Multifamily Housing Research Articles

Assessment of the Greenery Content in Suburban Multi-Family Housing Models in Poland: A Case Study of the Poznań Metropolitan Area

(1) Contemporary approaches to sustainable housing design tend to prioritize technological solutions supporting energy efficiency and climate change mitigation. On the contrary, spatial planning of housing estates does not always address all pro-ecological aspects, such as the role of greenery. This research aimed to assess the greenery content and its environmental importance in typical housing districts in the selected study area. (2) The research methodology was based on indicators reflecting the biologically active area ratio, the length of communication routes lined with trees, the tree number per area unit, the tree canopy, and the environmental benefits delivered by the trees. The above indicators allowed us to compare selected models of suburban residential districts typical of specific timeframes. (3) The results indicated that the greenery content and its environmental benefits in suburban districts are decreasing in the study area. Another finding concerned the importance of selecting tree species for their ability to develop a canopy and provide ecosystem services. (4) The proposed methodology, based on inter-related indicators, validly compared the greenery content in the analyzed districts, giving it application value. The problems observed contributed to the proposal of a revision of Poland’s planning practices. Local zoning plans could include streetscape standards, indicating paving solutions and plantings to improve the situation.

The spatial and social correlates of neighborhood morphology: Evidence from building footprints in five U.S. metropolitan areas.

Recent advances in quantitative tools for examining urban morphology enable the development of morphometrics that can characterize the size, shape, and placement of buildings; the relationships between them; and their association with broader patterns of development. Although these methods have the potential to provide substantial insight into the ways in which neighborhood morphology shapes the socioeconomic and demographic characteristics of neighborhoods and communities, this question is largely unexplored. Using building footprints in five of the ten largest U.S. metropolitan areas (Atlanta, Boston, Chicago, Houston, and Los Angeles) and the open-source R package, foot, we examine how neighborhood morphology differs across U.S. metropolitan areas and across the urban-exurban landscape. Principal components analysis, unsupervised classification (K-means), and Ordinary Least Squares regression analysis are used to develop a morphological typology of neighborhoods and to examine its association with the spatial, socioeconomic, and demographic characteristics of census tracts. Our findings illustrate substantial variation in the morphology of neighborhoods, both across the five metropolitan areas as well as between central cities, suburbs, and the urban fringe within each metropolitan area. We identify five different types of neighborhoods indicative of different stages of development and distributed unevenly across the urban landscape: these include low-density neighborhoods on the urban fringe; mixed use and high-density residential areas in central cities; and uniform residential neighborhoods in suburban cities. Results from regression analysis illustrate that the prevalence of each of these forms is closely associated with variation in socioeconomic and demographic characteristics such as population density, the prevalence of multifamily housing, and income, race/ethnicity, homeownership, and commuting by car. We conclude by discussing the implications of our findings and suggesting avenues for future research on neighborhood morphology, including ways that it might provide insight into issues such as zoning and land use, housing policy, and residential segregation.

부동산 중개사고 예방을 위한 실증연구

This study aims to recognize the seriousness of real estate brokerage accidents that may occur in real estate leasing contracts and to identify important factors that can be prioritized to prevent them. To prevent this from happening, let's take a look at the types of real estate brokerage accidents and how they occur, as well as the current state of lease damage. Then, based on the factors selected from government policies, reports, papers, and 1:1 in-depth interviews with experts, we prioritized the factors that are important to prevent real estate brokerage accidents in real estate lease contracts through the Analytical Hierarchy Process (AHP). The results of the analysis showed that the following steps were taken: researching and verifying the seniority of the security deposit and the date of occupancy for multifamily housing units, checking the seniority rights, checking and notifying the availability of a return guarantee for the security deposit, verifying the owner (trust property, registered owner), and checking the status of the property with public records (also checking the status of the building). The results of this study will be used as a basis for preventing real estate brokerage accidents when signing real estate leases to establish transaction order in the real estate market.

