Frequently Asked Questions

I want to build a composite structural insulated panel home. What is the first step?

A: For homeowners, the first step is to identify a quality builder who has experience with C-SIP construction. An experienced C-SIP builder will manage the plan conversion and review process. Contact MCT (info@merkelcomposite.com) to assist you with your entire planning process.

How does the composite structural insulated panel design and fabrication process work?

A: The construction of a C-SIP home or commercial building begins with the construction documents. Once the construction documents are in the hands of the C-SIP manufacturer, dealer/distributor, or design professional, they are converted to SIP shop drawings that give the dimensions of each individual panel. The shop drawings are reviewed by the builder, engineer, the building owner, and other involved parties. Once the shop drawings are finalized, the SIPs are fabricated and shipped to the jobsite for installation.

What is the R-value of composite structural insulated panels?

A: R-values for C-SIPs depend on the thickness of the C-SIP and the type of core material that is used. Exterior wall panels have an R-value of 30 and our 6" roof panels have an R-value of 42. Higher roof panel R- values are possible, depending on the thickness specified.

Where can I learn more about composite structural insulated panels?

A: Please contact MCT, for more information. (info@merkelcomposite.com)

How much faster can I build with composite structural insulated panels?

A: C-SIP homes go up faster than traditionally framed buildings. A properly trained C-SIP installation crew can reduce labor costs by more than 50 percent compared to traditional stick framing. Panels can be manufactured as big as 8- by 24-ft., so entire walls can be put up quickly, reducing dry-in time. C-SIPs can be supplied as ready to install building components when they arrive at the jobsite, eliminating the time needed to perform individual jobsite operations of framing, insulating and sheathing stick-framed walls. Window openings may be precut in the panels, and depending on the size, a separate header may not need to be installed. Electrical chases are typically provided in the core of panels, so there is no need to drill through studs for wiring.

How much labor can I save with structural insulated panels?

A: Because C-SIPs are prefabricated, the amount of additional framing required is minimal. C-SIPs are always straight and true, there are far fewer callbacks, no culling studs, or need to straighten walls. C-SIPs also provide a uniform nailing surface for both interior and exterior finishing.

How much money can I save with structural insulated panels?

A: Builders can save money through decreased construction and labor costs. The superior whole wall R-values and building tightness capable with SIPs allow HVAC equipment to be downsized and ductwork to be minimized. Builders can also significantly reduce jobsite waste disposal and temporary heat during construction. Homeowners that incorporate other energy efficient features with SIP construction can benefit from the energy efficiency of a SIP home with reductions in heating and cooling costs of 50 percent or more, possible qualification for Energy Efficient Mortgages, and higher appraised value.

How much do composite structural insulated panels cost?

A: Pricing information can be obtained by contacting MCT. (info@merkelcomposite.com) C-SIP's cost no more than traditional wood sandwich SIP's. However, building with C-SIPs can reduce framing labor needs by as much as 55 percent over conventional wood framing. Builders can also expect decreased jobsite waste disposal costs and savings on HVAC equipment. Energy-efficient C-SIP buildings demand a higher market price because of the utility savings they offer to home buyers.

How "green" are structural insulated panels?

A: Energy efficiency

Composite structural insulated panels are one of the most environmentally responsible building systems available. A C-SIP building envelope provides high levels of insulation and is extremely airtight, meaning the amount of energy used to heat and cool a home can be cut by up to 50 percent. The energy that powers homes and commercial buildings is responsible for a large portion of greenhouse gasses emitted into the atmosphere. By reducing the amount of energy used in buildings, architects, builders, and homeowners can contribute to a clean environment for the future.

B: Resource use

C-SIP's are manufactured using a composited derived from sugar can. The insulation is made with recycled materials.

C: Waste minimization

Since C-SIPs are prefabricated in the factory, there is less jobsite waste that needs to be disposed of in land fills. Factory fabrication is done using optimization software.

How strong are composite structural insulated panels?

