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Useful Information

This section provides snippets and links for cost conscious and environmentally concerned builders.  This includes new and upcoming Building Regulations, financial /mortgage, insurance considerations, etc.  For further information please follow the link in the first instance then, when you have a specific project in mind, call us to discuss optimising your project for sustainability. 

Books   Materials in Construction   Timber   Materials in Housing   The BedZED Project      
Sound Check   Sound Standards   Robust Details   Noise from Above   Testing Time  
 Logic Test   Affordable Housing   Land for Housing   Barriers to Brownfield  Highway Issues
Sustainable Drainage   Building Regs Part C   Water & Electricity    Energy Labelling   
Health & Safety    

Books
"Building Your Own Home" by Tony Booth & Mike Dyson,  a 'Daily Telegraph' publication.  Available at W H Smith, Waterstones, Amazon

Materials in Construction
Materials in construction make up over half of our resource use by weight.  They account for 30% of  all road freight in the UK.  The construction and demolition industries produce over 4 times more waste than the domestic sector, over a tonne per person living in the UK.  The environmental impacts of extracting, procession and transporting these materials and then dealing with their waste are major contributors to greenhouse gas emissions, toxic emissions, habitat destruction and resource depletion.

Some 420 million tonnes of materials are used in construction in the UK each year.  This equates to 7 tonnes per person.  The total consumption of all materials in the UK amounts to some 678 million tonnes or 11.3 tonnes per person.  So construction accounts for over half of our resource use by weight!  By selecting construction materials wisely we can really reduce our environmental impact.

Every activity involved in extraction, processing and delivery of construction materials results in energy consumption, pollution and waste.  The capacity of the earth’s natural systems to absorb these environmental loadings has reached or is approaching it’s limit in many areas,  the most prominent  and topical of these is the increasing production of greenhouse gases and the earth’s capacity to absorb them.  Hence this report looks at the embodied CO2 associated with each construction material.  Waste to landfill in the UK has reached its limit as suitable landfill sites are running out.  Other such critical issues include toxic emissions to water and air, acid deposition and ozone depletion. 

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Timber
The world’s forests currently cover about 30 million square km, about one fifth of the Earth’s land surface  Forest areas have declined by 50% since the advent of agriculture.  There are two critical implications of deforestation.  One is the loss of biodiversity in the world, the loss of habitats and species forever.  According to WWF’s Living Plants Report 2000, the state of the earth’s ecosystems has declined by about 33% over the last 30 years.  The other is a reduction in the earth’s capacity to absorb CO2.

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Materials in Housing
Looking more specifically at the housing industry, the environmental impacts of the materials in a house are less significant than the actual performance of the house over its lifetime.  Domestic household energy consumption accounts for 29% of the UK’s CO2 emissions.  By comparison, the materials used in a house’s construction account for just 2-3%.  
                             

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The BedZED Project
To consider what effect using materials that gave greater economy over the life of a building, the BedZED scheme was been designed primarily for long term energy efficiency during use.  It  then goes further by minimising the embodied impacts of the construction materials used to achieve that design,.

BedZED employs state of the art energy efficiency, with super-insulation, double and triple glazing and high levels of thermal mass.  BedZED meets all its energy demands from renewable, carbon-neutral sources, generated on site, and so eliminates the 29% contribution to CO2 emissions and global warming.  In achieving this energy efficient carbon-neutral design, BedZED invests in more construction materials than standard houses.  However, as their report shows, the embodied environmental impacts of  BedZED’s construction materials are within the same range as standard UK housing.  The total embodied CO2 of BedZED is 675kg/m2 , whilst typical volume house builders build to 600-800kg/m2.  Despite the increased quantities of construction materials, the procurement of local, low impact materials reduced the embodied impact of the scheme by 20-30%. 

