[CCMC 14102-R] CCMC Canadian code compliance evaluation

From: National Research Council Canada

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Compliance opinion

It is the opinion of the Canadian Construction Materials Centre that the evaluated products, when used as sheathing membranes installed over DensGlass® exterior gypsum sheathing in accordance with the conditions and limitations stated in this evaluation, comply with the following code:

National Building Code of Canada 2015

ID Code provision Solution type
05-01-04-01-05-0- By design complying with Subsection 5.2.2, for individual app ...Acceptable
05-01-04-02-01-b- Resistance to DeteriorationAcceptable
05-01-04-02-01-b- Resistance to Deterioration (i.e., degradation due to condensation)Acceptable
05-06-02-01-00-0- Except as provided in Sentence ...Acceptable
09-25-05-01-00-0- Except as provided in Sentences ...Acceptable
09-27-02-01-00-0- Except where exterior walls are protecte ...Acceptable
09-27-02-03-01-b- An open drainage material, not less tha ...Acceptable
09-27-02-03-01-c- The cladding is loosely fastened to the backing and ...Acceptable
09-27-03-02-00-0- Sheathing Membrane Material StandardAlternative
09-27-03-03-00-0- Sheathing membrane required in Sentence ...Alternative

The above opinion(s) is/are based on the evaluation by the CCMC of technical evidence provided by the evaluation holder, and is bound by the stated conditions and limitations. For the benefit of the user, a summary of the technical information that forms the basis of this evaluation has been included.

Product information

Product names

  • Si-COAT® 421AB™ – Liquid-Applied Sheathing Membranes
  • Si-COAT® 420AB™ – Liquid-Applied Sheathing Membranes
  • Si-COAT® 422AB™ – Liquid-Applied Sheathing Membranes

Product description

Si-COAT® 420AB™, 421AB™, and 422AB™ sheathing membranes are identified by CSL Silicones Inc. as an assembly of proprietary silicone-based component materials for sealing installed DensGlass® exterior gypsum wall sheathing(1). The products are spray-applied liquid silicone that are moisture-cured, elastomeric and monolithic, and form a membrane that resists moisture and protects against air infiltration. Si-COAT® 420AB™ is the base product, Si-COAT® 421AB™ is for cold-weather applications and Si-COAT® 422AB™ is a low volatile organic compound (VOC) formulation.

The products are sprayed on-site by CSL Silicones Inc.-approved installers certified by The Society for Protective Coatings (SSPC). The coatings are to be spray-applied to have a target dry film thickness (DFT) of 0.62 ± 0.13 mm (25 ± 5 mils). To achieve this thickness when dry, the coatings must be installed at a specific target wet film thickness (WFT). For the Si-COAT® 420AB™ and 421AB™ products, the WFT range is 0.76 to 1.14 mm (30 to 45 mils) to produce a DFT of 0.62 ± 0.13 mm (25 ± 5 mils), while the Si-COAT® 422AB™ product is to be sprayed to a WFT range of 0.64 to 0.88 mm (25 to 35 mils) to produce a DFT of 0.62 ± 0.13 mm (25 ± 5 mils). The cured coating forms a silver/grey silicone membrane; however, additional colours are also available.

Before the final overall coating is sprayed by the SSPC-certified installer, the joints and fastener heads in the DensGlass® gypsum sheathing substrate are to be sealed with CSL423 Liquid-Applied Air Barrier(2) Flashing Sealant or CSL424 Weatherproofing Sealant, which are applied in a serpentine fashion and then spread to form a 100 mm (4 in.) ribbon over the joint having a WFT of 0.635 mm (25 mils). The rough openings of windows and doors are to be flashed with the CSL423 Liquid-Applied Air Barrier Flashing Sealant. All applications must be in accordance with the CSL installation instructions specified below.

Scope of evaluation

Sheathing membrane function

This product evaluation is to qualify the proprietary Si-COAT® 420™, 421AB™, and 422AB™ liquid-applied membranes and sealant accessories as the designated sheathing membrane serving as the inner boundary(3) of the required second plane of protection from precipitation.

