Eave ventilation, over the fascia or up through the soffit.

[epsilonGreedy]

Over the fascia ventilation looks simple to implement with purpose made plastic vents whereas soffit ventilation will require more carpentry in my all wood eaves. Over the fascia eave ventilation was my original plan. Now I am having second thoughts due to concerns that sucking air into the attic space via a manky gutter will likely introduce moisture, microbes and smells into the attic space.

 

On the few occasions I have cleaned a gutter this has involved scooping up a microbial soup from the bottom of the gutter in my hand. When considering how air enters an attic space through over the fascia vents, the ventilation air route necessitates an airflow under an eave tray that is lipped down over the gutter. Furthermore when it is raining and windy the eave ventilation air flow will be passing right through water running off the roof as it drips over the eave tray into the gutter which seems like a perfect design to suck a moist mist into the attic.

 

Has anyone else considered the same?

 

What other pro's and con's of over/under eave ventilation should I consider?

 

 

[Iceverge]

Have you considered the sealed attic method with battens and counterbattens to create a 50mm space above the rafters breathable membrane. It'll keep all nasties out of your attic and help your insulation perform better.