Converting my garage by building new walls outside

[riandeheer]

Hi all,

I'm new here so please forgive me if I break any forum rules. I recently purchased a house in France including a large garage. The dimensions are l10,4m x w6,5m x h2,20m. The garage is already divided into two rooms, so it's easy to build a control and a recording space. The ceiling is quite low (2,20m) and although it's not a small building I want to preserve at much internal space as possible. The garage stands alone and is about 20 meters from the main house, located at the edge of the tiny village. I am thinking of using the box inside a box principle by building new walls OUTSIDE the current garage, there is plenty of space outside so that is no issue. I am planning to use the regular isolation techniques as described in this forum but I can't find anybody who used this OUTSIDE of a building. Is there anybody who has done this before or anybody who has ideas on this?

Another question is the floor isolation: does the rocky ground transfer sound outside, requiring me to not only isolate the walls and ceiling but also the floor?

[Eric Best]

For your box outside the garage, you would need to have the box go completely around the garage, including the roof to gain the sound benefit that you are looking for. The two structures need to be completely detached. I think you would just be better off by adding more drywall.to the walls that you have. I wouldn't worry to much about the floor. Your only solution would be to make a floating concrete floor, which is a MAJOR undertaking.

[riandeheer]

Hi Eric, thanks for the reply. So adding more drywall to the outside vertical walls in addition to adding isolation to the roof could be sufficient? It is easy to build walls around the garage but adding an additional roof would be an interesting undertaking indeed. Do you have recommendations to isolating the roof from the inside?

[Eric Best]

Drywall would not be good outside. Once it gets wet, it is done for.

I would just use resilient channel and drywall on the inside.