Substrates and required insulation

As per the test results in the Technical evidence section of this Report, the products are semi-vapour permeable and provide a breather-type performance when installed at the specified WFT over 12.5-mm DensGlass®. The combined water vapour permeance (WVP) is 187-251 ng/(Pa·s·m2), which is above the 60 ng/(Pa·s·m2) requirement. Therefore, no insulation is required, but it may be installed to improve the thermal resistance of the wall assembly.


The products and CSL-specified sealant accessories shall be installed in accordance with the CSL Silicones Inc. publication, “Si-COAT® 420AB™, 421AB™, 422AB™, Liquid-Applied Sheathing Membranes: Application Instructions for Building Envelope Solutions” dated 18-05-2018. The CSL-authorized installers are trained and certified installers by SSPC. The card-carrying SSPC installers shall have their certification cards on hand and a copy of the CSL installation instructions on-site for review by the building officials during their inspection. The WFT gauge shall be used to confirm that the film thickness is within the target limits of 25 ± 5 mils. (Extracts from the installation instructions are shown in figure "Typical application of CSL423 Liquid-Applied Air Barrier Flashing Sealant and CSL424 Weatherproofing Sealant where specified to maintain continuity against rain penetration" for information purposes only. See figure "CSL Silicones wet film thickness gauge" for the specified WFT gauge.)

Figure 1. Typical application of CSL423 Liquid-Applied Air Barrier Flashing Sealant and CSL424 Weatherproofing Sealant where specified to maintain continuity against rain penetration.
  1. Serpentine bread centered over sheating joint
  2. Spot all fasteners
  3. Feathered Edge
  4. Tool ribbon flat and feather edges
  5. Step 1
  6. Step 2
  7. Step 3
  8. With Back-Dam
Specified WFT gauge

Figure 2. CSL Silicones wet film thickness gauge

Manufacturing plant

This evaluation is valid only for products produced at the following plant:

Product namesManufacturing plant
Guelph, ON, CA
Si-COAT® 421AB™ – Liquid-Applied Sheathing MembranesProduct evaluated by the CCMC
Si-COAT® 420AB™ – Liquid-Applied Sheathing MembranesProduct evaluated by the CCMC
Si-COAT® 422AB™ – Liquid-Applied Sheathing MembranesProduct evaluated by the CCMC

Product evaluated by the CCMC Indicates that the product from this manufacturing facility has been evaluated by the CCMC

  Conditions and limitations

The CCMC’s compliance opinion is bound by this product being used in accordance with the conditions and limitations set out below.

  • Following the relevant limitations related to the proper installation of the products in conformance with the CSL-specified installation instructions entitled, “Si-COAT® 420AB™, 421AB™, 422AB™, Liquid-Applied Sheathing Membranes: Application Instructions for Building Envelope Solutions,” dated 18/05/2018.
  • The installation must be conducted by SSPC-certified installers to ensure the DFT is installed within the specified target of 25 ± 5 mils by ensuring that the target wet film thicknesses are not exceeded using the film thickness gauge shown in figure "CSL Silicones wet film thickness gauge". The manufacturer should be contacted if the installation does not conform to the CSL specifications.
  • All exterior wall penetrations must be sealed with the specified CSL sealant as per the CSL instructions before the Si-COAT® coatings are installed over the entire surface.
  • If the DFT is excessively over-spec (i.e., > specified 30 mils), the WVP may be below 60 ng/(Pa·s·m2), and insulation must then be installed to comply with the outboard/inboard ratio specified in Article of Division B of the NBC 2015.
  • The cladding fasteners must be installed at stud locations as exterior gypsum sheathing is not approved as a cladding attachment.
  • The components must be clearly identified with the phrase “CCMC 14102-R".

