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Exhaust Venting in Attics Do it Right!

Ductwork (aka exhaust venting) that is not correctly installed is one of the biggest contributors to mold growth in attics. These are some of the common mistakes we see:

  • Venting that runs many feet across the attic
  • Venting exhausting out of the soffits
  • Venting made of slinky material (plastic or metal)
  • Venting is that is not sealed and insulated
  • Venting with no shroud cover at the fan
  • Venting secured with that all-purpose grey duct tape

Mold in your attic will show as a grey, black, brown or white discolouration on the attic sheeting. This is often referred to as ‘staining’.

Your attic sheeting should be the golden wood colour of OSB or plywood.

Professionals have different opinions as to whether (or not) mold spores disperse throughout your home with air pressure when the doors are opened and closed.

Example of a Correct Vent Installation
An example of a correctly installed fan exhaust.

Based on our experience, we recommend the following when installing and/or repairing exhaust venting in
your attic:

  • The exhaust venting running from fans in your attic should be running in the shortest path possible from the fan to the roof. This includes bathroom and stove overhead fans. You may need to hire a roofer to cut a roof vent for your venting. The venting should be rigid metal – not slinky plastic or metal. Ideally, the rigid metal pipe and the roof
    vent hole should be 6” although 4” will work.
  • Attach the metal pipe to the roof vent with metal screws and aluminium foil tape or sealant. Do not use that ever-so-popular grey duct tape. Don’t let the word ‘duct’ fool you as Red Green’s favourite is not the best for this kind of work.
  • Every screw hole and seam on the rigid metal pipe should be covered with the aluminium foil tape and then the whole pipe wrapped with a ‘ductwork insulation sleeve’. Both ends of this sleeve should be secured to the rigid metal pipe with the red tuck tape. The insulation should not touch the roof. Make sure to leave a gap there.
  • The fan in the attic should be covered with a soft plastic vapour barrier cover (aka shroud). Use the red tuck tape to secure the
    shroud on all sides.

Want to know an easier way?

Call Home SOULutions and let us take care of it! contact us today.

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