The BedZED project has shown that in selecting construction materials, major environmental savings can be made without any additional cost.  In many cases, the environmental option is cheaper than the more conventional material.  For example, highly durable timber framed windows are cheaper than uPVC and saved some 6% of the total environmental impact of the BedZED scheme and 12.5% of the total embodied CO2 .  Recycled aggregate and sand are cheaper than virgin equivalents and are available as off-the-shelf products.  Pre-stressed concrete floor slabs save time and costs on site and by using less materials saved some 7% of the BedZEDS’s environmental impact compared with concrete cast in-situ.   New FSC softwood from certified, sustainably managed woodlands is available at no cost premium, while local FSC green oak weatherboarding is cheaper than brick and shows a life cycle cost saving over imported preserved softwood.  Reclaimed structural steel and timber are available cheaper than new and offer 96% and 83% savings in environmental impact.

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Time for a sound check
The new Approved Building Regulation Document E comes into force on 1 July.2003.  Here we look at the implications of the new regulations.

The new Approved Document E (ADE), ‘Resistance to the Passage of  Sound’, has been launched and is downloadable from the Office of the Deputy Prime Minister’s (ODPM) website at www.safety.odpm.gov.uk/bregs/approved.pdf/approvede.pdf  It is effectively a complete reworking of its predecessor (Part E: 1992 edition) which runs out on 1 July 2003, and at 76 pages is twice the size.

ADE deals with sound transmission generally, identifying flanking transmission and reverberation and naturalising the information on airborne and impact sound which comprised the limited of the previous guidance. The new section on acoustic conditions in schools (albeit only a paragraph, ominously cross-reference to yet another ‘to be published’ DfES Bulletin 93 ‘The Acoustic Design of Schools’).  This adds a non-domestic element to the regulations, pacing the way for the incorporation of other specific public sector acoustic memoranda (hospitals, health centres, laboratories, etc) into future amendments.  ADE: 2003 also applies to flats, hostels and hotel accommodation.

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Sound Standards
The regulations begin with a new Section 0 that prioritises a decibel reduction performance specification over the constructional and density requirements of the previous edition.

In Clause 0.6, it is recognised that improving the sound insulation of historic buildings may result in detrimental visual intrusion, in which cast, ‘it will be reasonable to improve the sound insulation as much as is practical, and to affix a notice showing sound insulation value(s)… in a conspicuous place inside the building.’

ADE:2003 goes into more detail than its predecessor and takes account of construction leakages which had not previously been factored in.  The method of determining the mass of a particular wall type has been expanded to include the effects of wall ties, mortar joints, brick frogs and voids, although fewer graphic examples are given,  All examples replicate the requirements in the 1992 edition, although there appears to be a change in the density of large concrete panels, previously listed at 1,500kg/m2, documented in the new edition as a composite figure.  A great deal of extra information has been added to usefully detail junctions and closers.  Also, there is  regular ‘dos’ and don’ts’ box containing handy titbits such as ‘Do stagger the position of sockets on opposite sides of a separating wall’; and, ‘Do not build cavity walls off continuous solid concrete slab floor’

Pre-completion testing is a new requirement (see box).  To carry out pre-completion testing, residential buildings  should be broken down into sub-groups, to enable a thorough evaluation of sound transfer between properties.  Tests will normally include four airborne tests and two impact tests at different locations in the sub-group, and ADE:2003 sets out suggested locations.

In Section 7, detailing the permissible reverberation in common internal rooms, once again, what might at first appear to be a straight forward section has been complicated by overworked examples. As a rule of thumb, soffits (of stairs and corridors) should be covered with absorptive material Class C.  However, where large areas are involved (and hence small areas of material saved result in large savings), and alternative method of calculation incorporates relaxations to take into account the absorptive coefficients of floor and wall finishes and fixtures and fittings.

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Robust details
At the briefing launch before Christmas, the ODPM officers charged with overseeing the issue of sound insulation sheepishly confirmed that the Robust Standard Details (RSDs) will not be harmonised with Approved Document Part L’s RSDs..

