Roof Design Research Articles

Evaluation of Aesthetic Perceptions of Public Buildings’ Façades by Design Professionals

Visual assessments are very relevant in the study of architecture since this is a profession that relies immensely on the visual sense of humans. This study contributes to the understanding of visual perceptions, as well as to the wider field of environment and behaviour studies. The main aim of this study was to evaluate the aesthetic perceptions of public buildings among design professionals with a view towards understanding the mindsets of different design professions towards façade designs. The study considered three types of design professionals: architects, engineers and industrial designers/artists. Two hundred questionnaires were analysed using a mixed methods approach. The variables used in analysing the façades of public buildings were roof design, façade colour, entrance design, fenestration arrangements and innovation in building form. Twelve images of public office buildings in Alagbaka in Akure, Nigeria, were selected for study using random selection and cluster classification methods. A photo-interviewing analysis method was adopted for analysing visual images of the buildings: first-hand visual data were obtained from the study site using digital photographs of each building, and questionnaires were then administered to respondents regarding the images. Data were measured using five-point semantic differential scales, and relevant information obtained through this method was analysed using descriptive statistics, such as frequencies and percentages. Also, inferential statistics using the Kruskal Wallis test was used to determine whether there existed significant differences within the groups of design professionals. Findings from the quantitative analysis showed that there were no significant differences among the groups, although qualitative interview sessions did reveal that while architects and industrial designers/artists exhibit similarities in aesthetic perceptions of public buildings’ façade designs, the perceptions of engineers differ slightly. While these results need to be treated, interpreted and considered with care, design professionals can learn from these subtle differences in the results. The views of each design profession are important during a design process as the final outcome of the design is greatly dependent on the collective contributions of individual professions due to their peculiarity.

Review of Wind Resistant Design for Tiled Roofs and Publication of New CFD Guidebook for Urban Wind Environment: Japan Country Report 2021

This paper introduces recent activities related to the structural and environmental engineering in Japan. Part 1 in this paper illustrates outline of recent research and standardization related to ensuring wind resistant performance of tiled roofs. We introduce the results of damage survey on tiled roofs caused by Typhoon Faxai in 2019, which was conducted by National Institute for Land and Infrastructure Management and Building Research Institute in collaboration with clay roof tile industry organization. Then, the outline of the wind load calculation method stipulated in the Building Standards Law and the amended Notification for roof tiles is illustrated. In addition, “Guideline for Standard Structural Design/Construction for Tiled Roof” was revised in July 2021 as a supplement to the law. The outline of monotonous pull-up test and the standard specifications, both of which are newly added to the revised version of the Guideline, are also introduced. These activities are aimed to reduce structural vulnerability of tiled roofs, based on the lessons learned from the damage caused by the typhoon. In Part 2, we introduce activities to promote the appropriate use of computational fluid dynamics (CFD) in wind environment prediction. A working group within the Architectural Institute of Japan compiled a new CFD guidebook and guidelines for urban wind environment prediction, mainly aiming to include the application of large-eddy simulation to pedestrian-level wind problems or dispersion problems relating to concentration and temperature in cities. Reflecting the latest domestic and international research trends and the WG’s validation works, achievements of their activities were published as “Guidebook for CFD Predictions of Urban Wind Environment” (2020, in Japanese), papers in international journals, and an extended experimental database for verification and validation of analysis codes.

STUDY ON THE INSTALLATION OF PERGOLA-STYLE STRUCTURES IN MODERN JAPANESE HOUSES (PART 2): PERIOD OF VOGUE AND FACTORS OF SHAPE DIVERSIFICATION THROUGH PRIZE COMPETITIONS

This study confirms the period of vogue for the installation of pergola-style structures in modern Japanese housing, as well as trends in the shape of the design. The material dealt with prize competitions related to housing. The analysis confirms that the installation of pergola-style structures was fashionable throughout the 1930s, reaching its peak in 1933-34. In addition, from about 1930, the shapes of pergola-style structures diversified in response to changes in the design of roofs and eaves. Then, at the end of the 1930s, they rapidly came to an end due to the demands of wartime response.

