Retrofitting Buildings for
Energy Efficiency
Day 1 –
First steps in retrofitting
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Building Standards and Regulation
Building Regulations
There are exemptions from the energy efficiency requirements that may apply to building
work to existing dwellings or extensions to existing dwellings:
Buildings which are:
Listed or in a conservation area
A schedule of monuments
For these buildings the exemption applies only to the extent that compliance with the
energy efficiency requirements would unacceptably alter the character or appearance of
such existing dwellings.
Historic and traditional buildings where special considerations may apply
Buildings which are of architectural and historical interest and which are referred to as a
material consideration in a local authority’s development plan or framework;
Buildings which are of architectural and historical interest within national parks, areas of
outstanding natural beauty, registered historic parks and gardens, registered battlefields,
the curtilages of scheduled ancient monuments, and world heritage sites;
buildings of traditional construction with permeable fabric that both absorbs and readily
allows the evaporation of moisture.( Authors italics. This provision allows appropriate levels
of insulation to be applied rather than the prescriptive standard)
3.10 The guidance given by English Heritage3 should be taken into account in determining
appropriate energy performance standards for building work in historic buildings……………
The English Heritage report Energy Efficiency and Historic Buildings describes buildings of
traditional construction as having “permeable fabric that both absorbs and readily allows
the evaporation of moisture.”
It goes on to say….
Most traditional buildings were designed and built before the development of reliable and
cost-effective impermeable membranes or moisture barriers. They rely instead on their
ability to allow moisture to evaporate rapidly away, and thus prevent the damaging build-up
of damp and resulting physical decay. While the majority of historic buildings are
‘traditional’ in terms of their construction, there are many thousands of traditional buildings
that are not legally protected.
This category includes nearly all buildings constructed prior to 1919, as well as a significant
proportion of those built before 1945. It is essential that adaptations made to improve the
energy efficiency of these structures should take into account the traditional technology and
characteristic behaviour of the building fabric, otherwise very real damage can be caused.
Well-meaning attempts to keep moisture out of these buildings using modern methods tend
to have the unfortunate effect of preventing the vital evaporation, and thus causing or
accelerating moisture-related decay to the fabric.
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3.12 Particular issues relating to work in historic buildings that warrant sympathetic
treatment and where advice from others could therefore be beneficial include:
making provisions enabling the fabric of historic buildings to ‘breathe’ to control moisture
and potential long-term decay problems.
Renovation of Thermal Elements
5.8 Where a thermal element is subject to a renovation through undertaking an activity
listed in paragraph 5.7a or 5.7b, the performance of the whole element should be improved
to achieve or better the relevant U-value set out in column (b) of Table 3, provided the area
to be renovated is greater than 50 per cent of the surface of the individual element or 25
per cent of the total building envelope. When assessing this area proportion, the area of the
element should be taken as that of the individual element, not all the elements of that type
in the building. The area of the element should also be interpreted in the context of
whether the element is being renovated from inside or outside, e.g. if removing all the
plaster finish from the inside of a solid brick wall, the area of the element is the area of
external wall in the room. If removing external render, it is the area of the elevation in
which that wall sits.
Retained Thermal Elements
5.11 Part L of Schedule 1 to the Building Regulations applies to retained thermal elements in
the following circumstances:
• where an existing thermal element is part of a building subject to a material change
of use;
• where an existing element is to become part of the thermal envelope where
previously it was not, e.g. as part of a loft or garage conversion where the space is
now to be heated.
5.12 Reasonable provision would be to upgrade those thermal elements whose U-value is
worse than the threshold value in column (a) of Table 3 to achieve the U-values given in
column (b) of Table 3 provided this is technically, functionally and economically feasible. A
reasonable test of economic feasibility is to achieve a simple payback of 15 years or less.
Where the standard given in column (b) is not technically, functionally or economically
feasible, then the thermal element should be upgraded to the best standard that is
technically and functionally feasible and delivers a simple payback period of 15 years or
less. Generally, this lesser standard should not be worse than 0.7 W/m2.K.
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3.1 Ways Of Complying With Part L
The following actions are included in Approved Documents L1B and L2B as ways of
demonstrating compliance with Part L.
Confirm Compliance Of Thermal Bridges And Minimise Air Leakage
This only applies where new thermal elements are provided. However, it is good practice
that all upgraded insulating elements are checked to avoid cold bridges causing
condensation, and all controlled fittings are checked to ensure they meet calculated
standards of airtightness.
Justify Reduced Standards Using Set Period Payback Criteria
This applies to upgraded or renovated existing thermal elements as part of a change of use,
or a renovation, or when an existing internal element becomes part of the thermal
envelope. Work which will only give an economic payback in excess of a set number of years
need not be carried out. This is subject to other conditions, and to a particular calculation
method.
Specify Efficient Boilers, Pipe-Work & Controls; Specify Energy-Efficient Lighting
These provisions apply when new or upgraded services are being installed. Provisions for
non-domestic buildings are more extensive and complicated than for dwellings.
Undertake Duct Leakage And Fan Performance Testing
This applies to non-domestic services installations where appropriate.
