The ThermRite MS Polymer Adhesive is a professional-grade cover board adhesive formulated specifically for bonding cover boards within underfloor heating floor build-ups. Built on advanced MS polymer (modified silicone) technology, it creates a strong yet permanently flexible bond that can accommodate the natural movement of a floor without cracking or losing adhesion over time.
Supplied in a 290ml cartridge for use with a standard cartridge applicator or caulking gun, this adhesive is designed to work alongside ThermRite routed board and cover board systems, and is suitable for a wide range of dry-fix underfloor heating overlay and floor construction projects where a reliable, flexible bond is essential.
290ml
Cartridge Size
1.8m²
Coverage per Cartridge
2.80 N/mm²
Tensile Strength
40 min
Open Time
24-48 hrs
Full Cure Time
-40°C to +90°C
Temperature Resistance
Recommended Application
Apply continuous straight-line beads roughly 75mm apart between the routed channels, using a nozzle cut to give a 3mm diameter bead. This bead size and spacing is the basis for the manufacturer's stated coverage rate of approximately 1.8m² per cartridge.
Allow Full Cure Before Final Use
While the adhesive has a 40-minute open time for positioning panels, full mechanical cure takes 24 to 48 hours. If panels are not additionally secured with screws, allow 4 to 6 hours before walking on them, and avoid subjecting the bonded panels to full load or further floor finishing until the adhesive has fully cured.
Wide Working Temperature Range
Apply the adhesive at ambient and surface temperatures between +5°C and +24°C for best results. Once cured, the flexible bond remains stable across a working range of -40°C to +90°C, suited to the temperature cycles seen in underfloor heating floor build-ups.
MS Polymer Technology
A modified silicone polymer formulation delivers a strong, professional-grade bond without the shrinkage or brittleness of some traditional adhesives.
Purpose-Built for Cover Boards
Specifically designed for bonding cover boards within underfloor heating floor constructions, rather than a generic multi-purpose sealant repurposed for the job.
Excellent Bond Strength
Achieves a tensile strength of 2.80 N/mm², giving a durable, high-strength fix suitable for demanding overlay and dry-fix floor systems.
Permanently Flexible Bond
Remains permanently flexible after curing, allowing the bonded assembly to accommodate minor floor movement over its service life without failing.
Simple Cartridge Application
Supplied in a standard 290ml cartridge for use with any conventional cartridge gun, with a recommended 3mm bead for consistent, repeatable application.
Wide Temperature Tolerance
Cures reliably in ambient conditions from +5°C to +24°C, and once fully cured tolerates a working range of -40°C to +90°C.
Product Details
Product Type
MS polymer cover board adhesive
Chemical Base
Modified silicone (MS) polymer
Cartridge Size
290ml
Pack Size
12 cartridges per box
Performance
Coverage
Approx. 1.8m² per cartridge using a 3mm bead
Tensile Strength
2.80 N/mm²
Open Time
40 minutes
Cure Time
24-48 hours (full cure)
Walk-On Time
4-6 hours if panels are not additionally screw-fixed
Application & Environment
Application Temperature
+5°C to +24°C
Temperature Resistance (Cured)
-40°C to +90°C
Recommended Bead Size
3mm diameter
Bead Spacing
Approx. 75mm apart between routed channels
Application Method
Standard cartridge applicator or caulking gun
Handling & Safety
Keep out of reach of children. The product contains N-(3-(trimethoxysilyl)propyl)ethylenediamine and may produce an allergic reaction in sensitive individuals. If medical advice is needed, have the product container or label available.
How much floor area does one cartridge cover?
Each 290ml cartridge covers approximately 1.8m² when applied as a 3mm diameter bead with beads spaced roughly 75mm apart. A box of 12 cartridges covers approximately 21.6m² on the same basis.
How long before I can walk on the bonded panels?
If the panels are not additionally secured with screws, allow 4 to 6 hours before walking on them. Full mechanical cure of the adhesive itself takes 24 to 48 hours.
What size bead should I apply?
The manufacturer recommends cutting the cartridge nozzle to give a 3mm diameter bead, applied in continuous straight lines spaced approximately 75mm apart between the routed pipe channels.
What is the working temperature range once cured?
Once fully cured, the adhesive maintains a flexible, durable bond across a temperature range of -40°C to +90°C, suited to the conditions experienced in an underfloor heating floor build-up.
Can this adhesive be used with any ThermRite cover board system?
Yes, it is formulated for use with ThermRite routed board and cover board systems as part of a dry-fix underfloor heating overlay build-up.