  Technical information

This evaluation is based on demonstrated conformance with the following criteria:

Evaluation requirements
Criteria number Criteria name
CCMC-TG-072510.14-15CCMC Technical Guide for Liquid-Applied Coating as Sheathing Membrane

The Report Holder has submitted technical documentation for the CCMC’s evaluation. Testing was conducted at laboratories recognized by the CCMC in accordance with the CCMC's Technical Guide for Liquid-Applied Silicone-Based Sheathing Membranes over DensGlass® Exterior Gypsum Sheathing. The corresponding technical evidence for this product is summarized below.

Performance requirements
Results on membrane elongation before and after aging
Property Unit Requirement Si-COAT® results
420AB™ 421AB™ 422AB™
Tensile elongation % Report value 251 175 125
After UV aging % ≥ 90% original value 228 201 176
After UV and heat aging % ≥ 85% original value 296 224 215
Table 1. Moisture resistance combined WVP of membrane-over-DensGlass®Table footnote footnote (1) panel assemblies
Property Unit Requirement Si-COAT® results
420AB™ 421AB™ 422AB™
Water vapour permeance ng/(Pa·s·m2) > 60 236 251 187
Water absorption coefficient (WAC) mg/(m2∙s1/2) < 4 000Table footnote footnote (2) 87 140 146
Water penetration at fastenersTable footnote footnote (3) g Water penetration must be ≤ that of the benchmark Pass Pass Pass
Table 2. Si-COAT®adhesion performance
Membrane adhesion Substrate conditioning Unit Requirement Si-COAT® results  
420AB 421AB 422AB
DensGlass®Table footnote (1) oven dry kPa

Panel failure (report strength) adhesive failure area must be below 5%

78 107 59 All specimens passed maximum 5% failed area criterion
50% relative humidity 163 123 134
wetting 259 211 204
Table 3. Membrane performance at wall sheathing jointsTable footnote footnote (1)
Property Unit Requirement Si-COAT® results
420AB 421AB 422AB
Joint disruption resistance (single-point load bending) n/a No cracking, debonding, delamination or other deleterious effects at a deflection of L/180 Pass Pass Pass
Report load (kN) at 13.5 mm deflection 6.0 kN 6.0 kN 5.8 kN
Table 4. Resistance to aging of Si-COAT® on DensGlass® substrate
Property Unit Requirement Si-COAT® results
420AB 421AB 422AB
Water vapour permeance after UV and heat aging ng/(Pa·s·m2) > 60Table footnote (1) 201 161 177
Water absorption coefficient (WAC) after UV and heat aging mg/(m2∙s1/2) < 4 000Table footnote (2) 161 150 163

Administrative information

Use of Canadian Construction Materials Centre (CCMC) assessments

This assessment must be read in the context of the entire CCMC Registry of Product Assessments, any applicable building code or by-law requirements, and/or any other regulatory requirements (for example, the Canada Consumer Product Safety Act, the Canadian Environmental Protection Act, etc.).

It is the responsibility of the user to confirm that the assessment they are using is current and has not been withdrawn or superseded by a later version on the CCMC Registry of Product Assessments.


The National Research Council of Canada (NRC) has evaluated only the characteristics of the specific product described herein. The information and opinions in this evaluation are directed to those who have the appropriate degree of experience to use and apply its contents (such as authorities having jurisdiction, design professionals and specifiers). This evaluation is valid when the product is used as part of permitted construction, respecting all conditions and limitations stated in the evaluation, and in accordance with applicable building codes and by-laws.

This evaluation is provided without representation, warranty or guarantee of any kind, expressed or implied, and the NRC provides no endorsement for any evaluated product. The NRC accepts no responsibility whatsoever arising in any way from any and all use of or reliance on the information contained herein or the use of any evaluated product. The NRC is not undertaking to render professional or other services on behalf of any person or entity nor to perform any duty owed by any person or entity to another person or entity.


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© His Majesty the King in Right of Canada, as represented by the National Research Council of Canada, 2023

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the CCMC.

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