Exterior & Structural

Green Leaf Brick is a strong, sustainable, healthy building product. It is a fired masonry brick made of 100% recycled content with up to 31% post-consumer waste-streams. Green Leaf Brick is Red List Free. It comes in a range of colors and sizes, and clients have the option to customize the brick size, color, and texture.

The raw brick that makes up Fireclay's Glazed Thin Brick is sourced through a supplier who has been in business for over 100 years and continues to source and manufacture all brick in California, within 150 miles from the Fireclay Tile factory. The brick qualifies for LEED points and is glazed by hand on-site at the Fireclay Tile factory in Aromas, CA. The bricks provide a durable, long-lasting, and easy-to-clean surface suitable for a range of projects.
*Note that the EPD listed is for the glazing portion of the tile and not the brick itself.

bioMASON grows tiles using technology similar to hydroponics - units mixed with microorganism are fed an aqueous solution to harden the tiles to specification. bioMASON’s process eliminates the need for firing by replacing the curing/hardening process with biologically controlled structural cement.

Thermacork is a 100% natural, renewable, recyclable, and biodegradable rigid-insulation material produced from natural cork. Under the effect of pressure and superheated steam, cork granules expand and are agglomerated, originating blocks, avoiding any type of added adhesives. Cork forests benefit the environment, acting as habitats for a diverse range of species and providing a carbon sink that captures CO2 and greenhouse gases from the atmosphere.

Per EPD, this product meets HML's criteria for low embodied carbon.

Like most cork producers, Amorim Isolamentos, S.A. is based in Portugal. Thermacork's R-value is declared at 4/inch.

Linseed Oil is a natural, solvent-free finish coating derived from flax seeds. Not only does it perform better than petrochemical alternatives - it is also much healthier. Linseed oil is free of toxics such as isocyanates and bisphenols, which are found in polyurethane and epoxy resins. Allback manufactures their Purified Linseed Oil in Sweden. Their Purified Boiled Linseed oil is a drying oil, making it ideal for a final finish on wood and metal.

Industrial Louvers, Inc. fabricates screens, vents and screens from extruded aluminum. Louvers and air vents allow air flow through openings in buildings while rejecting unwanted elements such as water and airborne debris. It is in coatings and finishes where hazardous substances need to be looked out for.
ILI’s standard finish is Valspar’s Fluropon® Pure which is declared and complies with Red List Free requirements for Living Building Challenge projects. The ingredient list shows a small percentage of Carbon Black which may cause irritation of the lungs in the manufacturing stage of its life cycle yet as it is not on the Red List it is LBC compliant.

Classico Limewash is a slaked-lime ( lime mixed with water) paint with which you can achieve wash off effects on interior or exterior brick and masonry. After application, it calcifies to the brick, turning hard as a rock. It does not chip or crack due to allowing moisture to evaporate. The high pH of the paint makes it naturally mold-resistant. As a result, maintenance is minimal. The application is done by brushing the paint on the wetted surface and creating the patina effect by hosing spots off the wall.

Arbor Wood Co.’s thermally modified wood is solid wood that is treated with only heat and steam. This impacts the cellular composition of the wood to remove moisture, hindering water absorption, and preventing mould, rot, and fungal decay. This process is done without any chemicals and the product is fully biodegradable. It can be used in exterior, interior, and decking applications. We recommend ordering without a finish and applying an alternative finish, options can be found in the Alternative Finishes Collection. Additionally, FSC-certified lumber is available upon request.

Accoya® wood is an acetylated wood product that absorbs 80% less water than untreated wood. Acetylation is a process that uses non-toxic acetic anhydride to make wood more water, mold, and insect resistant. Accsys' Accoya® products can be used for siding, decking, windows, and doors. The wood is FSC certified. These products are rated Cradle to Cradle | Gold overall, and received a Platinum rating for material health.

While this product is recommendable regarding material health, its transportation during fabrication between New Zealand and The Netherlands does not meet HML standards for GWP. A local option with comparable material health is recommended.

Limeworks ' Ecologic Potassium Silicate Paint is a durable interior and exterior silicate dispersion paint made from silicates. It chemically bonds to masonry substrates such as brick, stone, mortar, stucco and cement through penetration and curing. It is VOC free, naturally mildew resistant and water repellent. It dries with an opaque and matte finish. Note: Methyl Methacrylate is used as a dispersion agent and as a binder at up to 10%. Currently, research is not conclusive; per manufacturer, there aren't viable alternatives at this time. HML is continuing to watch this component.