‘It’s a dilemma,’ the spokesman said , ‘In general, the needs of heat conservation necessitate low mass construction, whereas sound insulation needs high mass construction.’ Reading the two documents together could show up any number of discrepancies, although, as with ADL;s RSDs, the details are not intended to show good construction practice, but simply the specific detail compliance with the relevant sound reduction elements.

However, even within the new document there are confusing details.  Diagram 4.2 (Clause 4.24) is a curiously scaled comparison between in situ and purpose-built drylining on masonry.  Improvements need to be made to many of the diagrams, not least the unintelligible diagrams 0-1 to 0-3 in the opening section, to make the document more readable, and discrepancies between this and the current regulations should be highlighted.  For example, the independent ceiling detail – shown as Floor Treatment 1 (Diagram 4.3) – now insists on 125mm between the top of the ceiling layer and the bottom of the separate soffit  above, instead of the current gap of 100mm.  This tendency not to highlight changes is annoying and will inevitable lead to needless errors in the future by architects not remembering, or realising, that they need to check.

DWELLINGHOUSES AND FLATS – PERFORMANCE STANDARDS FOR SEPARATING WALLS, SEPARATING FLOORS AND STAIRS THAT HAVE A SEPARATING FUNCTION

ROOMS FOR RESIDENTIAL PURPOSES – PERFORAMCE STANDARDS FOR SEPARATING WALLS, SEPARATING FLOORS AND STAIRS THAT HAVE A SEPARATING FUNCTION 

	Airborne sound insulation Sound insulation DnT1W + CtrdB (minimum values)	Impact Sound insulation L’nT1wdb (maximum values)
Purpose-built rooms for residential purposes
Walls Floors and stairs	43 45	- 62
Rooms for residential purposes formed by material change of use
Walls Floors and stairs	43 43	- 64

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Noise from above
About 10 years ago, I was a site architect for a conversion of an old warehouse in the North East into luxury flats, writes David Pickering.  Everything went well; the contractor was diligent, we had a dour permanent clerk of works, a hands-on-client’s agent, and regular visits from the financial guarantor/certification body.

Before completing a couple of the flats, all five of us, together with several tradesmen, walked around to identify possible areas of sound transmission between floors, walls, ducts, etc and to agree on the necessary practical detailing and workmanship standards on site to comply with regulatory guidance.

On practical completion, all of the flats were let.  Five months later, we  were called out by a resident to investigate her complaints that she could hear people upstairs.  We stood in silence as a 20 stone  brickie was dispatched to march about upstairs in hob-nailed boots.  When he reappeared, we all assumed that he gone to the wrong flat because we had heard nothing.  It was when the complainant then said that she could hear voices in her bedroom, while we all stood in her living room, that we realised that she was potty.  But after making a fuss, within 10 days, everyone in the block was complaining of noise problems,

After loads of inspections, nobody knew what the problem was, or the solution, or who’s liability it was, In fact, no one could really work out if there was a problem at all.  In the end, we resolved to visit each resident saying that, in order to detect the real cause of the problem, all flats would have to be stripped back to the original building shell and re-done.  Given that every resident had just finished decorating, we heard no more about it. 

Maybe this is what it means in ADE: 2003, Clause 1.35 where it stated that ‘once a dwelling-house, flat or room for residential purposes is occupied, any action affecting it should be a matter for local negotiation’.

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Testing time
The BRE Information Paper IP14/02 ‘Dealing with poor sound insulation between new dwellings’ published in November 2002, one month before Approved Document E:2003 (ADE:2003) was published, sets out procedures to rectify faults giving rise to inadequate sound insulation resulting from poor construction or workmanship.

Given that ADE:2003 includes a requirement for pre-completion testing, and that pin-pointing the exact location of sound leakage is notoriously difficult, this BRE guidance document is a handy though simplistic guide and is referred to in ADE:2003, Clause 1.37.  The only discrepancy seems to be that IP14.02 quotes a sound insulation margin of failure in tests as ‘up to 5db’ whereas ADE:2003 suggests ‘no more than 6db’.

