My process of elimination continues.
I’ve now got a good door with a tight seal and it works well, so I’m checking that off.
I now know that chopping a hole in the wall for a window AC doesn’t work and I undid that. My space is now near air tight, so a portable AC will not work and would also require cutting substantial holes in a wall. So a mini split is really the only choice.
Thanks to Rob, I’ve got a better understanding of wall construction and how rigid fixtures might affect transmission. I can’t practically change what I’ve built and I would build a do-over much differently, but it is what it is and it’s not bad.
The enemy all along has been low end bleed into an adjoining BR. Everything else is very acceptable. So that’s what I’m chasing.
Following the principle of try the easy, inexpensive things first, I could add mass between my room and the adjoining BR wall, which forms a triple leaf (not good). There is a 2” air gap there. I have a quantity of 2’x8’ scrap pieces left over from the build, enough to create almost two more layers of 5/8” drywall between the room and the BR wall. But that would reduce the air gap to less than an inch and the drywall pieces would be loose, not screwed or glued. So I’m wondering if that will actually get me anything.
After that, there is the concrete slab floor. From what I’ve read, a slab is good at blocking impact noise, of which I have very little, and is vulnerable to airborne noise, of which I have a lot. I see there are good solutions for both, but are expensive to do something that actually works.
The last resort option is to move the entire structure further away from the BR wall. I have about another foot to work with. This is actually possible because the plate is not bolted to the slab. I did this once during the build by raising a corner with a wrecking bar enough to get a 1” piece of pipe under the plate. Repeat at the other three corners and the entire room can be rolled to a new position. But I’m afraid of damaging the structure and the electrical would be disturbed. It’s a scary option.
The bleed seems to be coming through the wall and not so much through the floor.
Thank you for any input you might offer.
Mike