Will exhausting into rafter area cause mold or any issues?

doggee

Member
I have 2 tents (4x8) both flower tents in my garage that i have the 6'' exhaust ducting connected to ceiling and blowing into rafter area. Its all one open space up there above the garage and above living area of home so the exhaust can essenitally float around up there anywhere above home until it finds a roof vent to go out of.

My question is should I have to worry about any mold issues forming on roof decking boards, rafters or anywhere else up there?
 

bostoner

Active Member
Mold is usually from moist stagnant air. If more air is continuously being pushed around up there I doubt you will have any problems. Does your grow room have particularly high RH? Should be around 50% for flowering plants.
 

Brick Top

New Member
It would depend on how well, and evenly, your attic space is ventilated and what conditions you have. I have known people to not have any problems. I have known others who ended up with moisture in their insulation and corrosion in electrical junction boxes and ice, that later melted and was just moisture, on rafters and roof boards, I have seem mild climate areas where raising the temperature of an attic a degree or two by venting into it cause some or all the roof to be clear of snow, when normally it would not be, and either way that can make someone wonder, especially if they are used to seeing it totally coated thanks to good insulation.

If venting into a space like that you want your exhaust to exit as close to an attic vent or vents, or all along say a ridge vent, as possible. That or tap into something like a bathroom exhaust fan that exhausts through the roof, or a sewer/septic stack pipe, in either case of course using the proper type 'Y' connection.
 

CanBud

Well-Known Member
What are the outside temps around your parts? Condensation will happen depending on inside/outside temp difference and attic venting would also play a huge factor.
 

Brick Top

New Member
What about exhausting a portable a/c in the same place? will that cause any problems?
A/C units extract humidity from the air they cool and expel it elsewhere/outside/down a drain ... somewhere though, and unless modern portable A/C units are very different than I remember, or this is some extremely different design, the water will come off in anything from a frequent drip to a light constant flow depending on conditions. If that is the case, what are you going to do with that in an attic area?
 

phishtank

Well-Known Member
Portable AC units either have drip trays....drip lines....or self evaporate the moisture. As far as the hot air being created by the coils...I don't know if you can vent that into the attic or not. I'm actually wondering the same thing since I'll be doing a sealed grow.
 

doggee

Member
The home seems like it has plenty of roof vents its a single story home built on 2009. not very big about 1500 square ft . Ill try to post some pics, anymore input appreciated id hate to ruin my new home that ill be payin on for the next 27 years. Thanks in advance.
 

NewGrower2011

Well-Known Member
Same camp here.

I'm looking at my ridge vents for exhausting and then there are those little gutter looking trays of plastic/tin that run down to the soffit (I believe that's the term) and allow air flow... they only come up the roof decking for 4-5 feet and then stop open ended... they then run all the way down to where I can't see them any longer they've disappeared into the framing... I think those will be my intakes...

I think I'll basically take my intake and try to enclose a couple of those soffit vents and then tie the ducting into the enclosure. Then for the exhaust I'll take a section of the ridge vent and enclose it, attaching the exhaust ducting to it so that the air is hopefully forced out and not allowing much if any to be in the attics air space. I was thinking of the ridge vent for the intake, but hot summer air would be hottest at the ridge... versus my soffit would be in the shade @ a lower height and the way the sun sits for me that side of the house would get cooler before the others...

I also decided to not screw with this twice... I was going to do 6" exhaust and 4" intake but I'm taking the 4" gear back and getting 8" giving me 8/6 respectively....
 

4ndy

Member
you can fit extra soffit vents which cost pennies and are simple push fit fitting with 70mm holesaw, it's common practise so wouldn't look out of place. Also you can get roof tile vents which you can attach pipes to (used for soil vent or bathroom vent).
 
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