room in room and baffle boxes

[remco]

Hello, I am building a shed in my garden with an extra room in it, to use as drum room.
I understood for venting it is best to use 4 baffle boxes, 2 for extracting air and 2 for letting air in.

What I can't figure out is how and if the baffle boxes should be connected.
Should the box which extracts air from the inside room be connected to the box pulling it outside?
Or is it also possible that the inside box pulls the air in the space between the rooms and a nearby box pulls the air to the outside of the building?

this would have an advantage while I then could also ventilate the space between the rooms, avoiding moisture problems

Hope you can help me, thanks!

[Paulus87]

Hello, I am building a shed in my garden with an extra room in it, to use as drum room.
I understood for venting it is best to use 4 baffle boxes, 2 for extracting air and 2 for letting air in.

What I can't figure out is how and if the baffle boxes should be connected.
Should the box which extracts air from the inside room be connected to the box pulling it outside?
Or is it also possible that the inside box pulls the air in the space between the rooms and a nearby box pulls the air to the outside of the building?

this would have an advantage while I then could also ventilate the space between the rooms, avoiding moisture problems

Hope you can help me, thanks!

You just need a baffle box for each penetration, so if you have a 2 leaf system (room within a room) you would need one inlet on the outer leaf which is connected (not rigidly) to the corresponding inlet box on the inner leaf. Then you need one outlet box for the inner leaf which is again connected (not rigidly) to the corresponding outlet box on the outer leaf.

Each box needs to match the surface density of each leaf that it's on, and each box needs to have a sleeve (with the same surface density) which goes through the penetration. You can connect each pair of boxes with flex duct or if the sleeves are close then leave a small gap between them and caulk it so that they remain decoupled but air sealed.

If you only have a single leaf building then you'll only need half as many boxes, one for the inlet and one for the outlet.

Paul

[remco]

Thanks for the clear explanation
So these boxes are not going to help to ventilate the building, could it be a problem in cold periods?

[Paulus87]

Thanks for the clear explanation
So these boxes are not going to help to ventilate the building, could it be a problem in cold periods?

They will help ventilate to a certain extent, but yes these are primarily for allowing the exchange of air for you to breathe, depending on the construction of your building you may need roof vents/wall cavity vents.

If you tell me more about your build then I may be able to advise. If you have a cold roof then you will definitely need some roof vents.

Roof vents are not a problem in terms of compromising the isolation envelope, so long as it's designed properly.

Paul