Substantiating rational parameters for a stull-timbered device of the selective heading machine

Purpose. To carry out the studies of proposed options for overlapping to support excavation roof and ensure roof maintenance to avoid collapse and protect people and mechanisms. To study a specified goal, an expert assessment of the existing tools to maintain roof rocks in the working area where people and mechanisms are engaged has been carried out. Methodology consists in applying software and computer simulation of interaction processes of mining rocks with arched design options. Findings. A short analysis of the most commonly applied structures to provide temporary fastening of preparatory and permanent mine workings has been carried out. The options for a roof design and the elements for temporary fastening are proposed. The parameters for four sectional overlapping have been substantiated. The loads acting on the roof-supporting structure and the coefficients required to determine the rock loads, the strength of some roof layers and "soil" as well as the forces in the rack hydraulic cylinder have been calculated. Originality. Applying temporary arched fastening in the working area of a tunneling machine promotes reducing a number of technological operations and manual labor employment as well as enhancing maintenance personnel safety. The speed of tunneling works is supposed to increase. Practical value. It is based on the analysis of a selective heading machine performance with an easily collapsed roof, study results to achieve a constructive machine improvement are presented. Its components may vary depending on mining and geological conditions of the work. The obtained parameters are verified by calculations and design solutions. The minimum mass of the fastening that provides both rigidity and strength of the structure is significantly reduced. Obtained results can be applied in underground tunneling and other similar works as well as in constructing roads and railways. The design of the device gives the possibility to adjust the height depending on the mine roof condition.

Design of stick-framed wood roofs under tornado wind loads

Light-frame wood construction comprises nearly 90% of the housing industry in Canada and the United States. The roofs of these houses can be constructed either entirely on site or using prefabricated trusses. Assembling the roof structure on site, otherwise known as stick-framing, is a framing technique with current code guidelines that are based on past practice and limited consideration of wind loads. This makes these roof structures susceptible to failure in high-speed wind events, such as tornadoes. This research proposes improved stick-framing guidelines that would work for EF-2 tornadoes. Using non-linear finite element analysis, a stick-framed roof was designed following the guidelines in the National Building Code of Canada. Non-linear links were used to model all of the connections between the members in the roof structure, with frame elements used to represent the members. Increasing wind loads were applied to the structure and the first elements of the roof that failed were improved using an iterative performance-based design approach until the performance target of resistance to EF-2 tornadoes was achieved. The failure of the roof-to-wall-connections and the lack of members used in the framing were the two main issues highlighted and addressed. Damage survey photos were used to compare failures observed in the model with failures after real tornado events, which demonstrate many similar failure modes. The research recommends the requirements to ensure stick-framed roofs can withstand EF-2 tornadoes. Most notable is an improved gable end frame, which gives the structure more roof-to-wall connections, as well as a more structurally sound frame where the loads are the highest. Other additions include struts, hurricane ties at all roof-to-wall connection locations and increased number of nails in various connections throughout the repeating inner frames. Minimum member sizes and qualities for each type of member used in the roof structure are also recommended.

Substrate composition impacts long-term vegetation development on blue-green roofs: Insights from an experimental roof and greenhouse study

Green roofs provide ecosystem services and can promote biodiversity in urban areas. Blue-green roofs have an additional water storage compartment under the substrate to reduce roof water runoff, thereby also reducing drought stress which is beneficial for green roof vegetation. In order to study which blue-green roof design supports the highest plant diversity, we assessed the effect of different substrates and seed mixtures on vegetation development in a short-term greenhouse experiment and long-term blue-green roof experiment. A ten-week full-factorial greenhouse experiment was performed for six substrate composition and four seed mixture treatments. On an experimental blue-green roof, we annually surveyed plants from 2013 to 2021 in nine different treatments (five replicates each), that varied in substrate composition, substrate depth and seed mixture that was initially applied. Two treatments resembled conventional non-green roofs (100% gravel) and conventional extensive Sedum green roofs. The results of the greenhouse experiment showed that seed mixture is more important than substrate composition in shaping the initial species richness and species composition. However, on the experimental roof the substrate composition was an important determinant of species richness and species composition long-term. Plant species richness on the experimental roof was lowest in the gravel treatment (resembling conventional non-green roofs), and highest in treatments where locally collected soil was used, likely due to additional species that appeared from the seed bank present in the transplanted soil. Soil was never completely covered with vegetation on unfertilized substrates that contained 20% or less dense and organic materials. Plant species richness on conventional Sedum roof substrate was higher on the experimental blue-green roof compared to an adjacent non-blue roof, highlighting that blue-green roofs can promote biodiversity more than conventional green roofs. For future construction of blue-green roofs in our region, we recommend the addition of 30% locally collected soil to a 6 cm deep lightweight substrate to maximize long-term plant cover and plant species richness.