A: MCT C-SIPs can be engineered for most applications. The structural characteristics of C-SIPs are similar to that of a steel I-Beam. The composite skins act as the flange of the I-beam, while the rigid core provides the web. C-SIPs can be engineered for most applications. Detailed information on the structural performance of C-SIPs is available from MCT. (info@merkelcomposite.com)

How are composite structural insulated panels supported? Are there studs in the panels?

A: For most applications, C-SIPs are structurally self-sufficient. The structural characteristics of C-SIPs are similar to that of a steel I-Beam. The composite skins act as the flange of the I-beam, while the rigid foam core provides the web. This design is extremely strong and eliminates the need for additional framing. In large commercial applications SIPs can minimize the amount of structural support needed and reduce material costs. In roof applications, SIPs rely on beams and purlins for support. SIPs can span long distances, allowing a minimal amount of structural supports to be used.

How do I properly size HVAC equipment?

A: The high insulating properties of C-SIPs allow smaller HVAC equipment to be used. When working with an HVAC contractor, make sure their calculations take into account an accurate estimation of typically low levels of air infiltration in a C-SIP home. Proper HVAC sizing is crucial because an oversized HVAC system will fail to reach the steady operating rate the equipment was designed for. Short cycling HVAC equipment will be less energy efficient and require more maintenance than properly sized HVAC equipment.

How important is ventilation?

A: C-SIP buildings are extremely airtight and require mechanical ventilation. Ventilation systems bring fresh air into the building in controlled amounts and exhaust moisture laden and stale air to the outside. By limiting air exchange to controlled ventilation systems, SIP homes allow for all incoming air to be filtered for allergens and dehumidified, amounting to better indoor air quality. Proper ventilation is important in all homes to preserve indoor air quality.

Are vapor barriers required in composite structural insulated panel buildings?

A: Air barriers or vapor barriers are not required in C-SIPs buildings because properly sealed C-SIPs create a code compliant air barrier with a permeability rating of less than 1.0 perm. In addition, the core of C-SIPs is solid and continuous throughout the wall, eliminating the convection and condensation issues that can occur in cavity walls.

How do composite structural insulated panels improve indoor air quality?

A: The tightness of the C-SIP building envelope prevents air from gaining access to the interior of the home except in controlled amounts. A controlled indoor environment is both healthy and comfortable. Humidity can be controlled more easily in a SIP home resulting in a home that is more comfortable for occupants and less prone to mold growth and dust mites.

How do structural insulated panels react to fire?

A: C-SIP panels have a Class A (4 hour) fire rating.

Do composite structural insulated panels block sound transmission?

A: The sound resistance of a C-SIP wall is excellent. For special applications, such as multi-family and commercial applications, additional sound insulation properties can be specified.

Are composite structural insulated panels compatible with other building systems?

A: C-SIPs are compatible with other building systems. Wall panels can sit on a variety of foundation materials, including poured concrete, blocks, or insulated concrete forms. SIPs are sized to accept dimensional lumber and are seamlessly compatible with stick framing.

What considerations do you need to take into account when building with composite structural insulated panels vs. conventional framing?

A: The majority of construction with C-SIPs is very similar to conventional framing. C-SIPs accept dimensional lumber and are fastened together using a proprietary locking system. Panels larger than 4' X 8' can be unloaded and set in place without the need for heavy equipment.

What is the learning curve for composite structural insulated panel installation?

A: For construction professionals competent in standard wood framing techniques, the task of learning C-SIPs is not difficult. MCT offers onsite technical assistance for builders that are new to SIP construction.

Can composite structural insulated panels be modified on site?

A: On-site modification can easily be done using a few additional C-SIP specific tools. Since each panel is built to specifications, on-site modifications are seldom required.

How are electrical wiring and fixtures installed?

A: Electrical wires are pulled through precut channels inside the core of the panels called “chases” according to the electrical design of the home. Electricians can then use fish tape to feed wires through the panel chases.

