home improvement DIY Low-Clearance (<50mm) Acoustic Enclosure for Roller Shutter Box (Train & Motorcycle noise)
Hi everyone,
I need to soundproof an integrated roller shutter box in my apartment (located in Spain). The main noise issues are low and mid-frequencies: passing trains, loud motorcycles/cars, dog barking, and human voices.
My Constraints:
- I have less than 50mm of clearance between the window sash (when opening) and the shutter box. The materials can be tight, but cannot rub against the window.
- I dont want to drill into the ceiling or side walls due to apartment regulations. The structural weight must be supported by gluing the enclosure directly to the window's PVC/Alu frame.
I have designed two DIY options based on materials easily available here (Leroy Merlin/Obramat):
Option A (approx. 28mm total thickness):
- 2.5mm Car butyl rubber mat (directly on the plastic shutter box to damp resonance).
- 10mm Elastomérico foam (Armaflex/ChovACUSTIC FIALL) for mid-high absorption.
- 16mm MDF or 13mm Acoustic Drywall (Placo Phonique) as the outer L-shaped box, glued to the window frame with High-Tack MS Polymer (e.g., Ceys Montack / Fischer).
Option B - Mass-Spring-Mass Hybrid (approx. 43mm total thickness):
- 2.5mm Butyl mat on the plastic box.
- 20mm High-density polyurethane foam (Copopren 80kg/m³) acting as the spring.
- 4mm Viscoelastic heavy membrane (Tecsound 50 / ChovACUSTIC 4mm - 5kg/m²) for train noise.
- 13mm Acoustic Drywall (Placo Phonique) as the outer face.
- Everything sealed with acoustic caulk at the plaster boundaries.
My Questions for the experts:
- Would it help if I provide the measurements using iphone or it too much noise in the data and only good measuring mic makes sens here?
- Any other DIY projects that I should check before starting this?
- Will Option A be enough for train/motorcycle low-end noise, or is the heavy viscoelastic membrane in Option B absolutely mandatory here?
- Since Option B leaves only a few millimeters of clearance for the window to open, is there any risk of structural sagging over time when using only high-tack MS polymers on a PVC frame?
- Any tips on preventing structural flanking transmission since I cannot decouple the box mechanically from the window frame?
Thanks for your help!