A multi-criteria decision-making method for thermal insulation material selection in nZEB level questioned affordable multifamily housings

An affordable multifamily housing building archetype project was researched to improve the building envelope’s thermo-physical performance based on thermal insulation configurations to optimize the energy use, life-cycle cost, environmental impact, and thermal comfort with questioning nZEB concept. Five thermal insulation materials as extruded polystyrene (XPS), expanded polystyrene (EPS), rockwool (RW), glass wool (GW), and cellular glass (CG), were studied with four> attribute variations (thermal comfort, density, embodied carbon, and embodied energy) and five thickness variations (0.04, 0.08, 0.12, 0.16, 0.20 m). A total of 100 alternative scenarios> were obtained for the decision-making process, with four performance criteria to be evaluated in terms of energy, cost, thermal comfort, and environmental impact. Equal weights method (EWM), weighted sum method (WSM), and analytical hierarchy process (AHP) were examined for the multi-criteria decision-making among 46 scenariosvel. The analysis beyond the cost-optimal energy efficiency level, which varies between 64.89 and 72.62 kWh/m2a for primary energy use with a potential 10% further reduction, ensures the European Commission’s recommendations that target 50–70 kWh/m2a of primary energy use for housings in the continental climate to achieve nZEB. The best scenarios cover significantly the XPS at the head due to lover investment costs, where RW, GW, and EPS are followed among the best 10 scenarios, respectively. Besides, AHP provides a more effective distribution of weighting factors than the WSM where the best scenarios of the AHP covers 12 cm thermal insulation alternatives by balancing the investment costs and energy efficiency levels. The paper provides insight into thermal insulation material selection while searching for the advantages and priorities of thermal insulation materials’ attributes beyond the cost-optimal energy efficiency level to reach the nZEB range.

The history and evolution of warranty liability of apartment complexes

Regulations on defects in multi-family housing are stipulated by two positive laws: the Act on Ownership and Management of Condominium Buildings and the Multi-Family Housing Management Act. However, the characteristics and purpose of these two laws differ. The Multi-Family Housing Management Act is a public law securing the constitutional rights to housing, which includes administrative laws on the construction of housing (e.g., the Housing Construction Promotion Act) and those related to the management of housing (e.g., the Housing Act and the Multi-Family Housing Management Act). However, the Act on Ownership and Management of Condominium Buildings is a private law merely focusing on the property rights of condominium owners. Therefore, the stipulations of these two positive laws regarding defects in multi-family housing also differ in many aspects, such as the types of defects, standings to claim repair, distribution of responsibility, and statutory limitations. However, the legal aspect remains ambiguous, despite the gap being narrowed through several rounds of enactment and amendment to positive laws. In particular, the meaning of the project implementer's defect repair responsibility, which must be understood from a public law perspective, has been considerably ambiguous. Consequently, for defects in multi-family housing, the focus is merely on monetary compensation for defects, which is a matter of private law, rather than on the implementation of defect repair itself, which is a matter of public law. Accordingly, this study examines the problems related to the repair of defects in multi-family housing by analyzing the history of these positive laws, their detailed stipulations, and the differences in defect warranty liability. Based on these analyses, this study attempts to identify and suggest solutions to overcome these issues.

Public Law Regulations on Household-Increasing Remodeling Projects

The public law regulations for remodeling projects were introduced to improve residential environments through the development and maintenance of multi-family housing, and to prevent low-quality reconstruction projects. Remodeling projects were initially focused on preserving and managing multi-family housing, and so did the “household-increasing remodeling,” which was introduced to activate remodeling projects. Notwithstanding, nowadays, household-increasing remodeling projects are more akin to reconstruction projects because they involve the reconstruction of new apartments and, simultaneously, a comprehensive reconstruction of housing complexes. Despite similarities, remodeling projects are governed by the Housing Act and subject to weaker public law regulations, while reconstruction projects are governed by the Act on the Improvement of Urban Areas and Residential Environments and subject to stronger regulations. To initiate a household-increasing remodeling project for increasing household numbers by 30 or more, it is necessary to secure project plan “approval”; if the household number increase is less than 30, it is necessary to secure a “permission”. The “permission” relates to building management activities, whereas an “approval” involves a comprehensive assessment of the residential area in light of urban planning. Remodeling projects are also examined differently based on whether they affect the entire housing complex. Still, distinguishing the procedure for project initiation based on the increase in household numbers may not be rational and can lead to regulatory arbitrage. Traditionally, remodeling projects involved minimal changes in property ownership because the residents came back to their remodeled houses. This led to less attention being given to post-project rights, and although the Housing Act mandates the establishment of a “plan to alter rights” for household-increasing remodeling projects, it fails to establish the details. As household-increasing remodeling projects are becoming more similar to reconstruction projects, the uncertainty has intensified regarding resident rights assignment. These uncertainties can lead to disputes among residents regarding the content of plans to alter rights. Currently, there is a need for more detailed legal regulations to enable the reasonable assignment of rights among residents regarding newly constructed buildings and their land. This can foster efficiency in the use of these buildings and land in remodeling projects.