Complementary influence of green-roof and roof-slab thermal conductivity on winter indoor warming assessed by finite element analysis

A green roof can modify the roof outer surface temperature (Tr) to influence indoor air temperature (Ti). Green roof design and roof-slab thermal insulation jointly determine the coupled-roof system’s thermal performance. This study investigated their joint effects on subtropical winter warming, which were seldom investigated. Custom-built houses without (bare roof) and with a 20-cm soil layer at circa 20% moisture content (soil roof) provided experiment plots to collect field data. The measured data tested the corrected finite element analysis model and simulated the combined influence of soil cover (properties kept constant) and a gradation of roof-slab thermal insulation on Ti in the unsteady heat transfer mode. Such multiple-factor and complex spatiotemporal studies are difficult using only field experiments and measurements. Average Ti was raised by 0.44 °C on a typical winter day, bringing 4.55% energy saving to indoor-heating budget. With poor roof-slab insulation, the soil roof significantly retained indoor warmth. With improved roof-slab insulation, the soil roof’s influence on Ti waned. A tipping point at 0.95 W/(m K) thermal conductivity signified a maximum threshold above which the green roof would not retain additional indoor heat. An upper threshold of thermal insulation at 0.35–0.05 W/(m K) was found, above which further insulation increase would not keep additional indoor warmth. Subtropical winter indoor warming by green roof was verified via two heat preservation mechanisms: retaining indoor heat to bring passive warming and delivering heat indoors to bring active warming. They were triggered by slightly warmed and notably warmed green-roof soil, respectively. The results ascertained quantitatively the complementary thermal role of green roof and roof slab. The findings can optimize the subtropical green-roof design and achieve winter indoor warming and thermal comfort.

Investigating the performance of energy management in office buildings by using a suitable green roof design to reduce the building’s energy consumption

Today, the use of green roofs in architectural and city design has received special attention; if the use of green covering on the roof and facade of the building has grown significantly in most European countries and American states, the main reasons for this, in addition to the issue of architectural aesthetics, are responding to factors such as natural building insulation (heat, humidity, and sound), and the use of dead space. The roof is intended to create a pleasant environment and eye-catching surfaces on the façade, blending the manmade structure with nature, reducing atmospheric pollution and boosting the oxygen ratio in the air, and so on. A green roof system is an excellent way to minimize energy usage in these structures. This study intends to optimize energy consumption in office buildings, and it uses a descriptive-analytical research approach to investigate the issue of green roofs with minimum burden on the roof structure and their influence on the amount of energy used by these structures. Greenery on the roof space helps to cool the environment of the city and area, as well as the air within the building where the Hand was installed, by blocking solar radiation and surface evaporation and transpiration. This cooling is accomplished by lowering thermal fluctuations on the roof's exterior surface and increasing its thermal capacity, which keeps the area under the roof cold in the summer and increases the amount of heating in the winter. The results show that the green roof with grass vegetation, which has a shallow root depth and cultivation environment when compared to other plants, has caused the least load on the roof structure and optimized the energy consumption of the cooling and heating systems as well as the studied educational building. The proportion has reduced. In six months, the overall energy usage of this building was lowered by 3.6%.

