Preparation — the substrate matters
Clean the substrate. MLV needs a flat, dry surface to seal against. Dust, debris, and moisture all compromise the seal.
Plan the layout. Measure walls, count sheets, plan overlaps. MLV should overlap at seams by 5 cm minimum.
Attachment methods
Screwed to studs before the interior drywall goes on: the professional method. MLV hangs between studs and drywall, sealed at seams with acoustic caulk.
Adhesive-mounted to existing drywall: retrofit method. Works but delivers less isolation than sandwiched-mount because the drywall doesn't add rigidity to the MLV.
Loose-laid between studs: fastest but weakest — the MLV vibrates more freely. Reserved for rough construction where finish quality doesn't matter.
The critical detail — seal every seam
Every seam between MLV sheets: acoustic caulk (Green Glue or butyl equivalent). Not silicone — silicone doesn't seal well acoustically.
Every penetration (electrical box, HVAC duct, plumbing): caulk around the penetration. A single unsealed 100×100 mm electrical box leaks 6–8 dB of isolation from an otherwise well-built wall.
The perimeter (where MLV meets floor and ceiling): sealed with a continuous bead of acoustic caulk.
Ceiling installation — the harder job
Ceiling MLV installs between joists before the ceiling drywall goes on. Screwed and sealed same as wall MLV.
For retrofit ceilings, add MLV above the existing ceiling drywall (in the attic space) — you'll get most of the isolation benefit without demolition.
For upstairs footfall noise into a home theatre below, this is the intervention that makes the room usable. Do it before you spend money on speakers.
Floor installation for impact isolation
MLV under acoustic carpet on the floor above the room you're trying to isolate. This is not for airborne isolation — it's for impact noise (footsteps, dropped items).
MLV between subfloor and finish flooring in new construction is the maximum-effectiveness install. In renovation, MLV under carpet does most of the same job with less work.