View Smart Windows uses the latest technology to adjust for sunlight, maximizing natural light while minimizing heat and glare. The windows have adaptable tint control with electrochromic coatings and flexible configurations for different building needs. Choosing tinted glass over blinds reduces potentially harmful PFAS and flame retardants commonly found in shades. The product is declared per an HPD and provides LCA information per an EPD. The windows suit various settings, including offices, apartments, schools, hospitals, airports, and hotels.

Native Earth is a scaled manufacturer of Compressed Earth Blocks (CEB). The Blocks come in 3 standardized blocks for interior, exterior, and structural use. The materials are sourced from quarries in Texas and New Mexico. Rammed earth and mortar can also be made with similar clay, lime, and cement composition.

Colorado Earth makes unfired compressed earth blocks (CEB) and adobe bricks from clay and lime. The materials are sourced in Colorado from local quarries, by-products of the excavation operations, and are low-carbon masonry units. Earthen mortar and plasters can be made with the same compositions as CEB and adobe bricks for use with these products. This product has no Portland Cement content.

Arizona Adobe creates two types of bricks from local soils: puddled (a combination of earth and water mixed to a near mud consistency, sun-dried over 2-4 weeks) and pressed adobe bricks (a mix of soil and water condensed per hydraulic presses and machine automation, bricks emerge nearly dry). They come in standard and veneer sizes. All projects are provided a mortar with a matching composition. Custom and site-made bricks are available upon request.

Fungi Force is an exterior wood stain that is made of two components - a water-based stain with Aureobasidium pullulans fungi and a linseed oil finish. It has a transparent matte black appearance. This is a living organism and therefore, the linseed oil serves as food for the fungus and also keeps the moisture out of the wood. The fungus protects the wood as well as the oil against UV radiation. It is recommended to regularly treat with linseed oil during the first year of use. After the first year, regular maintenance is recommended every 3 to 5 years and can be reapplied as needed if color fades.

The fungus classifies as non-pathogenic to humans.

Finished wood products are available under the brand Xyhlo.

Ecococon's Wall Panel is made of straw and timber that is condensed per a special straw pressing technique. The result is a product used for wall sheathing. In combination with the appropriate wall finishes, this wallboard panel is Passivhaus certified.

Note: The plywood binder contains a phenol-formaldehyde-based resin. The plywood is FSC Certified Chain of Custody. 

The USHG Old World European Limewash is a natural, non-toxic stain suitable for porous surfaces like bare wood, plaster, and masonry. The formulation of slaked lime putty allows it to penetrate deeply into underlying materials and fine substrates. As a result, once cured, the limewash creates a surface that won't peel, is breathable, and allows vapor permeation. The Limewash uses 100% natural pigments.

Croft designs straw-based wall, floor, and roof panels for pre-fabricated assemblies based in Maine. They aim to source straw from organic farms when possible. Plywood is sourced from Roseburg and timber is FSC-certified. Note: Roseburg plywood contains 3-5% phenol formaldyehyde resin, a comparably lower content.

Schüco aluminum window systems hold a Silver rating in Cradle to Cradle (C2C) Material Health. They are free of lead stabilizers, minimizing greenhouse gas emissions and offer systems which are passivhaus-certified.

Starphire Ultra‑Clear® glass can be used in exterior and interior entrances, storefronts, and for safety and security applications. The product is partially made from cullet, scrap glass from the manufacturing process. Additionally, the glass product makes efforts to reduce embodied carbon and demonstrates a third-party-certified Global Warming Potential (GWP) 6% lower than the industry standard according to EPD. Starphire Ultra‑Clear® has a Gold rating in C2C Material Health, with a Bronze rating overall. The material composition is Red List compliant.

New Mexico Adobe makes unstabilized blocks from local mud and straw. The blocks are made by pouring the mixture through a wooden mold and sun-dried. They come in a standard and veneer size.

Lunawood Thermowood avoids chemicals in its manufacturing processes, relying solely on a treatment with high heat and steam that enhances the wood's durability. This allows for an extended lifetime and a surface that requires no finishing and less routine maintenance, regardless of climate. However, applying paints, oils, and other finishes is possible (please see HML's list of healthier finishes for recommendations). Since the processing eliminates natural resins, no resin will secrete through any applied finish or paint.

Per EPD, this product meets HML's criteria for low embodied carbon.