Experimental comparison of two extensive green roof designs in Northwest Mexico

Accelerated population growth and urbanization have negative environmental impacts, such as habitat destruction, biodiversity loss, natural resource depletion, and pollution. They speed up climate change, contribute to urban heat islands, and increase energy use. Green roofs (GRs) can reduce the ecological footprint and improve the quality of life within cities but require careful design for best results. This study analyzes the thermal performance of GRs in six experimental modules differing in roof cover: concrete, reflective coating, dry soil, wet soil, traditional GR with Sedum acre, and wetland GR with Salicornia pacifica. The two plant species have different carbon assimilation metabolisms: S. pacifica is a native wetland C3 species with diurnal transpiration that grows in flooded soils, and S. acre is an exotic Crassulacean Acid Metabolism (CAM) species with night-time transpiration, commonly used in GRs. GRs were monitored during the winter of 2020 in Ensenada, Baja California, México, a city with a semi-arid Mediterranean climate. We found that vegetated covers reduced the temperature oscillation with an insulating effect. During the warmest week, they reduced the internal roof surface temperature (Ts,in) up to 12.4 °C in comparison to the concrete roof. They maintained Ts,in up to 5.8 °C warmer than concrete roof during the coldest week, indicating that GRs are efficient thermal regulators in this region, potentially reducing buildings’ thermal load as well as providing additional ecosystemic services. Since S. pacifica had higher survival and coverage, we recommend its use in GRs located in Northwest Mexico and climatically similar world regions.

Vegetated Roofs as a Means of Sustainable Urban Development: A Scoping Review

Urbanisation affects the water cycle and heat balance in a negative way. Vegetated roofs have the potential to minimise the effects of urbanisation. A scoping review is presented here to examine how vegetated roofs are being evolved as an effective tool of sustainable urban stormwater management and overall urban development. It has been found that research on vegetated roofs has been increasing significantly and it can contribute towards achieving multiple sustainable development goals (SDGs). It has also been found that the uptake of vegetated roofs has been slow. A lack of regulatory acceptance caused by an absence of experimental data and a subsequent knowledge gap establishing the effectiveness of vegetated roofs are major reasons behind this slow uptake. Future research on vegetated roofs and their subsequent evolutions should put a focus on gathering experimental data towards establishing a performance benchmark for detention, retention and water quality in urban settings. Such data can be utilised towards developing a stand-alone guideline and software for green roof design.

Drivers of fungal diversity and community biogeography differ between green roofs and adjacent ground-level green space.

Green roof soils are usually engineered for purposes other than urban biodiversity, which may impact their fungal communities, and in turn impact the health of plants in the urban ecosystem. We examined the drivers of fungal diversity and community composition in soil of green roofs and adjacent ground-level green spaces in three Midwestern USA cities-Chicago, Cleveland, and Minneapolis. Overall, fungal communities on green roofs were more diverse than ground-level green spaces and were correlated with plant cover (positively) and roof age (negatively) rather than abiotic soil properties. Fungal community composition was distinct between roof and ground environments, among cities, and between sampling sites, but green roofs and their immediately surrounding ground-level green space showed some similarity. This suggests dispersal limitation may result in geographic structuring at large spatial scales, but dispersal between roofs and their neighbouring sites may be occurring. Different fungal taxonomic and functional groups were better explained when roofs were classified either by depth (extensive or intensive) or functional intent of the roof design (i.e. stormwater/energy, biodiversity, or aesthetics/recreation). Our results demonstrate that green roofs are an important reservoir of fungal diversity in the urban landscape, which should be considered in future green roof design.

