Limestone High Performance Cladding is principally used to protect external surfaces from water penetration, but its use internally is not excluded. Applied in one pass and one coat as a basic finish, with two or more passes depending on the thickness, type of substrate or desired finish.


New Construction:

  • Concrete blocks
  • Poured in place concrete
  • Tilt wall
  • Sheathing
  • Light weight blocks including Autoclaved Aerated Concrete (AAC)

Existing Buildings:

  • Bricks
  • Blocks
  • Stone

Unacceptable substrates: Specifically excluded are the following substrates:

  • Gypsum (Interior Grade)
  • Wooden boards
  • Lath (without a scratch coat)
  • Cob, adobe
  • Frozen masonry units
  • Over saturated
  • Waterproofed (unless adequate key has been provided)
  • Pre cast units with presence of de-molding oils
  • Painted, unless paint has been removed

  1. For all substrates: the application surfaces must be clean. No dust, traces of other materials, paints, salts, organic growth etc... should be present.

- Concrete surfaces should be brushed and washed. Traces of materials such as building finishes should be scraped off if they are over 1/3 of the proposed finish thickness.

- Wetting/Dampening: Thermocromex must be applied on a correctly dampened substrate. As a rule the substrate should be damp on the surface. Dampening must take into account the overall substrate suction and the climatic conditions at the time of application and should be done about half hour before application. Thermocromex should be dampened in hot weather conditions, in the presence of strong drying wind and on high suction substrates. Do not apply materials over saturated surfaces (when water runs off it after wetting) or on previously waterproofed surfaces unless these have been keyed properly.

- The suction of the walls must be uniform throughout.

2. On very smooth and non suction surfaces including tilt wall and poured in place concrete:

- apply a coat of Thermocromex with added bonding agent (Check with SPE for list of current approved bonding agent) or sand the surface to create a key

- surfaces should be free of any de-molding oil. If not, this has to be done by sanding or high pressure washing (min. 5800 psi)

3. For Concrete Masonry Units (CMU):

- new masonry units should not have Thermocromex installed as a finish for at least 1 month after the initial installation to be sure that these units have dried out and that most of the shrinkage has taken place.

- when installing on masonry units with vertical joints not filled, the joints should be floated smooth.

4. For sheathing substrates:

- apply two layers of building felt to allow for differential thermal movement between the substrate and Thermocromex

- mechanically attach/fasten the lath per ASTM E 1063 over the two layers of building felt

- apply scratch and brown coat per ASTM 926

- allow scratch and brown to cure per manufacturer directions

5. Before installation of Thermocromex, ensure all flashing, trim accessories and any other miscellaneous required materials have been installed.


Check the individual project specifications to see which one has been specified over lath, scratch coat or OCS. If it's a residential project, use OCS as this will satisfy the local building codes for the ICC, UBC and IRC.




Thermocromex may be pump applied or hand troweled


This is achieved when the finish thickness is at a minimum of 1/8 inch.

Coat(s) Thickness

Thermocromex may be applied from 1/8" to 1 1/2" thickness. The maximum overall thickness should not be over 1 1/2 inches.

Thermocromex over CMU and AAC Blocks/Panels

Apply Thermocromex at 3/8" thick directly over clean and properly prepared CMU block or AAC Blocks/Panels at 3/8" thick. The suction of the walls must be uniform throughout.

Thermocromex over sheathing

After sheathing, lath and scratch & brown (ASTM C 926)/OCS, apply Thermocromex at a minimum 1/8" thick. Allow scratch and brown to cure per manufacturer directions.

Smooth Surfaces

On very smooth and non suction surfaces including tilt wall and poured in place concrete, apply a bonding agent. Check with SPE for current list of approved bonding agents. 

This document is published to supply general information and recommendations only. Specifications should be site specific and issued by the Specifiers. No responsibility can be accepted by Southwest Progressive Enterprises for specifications issued by third parties or for bad workmanship.

* For further guidance, contact Southwest Progressive Enterprises.