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A Forrest Gump moment at Club Bean...

File:Forrest Gump poster.jpg

Herein reminder the Anableps - a four-eyed fish that can see above and below the waterline at the same time.

Bathroom Fan: Case of the AWOL Venting
stupid is as stupid does)
Copyright 2014 (C) Robert Bean, R.E.T., P.L. (Eng.), All world rights reserved.

This is a case of the shoemaker's son, and if it can happen to me it can happen to you.

Not too long ago we did an upgrade on the enclosure of our home which included both spray foam and blown in cellulose insulation. We also did a number of other major upgrades which required several trades to enter the attic and interior spaces for inspection and work.

Amongst the contractors we hired, was one of the oldest and top brand building performance firms with a nation wide reputation for their knowledge in building science and skills at sealing and insulating existing buildings...these guys are pro's (still are) and they like me, missed the bathroom fan buried in the existing vermiculite insulation.[1] Plus (and this is the part that irks me more than my own epic failure) during the placement of the new insulation the applicator either ignorantly or knowingly covered it up again.

Regardless, all of us so called "experts" forgot in this case to look above and below the water line to see the whole picture, translation: the fan was venting (albeit poorly) into the insulation. Good news for us is the room is used infrequently and in Calgary the attic is dryer than a bag of desiccant for most of the year.

Following is a series of photos showing the before and after which serves as a reminder to me (slap to forehead) and a warning to you that when doing anything above the ceiling, become an Anableps and always look above and below the water line.

Figure 1. Original bathroom fan vented into the old and new attic insulation. I didn't catch it pre-purchase inspection, nor did the third party inspector I hired; and I didn't catch it again pre upgrades nor did the roofer, central vac, electrician, plumber and building performance contractor. It was like the fan had a Klingon cloaking device![2] It wasn't until the fan failed that it was discovered by our new electrician.

Figure 2. Insulation moved away for new fan. It's unfortunate that the recently blown in cellulose had to be disturbed which is admittedly a minor issue but none the less annoying. The biggest issue was having to expose the electrician and HVAC contractor to the dust...yes they were wearing masks and goggles but again another annoying issue that didn't have to happen had the previous trades and I been paying attention. Note the central vac duct shown in the foreground. In the attic these should be insulated with piping insulation or buried under a layer of insulation. Why? Moist air pulled into the ducts during operation will collect and condense and run down and out the intake port leaving behind a nasty stain. Ask me how I know?

Figure 3. New bathroom fan with pan vapour barrier sealed against existing ceiling vapour barrier.

Figure 4. Insulated hard duct - no flex duct. Did I mention - NO FLEX DUCT!

Figure 5. The hard duct with 2 @ 45's and 1 @ 90 enables a low restricted air flow without risks due to kinks and sagging common with poorly installed insulated flex duct.

Figure 6. The paper towel test...working as required....and a Forrest Gump reminder of "stupid is as stupid does". Oy.

Thanks to Tony Herold and his technician Matthew Hodgson of Canyon Electrical and Jordan Bazinet of Knight Plumbing and Heating for the great service!

1. Yes we had the vermiculite tested for asbestos and yes it was safe.
2. Star Trek fans - watch out for the cloaking stuff - live long and prosper.

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