Description
Moisture Block Blue MB250 is a 2mm closed-cell EPE foam underlay built for laminate and timber floating floors, with an integrated double-sided PE film that gives it a 100% vapour barrier rating. The reinforced damp-proof membrane on the top side, combined with a joining flap and tape system at roll joins, is designed to stop moisture transferring both up through the underlay and sideways across the joins between rolls.
At just 25kg/m³ density, it’s a lighter-weight underlay than a rubber sound-block product, reflecting its focus on moisture management rather than acoustic performance. It still carries a genuine compressive strength rating (20kPa at 25% compression to ISO844), enough to support laminate and timber flooring without excessive compression under normal foot traffic.
Technical Specifications
| Thickness | 2.0mm + double-sided 40 micron PE film |
|---|---|
| Roll size | 50 lineal metres x 1.1m wide (55m² per roll) |
| Density | 25 kg/m³ |
| Water vapour transmission rate | 4.8g/m²/24hr (ASTM E96) |
| Compressive strength (25% compression) | 20kPa (ISO844) |
| Overlap | 100mm |
| Vapour barrier rating | 100% |
Where to Use
- Underneath laminate and timber floating floors
- Over concrete or timber subfloors, subject to moisture testing
- Installations where a moisture vapour barrier is required beneath the flooring
How to Apply
- Test the subfloor — confirm moisture content is below 14% for timber/particleboard, or below 80% relative humidity (or 4% by impedance meter) for concrete, per AS1884-2012 Appendix A.
- Prepare the subfloor — ensure it is dry, clean and free of sharp objects.
- Roll out the underlay — joining tape side up.
- Join adjacent rolls — remove the protective cover from the joining tape and roll the next length so the tape and flap seal together.
- Install the flooring — proceed with the laminate or timber flooring once the underlay is fully laid.
Important Notes
- Not a waterproof membrane — it does not protect against excessive or abnormal subfloor moisture.
- Store protected from moisture and direct sunlight prior to installation.
- Footwear with protruding surfaces should be avoided when walking on the underlay during installation.
Choosing between Moisture Block Blue and a heavier rubber sound-block underlay usually comes down to which problem matters more on a given job: where moisture management is the priority — over a concrete slab with borderline moisture readings, for instance — the lighter EPE foam construction with its integrated vapour barrier does the job efficiently without the extra cost and weight of a denser acoustic product. Where impact sound reduction between floors is the bigger concern, a heavier rubber underlay is the better specification instead, even though both products sit under the same category of laminate and timber floating-floor underlay.
