Sustainable Construction And The Environment Construction Essay

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Concrete stairs in the centre of the building creates a core joining two parts of the building. External walls are built of solid bricks rendered with pebble-dashed render - imitation of the 'harling'- old Scottish technique. Extended to the front porch and stairwell is left un-rendered, revealing a Flemish bond of bricks - alternate headers and stretchers of the brick. The Flemish bond was, and still is favoured for solid 1 brick thick walls construction (Picture 7). The solid build of walls was confirmed by examination of the 150 mm bore hole, made to house insert extract from ventilator (Picture 8). Part of the external wall, under the kitchen and bathroom window is different construction, probably insulated timber frame (Picture 9). Its size is 1.75 m width and 1.10 m height. With total area 1.93 m2 it is 3.7% of the all exposed walls area (perimeter 21.2 x height 2.44 = 51.73 m2). According to the point 2.13 of RdSAP Conventions for SAP 2009 v9.91 this is not regarded as an alternative wall.

The house has a 'cut' traditional, pitched, hipped roof where rafters are supported on purlins and struts (Pictures 1 and 10). The roof is cladded with clay tiles on felt sarking.

Windows to the property are double glazed PVC frames (Pictures 1 and 11). They are of rather old construction - made before 2002, therefore not providing satisfactory thermal insulation resulting with condensation and mould growth around the window's openings (Picture 26).

As located in a semi-detached house, the flat has three sides of external walls; the fourth side is adjacent to an unheated communal corridor (Picture 21).

The floors in the house are timber floors made of 5 x 2" timber. Suspended ground floor joists are supported by the honeycomb wall slippers (Picture 22). First floor joists are hung between external walls and a load bearing internal wall. The habitable room's floor covering in the analysed flat is hardwood flooring laid on softwood subfloor and insulation foam. There are linoleum tiles in the kitchen and the bathroom (Pictures 13, 23 and 24).

Ceiling's 4 x 2" joists are resting on the wall plate and load bearing internal wall (Picture 25). The loft space in insulated between joists with 100 mm thick mineral wool insulation (Picture 12).

2.1. Age of the dwelling and way to assess it.

A request to the council's building department to provide documents determining the time of building Andover Road council estate was fruitless (Appendix 1), therefore the age of the dwelling was established with the help of historic maps provided by Edina (University of Edinburgh, 2012).

On the first assessed map, from 1920, only a range of the allotments exist (marked green), although an old part of the Andover Road with its Victorian houses can be seen (yellow line).

C:\Users\Krzysiek\Desktop\RDSAP\Andover Road 1920.jpg Andover Road in 1920 (University of Edinburgh, 2012).

On the next available map, from 1934, the west extension of Andover Road with the council houses is already marked built.

C:\Users\Krzysiek\Downloads\Andover Road 1934.pngAndover Road in 1934 (University of Edinburgh, 2012).

In 1926 Twickenham was constituted as a municipal borough. This, as well as the opening of Whitton railway station nearby in year 1931 caused rapid increase in housing development. (British History Online, 2012)

The internet site: - property information site confirms the age of the property. (Calnea Analitics Ltd, 2012)

97 Andover Road, Twickenham, TW2 6PA

This property is a 2 bedroom flat. It was built in 1930. It has been given an estimated value by This value is displayed above and it's updated monthly. This property has quite an interesting transaction history. It sold 5 times since January 1995, with the most recent sale on 07/11/2011, for £215,000. We have previous estate agency listing data for both 97 Andover Road, TW2 6PA and a wide range of other homes nearby. This data includes photographs, listing dates, asking prices and detailed property descriptions.

2.2. Explain in detail why the age of the property is an important factor in assessing energy performance.

The age of the property is significant to its thermal properties.

The method of the build depends on the time the building was build.

Each historical period has its characteristic materials and techniques used in construction; medieval times- timber framed, post and beam structures, Victorian houses - solid brick walls and timber floors, early post WWII houses - usage of cheap substitutes of traditional materials, 60ies and 70ies - fascination with concrete.

Usage of different techniques and materials triggers thermal properties, particular for each period.

Other factors important to the dwelling's energy performance are: the heating system and its controls, loft insulation, type of installed windows and doors. They can be altered at any time of the property lifetime.

However, structural elements, which are crucial to the amount of lost heat, stay unchanged. The age band of the property helps to determine the technique used for construction which in turn affects its thermal properties.

Up to 35% of heat is lost through walls and up to 30 % through the roof. For example the type of the wall -solid, cavity- insulated or not, timber or metal framed significantly differs in heat transmittance from 2.1 for solid walls to 0.13 for SIP panels made houses.