Can plumbing be installed in structural insulated panels?

A: Plumbing should not be located in exterior SIP walls because of the possibility of condensation or supply lines freezing in cold climates. During the design phase of the project, all plumbing should be relocated to interior walls. If plumbing must be located on an exterior wall, it is recommended that a surface chase be installed on the interior of the wall to conceal plumbing. Another option is to construct a small section of the wall using conventional wood framing that can be used to run plumbing. Plumbing penetrations such as DWV can be placed through SIPs if they are thoroughly sealed to prevent air infiltration.

How do I attach siding or other exterior claddings to composite structural insulated panels?

A: Builders should consult MCT. (info@merkelcomposite.com) for instructions for how to attach exterior cladding to C-SIPs.

Can recessed lights be used in structural insulated panels?

A: Recessed lights should never be embedded in structural insulated panels. To install recessed lights, an interior soffit must be constructed.

Can kitchen cabinets be attached to structural insulated panels?

A: Yes. Please contact MCT (info@merkelcomposite.com) for details.

Are composite structural insulated panels susceptible to insects?

A: Since there is no wood used in the panels, C-SIP's are highly resistant to termite and insect infestation.

Are composite structural insulated panels susceptible to mold and mildew?

A: C-SIPs are solid and free of any cavities in the wall where moisture can condense and cause unseen mold growth.

Can composite structural insulated panels be replaced or repaired if damaged?

A: Yes. While this is not likely to be an occurrence with MCT C-SIPs, if it should happen, MCT recommends that a structural engineer needs to assess the damage to determine what is cosmetic and what is structural. If the damage is only cosmetic then the source of moisture must be determined and fixed, whether it is from inside or outside. If the damage is structural, then the source of the problem must be identified and a structural solution to the problem must be found. That can be done by either a site modification of the panels or replacement of the panels, depending on the extent of the damage. In the event that panels are damaged, the manufacturer and installer of the panels should be notified.

What about roofing? Does a building with a composite structural insulated panel roof need to be ventilated?

A: The area inside a C-SIP building envelope is considered conditioned space and will be ventilated by the building’s HVAC system. There is no need to provide a vented attic beneath a C-SIP roof, and doing so would compromise the conditioned space of the building. Most roofing manufacturers specify how to attach their product to C-SIPs. Please contact tMCT (info@merkelcomposite.com) for application instructions.

Do roofing manufacturers warranty asphalt shingles over composite structural insulated panel roofs?

A: Some roofing manufacturers warranty asphalt shingles over unvented SIP roofs, while others void their warranty because of higher shingle temperatures. Research conducted by Building Science Corporation reveals that although asphalt shingle temperatures increase slightly (2 - 3 degrees F) in an unvented roof assembly, the color of the shingles and the roof orientation have a much more profound impact on the durability of shingles. According to the Builder’s Guide to Structural Insulated Panels (SIPs) published by Building Science Corporation, the typical reduction of shingle life over an unvented SIP roof assembly is between one and two years. Builders seeking to comply with roofing manufacturer warranties can choose from a variety of more durable, non-asphalt roofing materials or provide a venting space between the SIP roof panels and the roofing material (known as a “cold roof”).

Does a building with a composite structural insulated panel roof need to be ventilated?

A: The area inside a SIP building envelope is considered conditioned space and will be ventilated by the building’s HVAC system. There is no need to provide a vented attic beneath a SIP roof, and doing so would compromise the conditioned space of the building. Some advocate venting the roof by providing an air space between the C-SIP roof panels and the roofing material (known as a “cold roof”). This practice is not a requirement for C-SIP buildings, but an extra measure to improve the durability and moisture resistance of the building.

What is shingle ridging? Does shingle ridging occur in composite structural insulated panel buildings?

A: Shingle ridging is a bulging of asphalt roofing material that occurs along the joints of engineered wood panels used in roof applications. Since C-SIPs contain no wood or wood products, this problem is not expected to occur.