BIOKIL BioFlex Damp & Salt Membrane – 1.2m x 15m (18m²)

BIOKIL BioFlex Membrane

Ultra-Thin Damp and Salt Protection for Internal Walls

BIOKIL BioFlex Membrane is a flexible, 1.5 mm polyethylene membrane with a dual polypropylene fleece backing. It creates a protective barrier between damp or salt-contaminated internal masonry and new plaster finishes.

Designed for use with BIOKIL BioFlex Adhesive, the membrane is bonded directly to the wall without drilling or mechanical fixings. Its ultra-thin profile makes it ideal where available space is limited or the new plaster must match the thickness of surrounding finishes.

Key Features & Benefits

• Only 1.5 mm thick for a minimal wall build-up
• Protects new plaster against residual damp and hygroscopic salts
• Flexible construction follows curved walls, reveals and detailed areas
• Bonded directly to the wall without drilling or mechanical fixings
• Dual polypropylene fleece provides excellent adhesion
• Suitable for plastering directly over once installed
• Easy to measure, cut and shape on site
• Helps protect decorative finishes against moisture-related damage
• Ideal where existing plaster thickness needs to be matched
• Suitable for use following the installation of a remedial damp-proof course
• 18 m² coverage per roll

Typical Applications

• Internal walls treated with a remedial damp-proof course
• Masonry affected by residual damp or salt contamination
• Walls that are slow to dry following damp treatment
• Properties where the original plaster thickness must be maintained
• Restricted spaces unsuitable for thicker membrane systems
• Curved walls, reveals and detailed masonry areas
• Refurbishment projects requiring a direct plaster finish

Surface Preparation

Identify and rectify the source of moisture before installing the membrane system. Where rising damp is present, install an appropriate remedial damp-proof course, such as BIOKIL BioDry ProCream, before proceeding.

The receiving surface must be sound, stable, clean and free from paint, laitance, dust, loose particles and other contamination that could prevent adhesion. Repair structural defects and damaged areas before installation.

Remove surface contamination by brushing or light abrasion. Where moss, mould or other biological growth is present, treat the masonry with an appropriate masonry biocide and follow the relevant application instructions.

Installation

1. Measure the wall and cut the membrane to the required dimensions, allowing it to finish approximately 25 mm above floor level.
2. Prepare and apply BIOKIL BioFlex Adhesive to the wall using a suitable notched trowel.
3. Spread the adhesive to a thickness of approximately 1–2 mm.
4. Position the membrane within 10 minutes of applying the adhesive.
5. Place the membrane against the wall with the fleece side in contact with the adhesive.
6. Press the membrane firmly into position using a clean, flat trowel.
7. Work from the centre outwards to remove trapped air and ensure complete contact.
8. Allow the bonded system to cure fully, typically overnight, before plastering.

Plastering and Finishing

Once the membrane is fully bonded and the adhesive has cured, apply a suitable undercoat plaster directly to the membrane. Gypsum-based undercoat plasters may be used.

Complete the system with Limelite High Impact Plaster or another appropriate durable finishing plaster. The plaster thickness can be adjusted to match surrounding finishes where required.

Decoration may begin once the plaster has dried completely. The membrane itself does not require an additional drying-out period.

Technical Information

Property	Specification
Material	Polyethylene with dual polypropylene fleece
Thickness	1.5 mm
Roll size	1.2 m x 15 m
Coverage per roll	18 m²
Colour	White
Salt resistance	Excellent
Tear resistance	At least 50 N
Application method	Bonded using BIOKIL BioFlex Adhesive
Minimum application temperature	Above 5°C
Expected service life	Lifetime of the structure when stored and installed as directed

Application Limitations

• For internal vertical wall applications only
• Not suitable for use as a flooring membrane
• Do not apply to unstable, contaminated or excessively wet surfaces
• Do not install in freezing or excessively hot conditions
• Not intended as a standalone solution against severe water ingress or hydrostatic pressure
• Use a suitable cavity drainage system where significant water ingress is present
• Provide adequate ventilation during installation and while the adhesive and plaster are curing

Storage

Store the roll upright and under cover in a clean, dry location. Protect it from damp, excessive heat, flames and other sources of ignition.