2.3. When and under what circumstances extension has to be entered on the survey form.

By definition, house extension is an addition to the existing house. So, it is constructed in a different time to the main building. It is very likely that the extension is built with a different technique. When it is built with the same technique - the degree of insulation and air tightness forced by BR requirements might be different. Hence, it is likely that extension is thermally different from the main building and therefore it should be entered as an extension on the RdSAP survey form. If a later added extension is built using the same construction technique and is insulated to the same standard as the main house, it is not an extension in energy terms and is to be measured together with storeys it is adjoined to. (BRE, 2012)

2.4. Describe when and under what circumstances, would you enter a storey as 'rooms in roof' and when an attic room is defined as a separate storey?

RdSAP Conventions for SAP 2009 v9.91 contains several points explaining when a loft room is considered a 'room in roof' and when it is considered a separate storey. A room in the roof is a room created inside a loft space.

To be treated as a 'room in roof' the access to it must be provided via a permanent fixed staircase, which allows walking downwards facing forward. (That excludes any kind of loft ladders).

To be classified as a 'room in roof' a loft space may have a fitted roof or dormer windows but this is not necessary.

To be classified as a 'room in roof' it doesn't have to be a habitable room. (It can be a utility room or a windowless store).

In the 'room in roof' the height of the common wall, which is a continuation of the external wall from the storey below, must be less than 1.8 m for at least 50% of its perimeter (excluding gable ends, party walls and dormer window).

Elements of the roof room (slope/stud/gable) may have the same amount of insulation or may have different levels. In the latter, detailed measurements are required.

Separate storey.

A space created in the loft within non-vertical walls of at least 70° pitch is defined as a separate storey and it is not treated as roof rooms. When non vertical walls are different then external walls use of alternative walls is required.

When property is a single storey entirely located within a roof, it must be treated as a normal storey, not as a 'room in roof'. If a two storey dwelling within roof space is analysed, then the lower storey is regarded as a normal storey and the upper storey as a 'room-in-roof'. ( BRE, 2012)

2.5. What an alternative wall is and when you enter it on the survey form and why?

An alternative wall type is where the part of the property walls is built in a different technique (construction type, built in the different age band or by amount of insulation) than the most of the external walls, but it cannot be regarded as an extension as it is not surrounding any floor area. According to this, walls built in the same technique, but of different thickness cannot be treated as alternative walls, unless they are stone walls and differ more than 100 mm. In the case where an alternative wall occurs in the analysed dwelling, but covers less than 10% of the total external wall area, it can be ignored. However, it has to be taken into account if visual evidence or a documentary states that retro-fitted insulation was fitted either in the alternative wall or in the any part of the remaining walls. (Boiler Works, 2012)

4. Construction and energy performance features.

Photographic evidence.

The wall type and brick bond.

Picture 6. External wall thickness

Picture 7. The Flemish brick bond.

Picture 8. 150 mm bore hole, revealing solid wall structure.

Different construction wall

Picture 9. Part of external wall of different construction.

Roof construction.

Picture 10. Rafters, purlin, struts and collar ties

The type of windows and glazing.

Picture 11. PVC double glazed window, draught proofed.

The type and the amount of the loft insulation.

Picture 12. 100 mm thick mineral wool in the loft.

Type of flooring.

Picture 13. Hardwood engineered floor laid on insulation foam.

External door's draught proofing.

Picture 14. Draught proofing of external doors.

Fireplace (ventilation).

Picture 15. Open fireplace.

Fireplace (ventilation).

Picture 16. Ventilation via open fireplace.

Low energy lighting.

Picture 17. Low energy bulbs fitted light.

Energy consuming lighting.

Picture 18. Halogen down lights.

Electric meter.

Picture 19. Single phase, pre paid electric meter.

Gas meter.

Picture 20. External gas meter.

Communal stair well - corridor.

Picture 21. Unheated corridor.

Suspended ground floor evidence.

Picture 22. Air brick below ground floor structure.

Type of flooring.

Picture 23. Linoleum tiles in the kitchen.

Type of flooring.

Picture 24. Linoleum in the bathroom.

First floor ceiling.

Picture 25. 10 x 4"ceiling joists laid on the wall plate.

Thermal insufficiency of windows.

Picture 26. Growth of mould and condensation on windows.


Picture 27. Radio controlled, programmable room thermostat.

Condensing combination boiler.

Picture 28. Worcester Greenstar 24 i junior, condensing combi boiler.

Gas Council number.

Picture 29. Identification of the boiler's Gas Council number.

Way to identify condensing boilers.

Picture 30. White, PVC condensate pipe.


Picture 31. Flat panel, convection radiator.

Radiators temperature controller.

Picture 32. Thermostatic radiator valve.