In approved Document L(ADL), clients can check over the contractor’s completed work with a thermographic survey or smoke text.  While the ODPM says that the need for ADE:2003 pre-completion testing may be phased out in favour of reliance on RSDs, the contractor and/or architect may decide to take on the liability and cost of ensuring that all has reasonably been done to deal with sound transfer – one of the more subjective construction complaints.  However, it will always be a case of discover after the event and remedial treatment will be difficult and expensive.

The other difficulty is that although ADE:2003 refers to pre-completion testing, this is meant in a contractual rather than construction sense, since elements or units cannot be acoustically tested prior to the building being completed.  On the other hand, in contractual terms, the completion certificate can be withheld if non-compliance is shown.  Testing must be done by a UKAS accredited body.

Pre-completion testing, which comes into force in January 2004 for new houses and flats, can be avoided if the building is constructed in accordance with Robust Standard Details (RSDs). These are being drawn up by the House Builders Federation and the date of enforcement is six months later than the implementation of ADE:2003 to give them time to be completed, tested and checked.  However, since pre-completion testing (and BRE IP14/02) deals with discrepancies of workmanship, compliance with RSDs will not necessarily translate into the way things are built on site precisely because of poor workman ship. It is all a bit of a catch-22.

The BRE’s IP14/02 suggests some likely causes of failure – and in typical wise-after-the-event troubleshooting, suggests remedial action – some more constructive than others.  One example reads: ‘Problem:Lower than expected airborne sound insulation (Through separating walls).

Probable cause: Excessive sound transmission through separating walls

Solution: Rectify construction error

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How to Achieve a Satisfactory Final Warranty Inspection

Background
The Council of Mortgage Lenders (CML) Lenders’ Handbook is to be amended to the effect that conveyancers should not submit the Certificate of Title (requesting the release of mortgage funds from the lender) until they have received confirmation that a new home warranty will be in place on or before legal completion.  Effectively, this means that the sale will not take place and hence homes will not become occupied (where there is a mortgage involved) until the warranty organisation has provided  the required confirmation – namely, that they have undertaken a pre-handover inspection and carried out a Satisfactory Final Warranty inspection on the property in question.  Amendments to the CML handbook are to come into force for sale contracts exchanged on or after the 1st April 2003.

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Objective
The objective of this paper is to provide practical industry-wide guidance as to how warranty organisations will determine what issues would prevent confirmation that a satisfactory Final Warranty Inspection has been carried out.  This approach has been agreed by HBF, NHBC, Zurich and Premier Guarantee.

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The Logic Test Basic Concept
Building Surveyors, Engineers and Building Inspectors are engaged by warranty organisations to manage insurance risk and to assist the industry to build in accordance with recognised standards.  This may include a combination of desktop appraisal of design proposals, combined with on site inspection of work in progress and work completed.  If information required to ensure compliance with standards is not forthcoming, or if any non-compliance with standards on site must be classified as either CRITICAL (prevents warranty) or NON-CRITICAL (will not prevent warranty) by applying the following sequential logic test:

 THE LOGIC TEST

 Will the issue result in

 *     A risk to health and safety?

*     A claim against the warranty?

*     Significant disruption to the occupier?

If the answer to any of the above questions is YES then the item will be classified as CRITICAL and confirmation that a Satisfactory Final Inspection has been carried out will be withheld until the relevant issue is resolved.

If the answer to the three standard questions is NO then the item will be classified as NON-CRITICAL and confirmation of this would be provided to the housebuilder.  It will remain the builder’s responsibility to address any outstanding NON-CRITIAL issues.  However it should be noted that, in come circumstances, a number of individual NON-CRITICAL issues affecting a property, taken together, would be regarded as a CRITICAL failure, for reasons of causing significant disruption to the occupier.  In such circumstances, confirmation that a Satisfactory Final Inspection has been carried out will be withheld until the outstanding matters are resolved.

It is important to understand that in this context the pre-handover inspection performed by the warranty organisation is concerned with the checking of warranty items.  It is not a snagging inspection and is not part of a building regulation service.

