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AlphaGuard BIO is ideal for providing a durable, fast curing, low odour, waterproof coating on any new build or refurbishment flat roof.


AlphaGuard BIO is a unique polyurethane, two-component, liquid applied membrane with a high bio-based content (castor oil) that can be used to weatherproof any new build or refurbishment flat roof. With its extremely low odour, ease of application and rapid curing properties, AlphaGuard BIO systems are the ideal specification for highly sensitive areas, such as hospitals and schools where pungent odours should be avoided.

System components include:

  • TremStik Spray Primer.
  • TremVap AVCL & Carrier Membrane.
  • TremStik PU Adhesive.
  • TremTherm Insulation.
  • AlphaGuard BIO Base Coat.
  • AlphaGuard BIO 225g Reinforcement.
  • AlphaGuard BIO Top Coat.

Features and benefits:

  • Fast catalyst activation.
  • Two component chemical cure technology.
  • Very low odour.
  • Flame-free installation.
  • System durability of at least 25 years.
  • High thermal resistance.
  • Excellent elongation properties.

General information






20 year


Ss_30_40_30_43 Liquid-applied warm roof covering systemsPrimary


J31/10 Warm deck roof coating

J31/120 Warm deck roof coating

Specification data - Liquid-applied warm roof covering systems

System performance

AlphaGuard BIO systems possess a variety of independently assessed accreditations for performance such as British Board of Agrément, European Technical Assessment and a Broof(t4) fire rating under BS EN 13501-5:2016 fire classification of construction products and building elements.

AlphaGuard BIO systems comply with the performance guidelines set out in relevant UK Building Regulations, BS 6229:2018 Flat roofs with continuously supported flexible waterproof coverings, and LRWA codes of practice.

AlphaGuard BIO membranes offer exceptional low odour application with an enhanced environmental profile.



Horizontal work

TremStik Spray-on Primer.

A solvent based synthetic rubber primer specially developed for the effective adhesion of self-adhesive or torch applied membranes to compatible substrates.

Once spray applied with the specific applicator gun, TremStik Spray-on Primer should be touch dry within 2-3 minutes achieving a coverage rate of approximately 12 m²/L dependant on substrate porosity. Spray applied application should be undertaken 10-20 cm away from the designated substate and with a single pass ensuring an even spread of product. Please refer to the Tremco technical data sheet for further details.

Skirtings and vertical work

As Horizontal work.

Air and vapour control layer


Bituminous self-adhesive air and vapour control layer (AVCL) / carrier membrane that is reinforced with composite aluminium foil and glass fibre mat. TremVap has an extremely high vapour resistance and can provide an effective barrier against warm moisture laden air rising through the system.

The upper foil facing is polyester coated and provides an ideal substrate for TremStik polyurethane adhesives when adhering TremTherm insulation boards.

Membrane laps should be minimum 80 mm with overlaps facing down the roof slope to avoid negative laps. Rolls should be laid out perpendicular to the specified falls on the roof.




Flat roof thermal insulation boards manufactured from either Polyisocyanurate or Mineral Wool.


TremTherm insulation is available in various incremental thicknesses, can be designed tapered, and will achieve the

design requirements of our clients or Part L Building Regulations.

TremTherm PIR.

Commonly specified throughout the industry for applications that require lightweight and thermally efficient insulation with good compressive strength.

  • Board size: 1200 x 600 mm.
  • Compressive strength: >150 kPa at 10% compression.
  • Type: Rigid Polyisocyanurate.
  • Facing and underside: Mineral coated glass.
  • Density: 32 kg/m³.
  • Board thickness: 25 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm.
  • Thermal conductivity: 0.024–0.027 W/m·K.

TremTherm Mineral Wool.

Specified for projects that require acoustic attenuation or A2 rated fire performance (non-combustible) under BS EN 13501-1 classification.

