Figure 2: Eco House5
Likewise eco house, there are number of factors can be considered in order to achieve the sustainable development in the construction industry.
- Use eco friendly materials
-
Reduce CO2 emission
- Improving thermal performance
- Reduce water and atmospheric pollution to minimum
- Improving construction method
- Build in harmony with the environment
- Recycling
- Reduce waste
The building regulations in England and Wales 20066 actually covering about energy conservation standards also record of energy consumption have to be kept by the law.
In order to achieve successful sustainable development in the construction industry, environmental responsibility, economical profitability and social awareness have to be well balanced and more impotantly, engineers always have to be aware of environmental impacts and have responsibility on what they doing.
HOW TO SUPPORT THE CONCEPT OF
SUSTAINABLE DEVELOPMENT
a) ‘Warm’ pitched roof construction
The main difference between warm pitched roof and cold pitched roof is simply the position of insulation and ventilation. In the warm pitched roof, the insulation follows the pitch of the roof (insulation at rafter) while the insulation of cold roof lies at ceiling.
Figure 3: typical ‘warm’ pitched roof7
Although the initial cost of warm pitched roof is more expensive than cold pitched roof, warm roof is more suitable in the concept of sustainable development as it is more energy efficient. Moreover, risk of condensation is eliminated by insulation at rafter.
-How efficient energy is achieved in the ‘warm’ pitched roof?
As there is no need of cross ventilation in the warm pitched roof space, cold air cannot infiltrate in the roof structure8. Reduction in energy consumption is expected by this effect. Moreover, the insulation along the pitched roof can achieve the lower U-Values and which means it helps the performance of the buildings.
Insulation along the roof and the no need of ventilation on the warm roof space both can reduce the energy consumption in heating or cooling of the building and therefore, this energy efficient building will have lower emission as well. Hence, it supports the concept of sustainable development.
-Condensation
A warm roof has the insulation along the pitch of the roof (at rafter), which means the roof space is effectively inside and therefore the roof space is kept warm. The temperature difference between roof space and inside of building will be therefore lower which could not reach the dew point.
Dew point on the roof space is critical as it is directly connected with condensation. Condensation in the roof space will weaken any timberwork and problem of mould or moisture will rise.
Figure 4: condensation in the roof space9
By eliminating condensation problem, warm pitched roof can therefore improve the durability of building and enhance the quality of environment.
b) Suspended prefabricated concrete ground floor construction.
Prefabricated concrete floor system is relatively new construction method and has a number of advantages over timber floor system.
Figure 5: Beam and pot floor10
Precast concrete T-shape beams reinforced with steel are laid at typical interval of 520mm and the blocks are fitted into the gaps between them. As it is constructed with precast concrete, it can save the construction time also high quality of floor provides good thermal performance and sound insulation performance. Other properties of suspended prefabricated concrete ground floor, related to sustainable development concept, are as follows11.
- Can eliminate clay heave or settlement problems
- No concrete or sand blinding is required or costly imported fill materials.
- Avoid bad weather delays (dry construction)
- Improved thermal performance over ground bearing slabs reducing heat loss by as much as 40% when used in conjunction with Celcon Foundation blocks
- Better moisture insulation
Above factors can support the concept of sustainable development in various ways. For example, precast concrete and no need of deep fill in poor soil condition, can reduce the period of construction and therefore cost reduction on labour can be expected. Moreover, improved thermal performance on the floor can reduce the energy consumption on heating (less emission) and sound insulation improves the quality of life.
However, there are few problems of this construction system such as moisture penetration and gas from ground rock in the sub floor space, which can harm the human health. These problems can be reduced/eliminated by putting vapour control layers, damp proof membrane and ventilation in sub floor space.
Victorian House
Victorian domestic building (house) is the building that built during the reign of Queen Victoria (1837-1901). During the industrial revolution, successive housing booms resulted in the building of many millions of Victorian houses, which are now a defining feature of most British town and cities12. The key aspects of Victorian houses are as follows13.
- Bay windows
- Iron Railings
- Flemish brick bonding
- Patterns in the brickwork made from coloured bricks
- Stained glass in doorways and windows.
- Roofs made of slate.
- No garage
- Sash windows
Figure 6: Typical terraced Victorian houses14
However, the methods of Victorian domestic construction have several problems associated with the concept of sustainable development.
- Heat loss
Single-glazed window have higher heat loss and therefore more energy is needed to heat the building (more emission). Moreover, it is found that some Victorian houses were built with regardless of solar energy gain. As there is not enough solar energy gain during the day, more energy is needed for heating the building.
Traditional solid wall system, which is normally used in the Victorian house, is another problem of heat loss15. Comparing with recent cavity wall (with insulation), traditional solid wall have very low thermal performance and this needs more energy to be consumed.
- Sound insulation
As most of Victorian house is built with timberwork, poor sound insulation between floors or over the wall rises and this is not compatible whit the concept of sustainable development.
- Foundation
Foundations of Victorian houses are relatively shallow and this could lead to movement, such as settlement and heave in clay areas16. Moreover, some of brick foundation in the Victorian house, which is not stable enough, can lead the safety problems.
- Damp proof course
From the 1770’s, damp proof courses officially had to be added16. However, most of old Victorian house does not have damp proof course and therefore damp problems can occur, which can weaken the building and produce mould. These problems could harm the human health and therefore not suitable with sustainable development.
- Drainage
Most of old Victorian houses have a poor drainage system, which consumes large amount of water.
Remodelling, using eco-friendly materials can treat most of above factors. By this process, Victorian house can be compatible with the concept of the sustainable development, which is energy efficient, low emission of CO2 and supporting the human health.
REFERENCES
1. ’Effect of global warming’, (accessed 09.04.2010) , ()
2. United Nations. 1987. General Assembly Resolution 42/187, 11 December 1987.
3. ’40% Of UK’s Energy Consumption Is Building Related’ ,
(accessed 10.04.2010) , (http://www.levolux.com/L_Misc/40%25_energy_consumption.htm)
4. UK Government sustainable development strategy 2005
5. http://www.u3atweeddale.org/Webpage/Ecohouse.jpg
6. ’Building Regulations in England and Wales
,(accessed25.04.2010),(http://www.energysavingtrust.org.uk/business/Business/Housing-professionals/Building-Regulations-covering-energy-efficiency/Building-Regulations-in-England-and-Wales)
7. Sure vent. Condensation and Ventilation in Energy Efficient Cold and Warm Pitched Roofs.(accessed 01.05.2010) http://www.surevent.org.uk/Documents/Surevent_cpd_4_1.pdf
8. Low Energy House - Rafter Insulation - House Insulation
,(accessed 01.05.2010),(http://www.lowenergyhouse.com/rafter-insulation.html)
9. http://home.comcast.net/~mahamm/remodel_blog/remodel_blog.html
10. Robust construction details
11. http://www.azobuild.com/details.asp?ArticleID=7849#_Ground_Floors
12. Victorian house typical features,(accessed 05.05.2010),(http://en.wikipedia.org/wiki/Victorian_house#Typical_features
13. http://www.woodlands-junior.kent.sch.uk/Homework/houses/victorian/index.htm)
14. Victorian house,(accessed 05.05.2010), (http://www.woodlands-junior.kent.sch.uk/Homework/houses/victorian.htm)
15. What specific problems do Victorian homes have, (accessed 07.05.2010), (http://www.trulia.com/voices/Home_Buying/What_specific_problems_do_Victorian_homes_have_-62566)
16. building-surveying-questions-victorian-edwardian,(accessed 09.05.2010), (http://www.1stassociated.co.uk/building-surveying-questions-victorian-edwardian.pdf)
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