Replies

1. 
   Don_Hamel | Jul 02, 2001 09:15pm | #1

   *
   Mark, could the dryer originally been in the basement? It also could also have been a power exhaust vent to draw fresh air into the basement, perhaps for humidity control or just for an air change to control odors. I have something very similar to vent a darkroom.

1. 
   bill_burns | Jul 05, 2001 05:08am | #2

   *maybe for a downdraft stove?

1. 
   Norm_Kerr | Jul 05, 2001 06:07pm | #3

   *Maybe the rats snuck it onto the plans at night when the place was being built?

1. 
   Just_Another_Guy | Jul 05, 2001 09:48pm | #4

   *Does the house have an Air exchanger, or did it ever?? In my last house (which was the first in my county to be built with an exchanger) they put all kinds of ducts where they didn't need to be, extra vents in the house, and one vent (like what you describe) on the exterior. I called the HVAC contractor about it and he said it was installed to guared against Radon or Xenon or whatever the vogue gas of the day is thats collecting in basements. I asked wasn't that what the air exchanger was supposed to be for, and he said the vent was just extra assurance in case the exchanger stopped working.I plugged the sucker with expanding foam, and never had any trouble in the 5 yrs I lived there.

1. 
   Rob_Susz_ | Jul 06, 2001 07:10am | #5

   *It may be a code required "makeup air intake" that some states and municipalities require. The idea was that this damper would open to prevent natural draft furnaces and water heaters from backdrafting.The problem is that when the wind blows against one side of a house, the other 3 sides are at a negative pressure. So when the wind is blowing, there is a 75% chance it will not let air in.Most Building-Science types I knoe of just plug them up, and then do a combustion safety test just tobe sure.-Rob

2. 
   MarkF_ | Jul 06, 2001 06:02pm | #6

   *Thanks for all of your responses. I think Rob may have nailed it. I'm going to check on the local code. Comments from the crew that replaced my furnace a while back was that my builder didn't know anything about HVAC....based on duct sizing and return locations. From neighbors I heard that the builder had his crew install the ductwork because of sub availability or something. That makes me confident that he wouldn't have attempted an air exchanger. I don't know. I'm considering having another Radon test done though...just for peace of mind.

2. 
   MarkF_ | Jul 06, 2001 06:02pm | #7

   *
   Shortly after I moved into my house 5 years ago, I extended the width of the deck on the back of my house. In order to extend the ledger board, I had to remover this odd, one-way vent that went through the siding and rim joist and daylighted just a few inches into the basement. It looked like a big dryer vent on the outside. I had heard from neighbors that the prior owners had trouble with rats and this vent certainly could provide them easy access...I mean a cat could easily fit through this thing! The flap just required a little nudge from a critter's nose and it could just climb right in. Anyway, I removed it and covered the hole. Now I wonder if it was "something important". At the time, I checked with friends that had unfinished basements and none of them had this vent. I also have 3 small basement windows so I couldn't see a ventilation issue. It did appear to be original to the house (1980). I have an oil-fired, forced hot air heating system. Also, I had the house tested for radon when I had it inspected and there was no problem.

   Does anyone have any insight on this mysterious vent?

   Thanks.