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Examples of the Logic Test in Operation
Critical Items – Risks to Health and Safety

Example 1

Inadequate means of escape window from 1^st floor bedroom.

A risk to health and safety.  This fails the logic test and hence would be classified as CRITICAL.

Example 2

Self-closing device missing from fire door

A risk to health and safety – therefore fails the logic test.  This would be classified as CRITICAL.

Example 3

Flat development- internal layout – proposals indicate excessive travel distances to corridors and no proposals for smoke ventilation have yet been provided.

Fundamental health and safety issues that are also likely to affect spatial planning therefore fails the logic test and hence would be classified as CRITICAL until such information is received and approved.

Example 4

Earth bonding not secured  to rising main.

A risk to health and safety and therefore fails the logic test and hence would  be classified as CRITICAL.

 Example 5

Inadequate provision for access for disabled persons (level site, no ramp)

Rectification would involve considerable disruption to the homeowner and therefore fails the logic test and hence would be classified as CRITICAL.

Example 6

Small area of roof insulation missing.

Passes the logic test therefore classified as NON-CRITICAL.  Note that a large expanse of mission insulation might be classified as CRITICAL, for reasons of potential disruption to the building occupier

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PLANNING
Circular 6/98: Provision of Affordable Housing

As with C1/97 the starting point for discussions regarding any change to this Government guidance is to enforce and clarify the existing guidance.  The debate on the provision of affordable housing through the planning system will be a major issue between HBF and the ODPM over the coming year.

Land for Housing
The creation of sustainable communities is high on the Government’s agenda.  HBF will pursue, in agreement with others, the continued identification and release of land for housing on both brownfield and greenfield sites

Regional Housing Forums
HBF will strengthen links with regional housing forums in all Government Office regions.

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Barriers to Brownfield
We support the HBF in continuing to press both Government and the Environment Agency for the relaxation/dispensation of inappropriate waste management procedures and will continue to support research projects seeking solutions to technical problems on brownfield sites.

Highway Issues
We support the HBF in continuing to work with the ODPM and other stakeholders to remove areas of conflict between highways legislation and PPG3.  HBF is also collecting evidence to challenge inappropriate commuted sums payments being sought by Local Highways Authorities.

Sustainable Drainage
The HBF is pressing for the removal of barriers to the use of sustainable drainage systems, building on HBF representations made during the Part H, Sewers for Adoption and PPG25  consultations.

Building Regulations Part C
We support the HBF in its continuing efforts to assist the ODPM in the pre-consultation phase for Part C (Contamination and Resistance To Moisture) and will prepare an industry response when it moves into the public consultation phase.

Water and Electricity Industry Issues
The HBF has established a Standing Committee with water industry representatives to monitor the implementation of Sewers for Adoption Edition 5.  HBF is also working with OFWAT and OFGEM on means of removing barriers to competition in the supply of electricity and water services.

Energy Labelling
We support the HBF in continuing to promote its energy-labelling scheme for new homes as an alternative tot the mandatory SAP notice.

Health and Safety
Following the agreement of revitalising targets for housebuilding, the HBF’s H&S Group is seeking to establish common procedures within the industry and will continue to work on benchmarking and the recording of health and safety performance.  HBF will continue to press HSE for recognition of housebuilders’ needs as separate to those of other construction sectors.

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Books   Materials in Construction   Timber   Materials in Housing   The BedZED Project      
Sound Check   Sound Standards   Robust Details   Noise from Above   Testing Time  
 Logic Test   Affordable Housing   Land for Housing   Barriers to Brownfield  Highway Issues
Sustainable Drainage   Building Regs Part C   Water & Electricity    Energy Labelling   
Health & Safety    

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Wherever you are ... Whatever you need ....

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New Books
"Building Your Own Home" by Tony Booth & Mike Dyson,  a 'Daily Telegraph' publication. 
Available at W H Smith, Waterstones, Amazon