Assessing current state and prospects for housing construction development in the Far Eastern Federal District of the Russian Federation

Housing commissioning in the Far Eastern Federal District of the Russian Federation was low until 2019, which resulted in housing availability lower than the national average. The Government of the Russian Federation implemented the program on preferential mortgage lending “Far Eastern Mortgage” that led to an increase in the housing availability in apartment buildings in the macro-region, purchased on credit, while stimulating price growth at a rate outpacing the increase in household incomes. The purpose of the study is to develop proposals for improving measures to support the housing construction market of apartment buildings in the Far Eastern Federal District. The data on the volume and structure of multifamily housing under construction, the main factors of construction cost formation in the macro-region have been analyzed. The mechanism of mortgage influence with state support on the supply growth has been described. It is shown that the dynamics of supply is insufficient to achieve the average Russian values on housing provision of the population, in this connection stimulation measures require improvement. The high dependence of the housing market on mortgage lending programs with state support has been revealed. Based on the comparative analysis of the Far Eastern Mortgage program with other preferential mortgage programs, the article presents proposals for improving the measures of state support for multifamily housing construction in the Far East.

Technical and Economic Feasibility of Multi-Family Social Housing and Nearly Zero-Energy Buildings in Southern Brazil

Several studies have shown that social housing in Brazil usually fails to provide thermal comfort to its occupants. This study aimed to define energy efficiency measures for a representative social housing model to, together with local production of renewable energy, achieve the nearly zero-energy target. The thermal performance and energy efficiency of the representative model were evaluated using computer simulation, considering the southern Brazilian climatic context. An analysis of the economic feasibility of energy efficiency measures was also carried out. The results showed that the nearly zero-energy model with energy efficiency measures on the envelope (EPS and gypsum board in the external walls and rock wall in the roof) and a solar water heating system reduced 13.1% of the annual primary energy consumption in comparison with the representative model. Considering the renewable energy generation in the nearly zero-energy building, the electricity consumption was 38,777.6 kWh/year lower than that in the representative model (57.0% reduction). The economic analysis of the energy efficiency measures indicated a positive net present value and a payback of nearly six years. It was concluded that using energy efficiency measures and an on-site renewable made it possible to reach the nearly zero-energy target in a representative social housing model.

Field Trial Evaluation of a Hybrid Heat Pump in an Existing Multi-Family House before and after Renovation

Renovation of existing buildings is fundamental to reduce greenhouse gas emissions of the building sector and to ensure the efficient operation of renewable heating systems. In multi-family houses, the suitability of heat pumps is limited by high required temperatures for the hot water preparation, which can be mitigated by hybrid heat pump systems. In this study, the energetic performance of a hybrid heat pump in a multi-family house, built in 1964, is investigated based on field data before and after a renovation. Multiple months are measured and mapped to a full year period. The combination of different renovation measures in the heating system and building envelope is rated w.r.t. their ecological and economical impact by taking into account the actual investment costs. The evaluation shows that the installation of a hybrid heat pump can achieve an accumulated greenhouse gas emissions reduction of 45%, which is similar to a building renovation to a new-build standard, which reduces the space heating demand by up to 62%. Nevertheless, only a combination of both measures can substantially reduce the emissions, which in this case are 81% lower compared to a gas boiler in 1990, which is still below the German climate target for 2040. Due to the low investment costs of a hybrid heat pump system, tenants are more likely to profit from a renting costs reduction, while a building renovation is especially economically beneficial at high energy prices. The results therefore emphasize that the insulation level should be selected carefully, as heat pumps already prepare space heating efficiently and that the heat pump must be able to support the hot water preparation to reach high emission reduction targets.

