minimum; ideally a low intake.
  • BUT Have to mitigate whatever moisture there is tho:
    • Whether it is a leak higher up on the roof
    • Bathroom steam and insufficient fan
    • Time bathroom fan runs is too short
    • Bad piping, not exhausting outside, bad sealing.
  • Some kind of vapor barrier/air sealing over that space could help as well, but still, an active moisture problem with the fan or lean needs to be fixed (a leak, I'm imagining, will be fixed with the new roof--so its really the fan I'm looking at)
  • Baffles for insulation.
 

·
Registered
Joined
·
6,791 Posts
The photo framing? Attic conversion or dormer? If rafters insulated, passive venting will not work without air space between the decking and insulation. Bath ceiling suggests the leak is at the ridge or near the top of the roof than lower parts like the eave. Your vents may be leaking from wind driven rain also. It looks like the ceiling should be opened anyway, insulation cleared, then problem should be easier to see. If roofers are giving up, they may be reluctant to say total replacement of the vent caps and such. Do you have new roof? Was ridge vents added? Ridge vents can also leak.
BTW, if a dormer, ridge caps can leak also. Wind driven rain or sometimes sloping down towards the overlaps.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #16 ·
It's an attic with a scuttle hole. Not meant to really put anything up there I think. My roof is near dead, so I'm looking at replacing it. Don't have ridge vents currently, just turtle vents and a power vent (see the pdf posted above)
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #18 ·
In that case & for a better option - what's the snowload? If under 50 PSF, consider going with a hot roof assembly by putting foam over the sheathing. Over 50, can do the same thing but you have to do a cool roof - i.e. add venting above it. Air Sealing: The Hot-Roof Option (thehtrc.com)
I'm in Chicago, so I imagine fairly high. Attic guy came out and said fans exhausting outside through the roof and flow is good. I also learned from the owner they had air sealed part of the attic. My last question is: I can't see the spot over my bathroom, and thus I can't tell if there's any airflow. view of it from the attic is obstructed. Is there any non-destructive way I can figure this out?

651622
 

·
Registered
Joined
·
191 Posts
On snow load you are fine as I am in the same area - according to the maps 25 though some jurisdictions list higher - can't recall ever hearing more than 30 or 40. So they spray foamed some areas & put in baffles - good start if done properly. Looking back on what you posted it looks like the issue is in this part of the attic not your "sloped down" section. Clear that area out & see if you have gaps, etc... pipes above, how good is the drywall / plaster up top?
 
1 - 19 of 19 Posts
Top