Venting Attic before Finishing

Both an inspector and contractor told me I need to add more venting to my attic before I finish it for a studio. The contractor suggested adding a ridge vent to the existing venting before finishing, but in my original thread Soundman2020 suggested that might reduce isolation too much. So what kind of venting should I consider? Background street noise is currently around 51 db. Over the course of an hour, street noise peaked at 76 db. Getting adequate venting seems to be my first construction decision. What do you think? Total construction budget about $25K. --Nick

If code (or the inspector) say that you need more venting, then you need more venting! There's no way around that. Yes, it will decrease your isolation: there's no way around that, either. So the only option you have is to compensate for that by increasing the isolation of your inner-leaf. That said, what was the reason they gave you for requiring more ventilation? Is this an issue with heat/humidity up against the roof deck surface itself, or is it an issue with human occupancy? If it is about issues with the building structure, then you have no choice: you have to do what they say, and a ridge vent is good option. However, if they are talking about the air requirements for the PEOPLE who will be in your studio, well, that's a different issue! That's part of your HVAC design, which you haven't even started on yet. When you do the calculations for your HVAC design, you will take into account things like how many people will be in the room at the same time, how strenuously they will be exercising, heat generated by other sources (equipment), etc., and that will lead you to how much air conditioning capacity you need (BTU/hour), and how much fresh air you need to bring into the room per hour / stale air you need to exhaust / changes per hour / flow rates / flow velocity / humidity / etc. That's when you will be figuring out duct sizes, fan capacities, cooling rates, silencer boxes, and all those types of things. So talk to the inspector again, and ask if he is talking about the ventilation requirements for the roof itself, or for the people who will be up there. In either case, ask what the required numbers are, according to code. And if it is about human occupancy (people), then explain that you are still working on the design for your HVAC system, which will be separate from the existing room ventilation system, and that you'll send him your plans for that once you have them ready. - Stuart -

Thanks again, Stuart! I'll find out.

you'll need both the ventilation for the building and for the people...

... and there is no ventilation in the attic.

Really? So what is that vent thing in the roof then? Just decoration, maybe? If you don't have anything useful to add to someone else's thread, then it would be nice if you didn't say anything at all. - Stuart -