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randlefactor 01-13-2013 11:08 AM

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I noticed drip patterns on my garage floor and looked up to see what I think is condensation. The last 2 days we've had really high temps compared to normal in Syracuse NY so the snow has been melting like crazy. The water is running along down and maybe collecting in the soffit. I see drips on the soffit vents.

It appears I have plenty of soffit vents but no ridge or gable vent. Is this the likely cause of the condensation and what would you suggest installing? Notice the foam that someone sprayed along the ridge.

Also I should note I found out this garage was built by a DIY owner in 2000. ... So don't hold back if you see anything strange or wrong with the structure.

SeniorSitizen 01-13-2013 11:41 AM

Your warm wet car is raising the dew point temperature until the roof temperature can't take it any more and drips plus channels water to the soffits. A couple of reasonable choices are to heat the garage to lower the dew point or perfect insulating job. A not so reasonable suggestion is to leave the car outdoors until it cools and dries.

joecaption 01-13-2013 01:54 PM

No ridge vent and not enough soffit vents.
No air sealing, insulation and sheetrock on the ceiling.

jagans 01-14-2013 11:09 AM

Does it drip if you leave the garage door open? or just after you close it?

randlefactor 01-14-2013 10:14 PM


Originally Posted by jagans
Does it drip if you leave the garage door open? or just after you close it?

I think what happens is the warm moist air freezes on the underside of the cold metal roof each time I pull my car into the garage. Then during the warm weather, all of that collected moisture melted and dripped all at once causing a big mess.

I think I'll add either a ridge vent or gable vents and see if that helps. Does anyone know if wasps can fly through the holes in a ridge vent?

joecaption 01-14-2013 10:29 PM

One way around that is to buy some Cobra vent and cut it to width so it fits inside the metal vent.

jagans 01-15-2013 09:36 AM

That's why I asked if it drips when you have the Garage door open.

You have a thermal bridge. Heated air containing moisture is hitting the underside of the deck, condensing and dripping.

I have to disagree with Joe on the Cobra, as I consider it to be trash, but I agree with the concept. A good ridge vent can be fabricated for a metal roof that provides excellent ventilation, as long as your soffits are fully vented.

Another option is a powered ventilator that works on a timer when you open or close the garage door? Pretty simple circuitry for a IC nut.

A third option is to have your metal roof sprayed with PUF and coated with Silicone. That will stop it cold, as the insulation will be on the outside, and the dew point will fall in the insulation.

A fourth option is to take that silly metal roof off, add trusses, sheathe it and put a shingle roof on it. The plywood and shingles are an insulator, as opposed to metal, which is a conductor. Through fastened metal roofs leak after a few years anyway, as the fasteners egg hole due to movement.

This is silly construction for a cold region, IMHO

Gary in WA 01-15-2013 10:24 PM


"So don't hold back if you see anything strange or wrong with the structure."--------- the front side walls of the garage appear to have hold-downs for shear resistance because the concrete looks like spalling below the siding--- good. Bad; the windows in the shear panels defeat the purpose. You also appear to be missing these, per minimum code for uplift;

For your high wind area:


joecaption 01-15-2013 10:30 PM

A ridge like this will work and keep the bugs out.

jagans 01-16-2013 07:53 AM

Joe, a ridge like what?

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