Ventilation Issues?

Hi, I am having what I believe are ventilation issues. We discovered mold in the attics of some of our buildings (apartment complex) and dripping on the nails. Being a former roofer I knew it wasn’t moisture from the gutters and it had to be ventilation. We discovered the soffit vents were covered by insulation and quickly removed it. This corrected the problem on many units but we are still having difficulty with some. The ridge vent is cut fine and we are getting air flow in the attic.

Our rafters run parallel with the gutter and I feel this is the problem (we are now only getting moisture in between the middle rafters). Is there any way to solve this problem without replacing every single (54) roof?

are you sure that is the problem. might not be enough ventilation? i would add a few turbine vents before spending lots of time and money. couldn’t hurt to try on one building.

Do not mix turbines with ridge vent.

How are the rafters running parallel to the gutter? I cannot envision this.

I cannot figure out how to upload a picture on here. The apartments were built in Ohio in the 80’s and shipped to TN. The Rafters are spaced appx 24" apart and are running parallel with the gutter/ridge line going from soffit to ridge. The pitch of the roof is not much (I don’t know how to figure that out)

I agree that it may be the lack of ventalation, and I also agree on do NOT mix ventalations, they will work against each other. I wouldnt think your gutters have anything to do with it unless you have water backing up. Check your attic insulation because if there is a lack of that, heat loss mixed with in poor ventalation will cause your moisture problem. You may want to put on a new ridge vent, sometimes olds venting will get clogged. New stuff will allow better air flow. Check your soffit vents as well to see if there is enough of them. They are just as important as the roof vents are.

If the rafters run parallel with the gutters, you have a flat roof (0 pitch roof). That can’t be right, really, is it? I think we need to understand that before we can diagnose anything else.

It is not flat. How the rafters run is what I believe is the problem. We are getting airflow through the attic but it is just not hitting in between the rafters in the middle of the roof.

My guess is that the roof is a 4/12 pitch

Rafters running parallel to the ridge and gutter?

In that case, maybe a gable vent (or two) at one end and a powered ventilator at the opposite end.

And don’t worry about mixing vents. That’s just a silly old wives tale.

[quote=“dennis”]Rafters running parallel to the ridge and gutter?

In that case, maybe a gable vent (or two) at one end and a powered ventilator at the opposite end.

And don’t worry about mixing vents. That’s just a silly old wives tale.[/quote]

Do not mix ridge vents and turtle vents. Your roof needs to ventilate from the lowest point to the highest point. If you add turtle vents 2-3 feet below where your ridge vent is this will become your new low point for your roof and your roof will not ventilate properly. Your attic will want to ventilate between the two vents and not below.

A power vent is a good way to force air to circulate and if you don’t have good soffit vents accessible this may be a solution.

Timberland, obviously you are new to the forum and don’t know how smart I am, unlike the other regular posters on this site. :smiley:

Welcome.

[quote=“dennis”]Timberland, obviously you are new to the forum and don’t know how smart I am, unlike the other regular posters on this site. :smiley:

Welcome.[/quote]

:stuck_out_tongue:

anyone think of the R value of the insulation? If there is just r-19 well thats not enough for ohio. You need an R value of 49 and that is 15 and 3/4 inchs. condesation will build when the tenent raises the temp and where does it go up. Dont know would have to see would not just guess. But im willing to bet thr insulation is a part of the problem. If the heat is free i would bet alot.

Ok lets just really have fun and add a power vent keep the ridge vent throw a 100 turtle vents and see what that does?

Power vents i dont use them did one time only

I would check for airleaks in the ceiling.
Is there a vapor and/or air barrier in the ceiling
and how intact is it? All penetrations like plumbing stacks and wiring needs to be sealed.

Did you say modular units? If so, that could mean extra quirkiness. My apartment complex, as an example, is also made up modular units stacked together like chinese shipping containers.
As a result, I now have many 1 inch wide airgaps running from the roof to the foundation between all the stacked together boxes. It ends up causing stack effect and sucks in moisture laden air.

Check all boundaries between mod sections as well as the whole perimeter where the walls meet the roof - there could be airleaks everywhere.

Dumping a thick layer of cellulose on the attic floor could also stop airleaks to an extent.

Make sure none of the tenants are venting their dryer into the attic.Usually it is buried under the insulation. I thing gtp is right,about the R-Value scenario. Would an attic fan with a humidistat Help?If the soffits are not fully vented,ridge vent is useless. Good luck

Thanks so much everyone for the input.

The soffits are completely vented now.

The dryer vent goes into the floor.

There is no vapor barrier (do I install that over the rolled batts of insulation on the attic floor)

There may be some moisture coming up from the bathroom but not enough to spread like it does.

Does the rafter running the wrong way matter?

[quote=“leasingagent”]Thanks so much everyone for the input.

The soffits are completely vented now.

The dryer vent goes into the floor.

There is no vapor barrier (do I install that over the rolled batts of insulation on the attic floor)

There may be some moisture coming up from the bathroom but not enough to spread like it does.

Does the rafter running the wrong way matter?[/quote]

You want to install the vapor barrier to the warm side otherwise you will trap the moisture in the insulation

Ventilation is the big issue for a home owner. If a house having the perfect ventilation is always a good place to live the life. A proper way to build the ventilation always keeps you comfortable.

David;

While the rafters are a problem, there is nothing you can do about that. I am not an insulation expert, but this is my opinion of the situation.

Does the moisture occur in the winter, do you know? If so, that is because the moisture barrier created by the felt and shingles is your moisture barrier. That is why rafters go up and down normally.

I think you need to set up stronger ventilation in the attic, particularly across the middle of the underside of the roof. However, you don’t want to be blowing around fiberglass from the insulation. So, you need to be careful to get the “fan” onto the decking.

Do not install a moisture barrier over the insulation, particularly if there is a moisture barrier under the insulation.

In warm climates, it is typical to use no attic moisture barrier. I think the moisture barrier goes at the bottom of the insulation in the north.

I think your efforts to remedy the problem so far will help…maybe even curing the problem.