Master of Science / Department of Architectural Engineering and Construction Science / Sutton F. Stephens / Conventional wood framing, also known as stick framing, has been around for hundreds of years. It is an easy, effective method for building new houses and small commercial projects. However, it may no longer the best option for new construction. The development of Structural Insulated Panels (SIPs) began over 70 years ago at the United States Forest Products Laboratory in Wisconsin. Scientists believed that plywood sheathing alone could provide adequate strength to support the loads a structure encounters. Over the years, SIPs have evolved to what they are today: a rigid insulation foam core sandwiched between two skins, often made of oriented strand boards (OSB). Compared to stick framing, SIPs are faster to erect in the field and also provide more strength to resist most loads; they are better with axial and transverse loads. Stick framing can be built more robust to resist in-plane shear loads. The quality of the material of SIPs also means better quality construction. The insulating values SIPs provide are far superior to that of fiberglass insulation used in stick framing, saving money for the owner as well as energy from natural resources. Not only do they provide better thermal protection, but they are also better for the environment because of manufacturing processes and construction practices. When it comes to other issues such as fire, smoke, termites, and ventilation, SIPs are no worse than stick framing. SIPs follow the same steps for construction used in stick framing with, perhaps a little more care needed to insure proper ventilation. SIPs have proven themselves in the laboratory and in the real world. SIPs should be considered more often as an option, replacing stick framing for the major structure elements and insulation for new buildings.

Series of full-scale tests were conducted on polyurethane foam-core Structural Insulated Panels (PUR SIPs) to study the load response and creep behavior of such panels. The load response of PUR SIPs was compared with conventional stud wall panels. The effects of de-bonding between the foam-core and the OSB face-sheets were also studied to understand the effects of such change on the overall performance of PUR SIPs. At last, computer modelling was employed to simulate and predict the behavior of PUR SIPs in different loading orientations and dis-bond ratios. It was found that PUR SIPs can outperform conventional stud-wall panels in every aspect. In the case of 165 mm (6.5 in.) thick PUR SIPs, 33% dis-bond between the PUR foam-core and the OSB face-sheets caused an average of 64% reduction in ‘axial load’ capacity, an average of 75.8% reduction in ‘transverse load’ capacity, and an average of 7.9% reduction in ‘racking load’ capacity of the panels compared to brand new fully-bonded SIPs. It was also found that 33% dis-bond in 165 mm (6.5 in.) thick PUR SIPs has minimal effect on the racking load capacity of the panels. In the case of 114 mm (4.5 in.) thick PUR SIPs, 33% dis-bond be-tween the PUR foam-core and the OSB face-sheets caused an average of 63.3% reduction in ‘axial load’ capacity, an average of 79% reduction in ‘transverse load’ capacity, and an average of 29% increase in ‘racking load’ capacity of the panels compared to brand new fully-bonded SIPs. All tested panels satisfied the code requirements for the creep deflections (span/180) and they fully rebounded to their initial estate, 90 days after removal of the simulated snow loads. It was also found that weathering has minimal effect on the bond between the face-sheets and the PUR foam. After computer simulations of fully-bonded and dis-bonded PUR SIPs in two different thicknesses, it was found that SOLIDWORKS simulation software is a useful tool to predict the load response of PUR SIPs only when fully-bonded panels are exposed to transverse load orientation regardless of the thickness of the panel. In general, available Canadian and American standards were followed in this study. Where applicable, standards were adopted from other material testing methods for testing PUR SIPs. It is believed that this independent research has addressed most frequently ex-pressed concerns regarding the use and application of structural insulated panels such as de-bonding issues and creep behavior and their relationship to durability. The hope is that is research help increase the use and application of SIPs in green, high-performance, light-frame building construction in Canada. / October 2016

Modern timber frame buildings are a unique combination of ancient carpentry techniques coupled with one of the newest enclosure systems found on construction sites around the world. Contemporary timber frame structures typically utilize structural-insulated panels (SIPs) attached to a timber frame skeleton to create functional, enclosed structures, such as houses, churches and a myriad of retail and industrial buildings. The skeleton contains large wooden members connected using wooden joints held together with wooden pegs or wedges. SIPs consist of a layer of rigid expanded polystyrene insulation covered on one side by oriented strand board and on the other side by oriented strand board, drywall, or some other interior finish. In timber frame buildings, SIPs also serve as diaphragm elements, which are flat structural assemblies loaded by shear forces in the plane of the panel. Current design methodologies for timber frame structures do not formally incorporate the structural benefits of SIPs as diaphragm elements, which contribute significantly to the ability of these buildings to resist lateral loads. The contribution of this research was to quantify necessary design parameters to enable timber frame designers to capitalize on the significant in-plane strength and stiffness of SIPs when designing timber frame structures to resist lateral loads. Strength and stiffness tests were conducted on three 8 ft (2.44 m) deep and 24 ft (7.32 m) long roof diaphragm assemblies, and two 20 ft (6.10 m) deep and 24 ft (7.32 m) long roof diaphragm assemblies. Data from these tests were collected, tabulated and analyzed according to existing methods typically utilized for post-frame diaphragm testing. Strength and stiffness of timber frame and SIP roof diaphragm assemblies were determined from monotonic test results and a value for Response Modification Coefficient, R, for use with seismic design procedures, was estimated utilizing cyclic test data. Procedures for calculating strength and stiffness of a roof diaphragm based on the strength and stiffness of test panels were presented and incorporated within post-frame diaphragm design methods. Diaphragm-frame interaction analyses were performed utilizing test data from roof diaphragm assemblies that demonstrated the code conformance of members within timber frames subjected to lateral loads. Using roof diaphragm test data and procedures developed for adjustments from the test panel to building roof length, example designs were conducted which confirmed the effectiveness of including SIPs as diaphragm elements for code conforming designs for wind and seismic load resistance of timber frame and SIP buildings. / Ph. D.

