By Jay Fox

Exterior insulation and masonry construction are not an ideal combination. Particularly with historic retrofits, adding a layer of exterior insulation may boost performance and help prevent thermal bridging, but it can cover up heritage facades and embellishments that are vital to historic preservation. Meanwhile, installing a layer of continuous insulation on the inboard side of a concrete or masonry wall has traditionally presented challenges with moisture control, thermal bridging, and maintaining substrate integrity.

To address these difficulties, the two heavyweights in the world of high-performance building have teamed up to create ROCKWOOL Smartrock®, a product designed to provide continuous insulation on the interior of concrete and masonry walls while speeding up installation and reducing thermal bridging. Smartrock combines Pro Clima INTELLO PLUS, a best-in-class smart vapor retarder, with high-performance stone wool insulation from ROCKWOOL, and protects assemblies against changing moisture and humidity conditions—while delivering long-term thermal performance and airtightness.

The announcement comes following years of behind-the-scenes collaboration, development, and refinement, and is sure to be a gamechanger in the world of high-performance building. Beyond historic masonry walls, Smartrock is also effective for new construction with prefab concrete or masonry, especially when accessing exterior walls poses a challenge.

Smartrock is currently available through 475.Supply. The company is so excited about the product, and confident in its performance, that they used it while renovating their Brooklyn headquarters. While this post will cover some of the benefits of Smartrock and how it’s installed, you can take a deeper dive on May 22 when Ryan Martin of ROCKWOOL and Aaron McCormack of 475 drops by the Accelerator for a Component Spotlight to talk about the properties of Smartrock and the experience of using it in 475’s HQ.

The Benefits of Smartrock

Smartrock combines the benefits of stone wool insulation with the benefits of a smart vapor retarder to create a thermal, vapor, and air control layer in one product. Smartrock provides Class A fire rated insulation in accordance with IBC Section 703.3.1, as stone wool is non-combustible and can withstand temperatures of over 1000°F. Stone wool is also inorganic, meaning that it cannot be used as a food source for rodents, insects, mold, or mildew, even if it is exposed to moisture. Moreover, stone wool is vapor-permeable (rated at 27 perms), allowing assemblies to dry via diffusion.

Meanwhile, the INTELLO PLUS membrane, pre-applied to the board, functions as both a vapor-intelligent control layer and an airtight layer—once seams are sealed with TESCON VANA tape. It adapts to changing humidity conditions, protecting masonry walls by allowing them to dry in both directions while reducing the risk of condensation. This helps make Smartrock perfect for cool to cold climates (Climate Zone 4 and higher) that need interior vapor control.

Smartrock’s humidity-dependent properties provide protection against wintertime moisture ingress with a Class 1 perm rating (0.09). In warmer weather, the smart vapor retarder opens as needed, rapidly increasing vapor permeability above 70% relative humidity to allow inward drying.

Smartrock provides excellent thermal resistance, with an R-value of 4.2/inch, and is available through 475.Supply in a variety of thicknesses, ranging from 2 inches (R-8.4) to 5 inches (R-21).

The seams of the Smartrock board are then sealed with TESCON VANA 2 ⅜” wide tape, while any fastener washers must be taped over with TESCON VANA 100 (4”). These width options of TESCON VANA provide the proper overlap to the INTELLO PLUS membrane.

Finally, All penetrations need to be properly sealed using TESCON VANA tape or specific ROFLEX gaskets or KAFLEX mono or duo wire gaskets. CONTEGA SOLIDO IQ tape is used at windows openings and frames. This SOLIDO IQ tape can be used as well as to connect concrete floors/masonry walls without the need to primer these materials. For more details on sealing penetrations, see 475.Supply’s blog post: How to seal air barrier penetrations.

If you want to learn more about Smartrock or if you have questions that you’d like to ask either Ryan Martin of ROCKWOOL or Aaron McCormack of 475.Supply, you can register for the Component Spotlight on Thursday, May 22nd at 9am PT / 12pm ET. The presentation on Smartrock will be followed by an extended Q&A session.