Theoretical Analysis on the Effectiveness of Pipe Roofs in Shallow Tunnels

When a pipe roof is used as a pre-support for the surrounding rock in a shallowly buried tunnel, accurate prediction of the support effectiveness of the pipe roof is important in order to ensure the rationality of the pipe roof structure design. Based on analysis of pipe roof pre-support effects, considering the construction time of pipe roof structures and the interaction mechanisms between the steel pipes of the pipe roof and the surrounding rock, we establish a calculation model of the surrounding rock pressure acting on each steel pipe of the pipe roof on the semi-circular pre-support boundary. Through comparison and analysis with the measured results, we demonstrate that the calculation model for surrounding rock pressure and the calculation model for stress and deformation of the pipe roof are reasonable. According to the deformation coordination conditions between the steel pipe of the pipe roof and the surrounding rock on the pre-support boundary and alongside the Peck formula, we establish a theoretical analysis method for pipe roof pre-support effectiveness based on the indexes of the ground loss rate, settlement trough width, and maximum ground surface settlement, thereby realizing a quantitative evaluation of pipe-roof pre-support effectiveness. At the same time, the effects of steel pipe diameter, circumferential spacing, and excavation footage length on the pre-support effectiveness of the pipe roof are analyzed. The conclusions can be used as a basis for the design and optimization of pipe roofs and as a guide for the application of pipe roofs.

Method to assess the potential of photovoltaic panel based on roof design

The photovoltaic (PV) panel makes it possible for everyone to produce electricity in their own house. However, the panel is quite a costly investment and requires much consideration to maximize its potential. The roof has variables that would impact electricity generation. The roof of housing in Indonesia was built generally in a complex shape, a combination of gable and hip roofs. This research is conducted to break down factors affecting PV productivity in regard to the roof’s aspects. A computer simulation using Ladybug plugin in Rhinoceros software has been done to achieve the target. Initially, the performance of PV panels on the gable, and hip roof, is analyzed respectively. It is found that the roof’s slope, and orientation, contribute more to the amount of electricity produced than the shape itself. These factors were used to assess the PV potential in several housing models employing simple and complex roof (more than 2 surfaces) construction in the city of Gorontalo. Eventually, a comparison between the estimation of real PV production on housing, and the estimation provided by the simulation is conducted to verify the assessment method. The difference is about 4%, as proof the simulation result is reliable.

The energy-efficient design of sustainable green roofs in Mediterranean climate: An experimental study

Green roofs were proposed to broaden nature-based solutions within the perspective of the ecological transition for the built environment. In this paper, an innovative and sustainable green roof was designed to optimize the energy performance in Mediterranean area during summer season by means of local-available and recycled materials, thus reducing the environmental impacts. This new green roof technology consisted of recycled polyethylene granules from the regeneration of disused agricultural plastic films as drainage layer and a substrate made of local-sourced materials with high percentage of organic matter and it was compared to two traditional green roofs and to the existing roof. The energy-efficient design was based on the thermo-physical parameters of the green roof (surface temperatures, heat flows and volumetric water content) and of the building (surface temperature of the ceiling) and on the thermal dynamic parameters (decrement factor, time lag and cooling potential). In addition, these thermo-physical parameters were correlated to the Mediterranean climate during summer season. The result demonstrated that although the proposed green roof reached higher surface temperatures than commercial solutions, it maintained an almost constant volumetric water content, it reduced daily fluctuations between minimum and maximum temperatures, it resulted in lower thermal flow through the cross-section, it reduced the surface temperatures inside the building by about 2 °C compared to the traditional roof, thus decreasing the energy consumption for building cooling and greenhouse gas emissions, and it had better dynamic thermal performance than commercial green roofs. Once the energy-efficient design of the proposed green roof technology was proved, the sustainability and the life cycle performance of the recycled polyethylene was discussed, also considering the costs.