  • Board size: 1200 x 1000 mm.
  • Compressive strength: 70 kPa at 10% compression.
  • Type: Dual density mineral wool.
  • Facing: Glass fibre fleece.
  • Underside: Unfaced.
  • Density: 160 kg/m³.
  • Board thickness: 60 mm, 85 mm, 105 mm, 115 mm, 150 mm, 185 mm.
  • Thermal conductivity: 0.039 W/m·K.


TremStik PU Adhesive.

Insulation boards should be laid out in break bond pattern, fully supported, and with all edges closely butted together to ensure thermally continuity. When laid on metal decks with partial support, the long edges of the boards should be laid perpendicular to the crowns of the metal deck with all board joints fully supported.

Insulation boards are typically adhered using TremStik PU adhesive but in certain circumstances the boards can be mechanically secured with appropriate fasteners and pressure plates. Mechanical fixing patterns are subject to project specific wind uplift calculations.

Carrier membrane




Bituminous self-adhesive air and vapour control layer (AVCL) / carrier membrane that is reinforced with composite aluminium foil and glass fibre mat. TremVap will provide an ideal base layer to carry and retain the specified liquid system.

Membrane laps should be minimum 80 mm. Rolls should be laid out perpendicular to the specified falls on the roof. TremVap should be dressed 50 mm above the line of the thermal insulation or to the height of any vertical thermal breaks.



TremVap is applied to TremTherm insulation by means of the self-adhesive backing. The insulation surface must be suitably primed with TremStik Spray-on Primer prior to application.

Liquid-applied waterproofing



AlphaGuard BIO.

A fully reinforced, two-component, polyurethane liquid applied membrane with catalyst technology. AlphaGuard BIO has exceptional low odour properties and provides a robust waterproofing layer that can easily cope with normal levels of structural or thermal movement.

AlphaGuard BIO Basecoat is hand-applied in two separate coats with AlphaGuard BIO 225g Reinforcement installed between each coat. AlphaGuard BIO Basecoat should be applied at a rate 0.8 kg/m² achieving a final coverage of 1.6 kg/m². To complete the membrane system, AlphaGuard BIO Top Coat is hand-applied in a single coat at 0.8 kg/m².


AlphaGuard BIO 225 g Reinforcement.

A strong, chopped strand matting, glass fibre reinforcement that provides enhanced strength to liquid applied membrane systems.

AlphaGuard BIO 225g Reinforcement is applied between separate coats of AlphaGuard BIO Basecoat. AlphaGuard BIO 225g Reinforcement should be carefully embedded into the base coat, lapped by minimum of 50 mm, and laid flat without creases, air pockets or prominent fibres.

System accessories


A traditional domed style rooflight that includes a thermally broken insulated kerb with excellent natural light transmittance properties. TremDome rooflights come with a variety of ventilation accessories and can be operated manually or electronically. Design is subject to survey or client requirements.


Gravity drainage outlets that have an integral membrane flange for sealing flat roof membranes. TremDrain outlets are manufactured from aluminium, are suitable for all roof types and offer excellent flow rate. Type, size, and design is subject to survey or client requirements.


Lightning protection systems are frequently installed to buildings to avoid damaging and costly lightning strikes. TremClip has a threaded securement base that includes a separate retaining clip to secure lightning conductor tape at predefined centres across the roof.


A1 non-combustible secondary cover flashing manufactured from soft and workable zinc alloy. Primarily used as lead substitute in flat roof details such as wall chases or abutment flashing.

Ilbruck SP510.

General purpose low modulus sealant that is silicone free and cures to form a tack free surface. TremSeal mastic can be used to enhance the waterproofing integrity of a wide variety of detailing situations.


RAL 7031 (Blue Grey).


AlphaGuard BIO 20 Liquid Applied Flat Roof System

AlphaGuard BIO 20 Liquid Applied Flat Roof System

Flat Roof Systems for Refurbishment and New Build Brochure

Flat Roof Systems for Refurbishment and New Build Brochure

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