Long...sorry. Any crawl space or HVAC experts welcome.
Have a crawl space about 5-6 ft at highest and 1ft at lowest. Anyway, i have 2 ducts that are leaking at vent box going into subfloor under house. Appears to be consendensation.
I checked them all and have 18 vents (floor vents) in crawlspace but only 2 leaking. These are both under kitchen cabinet and master bath vanity. I removed the vent plates under both cabinets and the sub floor around both vents inside the house is dry so thinking it is condensation from 100 degree crawlspace temp hitting cold air at vent box in crawl. Like a glass of ice water sweating. Only happens in summer when AC is running 12+ hrs plus/day.
I called a contractor i know and he sealed with spray foam where duct connects to vent box and around subfloor trying to prevent any leakage that would condensate. That was in Oct so wont know for sure if solved until May or June.
House was custom built in 2013 so not that old. The foundation vents around the house are open and there is a vapor barrier covering entire floor. There are no signs at all of water under house, not even after 16in of rain in 2016. Ground floor is always dry as a bone.
Subfloor around both problem vent boxes is dry now but can see staining from where it gets wet (summer) and drys (winter) around vent box in crawl. The vent box that runs under kitchen cabinet actually condesnes for 2 ft on either side of the vent box and can see the staining. The wood doesn't appear compromised....yet. Thinking this is because only moisture at bottom surface as opposed to leaking thru from top down aka a water leak.
Obviously want to solve vs having a bigger issue at a later date if it continues. My questions are.
1. Is it a coincidence both problem vents are under cabinets vs air vents in open floor? They basically set the cabinets above the vent box and the cabinet itself forces the air out thru vent in cabinet. As i said though, i took the cabinet vent covers off and the floor inside appears dry. Did this in summer when wet underneath.
2. Have researched encapsulation which i think would solve, but is that overkill given dont think i have a moisture or water issue in crawspace. That is very, very pricey as well. Hate to spend 10+k if there are other options.
3. If cabinets vents are the issue, guess i could hire HVAC to cap those 2, and move vents to floor in other areas of kitchen and master. Like the aesthetics as is though if can stay where they are vs moving to floor. That would also entail cutting hardwood (kitchen) and tile (bathroom) for the new floor vents.
A buddy suggested sealing the subfloor/adjoining joists problem areas with water proofer since now dry. This would prevent the condensation from penetrating the wood underneath and doing damage. Sounds plausible but afraid to spray something on that is a pia to remove if necessary.
I'm open to suggestions. In Lexington area if any pros would like to take a look. Happy to pay someone to solve permanently.
Have a crawl space about 5-6 ft at highest and 1ft at lowest. Anyway, i have 2 ducts that are leaking at vent box going into subfloor under house. Appears to be consendensation.
I checked them all and have 18 vents (floor vents) in crawlspace but only 2 leaking. These are both under kitchen cabinet and master bath vanity. I removed the vent plates under both cabinets and the sub floor around both vents inside the house is dry so thinking it is condensation from 100 degree crawlspace temp hitting cold air at vent box in crawl. Like a glass of ice water sweating. Only happens in summer when AC is running 12+ hrs plus/day.
I called a contractor i know and he sealed with spray foam where duct connects to vent box and around subfloor trying to prevent any leakage that would condensate. That was in Oct so wont know for sure if solved until May or June.
House was custom built in 2013 so not that old. The foundation vents around the house are open and there is a vapor barrier covering entire floor. There are no signs at all of water under house, not even after 16in of rain in 2016. Ground floor is always dry as a bone.
Subfloor around both problem vent boxes is dry now but can see staining from where it gets wet (summer) and drys (winter) around vent box in crawl. The vent box that runs under kitchen cabinet actually condesnes for 2 ft on either side of the vent box and can see the staining. The wood doesn't appear compromised....yet. Thinking this is because only moisture at bottom surface as opposed to leaking thru from top down aka a water leak.
Obviously want to solve vs having a bigger issue at a later date if it continues. My questions are.
1. Is it a coincidence both problem vents are under cabinets vs air vents in open floor? They basically set the cabinets above the vent box and the cabinet itself forces the air out thru vent in cabinet. As i said though, i took the cabinet vent covers off and the floor inside appears dry. Did this in summer when wet underneath.
2. Have researched encapsulation which i think would solve, but is that overkill given dont think i have a moisture or water issue in crawspace. That is very, very pricey as well. Hate to spend 10+k if there are other options.
3. If cabinets vents are the issue, guess i could hire HVAC to cap those 2, and move vents to floor in other areas of kitchen and master. Like the aesthetics as is though if can stay where they are vs moving to floor. That would also entail cutting hardwood (kitchen) and tile (bathroom) for the new floor vents.
A buddy suggested sealing the subfloor/adjoining joists problem areas with water proofer since now dry. This would prevent the condensation from penetrating the wood underneath and doing damage. Sounds plausible but afraid to spray something on that is a pia to remove if necessary.
I'm open to suggestions. In Lexington area if any pros would like to take a look. Happy to pay someone to solve permanently.
