ACTFLEX 900R Butyl sheet membrane
Dual-fabric butyl rubber internal undertile sheet membrane, heat-welded laps
Internal wet area butyl sheet. Tile or screed from 1 hour after installation.
ACTFLEX 900R coverage, coats and cure times
Dual-fabric butyl rubber sheet for showers, bathrooms, ensuites and laundries. It is bonded with water-based ACTFLEX 302 ADHESIVE and its laps are hot-air welded.
- Gauge
- 0.9 mmtotal, white nonwoven fabric on both faces · TDS p3
- Roll size
- 1.4 m x 20 m28 m² gross · TDS p3
- Coverage
- ≈ 25–26 m²practical per roll; 27.2 m² effective after side laps · TDS p9
- Laps
- 40 mm minside and end laps, hot-air welded · TDS p6
- Cover from
- 1 hourtile, screed or flood test, after installation · TDS p10
- Flood test
- 24 hours50 mm minimum depth at the highest point · TDS p10
- Apply at
- 5–35°Cambient (average) · TDS p3
- Adhesive
- 8–10 m²/LACTFLEX 302 ADHESIVE, per coated face · TDS p3
- Upturn
- 150 mm minfloor sheet above finished floor, over solid backing · TDS p7
From the FORSPEC data sheet, TDS-900R · Revision 3 · 2 October 2026. Times are at 25°C and 50% relative humidity unless the data sheet says otherwise.
ACTFLEX 900R on site
More FORSPEC jobs
Where ACTFLEX 900R is used
Use it for
- Showers, bathrooms, ensuites and laundries
- Under direct-stick tiling on the upper fabric face
- Under bonded screeds
- Over existing cured screeds, primed with two coats of ACTFLEX EP250
- Wet areas with fully encapsulated electric underfloor heating
- Hybrid walls and terminations with ACTFLEX 906 WPU or 989 CWP
Know before you start
- Internal only: not for external, below-grade or UV-exposed areas, use ACTFLEX 1300R
- Not a wearing surface: always cover with tiles, screed or a protective finish
- Heating cables must never sit directly against the membrane underside
- Not below 5°C or above 35°C ambient
How to apply ACTFLEX 900R
- 01
Prepare
Clean, sound, dry and vacuumed. New concrete cured 28 days. Falls 1:80 to 1:50 to the waste. Pack out gaps so the 150 mm floor upturn is solidly supported.
- 02
Prime if needed
No primer on sound, dry substrates. Two coats of ACTFLEX EP250 over an existing screed or where moisture is above 80% RH or 15 g/m²/24 h.
- 03
Bond the floor
ACTFLEX 302 ADHESIVE on both faces at 8–10 m²/L per face. Let both go tacky, bed the sheet from one edge, roll it, and run it 150 mm up every wall.
- 04
Detail
Form corners, penetrations and the floor waste from cut strips (200–300 mm wide) or ACTFLEX SA TAPE. Weld every detail to the sheet and probe each weld.
- 05
Walls
Wall sheets lapped 40 mm over the floor upturn and welded, to 1800 mm or 50 mm above the shower rose, whichever is greater. Or use ACTFLEX 906 WPU or 989 CWP.
- 06
Test and cover
Probe every seam, then flood test from 1 hour after installation: 50 mm deep for 24 hours. Tile or screed after the test passes.
A short guide from the data sheet. Read the full ACTFLEX 900R TDS before you start.
ACTFLEX 900R test reports and compliance
- AS/NZS 4858:2004
- Designed and manufactured to complyManufacturer classification
- AS 3740:2021
- Details comply: 150 mm upturns, 1800 mm shower wallsFalls 1:80 to 1:50 to waste
- AS 3558.1
- Water absorption 2.0% maximumTypical R&D value
- EN 12316-2 / 12317-2
- Weld strength determined to these methodsCertified values to follow
- AS/NZS 4020
- Not certifiedWritten FORSPEC confirmation needed
Results as stated in the data sheet, TDS-900R · Revision 3 · 2 October 2026. Warranty up to 25 years, depending on the system: ask FORSPEC which term applies to your system.
ACTFLEX 900R questions
How much ACTFLEX 900R do I need?
A roll is 1.4 m x 20 m, 28 m² gross. Practical coverage is about 25–26 m² per roll. Allow for 150 mm floor upturns, wall sheets to 1800 mm, detail strips and about 10% wastage.
When can I tile over ACTFLEX 900R?
From 1 hour after installation, direct onto the fabric face with ACTFLEX BIOSET or a compatible cement-based tile adhesive. No primer or abrasion is needed. Flood test before tiling.
Do I need a primer?
Not on sound, dry internal substrates. Two coats of ACTFLEX EP250 are needed over an existing screed, or where moisture is above 80% RH or 15 g/m²/24 h.
Can it go over underfloor heating?
Yes, if the cables are fully encapsulated in a FORSPEC screed or levelling compound beneath the membrane. Cables must never sit directly against the membrane underside.
Can I use it outside?
No. ACTFLEX 900R is internal only. For external, below-grade or UV-exposed areas use ACTFLEX 1300R, or ask FORSPEC Technical Services.
Which adhesive does it use?
ACTFLEX 302 ADHESIVE, a water-based, low-odour contact adhesive with water clean-up. ACTFLEX 301 ADHESIVE (solvent-based) is an approved alternative in well-ventilated areas only.
Used with ACTFLEX 900R
ACTFLEX 900R TDS and SDS
Always work from the current data sheet. Every FORSPEC TDS and SDS →
Specify it. Or buy it.
Send the drawings or photos and FORSPEC comes back with the system, the details and the quantities. Or find a FORSPEC stockist for ACTFLEX 900R.