Frequently asked questions

Guardian Shield™ Panels are a high-performance engineered thermal envelope panel system. Cold-formed galvanized steel studs are embedded flush into an expanded polystyrene (EPS) core on both sides and fastened with industrial-grade metal fasteners. The assembly behaves as an I-beam: the steel studs are the flanges, the rigid EPS core is the web. Panels are used for basements, walls and roofs — the complete exterior envelope.

Source · Technical Product Description; Products page

A structural insulated panel gets its strength from the adhesive bond between sheathing and foam, so its strength depends on that bond and that sheathing lasting. A Shield™ panel gets its strength from steel studs mechanically fastened through the core, and it carries no wood sheathing to rot or attract pests. Shield™ panels are also far lighter: SIPs can weigh up to 800 pounds and need lifting equipment, while a Shield™ panel can be lifted by one or two installers. Published R-values for the two systems are very close.

Source · Products page comparison; Differentiation sheet

ICF material costs are very high, installation needs concrete pumps and complicated bracing, the work is labour intensive and lengthy, and it requires specialised skills. ICF also has no roofing application, because of the concrete in the interior space. Shield™ panels install quickly with rough carpentry or a light-gauge steel crew, and the same system covers walls and roof.

Source · Products page comparison

Stick framing is labour intensive, needs framers who are increasingly hard to retain, needs a separate insulation contractor, and loses thermal efficiency to bridging through the wood studs and plates. Wood is also open to rot and pests. Shield™ panels install faster with less skilled labour, at substantially higher R-values and lower labour cost, and the time to erect the building is substantially less.

Source · Products page comparison

Panel size and configuration are individual to each project. Wall panels are typically 3½ to 12 inches thick, with a maximum overall size of 10 feet by 38 feet for ease of shipment. Curtain wall panels come in vertical or horizontal sections up to 33 feet standard length. Roof panels are a maximum of 4 feet wide and 33 feet long, typically 7¼ to 12 inches thick and up to 15 inches on a custom basis.

Source · Technical Product Description

Yes. The panels are described as easily field modifiable and can be modified in the field if needed, which is one of the practical differences from systems that must be cut and sealed under controlled conditions.

Source · Differentiation sheet

The panels are compatible with all finishes, exterior and interior, and standard industry finishes are installed on both faces. Masonry veneer for a stone or brick look is easily accommodated. Sealants, primers, elastomeric coatings and facings must be applied under the conditions set by the manufacturer of those products.

Source · Technical Product Description; 3-Part Specification 1.8 E

It depends on the assembly and the thickness. The specification publishes thermal resistance at two mean temperatures. Wall panels: 9¼ inch is R-38 at 40 °F and R-35 at 75 °F; 7¼ inch is R-30 and R-28; 6 inch is R-25 and R-23. Roof panels: 12 inch is R-50 at 40 °F and R-46 at 75 °F; 8 inch is R-33 and R-30; 6 inch is R-25 and R-23. Across the product range Guardian publishes R-16 to R-75 depending on panel type and thickness.

Source · 3-Part Specification 1.5 E.5; Technical Product Description

Because the R-value of insulation changes with temperature. The specification reports each panel at a 40 °F and a 75 °F mean temperature, which is more honest than a single headline number and lets an energy model use the right one for the climate and season.

Source · 3-Part Specification 1.5 E.5 b

A thermal bridge is a conductive path that short-circuits the insulation — in a framed wall, the studs and plates themselves. In a Shield™ panel the cold-formed steel is integrated into the EPS opposed on the inside and outside specifically to eliminate thermal bridging, which is what makes the composite panel super energy efficient rather than merely insulated.

Source · Technical Product Description

Guardian states that Shield™ panels reduce heating and cooling costs substantially over conventional construction. Up to 40 percent of a home's heat loss is due to air leakage, and the system's low air infiltration is a large part of the saving. On the Federal Social Security Administration facility in Lakewood, Ohio, the average monthly HVAC bill was reduced by 81 percent, from an estimated $8,000 to $1,482 per month, based on Energy Wise® certification.

Source · Products page; Federal Social Security Administration Facility case study

Guardian states there is no degradation of the EPS insulative qualities, and that components are long-life. EPS does not off-gas a blowing agent the way some foams do, so there is no thermal drift of the kind those products show.

Source · Differentiation sheet

Standard 9-foot wall heights have a design wind load of up to 40 pounds per square foot and a design axial load of 2,250 pounds per lineal foot. The system can be engineered to wall heights of up to 20 feet at the same 40 psf design wind load. Every project is customised to its own architectural and engineering drawings.

Source · 3-Part Specification 1.5 E.1

Roof panels span from 8 to 15 feet at a live load of 30 to 50 pounds per square foot, with appropriate purlins or ridge beams at 12 feet on centre, per the project's architectural and engineering drawings. Standard roof panels have a design horizontal roof load of 40 psf.

Source · Technical Product Description; 3-Part Specification 1.5 E.1 d

Yes. Load-bearing exterior walls can be designed to carry multiple floors and can eliminate some or all of the red iron structural framing. Shear wall structure can be integrated into the bearing wall panels per the architectural and engineering plans. Demising and corridor walls can also be designed to carry multiple floors.

Source · Technical Product Description

The market material describes up to 5 storeys of structural support. Canal Street Veterans' Housing in Winooski, Vermont used Shield™ load-bearing walls for five stories over a habitable basement, which minimised additional structural steel.

Source · Market page; Canal Street Veterans' Housing case study

Yes. Guardian describes the panels as load-bearing and engineer-stamped to ensure true structural integrity, and the system is subject to review and approval by the authorising building officials.

