Why the sheet on its own is not a wall
An open area of roughly 1% of a wall caps its transmission loss at around 20 dB, whatever the build-up. Mass loaded vinyl supplies mass; what turns the mass into a barrier is a bond that does not bridge the layer rigidly and a seal that leaves no opening. The three accessories together cost less than a fifth of the sheet they go with, and they decide whether the sheet was worth buying.
| SKU | Name | Job | Where | Price |
|---|---|---|---|---|
| BA990 | BlastAdhesive | Bonds the sheet to the substrate while staying permanently flexible | Zig-zag beads on the back of the sheet; concrete, block, steel, timber, plasterboard | 546 (510) per cartridge |
| BA890 | BlastSealant | Closes the gaps sound would use, without hardening or cracking | Every sheet edge, overlap, pipe penetration, door and window frame, board perimeter | 447 (418) per cartridge |
| BA650 | BlastPutty pad | Closes the sound path behind socket and switch boxes | Wrapped over the back and sides of each box in the wall; 18 × 18 × 0.3 cm, one per box | 450 (421) per pad |
BA990 adhesive: why it has to stay flexible
Ordinary construction adhesives cure hard, and every hard point is a bridge that carries vibration straight across the layer you are trying to isolate. BA990 is formulated to remain flexible according to the manufacturer, and is non-flammable according to the manufacturer. It bonds to concrete, block, steel, timber and plasterboard.
- Apply in zig-zag or parallel beads at about 300 mm centres onto a clean, dry substrate.
- Always pair it with mechanical fixings along the top edge and studs. A 5 m² roll weighs about 25 kg; adhesive alone will not hold that on a wall or a ceiling over time.
- About one cartridge per 3 m², or roughly two per roll.
BA890 sealant: the item that decides the result
Bathroom silicone and general acrylic sealants cure to a firm bead that pulls away from the substrate as the building moves with temperature, and the resulting hairline is an open joint two years after the job was finished. BA890 is formulated to stay permanently flexible and is non-flammable according to the manufacturer, so the seal it makes on day one is still a seal in year ten.
| Location | Why |
|---|---|
| Base of the sheet at the floor | The most commonly skipped joint, because people assume the skirting will close it. Skirting is not an acoustic seal |
| Head at the ceiling and both side edges | An unsealed edge is a slot the full length of the wall |
| Every overlap between sheets | A bead in the overlap before it is pressed down, then tape |
| Around every pipe and cable penetration | Never rigid mortar here: it bridges the layer and cracks |
| Door and window frame perimeters | Seal, then cover with a bead or architrave |
| The plasterboard perimeter, before skimming | The second line of defence when the first has a gap |
About one cartridge per 3 m², plus one extra where the wall has many penetrations or joints. A spare cartridge is always useful; a missing one halfway through the job leaves a gap that never gets sealed.
BA650 putty pads: the hole everyone forgets
A socket box is a hole through the wall, and in condominiums it is often installed back to back with the neighbour’s box in the same stud bay. The pad is a soft 18 × 18 cm sheet, 3 mm thick, moulded over the back and sides of the box to restore the mass of the wall where it was cut.
- Isolate the circuit, then remove the socket or switch faceplate.
- Pull the mounting plate, press the pad over the back and sides of the box, and mould it round the cable entry.
- One pad per standard box. Count the boxes on the wall being treated and order that number.
How many to order
| Job | BA990 | BA890 | BA650 | Accessories total |
|---|---|---|---|---|
| Lagging 6 m of drain pipe (1 roll) | — | 2 | — | 894 |
| Pump enclosure (1 roll) | 2 | 1 | — | 1,539 |
| One bedroom wall, 12 m² (3 rolls) | 4 | 4 | 4 | 5,772 |
| Two bedroom walls, 24 m² (6 rolls) | 8 | 8 | 8 | 11,544 |
Accessories can be ordered from one unit, but a basket containing accessories only — no MLV — must reach THB 1,500 including VAT before checkout opens. If you find yourself one cartridge short mid-job, that minimum is why ordering a spare with the rolls costs less than a second delivery.
What not to substitute
- Bathroom silicone for BA890. It works for a season; many formulations then harden and lift from the edge, and the acetic odour in a closed room is a separate problem.
- Construction adhesive for BA990. Most cure rigid, and every rigid point transmits.
- Expanding foam around pipes. It is light, porous and not an acoustic seal.
- Mortar around pipes. A rigid bridge into the structure, and worse than leaving the gap in some cases.