Mold On Ridge Vent/Ceiling

[DoubleARS]

I'm sorry if this has been addressed before. I'm not finding what I'm looking for when searching.

I moved into a new house a year ago with a a 40'X50 steel building. It has 16' walls with a 17.5' peak. It has two 12'X14' tall garage doors. It had some sort of insulation sheets hung on the ceiling. I had 2" of closed cell foam sprayed on the walls last fall. I also installed some pretty tight seals on the garage doors and had a 5 ton HVAC system installed though it is not wired up yet. I had to have a new larger panel installed with a dedicated service. It appears to have a ridge vent as I can see some light on the ends and there is no insulation at the peak.

My problem is, I'm starting to see quite a lot of black spots on the ridge where there is no insulation. I'm assuming mold/mildew. I'm going to have to hire someone to clean it or rent a lift as I'm not getting 17.5' up on a ladder at my age. Should the vent be sealed or should it be closed? Will my issue go away once I keep it better climate controlled?

 

[billconner]

What climate?

I think there are many things screwed up here. Soffit and ridge vents are for attic, above the thermal (insulation) barrier. Your venting through ridge vents the interior conditioned air is just nuts.

I don't think this building was built to ever be conditioned. The stuff under the roof deck was just to lessen condensation in an unconditioned building.

I guess one solution is pull all that stuff down, remove ridge vent and close it. Clean and disinfect. Then close cell spray foam roof. If I knew where you were I could give an idea of how thick, but probably at least 2" and maybe much more.

I have to add exposed foam - walls or roof - is a fire hazard. Codes most places require a covering or coating.

Sorry it's such poor news.

 

[DoubleARS]

That is critical information I left out. The building is in East Texas.

I am building out the interior with two large rooms (one for woodworking and one for working on cars).

The foam has been covered with a thermal barrier, NoBurn Plus ThB.

 

[billconner]

Close vent and do same thing on ceiling, only a little thicker to han walls.

 

[FredWanaker]

where cold meets humid air condensation results. Mold likes moisture and organic substances. It really is that simple. Get the HVAC system working, and seal up that vent, foam that area too. Otherwise that steel is cold, moisture comes in and condenses on it. Rust or mold results. You cannot get rid of the moisture in the air outside so without HVAC you will also get condensation on cold tools, all sorts of things until you condition the air to remove the moisture. Ill give you a good example - we have an aluminum patio cover - can't get better ventilation than that. It gets cold at night, in the morning when it is cold and humidity is high, moisture condenses on the underside which molds slowly over time. Once a year I have to bleach the underside and scrub it.

 

[bb29510]

unless you plan on climbing up there and licking on it, its not a issue. if it really bother you, spray it with bleach

 

[mepstein]

Clean up is easy. Telescoping aluminum pole with a sponge mop on the end dipped in vinegar. Unlike bleach, the vinegar is easier to handle if some drips in your face.

 

[Fav Onefour]

@billconner , Covered it well in post #2 with the first two sentences.

You are already seeing the issue in one year. Cleaning is a temporary solution. How often do you think that will be happening? I don't like temporary solutions to long term problems. I'm sure you don't want to keep throwing away HVAC dollars and cleaning the results.

The original ceiling insulation is a radiant barrier with the building design. It's nice that they spent the money on that extra step, but the overall design is not for a conditioned space.

I wish there was a nice answer. The wall insulation and HVAC aren't free. Those two upgrades won't fix the issue you are currently seeing.
Partial solutions will help. Close the ridge and at a minimum add radiant barrier to that area. You will still have walls that are insulated and sealed better than the roof. The HVAC will help manage humidity if you use it properly. That will get you by without going nuts.

 

[FredWanaker]

I have to wonder where the excess humidity is coming from.

 

[Fav Onefour]

@FredWanaker , Your question got me thinking. I'm sure there is plenty of humid air in East Texas. That alone wouldn't cause condensation. You also need a temp variance at the ridge.

@DoubleARS , It might be worth checking to see if it's wet on those mornings when you have dew. I'd also want to see if there is water blowing on to the underside of the ridge during a windy rain.
I'm wondering if it may be staining from dust or soot. It seems hard to believe that ridge could stay wet long enough on a regular basis to already have mold/mildew forming.
I've dealt with mold/mildew issues in buildings I've picked up over the years. It's usually not a quick fix. It's also pretty rare on open surfaces with air movement. I find it where there has been long term high humidity. The **** usually starts in dirty spots with dead air in well sealed buildings. In the clunker buildings it seems to form around inside - outside leaking points. (That is in a cold environment though.) I'm obviously not as familiar with warm climate mold, but without the HVAC running there shouldn't be too much hot/cold exchange.

Either way, in the end the open ridge should be addressed if this is going to be a conditioned building.

 

[bb29510]

ceiling fan