Source · Differentiation sheet; 3-Part Specification 1.6 C

Fire resistance is a property of the assembly. Half-inch or five-eighths-inch drywall provides the rating required by the uniform building codes, and an ASTM E119 load-bearing assembly is available. Load-bearing exterior walls and demising and corridor walls have been tested to ASTM E119-08a together with the ASTM E2226-08 hose stream practice. Demising and corridor walls can be classified as non-combustible.

Source · 3-Part Specification 1.5 E.2; Technical Product Description

EPS rigid foam has a flame spread index of 5 to 20 and a smoke developed index of 95 to 300 under ASTM E84, from the EPS manufacturer's results for the specified material. It may ignite between 600 and 650 °F, compared with about 500 °F for Douglas fir wood products, and it contains 0.0833 percent of the combustibles present in wood products. As in any construction, the code-required finish layer is part of the fire design.

Source · 3-Part Specification 1.5 E.2 c, d and e

An STC rating of up to 59 is available in an engineered assembly. Measured sound absorption is 0.36 at 1,000 cps, 0.54 at 2,000 cps and 0.38 at 4,000 cps. Guardian also notes an inherent sound reduction from the EPS itself.

Source · 3-Part Specification 1.5 E.3 and E.4; Differentiation sheet

Guardian states the panels are moisture and mould resistant and do not decay, expand or warp. EPS is totally absent of any nutritional value, so no fungi, mould or micro-organisms can grow within it, and there is no wood in the structure for pests or termites to attack.

Source · Differentiation sheet; Products page

Foundations and all sub-structures the system connects to must be dimensionally accurate, square, level and plumb, and inspected and approved as such within accepted building tolerances. The contractor confirms that accuracy to Guardian. Concrete foundations or slabs on grade must be complete and properly cured, ready to accept the wall panel anchorages, before installation begins.

Source · 3-Part Specification 1.8 and 1.9

No special equipment is required: the panels can be installed by a rough carpentry or light-gauge steel crew, and can be placed by hand or with a Lull or Gradall. Guardian offers on-site installation training or can recommend experienced installation teams.

Source · Differentiation sheet; Products page

Unload and handle the panels so as not to compromise their structural and thermal integrity. Store them in a clean, dry, safe area supported at least 6 inches above the ground, and protect all components from corrosion, deformation, deterioration and damage. Avoid concentrated loads beyond the design criteria during construction, and cover roof panels after installation to protect them from prolonged weather exposure.

Source · 3-Part Specification 1.7

Guardian states a reduction of the rough construction of the exterior envelope by over 50 percent, and a build 20 to 35 percent faster overall, with a typical 2,000 sq ft home under roof in 2 to 3 days. Panels can also be manufactured while the foundation is being completed and shipped when the site is ready, so the two run in parallel.

Source · Differentiation sheet; Market page

No. Guardian describes the system as all-in-one: there is no need for an insulation contractor, and mechanicals are easily installed. Panels arrive with rough openings for windows and doors and with all the components needed for installation, including interior wall attachments.

Source · Differentiation sheet

Yes. Guardian states it is the first, and currently the only, panel system in the United States certified by the Passive House Institute US (PHIUS). The full certificate is published on this site.

Source · Products page; PHIUS certificate

The panels can be designed to meet or exceed all code requirements for structural and fire safety and can be in accordance with all applicable building codes, including the code requirements for high-velocity hurricane zones. Use of the system is subject to review, inspection and approval by the authorising building officials.

Source · 3-Part Specification 1.6 B and C

Yes. Guardian publishes a three-part specification under Section 07480, with related sections for structural metal framing, cold-formed metal framing, thermal protection, roofing and siding panels, partitions and pre-engineered structures. It is on this site as a PDF.

Source · 3-Part Specification 1.1 and 1.2

A purchase agreement setting out the scope of work, and Guardian's Project Information Sheet. Shop drawings are then provided.

Source · 3-Part Specification 1.4

Guardian provides a limited warranty that the wall and roof panels will conform to the panel specifications and layout drawings at delivery and be free from material defects in workmanship and materials for one year from delivery, under Guardian's standard terms and conditions. Third-party manufacturers' warranties for goods Guardian does not make are assigned to the buyer. The full terms are in the three-part specification.

Source · 3-Part Specification 1.10

Guardian Structural Technologies is the exclusive fabricator of the system's wall and roof panels, and certifies third-party supplied components such as EPS, light-gauge steel, fasteners and adhesives as to their quality and suitability for use.

Source · 3-Part Specification 1.6 A

Guardian states the components are made from 100 percent recyclable material. Cold-formed steel framing has infinite recyclability, contains a minimum of 25 percent recycled steel, and all EPS and steel scrap from Guardian's manufacturing is completely recycled.

Source · Differentiation sheet; Products page

EPS insulation is 98 percent air. Guardian states it can return up to 200 times the energy required to produce it and reduce emissions by up to 100 times the volume produced during manufacture. It is non-toxic and inert, and contains no chlorofluorocarbons or hydrofluorocarbons at any point in its life cycle.

Source · Products page; Differentiation sheet

Guardian states the system saves 20 mature Douglas Fir trees for every 1,000 square feet of stick construction. Built in steel instead, a 2,000 square foot home needs about the equivalent of six recycled automobiles, against roughly 40 to 50 trees in wood.

Source · Differentiation sheet; Products page

Guardian states the panels are PHIUS, LEED and Net Zero capable designs. Cold-formed steel meets the requirements of the major green standards including PHIUS, LEED and the National Green Building Standard ICC-700 for residential buildings.

Source · Differentiation sheet; Products page