Environmental Comfort Perception in the Alvorada Sustainable Low Cost House

Environmental Comfort Perception in the Alvorada Sustainable Low Cost House

(Parte 1 de 3)

PLEA 2003 - The 20th Conference on Passive and Low Energy Architecture, Santiago – CHILE, 9 - 12 November 2003

Environmental Comfort Perception in the Alvorada Sustainable Low Cost House

Alessandro Morello; Giane de C. Grigoletti Aline Barroso; Constance Manfredini; Miguel Aloysio Sattler

Núcleo Orientado para a Inovação da Edificação. Programa de Pós-Graduação em Engenharia Civil.

Universidade Federal do Rio Grande do Sul

Av. Osvaldo Aranha, 9. Porto Alegre. RS. Brazil

Tel.: (51) 3316 3900 / Fax: (51) 3316 4054 Email: sattler@vortex.ufrgs.br

ABSTRACT: This paper describes part of a larger study, developed by Núcleo Orientado para a

Inovação da Edificação (NORIE), that deals with the urban and architectural design, construction and post occupancy assessment of Centro de Tecnologias Habitacionais Sustentáveis (CETHS), started in 1999. The settlement is located in the city of Nova Hartz, in the metropolitan area of Porto Alegre, capital city of the Southernmost State of Brazil. The settlement, so far, has eight occupied one-floor single-family houses.

CETHS was submitted to post occupancy evaluation on several features that were considered in the design stage, such as: local food growth, income generation, environmental comfort, building functionality, spaces appropriation, among others. These studies intended to verify the efficiency of sustainable strategies that were adopted in the design stage. The results of research will allow modifications of the original design for future implementations. The presented results were obtained through post occupancy evaluation of building environmental comfort (thermal, luminous and acoustical) and design aspects. The tools used in the survey were interviews and questionnaires carried out with the residents of six houses of the settlement. The aim was to verify the residents’ satisfaction. It is hoped with the obtained information, to better develop and improve the design of the house.

Conference Topic: Design for low-income housing Keywords: low-income house, post occupancy evaluation, environmental sustainability

NORIE has been developing, since 1997, studies on low cost housing, that were designed in accordance with principles of environmental, social and economic sustainability. One of these studies is the urban and building design, construction and evaluation of the Centro Experimental de Tecnologias Habitacionais Sustentáveis (CETHS), which was started in 1999, in

Nova Hartz [1, 2]. Nova Hartz is a small town in the metropolitan region of Porto Alegre, capital city of the southernmost State of Brazil. CETHS has, so far, eight one-floor single-family houses [3], already occupied by residents. The design of CETHS aimed at the implementation of an urban settlement based in sustainable principles and technologies applicable to low-income housing, including: local food growth, jobs and income generation, passive and low energy strategies, use of low environmental impact materials, among others. CETHS was recently submitted to a post occupancy evaluation on several issues that were considered in the design phase, such as: environmental comfort, building functionality and spaces appropriation by users. These studies intend to verify the efficiency of the sustainable strategies adopted in the design stage. The results of the research are expected to allow adapting the original design for future implementations. The research aims to verify the residents’ satisfaction with the previously referred implemented strategies, as well as to identify possible improvements that can be implemented with basis on the residents’ perception. Interviews and questionnaires were used in the assessment. These were applied on the residents of six houses of the settlement. The obtained information is expected to help in the implementation of future projects.

Nova Hartz is a small city with approximately 15,0 inhabitants. It has a territorial area of around 60 km2.

CETHS is being implemented in an area of 2,3 ha located in the urban perimeter of the municipal district, about 2 km far from its city centre, in an area

PLEA 2003 - The 20th Conference on Passive and Low Energy Architecture, Santiago – CHILE, 9 - 12 November 2003 still not totally urbanized. So far, eight houses were built and inhabited (users moved in on July 2002). Six of these houses have the characteristic of being oriented with their main façade to the North direction (Fig. 1 and 2).

Figure 1: Location of the houses (in darker shade) in the settlement.

Figure 2:General view of CETHS.

The six houses described in this paper, have each a floor area of around 48 m², in a plot of about 200 m². Each house has four usable spaces: two bedrooms, a living room/kitchen and a bathroom (Fig. 3), whose materials cost was about US$ 3,0.0.