5. Space and water heating.

The heating and hot water system is powered by a combination combi boiler, controlled by radio frequency (RF) central heating temperature control. This controller is time and temperature programmable, assuring switching on and off water boiler in two temperature zones - 'day' and 'night' (Picture 27).

The boiler installed is Worcester - Bosch's Greenstar24i Junior (Picture 28) with Gas Council Number 47-311-86 (Picture 29). (A Gas Council Number is a method of identifying a product. It is a seven digit number in the format: xx-xxx-xx which identifies group, type, manufacturer and a model of the appliance. Unless the GC Number is provided to suppliers cannot to supply the correct spare part.)

This is an energy-saving, condensing, gas-fired combination boiler. Output to domestic hot water and to central heating is 7.2 - 24kW.

Combination boilers combine functions of a central heating boiler and an instantaneous multi point water heater, giving priority to the supply of domestic hot water. They don't require a hot water cylinder, a cold water cistern and they are compact and easy to install. Central heating water expansion/contraction is accommodated in a pressure vessel within the boiler. The main drawback of combination boilers is a fairly slow flow rate. Combination boilers are therefore best suited to small households or flats.

'Condensing' is a design of boiler which can have an increased efficiency of up to 87%- 90%. This model SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK) value is 90.1%.This is delivered by recycling exhaust gases to extract and re-use latent heat. The combustion gases pass through the primary heat exchanger, but instead of passing the combustion products directly into the flue, they are circulated around the secondary heat exchanger where more heat is given up to the return water entering the boiler. These can reduce the flue gas temperature to about 55°C. Heat is extracted from the combustion products in two ways:

1. In the form of sensible heat - by the transmittance of heat from a hotter medium (combustion gases) to the cooler return.

2. By the latent heat of evaporation (water vapour in the combustion products reverts to a liquid when condensed, giving up the heat that caused it to become a vapour.

The condensate has a light acid pH 3-4, (level of a lemon). So, to prevent corrosion, the condensate pipe is PVC made. This is, by the way, easy visual way to identify condensing boilers (Picture 30).

All rooms in the flat, except a 1 square meter entrance hall are fitted with radiators. They are single panel convection radiators (Picture 31). Most of them are fitted with Thermostatic Radiator Valves (Picture 32).

6. Final EPC print off.

7. Recommendations and the Green Deal.

Green Deal is a government initiative promoting investing in green technologies in the UK. It is directed to homeowners, both domestic and corporate. The idea is to encourage homeowners to install energy saving measures without upfront costs, repaid via electricity or gas bills. Green Deal finance will not be a personal loan on the householder or building owner but will in fact be a debt held on the property. Future owners of the property will have to take on the remaining amount of the Green Deal until payment is complete.

At present there is a limit of £10,000 for domestic homeowners. Green technologies covered by the scheme are: wall insulation solid and cavity walls, loft insulation, double glazing, door insulation, smart meters. The others that will be covered by the Green Deal in the future are: Solar Thermal and Photo Voltaic panels, Air and ground source heat pumps and Biomass boilers. (Green Deal Initiative, 2012)

The "golden rule" of the Green Deal is that the cost of the energy saving changes cannot be bigger than energy savings on energy bills. The idea of the Golden Rule is to protect homeowners to not pay back more than they would pay anyway without investing in changes, year by year, up to a 25 year period. In every case, detailed assessment of a property would be crucial to balance the likely cost of energy efficiency improvements against the likely benefits. The assessment of the property will produce an Energy Performance Certificate (EPC) and this will identify the applied green technologies and possible improvements together with possible savings in pounds.

Some improvement possibilities are pointed out by a green tick. This confirms that Green Deal finance should be available.

An orange tick against improvement proposition means that it could qualify for the Green Deal, but other finance may be needed.

(Public Service Ltd, 2012)


1. Boiler Works, 2012, 3|NES one and the RDSAP software | p. 3-9 RDSAP Training Manual Version 5.1March 2012. Retrieved 01.12.2012 from

2. British History Online, 2012, Twickenham, introduction. Retrieved 02.12.2012 from

3. Building Research Establishment, 2012, RdSAP Conventions for SAP 2009 v9.91 Issued 6 January 2012 (v5.0). Retrieved 01.12.2012 from

4. Calnea Analitics Ltd, 2012,Mouseprice, Sold prices and valuations. Retrieved 03.12.2012 from

5.Green Deal Initiative, 2012, About the Green Deal. Retrieved 02.12.2012 from

6. Public Service Ltd, 2012, Green Deal - never forget the golden rule. Retrieved 04.12.2012 from

7. University of Edinburgh, 2012,Digimap Historic. Retrieved 02.12.2012 from