Adding Balconies to Historical Tenements – Local Approaches to the Retention of Heritage Value in Poland, Germany, and Denmark

ABSTRACT Approximately 22% of the existing dwellings in the EU were built before 1946. In Wrocław, Poland ca. 21% of all dwellings in multifamily houses are protected for their heritage value. For such a significant share of the residential building stock pursuit of sustainability through amenity improvement is inevitable and will gain pace with the EU endorsed Renovation Wave. The discourse about the scope of renovations should be extended to consider an improvement of historical housing’s spatial quality without compromising its heritage value. Balconies are perceived as an indispensable part of new-built apartments; however, they are scarce in tenements built at the turn of 20th century. Adding balconies as a part of retrofitting is common in Germany or Denmark, but rare in Poland. By analysing heritage preservation practices in Chemnitz, Copenhagen and Wrocław, this paper aims to understand how retention of heritage value shapes local approach to adding balconies. Semi-structured interviews (18) were conducted with heritage conservation officers and other stakeholders. The results revealed a shared recognition of balcony’s role as an element contributing to heritage housing preservation through enhanced usability. Factors that impede balcony additions in historical tenements in Wrocław were identified for different tenure types, followed by recommendations.

Spatial Disparity and Residential Assessment of Housing Cost-Burdened Renters

With the expanding rental sector and rising housing expenses, this research aims to compare the socio-demographic, economic, and housing statuses of renters burdened by housing costs in four regions, and also to explore predictors affecting their residential assessment. Using data from the 2020 Korean Housing Survey, this cross-sectional study identified 245 cost-burdened households whose housing expenses accounted for more than 25% of their total gross income and living expenses. The results revealed that the majority of renters were single-person households residing in single-room occupancy units of multifamily housing, primarily comprising unemployed older adults aged 50 and over. While earning less than half of the minimum wage, the renters’ living expenses fell well below the minimum cost of living, and more than 40% of the expenditure was spent on housing costs, resulting in cost-overburdened households. With the correlation between income, deposit, and rent, the burden of housing costs and the quality of the residential environment varied among regions. Indeed, the residential assessment of the renters was significantly influenced by urban amenities, and both income deficits and excessive housing cost burdens required inclusive and prompt housing interventions including housing assistance, provision of affordable public housing, income transfer, and transitions from renting to Chonsei arrangements.

Missing Housing: How Los Angeles Is Wasting Multifamily Housing Units in the Midst of a Housing Crisis

Like other US cities, Los Angeles faces a housing crisis, with sale and rental prices exceeding the national average. We used data on property characteristics and zoning status to examine properties zoned for multifamily use in the city of Los Angeles, particularly those not building to their legally permitted maximum number of units, to determine whether those properties were capable of reaching this level of development. Our study reveals a 400,000-unit unbuilt allowable housing gap, predominantly in properties over 50 years old. We analyzed the properties as-built and developed scenarios under which they were built to their legal maximums, and found evidence that regulatory limits, mainly minimum parking requirements (MPRs), inhibit full development of these properties. However, there are also a large number of additional allowable units in buildings that do not face regulatory constraints. Our analysis of the upzoning Transit-Oriented Communities policy reveals that while zoning changes allow for more multifamily developments, many eligible properties still face regulatory hurdles. Our research shows that a core strategy for improving the Los Angeles area housing shortages should be policies to facilitate older properties redeveloping or adding units.