‘Arkeolojik Alanda Mimarın Rolü’: Uygulamalı bir Eğitim Modeli

The architect working in the historical environment is expected to have some basic knowledge, regardless of the specific purpose of their work, whether it is the design of a protection roof to be built for more effective preservation of archaeological data, the documentation of new architectural data revealed by excavations, or the planning of an anastylosis application to be carried out in the area. First of all, the architect; must be able to perceive, understand and evaluate the historical structure and environment. It is observed that the provision of this knowledge in architectural education and the training of architects for the archaeological site is lacking. In this study, in archaeological field research that requires the contribution of many different disciplines; a practical training model proposed for the education of architects and architect candidates who will take responsibility in studies related to the identification, documentation and evaluation of immovable cultural heritage is discussed. A series of summer schools were organized in selected sites with undergraduate architecture students during the active season of archaeological excavations in order to create an education model for this and to enable this topic to be able to take its place in architectural education as a credit course in the future. The difficulties in archaeological sites and the multidisciplinary nature of the excavation teams were observed in the summer schools, and it was emphasized that the architect could take on many other roles besides documentation. During the training, traditional measurement techniques were taught and applied, and introductions to digital methods were given. In this study, considering the possible steps to be taken in the future, the theoretical framework and practical applications of these summer schools held directly at the archaeological site, the observations made, and the evaluations of the feedback of the participants are handled.

Peak Net Pressure Coefficients of Elliptical Center-Open Dome Roofs.

Recently, the demand for spatial structures such as retractable dome roofs is increasing. The safety of dome roofs must be ensured even when they are open. Hence, studies analyzing the peak pressure coefficients of spherical dome roofs are actively being conducted. However, no peak pressure coefficients for the cladding design of elliptical retractable dome roofs have been proposed. Although several studies on elliptical open dome roofs that open from the edge to the center have been conducted, studies on those that open from the center to the edge are still insufficient. This study investigated the peak pressure coefficients of elliptical center-open dome roofs. For wind tunnel tests, a model was fabricated with an opening ratio of 30%. Under experimental conditions, five different wall height-to-span ratios (from 0.1 to 0.5) were used, with the roof rise-to-span ratio set at 0.1. Accordingly, the experimental values of the peak pressure coefficients of elliptical center-open dome roofs were compared with those of the closed dome roofs proposed in the Korean and Japanese wind load codes. Subsequently, their efficiency was verified. The findings were also compared with previous research outcomes. Based on the results, peak net pressure coefficients are proposed for cladding designs suitable for elliptical center-open dome roofs.

Green Roof Design of Residential Area Based on Sponge City Theory

With the acceleration of urbanization, the contradiction between building land and living environment is becoming increasingly prominent. Building sustainable urban architecture has become a topic of great concern, and roof greening has gradually become the inevitable trend of modern architectural development. With the support of sponge city theory, this paper studies the design of green roof in residential area. Firstly, taking roof greening as the research object, this paper makes a preliminary study on its environmental improvement effect by means of experimental research and theoretical analysis and designs the conventional design of roof greening based on the research conclusion. Through the cooling effect experiment, the cooling effect of roof garden in summer is preliminarily studied. It is found that the daily change of temperature of green roof is closely related to solar radiation. With the increase of solar radiation, the temperature rises, and the surface temperature of cement roof and green roof increases. However, due to the difference of heat capacity, the temperature difference of cement roof is the largest, and the change of green roof is the smallest; in the high temperature period in the afternoon, the cooling effect of green roof is the most obvious and enters a stable cooling stage with the passage of time; from 14:00, as the temperature began to drop, the temperature of cement roof decreased rapidly, and the surface temperature of green roof also continued to decline slowly. This surface temperature variation of green roof can form a good cooling surface. Therefore, the green roof plays a positive role in regulating the near ground temperature and protecting the building surface.

Comprehensive energy efficiency study of different climate -adapted BIPV roof forms in single-family houses for five climate zones of China based on PV energy substitution rates (PVESR)