Compressed Agricultural Fiber Boards (CAF boards) are made with a patented mill technology for affordable, large scale straw assemblies. The straw is locally sourced with no added binders or adhesives. They use H-steel framing and obtain structural integrity from densely pressed straw. Note: 1% borate is to prohibit mildew.

New Frameworks build prefabricated structural straw panels. The wheat straw is locally sourced from a certified organic farm by NOFA-VT and densely packed at 9lbs/cu.ft. A clay/lime plaster as interior air barrier is a preferable solution. Different air sealing methods can be applied to exteriors, opt for plywood or other options free from petrochemicals. The R-Value is 1.8/inch. 
Note: clay/lime is a direct surface protection of the straw; the plywood currently used contains phenolic resin. Consult the substantial research New Frameworks has done.

Savick creates roof, flooring and wall assemblies from locally sourced wheat and barley straw in Canada. Straw gets chopped up and densly packed (90 kg per cubic meter). This density and the high silica content in wheat acts as natural flame retardant. Savick carpenters assemble the wood frames from FSC certified wood and plywood. The R-Value is approx. 3.1/inch.

Note: The plywood binder is unknown.

Pozzotive is made from ground glass that has been diverted from waste streams. The ground glass acts as a pozzolan, a critical component in cement mixtures. Pozzotive displaces typical pozzolans such as fired limestone or coal fly ash in the cement matrix. This non-toxic replacement reduces embodied carbon while improving the concrete's structural performance. 

Per Pozzotive's product-specific EPD, this product meets HML's criteria for low embodied carbon.

This modular building product repurposes discarded wood from regional sources (EU) into a block, leveraging a three-axis dowel system to form robust structural walls that do not require adhesives. The brick system can accommodate windows and cable ducts, and disassembly is as easy as removing the wood dowels from the structure. TRIQBRIQ components are prefabricated, which results in reduced construction timelines. 

Per TRIQBRIQ's product-specific EPD, this product meets HML's criteria for low embodied carbon. 

Baumit Kalkputz Klima RK39 is a naturally white plaster made from hydraulic lime. It is free of cement or petrochemically based ingredients and microplastics. This plaster can be used as plaster and mortar. It is suitable for both manual and machine application and is non-flammable.

StructureCraft's dowel laminated timber panels are an all wood product. The use of hardwood dowels replaces the use of metal fasteners. Per manufacturer, the product uses less than 1% of the glue used in CLT, and it can be used in roof, wall, and floor applications. The CNC manufacturing process allows for a high degree of customization and integration with acoustic, electrical, and other building systems. Assembled using FSC- and PEFC-certified dimensional lumber, these panels act as carbon sinks that avoid harmful finishes that emit VOCs.

If an artificial grass is preferred over native grasses, SynLawn is a biobased alternative to fossil fuel based artificial grasses. SYNAugustine 547 contains 70% Biobased Content and has been awarded the USDA Certified Biobased Product Label in the BioPreferred® Program for the Bio-based System. EnviroLoc+ is a plant-based backing system, which replaces 60% of polyurethane with a soybean-based polyethylene. PFAS free.

Cambium's Carbon Smart Wood™ is made from wood that has been affected by disease, decay, disaster, and development. The company salvages this wood from local waste streams and upcycles it to create a carbon-negative material. The salvaged wood is processed into lumber for use in residential and commercial projects. Applications include decking, siding, fencing and millwork. Carbon Smart Wood™ contains 100% Biobased Content and has been awarded the USDA Certified Biobased Product Label in the BioPreferred® Program. The product is Red List Free.

Gamle Mursten upcycles and reuses bricks from demolition of old buildings. As the bricks are cleaned by hand or per patented vibration technology without water or chemicals, substanial embodied carbon savings result from it. Due to being recycled, there is no information on the material health and composition of the original bricks. As per the manufacturer, bricks typically come from buildings with lime mortar construction, dating from 1900 to 1960. These bricks were fired in ring ovens, which gave the clay a unique spectrum of colors and helped give these materials a longer lifespan. Per Gamle Mursten's product-specific EPD, this product meets HML's criteria for low embodied carbon.

Superwood uses a patented technology to impregnate spruce for exterior applications without heavy metals or solvents. The impregnation process uses recycled carbon and organic fungicides to increase board durability, eliminating the need for additional surface treatments. After impregnation, the carbon and excess fungicides are recycled. 

Note: 1 gram of fungicide is left per board at the end of the process but the wood remains biodegradable. 

Per Superwood's product-specific EPD, this product meets HML's criteria for low embodied carbon.