Effects of Periodic Materials on Distance Attenuation in Wall–Slab Structures: An Experiment

This research examines the application of periodic materials in wall–slab structures to mitigate impact noise and vibration propagation, a prevalent issue in multifamily housing. Traditional methods, such as floating floors, have proven insufficient in addressing low-frequency impact noises and in facilitating the identification of noise origins, leading to increased resident annoyance. Periodic materials, known for their effectiveness in controlling plane waves in civil engineering, were applied to the intermediate slab of a wall–slab experimental setup. The research involved assessing the attenuation of noise and vibration over distance before and after the application of periodic materials by measuring indoor sound pressure levels and the natural vibration amplitude of the structure’s members upon impact. The results showed that periodic materials not only facilitated distance attenuation but also significantly diminished noise and vibration throughout the structure, without the side effects of vibration amplification seen in prior civil engineering applications. This indicates a practical advancement in using these materials, offering a novel approach to sound insulation and enabling more precise impact source localization. Ultimately, this study contributes to improving urban living by suggesting a method to enhance acoustic comfort in multifamily housing, underlining the importance of further exploration in architectural applications of periodic materials.

Advancement of the exterior façade measurement method by Jerry Christoff

Acoustical design of façade elements is a key element in architectural acoustics. The assessment is required for multi-family housing projects and environmental projects. In the 1980s, when labs around the US were measuring the transmission loss (TL) of exterior façade elements, it was assumed that measurement of TL with a diffuse sound field method is valid for TL of real facades where a diffuse sound field does not exist. Jerry evaluated how the TL of exterior façade elements change based on the incident angle. In this talk, we will shed some light on the history of the work done by Jerry in the advancement of the exterior façade assessment methods.

"Exploring Aerated Autoclaved Concrete (AAC) Acoustic Properties Across Diverse Frequency Bands"

Aerated Autoclaved Concrete (AAC) stands out as an environmentally friendly and lightweight construction material. Known for its durability, load-bearing capacity, and excellent insulation, AAC surpasses traditional concrete blocks and red bricks in construction preferences. Its suitability as a wood alternative is evident, given its resistance to decay and comparable lightweight characteristics. Comprising a blend of cement, fly ash, limestone, and gypsum in an 8:69:20:3 ratio, with aluminum powder as the expansion agent, AAC serves as a versatile building material. In addition to its various attributes, understanding the acoustic properties of AAC is essential. Structures such as schools, hospitals, hotels, offices, and multi-family housing demand effective sound insulation, necessitating the use of materials with favorable sound absorption coefficients and minimal sound reflection coefficients. Due to its porous composition, Aerated Autoclaved Concrete exhibits notable sound absorption coefficients, making it ideal for applications in environments like schools and hospitals. This research delves into the determination of AAC's sound absorption coefficient and sound reflection coefficient across a spectrum of frequencies ranging from 1 kHz to 10 kHz. The analysis extends beyond frequency variations to encompass different sound intensities, offering a comprehensive exploration of AAC's acoustic characteristics.

Exploring Building Boundary Expansion in NYC's Gowanus District : Focused on Multifamily Housing Development with Revised Zoning Regulations

Exploring Building Boundary Expansion in NYC's Gowanus District : Focused on Multifamily Housing Development with Revised Zoning Regulations

Drivers of Tree Canopy Loss in a Mid-Sized Growing City: Case Study in Portland, OR (USA)

The benefits of the urban tree and tree canopy (UTC) are increasingly crucial in addressing urban sustainability. Yet, increasingly evident from earlier research is the distributional inequities of UTC and active efforts to expand tree plantings. Less is known about the dynamics of UTC loss over time and location. This study aims to understand the dynamics of UTC change, especially canopy loss, and to investigate the drivers of the loss. This study draws on a high–resolution dataset of an urban canopy in Portland, Oregon, USA, assessing changes in UTC from 2014 to 2020. By integrating demographic, biophysical, and policy data with UTC information, we use a spatial autoregressive model to identify the drivers of UTC loss. The results reveal an unexpected spatial distribution of UTC change: less gain in the neighborhoods with the least UTC, and greater loss in the neighborhoods with moderate UTC. This study identifies four primary drivers of UTC loss: socioeconomic characteristics, urban form, activities on trees, and residential status. Factors such as population density, race, and income have an impact on canopy loss, as well as the building footprint and the number of multifamily housing units; residential statuses, such as the proportion of owner-occupied housing and residential stability, impact canopy loss.

