Thermlock PVC window reinforcement

Sheerframe has patented a unique reinforcing system - Thermlock® - which provides greater strength, better window security and better thermal performance than traditional reinforcing.

Thermlock FP is part of the fully reinforced zero carbon window construction.

More secure windows - up to 20%

Screw pick up ridges make fixing easier. Thermlock delivers 20% greater pull-out strength on handles, keeps, shootbolts and hinge fixings.


Warm and clean to the touch, Thermlock is more pleasant and safer to work with than steel or aluminium. Manufacturing processes are quieter and quicker than standard methods.