The constructional system employed ceramic bricks masonry. The walls are rendered only where a higher value for thermal or humidity insulation is justifiable or radiation and/or light reflectance requires it (mainly external south and west walls). The foundations were made using the locally available sandstone, topped with fly ash cement concrete beams. The foundation beams are of concrete. The floor simply sits on the ground having a layer of cement mortar topping construction rubble mixed with clay. The roof has a structure in timber, covered with ceramic tiles, with an intermediary layer of recycled aluminium offset sheets, to minimize long wave radiation transmission. As far as possible, the timber structure was made up of recycled wood used in the formwork, being the wood from sustainable managed forests, with no toxic treatment. The same principles of minimum toxicity were also applied to windows, made from eucalyptus and treated with linseed oil, for controlling humidity, and natural substances, for the control of termites.

Figure 3: Plan of the house.

3.1 Building Design In order to assess the perception of the residents on building design, the following topics were included in the interviews:

Table I: Users' perception and satisfaction with the design of the house.

1: size of the house 2: satisfaction (house) 3: number of rooms

4: satisfaction (kitchen) 5: satisfaction (bathroom)

6: space for professional work 7: open areas

8: aesthetics assessment 9: aesthetic modifications

10: changes (made)

1: changes (desired) 12: largest room 13: smallest room

14: windows handling 15: easiness of cleaning

16: artificial lighting 17: easiness of access to switches and outlets

18: number of electrical switches and outlets

Table I, below, presents the answers obtained from the interviews:

PLEA 2003 - The 20th Conference on Passive and Low Energy Architecture, Santiago – CHILE, 9 - 12 November 2003

After the analysis of the collected data, it was verified, in relation to design’s aspects, that most of the users were satisfied with the houses. However, half the users considered the house small, suggesting the addition of one more room. The kitchen is the room that denotes the highest degree of dissatisfaction. Most of the users would like to have the living room and the kitchen in separate spaces. It is interesting to point out that the opposite happens with the bathroom: 50% of the interviewees considered it larger than necessary (it was designed for universal accessibility).

The great majority believes that the house does not provide an appropriate space for professional activity at home. This, when performed, happens in the living room/kitchen space. In relation to the open areas, half of the respondents considered that the available space was insufficient to supply the users' needs. All homeowners considered their house aesthetically nice. However, one of the users would like to introduce small aesthetic modifications, in order to make it more attractive, such as painting the walls and varnishing the doors and windows.

Half of the users made already some sort of change in their houses. Two extra extensions were made: in one of the houses, a space for a kitchen was built in the backyard and in another house a storage space/garage was built. However, most of them would like to modify their houses in the future, like: application of ceramic tiles on the floor, enlargement of the veranda, implementation of a garage, fencing of the patio, painting of the walls and construction of a kitchen in the backyard area. The windows were considered of easy handling and cleaning, with just one complaint regarding the higher windows, which were considered difficult to clean, by one of the users.

The number and location of lamps, switches and outlets were considered satisfactory, with only one user complaint on the reduced number of lamps, and two other that considered the amount of switches and outlets as being insufficient in the kitchen. It is important to emphasize that two inhabitants considered the number of lamps in the kitchen higher than their actual need. It was verified that all inhabitants, in one way or other, complained about the buildings’ constructional problems. These problems were related to the used constructional system (determining small gaps and humidity in the walls, loose tiles, etc), as well as to poor finishing (doors and windows, floor and walls).

3.2 Plot To evaluate the inhabitants' perception in relation to the plot and to the implementation of the house, the following topics were analysed:

1: front yard area size 2: backyard content

3: front yard content 4: what could there be in the yard

5: activities in the front yard

6: activities in the backyard

7: playing area for children, in the plot

8: type of plants, in the yard 9: characteristics of the plants 10:proximity of the houses

The obtained results are demonstrated in Table I, below:

Table I: The users' perception and satisfaction in relation to the plot and to the implementation of the studied house.

HOUSE NR. 1 2 3 4 5 6 1 medium medium small medium medium small

2 yes yes yes yes yes yes 3 yes yes yes yes yes yes 4 yes yes yes no yes yes 5 no no no yes no yes 6 yes yes yes no no yes 7 no no BY G BY/G G/side 8 yes yes yes no yes yes

9 fruit, teas,herbs food food vegetables, fruits, teas,herbs shade shade, fruit, teas, herbs

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