I want light and sound isolation

[Almavague]

The room is coming along - see photo. The wood inner structure is done, wood fiber insulation is in place, the rest is on it's way...

I haven't yet decided what to do with the floor. And I'd like to decide before putting up the drywall, in case I decide to do a screed, which might warp the drywall. The existing floor is a slab that's not very level. In one corner I have 4cm difference with the highest point.

I had originally thought of just putting down an underlay underneath a laminate floor. Something like this: https://www.leroymerlin.fr/produits/rev ... 67108.html

But now I'm thinking maybe I should level the floor once and for all. For this I see 2 options:

Option 1 - install a screed (self leveling cement) between 0-4cm. Then follow with the original idea, a thin underlay and laminate floor. This would be a cheaper option with less isolation.

Option 2 - a dry vermiculite screed for leveling, with a layer of something hard, such as OSB on top, then finished with stratified flooring. If you search for fermacell dry screed you'll see what I'm refering to. This is a more expensive option with (I believe) better isolation.

I have two questions:

I would like thermal as well as acoustic isolation. I believe the weakest part in my design is the double glass doors. As I believe that sound isolation is a "weakest link" kind of thing, would the extra sound isolation from option 2 be of any use?

I believe most types of insulation sold for use on floors with thermal and acoustic properties are meant to dampen mainly foot noise between floors. Because in my case I would want to prevent as much flanking as possible escaping the room through the slab (for example drumsets or bass amps sitting on the floor) Would any of these products actually be doing me any good?

[gullfo]

the fermacell approach looks like an option if it's in your budget (https://www.fermacell.com/en/flooring) as is the self-leveling compounds. either way you could put a hard layer (e.g. OSB) then your finish flooring.

on the isolation question - i'd recommend you use isolation platforms for the drums and amps.

for the doors - if you need more isolation - adding a second set of doors can address the isolation level as well as increasing mass and lamination for damping to reduce resonances.

[Almavague]

Hi Again,

I've got a 2 random questions:

1. My electricity/internet is coming into the room through 2 plastic conduits - one for high voltage (230v - 2 outlet circuits, one light circuit) the other for an internet cable. As I was closing up the inner leaf, I attached the two conduits with zip ties, thinking that I don't want them to vibrate against each other, then I closed the wall (insulation and vapor barrier - drywalling not yet done). Then of course, I remember that high voltage and internet need to be seperated (in France, the code specifies 20cm of distance between them) So these two conduits are side by side for about 4m between my two leaves. Do I need to reopen the wall and rectify this ? Or is 4 meters not such a big deal?

2. I'll be doing the drywalling soon - two layers of acoustic drywall. Every indication for drywalling in normal constructions tells me that you're supposed to leave a 1cm gap between the floor and the drywall, to avoid the drywall absorbing any humidity or spills, and also to avoid any cracking of the drywall in case of movement in the structure or floor. However the 1cm gap from a sound isolation perspective is clearly not ideal. I don't have any plumbing in the room, except the condensation tube from my heat pump.

My electrical will be in a plastic base board that will cover the potential gap, and could be caulked to seal the inner leaf.

Do I leave the 1cm gap and use the plastic base board and caulk to create a seal ? or do I put the drywall up against the floor ? Or is there some other solution ?

[gullfo]

#1 - they are in conduit, so most codes would see that a wholly separated. the main reason would be potential interference from the digital circuits or mistakenly plugging your internet gear into 230v... if you have proper grounding (star grounding etc) then the possible interference from the network is very low. and just don't plug network things into AC outlets

#2 - i'd suggest you go to 0.5cm-0.6cm on the drywall to floor gap and using backer rod and caulk to seal it up. then leave a 2mm gap under the trim (avoiding hard contact with the floor).

[Almavague]

Hi Glenn - Thanks! I always appreciate your clear responses!

Backer rod and caulk sounds like a good solution. But what is the logic on leaving 2mm under my baseboard?

[gullfo]

the 2mm on the trim is my habit. i leave it off the floor and seal it with caulk before painting. it matters slightly if you have decoupled the walls from the floor (e.g. Kinetics Noise Wallmat etc).