Environmental consequences of shifting to timber construction: The case of Denmark

Many life cycle assessments (LCA) studies on wooden buildings show potential to decarbonise the building industry, though often neglecting to consider the systemic changes of such a shift at the building stock scale. This study applies a consequential LCA to evaluate the transition from conventional construction to increased wood-based construction in Denmark from 2022 to 2050. The assessment models a material flow analysis of the two construction scenarios, incorporating an area forecast and case buildings. By that, we assessed suppliers' capacity to likely meet the demand for wood, steel, and concrete, employed an input-output model to enhance completeness and country representativeness for other materials' markets, and considered the competition for land by indirect land use change. We implemented a dynamic IPCC-based assessment of GHG-emissions concurrently with a carbon forest model to anticipate the relationship between the delayed carbon storage resulting from using wood in buildings and forest regrowth management. The findings indicate wood construction is the most climate-friendly option for multifamily houses. In contrast, single-family houses (SFH) and office buildings (OB) exhibit the lowest climate impacts in the conventional scenario. The SFH result could be credible due to the sizable GWP impact gap between construction scenarios despite uncertainties related to the weight proportion of sedum roofs. The less conclusive OB findings relate to the substantial steel quantities in the wood case buildings, requiring further investigation. Generally, metals, cement-based- and biobased materials demonstrate the largest climate impact among the material categories. Across all three building typologies, the change to timber construction increased the impact on nature occupation (biodiversity). In conclusion, this study emphasises the need for further research on forest management model inputs, land use change approaches, potential steel suppliers' impact, and a broader array of case studies. It is because these are influential factors in facilitating informed decision-making of the increased implementation of wood in buildings. As the first study to integrate these modelling characteristics, it contributes to the research gap concerning geographical circumstances, forestry, and markets relevant to decision support for increased wood utilisation in Europe's building industry.

Design and operation of a local cogeneration plant supplying a multi-family house (9,5 kW electrical / 35 kW thermic power) – a field report

In the paper at hand a small cogeneration plant that is suitable to supply heat and electric power to a three family house is presented. The plant is capable of delivering 9.5 kW electrical power to the mains and 30 kW thermal power used for heating the domestic hot water and the building respectively. Woodchips, a renewable energy carrier, are used to power the plant, so it is CO2 neutral. Powering an internal combustion engine with wood gas made from woodchips has turned out to be the right technology for small cogeneration plants. Such units are not available from stock; hence a prototype has been constructed. More than two years of operation experience with this prototype show the practicability of the system. The amount of maintenance work is acceptable and will be reduced in the future by optimization. Measurements concerning the electrical as well as the thermal efficiency are presented. During these measurements further room for improvement has been discovered to maximise output power and to lower losses. In summary it figured out that the plant operates reliable with acceptable amount of maintenance work. And, if we don’t calculate the amount of development work for the prototype, it is profitable.

Renewable Energy Source (RES)-Based Polygeneration Systems for Multi-Family Houses

This research work synthetizes the energy, economic, and environmental aspects of a novel configurational analysis of four polygeneration schemes designed to fulfill the demands of a multi-family building that includes 12 dwellings. The design aims to meet the requirements (water, electricity, heat and cold air) from Renewable Energy Sources (RESs), in particular by selecting photovoltaic and photovoltaic-thermal panels, thermoelectric generators, and biomass as auxiliaries. Electricity is available from the grid, and no electrical storage is planned. Water and cooling may be produced by alternative technologies that configure the polygeneration alternatives. The case study is in Valencia, a coastal Mediterranean city in Spain. The Design Builder Clima estimated demand calculations, and the system performance was modeled in TRNSYS. Desalination was linked by using EES models. Results show that the suggested schemes offer substantial energy and CO2 savings. The innovative life-cycle analysis applied further enhances the cumulative CO2 savings across the four configurations if the impact of the installations is compared with the conventional external supply. The electric option (combining heat pump and reverse osmosis for cooling and desalination) emerged as the most appealing solution due to its reliability, lower investment cost, and environmental impact.