This dissertation presents the development of a new framework for international commercialization of innovative structural products in residential construction. Development of his framework required the examination of six subjects related to international commercialization. 1) commercialization models previously developed, locally and internationally, 2) barriers to the process, 3) stakeholders, actions, and decisions critical to the process, 4) characteristics of innovations that are suitable for international use, 5) characteristics of foreign markets that are ideal to adopt such innovations, and 6) strategies to overcome barriers The framework development was based on one structural product, SIPs. This product has been successfully developed and implemented in the United States and is being considered for commercial use in Saudi Arabia. Structural product clusters are particularly appropriate because of their innovative nature and their major influence on the structure of residential buildings. The study relies on sequential explanatory mixed-method research design, consisting of two distinct phases (Creswell 2003), to gain insight into processes surrounding commercialization. The rationale for this approach is that quantitative data and its results provide a general picture of the barriers to international commercialization in the available sample, which can mapped onto an initial framework. The qualitative data and its analysis help to refine and expand statistical results by exploring participants' actual decision processes that can be also mapped to a second framework. Both data sets can be merged, mapped onto one final framework. Variables related to the six subjects, mentioned above, were distilled from literature into open-ended questionnaires for two groups of key stakeholders in the supply chain of innovative structural products: 1) SIPs stakeholders in the US and 2) stakeholders of innovative structural products in Saudi Arabia. The primary purpose of the open-ended questionnaires was to ensure usage of correct terminology used in this study and to encourage full, meaningful answers—capturing all possible factors affecting the process of international commercialization. The author collected responses using web-based surveys. The results yielded the development of a reliable instrument to be implemented in further steps of this research. Next, the researcher collected variables related to the questions from previous open-ended questionnaires into closed-ended questionnaires to collect the data (on perceived barriers to international commercialization), using web-based surveys, and performed a preliminary analysis of the data using frequency analysis. This process yielded market-based strategies for developing an initial framework for international commercialization in residential construction. Subsequently, a focused examination of barriers to international commercialization was needed. The researcher collected such data through an applied understanding of the specific development processes for SIPs to be introduced to a new, international market, namely Saudi Arabia. Based on the model's structure, the researcher conducted six case studies of real stakeholder processes along the supply chain, SIPs development domestically and internationally, and tracked data for real risks of the commercialization process. Findings suggested perceived versus actual risks and barriers to the commercialization process for an integral product to the residential construction process. This was an important distinction because of proposed development methods and the application of market diffusion. Based on the barriers identified, the researcher developed market-based strategies to be incorporated into a second framework. This framework along with the initial framework and the literature-based framework have been triangulated to develop one final framework. The final framework was then introduced to a few experts in the industry to increase its validity. / Ph. D.

Currently 10% of all single family homes produced in the U.S. are manufactured homes with 75% of these households making less than $50,000 in annual income (Manufactured Housing Survey). Manufactured homes typically use twice as much primary energy per square foot than site built homes yet there is no agenda within the industry or its governing bodies to address this excess energy consumption. The research presented in this thesis compares the thermal envelope performance of the typical wood stud framing used in the manufactured home industry to the thermal envelope of structural insulated panels (SIPs). This comparison examines the energy savings a SIP manufactured home could create for a home owner while speculating on the financial and technical feasibility of using SIPs in the manufactured housing industry. Ultimately, the comparison reveals the short comings of the Manufactured Homes Construction and Safety Standards (HUD Code) regarding thermal envelope requirements and energy use intensity. These short comings are revealed when the energy use of HUD compliant manufactured homes is scrutinized and compared to the energy use of a similar home built with SIPs for the thermal envelope. The continuous insulation and airtight qualities of the SIP home allow it to use 32%-46% less energy than the HUD compliant homes in the same locations. Manufactured homes require much more energy to heat and cool because the HUD code does not require a certain performance criteria be met for the airtightness of manufactured homes and the overall U-values it requires for the thermal envelopes of such homes is too high for the varying climate zones found in the U.S. If SIP panels were to be used for the thermal envelope of the manufactured housing industry, low income manufactured home owners could be saving $300-$700 annually in energy costs. These savings are not insignificant to low income households and could create a 5-8 year payback period of additional ownership costs under $2500. Unfortunately, the SIP industry cannot offer its product at a low enough price to compete with the economies of scale achieved by the manufactured housing industry when buying raw construction materials. The value of this research then, is the exposure of the manufactured home’s inferior envelope performance when compared to more modern construction technologies and the speculation of how the manufactured housing industry could begin to incorporate a more robust building envelope without putting its customers at a monetary disadvantage.