As a type of energy production construction, building integrated photovoltaics (BIPV) roofs are contributing for achieving NZEB goals. Considering building sites’ climate attributes with possible size of PV systems can help to reduce the initial investment and energy consumption of building operation and maintenance. This paper investigates the energy production and energy consumption patterns of single-family houses, which is designed to evaluate the comprehensive energy efficiency of BIPV roofs to meet energy demands by photovoltaic energy substitution ratio (PVESR) calculations. Five typical cities were selected, corresponding to the five climate zones in China; eight forms of BIPV roofs were developed according to single-family houses’ common scale and spatial characteristics. The results show that (1) The PVESR varies significantly between different climate zones and different forms of BIPV roofs, so pre-survey of BIPV roof application sites and comparison of roof forms are relevant in preliminary architecture design. The climate zones where energy balance can be achieved are hot-summer & warm-winter zones, hot-summer & cold-winter zones and moderate zones, and the average PVESR based on the eight roof prototypes are 0.987, 1.136 and 2.272 respectively; the corresponding PVESR for cold zones and severe cold zones are 0.807 and 0.475. (2) The peak and trough values of capacity and energy use are not exactly matching in the five climate zones, especially in severe cold zones, cold zones and hot-summer & cold-winter zones’ winter. (3) The high heating demand in winter is the main reason for the failure to balance BIPV production and energy consumption in severe cold zones and cold zones. The comprehensive energy efficiency evaluation method of BIPV roofs proposed in this paper can provide data support and application guidance for form design and size determination of BIPV roofs in five climate zones in China.

A Pilot Study Considering Ecoroofs as Therapeutic Landscapes

The potential for urban open spaces to convey therapeutic benefits is increasingly substantiated. More work is needed to specifically consider how low impact designs to manage stormwater such as ecoroofs perform in this context. Here, we report on a pilot study addressing: (1) factors determining whether a hospital has an ecoroof, and (2) how ecoroofs might convey therapeutic benefits. We utilized a mixed methods approach which encompassed phone interviews of hospital ecoroof managers as well as analysis of national hospital databases. We also conducted a local case study which compared cortisol samples and stress indicators from patients, staff, and caregivers visiting an ecoroof to those waiting indoors at the Oregon Health and Sciences University in Portland OR. Behavioral observations took place at this same location. In 2017, we identified 105 hospitals with ecoroofs in the contiguous United States. Our analysis of a national hospital database found two factors that significantly increased the likelihood of a hospital having an ecoroof: Medicaid discharges per year; and non-profit status. Interviews with practitioners nationally revealed a wide range of motivations but that therapy was a consideration for a majority, but notably not all, of the hospitals surveyed. They similarly noted variation in roof design, maintenance, and programming around horticultural therapy; we highlight some best practices here. Our physiological case study was limited in sample size. Preliminary findings showed that salivary cortisol levels varied by ecoroof visitor type, ranging on average from 0.09 μg/ml for caregivers to 0.30 μg/ml for patients. We did not observe any significant changes in visitor cortisol. This could be explained by low replication or the short treatment duration. Alternatively, these pilot data may indicate a gap in horticultural therapy theory vs. practice. Behavioral observations demonstrated a wide array of different uses of the ecoroof space such as cell phone use and passing by. Though preliminary, our findings suggest that therapeutic effects may vary by user type and activity and depend on roof design and goals. This study offers both information on the therapeutic potential of hospital ecoroofs as well as lessons learned regarding different approaches to researching this somewhat new topic.

A TAXONOMY STUDY OF MOSQUE ROOF DESIGN IN KLANG VALLEY, MALAYSIA

Energy is the most important issue to focus on as it contributes to economic development and social growth. Buildings were identified to significantly impact energy usage, where 40% of global energy comes from buildings. Nowadays, many buildings in a tropical climate are equipped with air-conditioners as it is seen as the fastest way to cool down buildings. However, this action impacts the environment. One of the affected buildings that are equipped with air-conditioners is a mosque. However, minimal attention has been given to mosques even though this type of building has a significant total space as other commercial buildings. Furthermore, mosques have a unique pattern of occupancy and energy use. While the major contributor to buildings' energy consumption comes from the roof, scarce information is found regarding roof design and energy consumption for air-conditioned mosques in Malaysia. The study aims at exploring the roof types of mosques in the Klang Valley. The objectives are 1) to identify mosques with air-conditioners in the Klang Valley built between 1998 and 2018, 2) to characterize and classify the specific roof types designed for these identified mosques, and 3) to investigate building energy intensity for mosque buildings in the Klang Valley. This paper presents a taxonomy study to classify roof design for air-conditioned mosques in Klang Valley. The study showed that the flat roof demonstrated high energy consumption and cost. The use of HVLS fans and the association with air-conditioners probably increased the building energy.