Provide For Energy Metering
This only applies to new plant installations in non-domestic buildings, but includes
differential monitoring between systems (dwellings are excluded as they are normally
adequately metered).
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Provide an Instruction Manual For Heating, Cooling, Ventilation And Lighting
To enable building users to realise the optimum levels of energy efficiency to which their
buildings are designed.
Propose Consequential Improvements Where Required
This applies to all buildings. Consequential improvements may include improving the
insulation of thermal elements, upgrading old services systems, or adding on-site zerocarbon energy-generating equipment. This requirement
is, however, limited to those
improvements that can demonstrate economic payback within a set number of years, and,
in the case of extensions, to no more than a set percentage of the value of the principal
works.
Ensure U-Values and Areas Of Openings Comply
U-values of thermal elements and controlled fittings should meet the minimum required in
the Approved Documents for any particular circumstance. For dwellings this is a basic but
inflexible method of achieving compliance, but may be modified subject to certain criteria.
Show Compliance Using Area-Weighted U-Value Calculation
An area-weighted U-value allows the value for
all elements of a particular type to be
averaged, thus enhancing flexibility over basic U-value calculations.
Show Compliance Using An Approved Computer Modelling Process
This is potentially the most sophisticated and flexible way of achieving compliance.
Dwellings should demonstrate compliance using the Standard Assessment Procedure (SAP).
Other buildings should use the Simplified Building Energy Model (SBEM) or other approved
software that conforms to the National Calculation Method (NCM). Note, however, that
these methods do not at present make proper allowance for the specific requirements of
historic buildings or traditional ‘breathing’ construction.
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Flooding Resilience
Society for the Protection of Ancient Buildings (SPAB) Guidance - Technical Q&A 31 :
Floods and Old Buildings (www.spab.org.uk/advice/technical-qas/technical-qa-31-floodsand-old-buildings/)
For free technical advice and information on every aspect of repairing and caring for old
buildings including appropriate materials, contractors & professionals phone 020 74560916
Mon to Fri 9.30 to 12.30
Historic England Guidance - Flooding and Historic Buildings
(https://content.historicengland.org.uk/images-books/publications/flooding-and-historicbuildings-2ednrev/heag017-flooding-and-historic-buildings.pdf/ )
RICS Guidance - A clear, impartial guide to Flooding
(www.winfields.uk.com/pdf/RICS%20Guide%20To%20Flooding.pdf
www.winfields.uk.com/pdf/RICS%20Guide%20To%20Flooding.pdf)
CIRIA Guidance - www.ciria.com/flooding/ OR
www.ciria.com/flooding/repairs_introduction.htm
National Flood Forum - Supporting & Representing Flood Risk Communities
Old Snuff Mill Warehouse, Park Lane, Bewdley DY12 2EL Tel: 01299 403101 Fax: 07734
899708 Email:amanda.davies@floodforum.org.uk Web:www.nationalfloodforum.org.uk
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SPAB Q & A
Q. What precautions might I take against flooding?
• Where no permanent barriers exist, temporary measures can be taken to delay
floodwater from entering a building. These include fitting removable door and
window boards, snap-on vent covers, using sandbags, and applying sealant to gaps
and holes. Maintaining the condition of external render and pointing is also wise.
• Steps can be taken to combat the effects of floodwater once it enters a building,
such as providing improved access and drainage to underfloor spaces, fitting antiflood devices to foul drains and repositioning electrical installations higher up.
• It is generally advisable to avoid tanking, water-repellent solutions, modern gypsum
plaster and fitted carpets. Sensible flood precautions may sometimes help you
obtain insurance cover in high risk areas.
Q. How is a flood-damaged building best cleaned?
• Act swiftly, rather than hastily, and never remove wet plaster, joinery or other
building components indiscriminately.
• Firstly, make sure the building is safe (ie services turned off pending inspection and
no obvious structural damage), and fully photograph and record damage for later
insurance claims. Then, after letting the floodwater recede by itself, remove any
remaining standing water and drain voids (underfloor spaces, electrical ducts etc).
• Mud, silt and debris should be shovelled up and appropriately disposed of, and air
bricks cleared. Surfaces should be completely rinsed down with detergents and,
where required, disinfected.
• Wear suitable protective clothing and beware of hazardous materials that need to be
dealt with by the authorities. Enzyme bioremediation can be effective for removing
oil contamination non-invasively.
Q. How should an old building be dried out after flooding?
• To prevent serious damage, dry the building slowly, first by natural ventilation, and
then, where required, with extract fans, background heating and/or, unless wall
paintings exist, dehumidifiers.
• Keep opened doors and windows secure against intruders, perhaps using temporary
perforated boarding or metal grilles. Selected floorboards might need lifting carefully
to prevent buckling, and wall paneling and door and window linings dismantled to
hasten the drying of awkward spaces if specialist non-invasive techniques are not
employed.
• Protect soft external brick or stone from frost with water-resistant insulation and
ventilated shelter.
• Drying may take several months and should be continued until: moisture levels are
at or lower than before flooding (ascertained by assessing unaffected adjacent areas
or properties); remaining moisture will not support active timber decay; and building
materials can finish returning to equilibrium by themselves without further damage.
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Q. What repairs may flooding necessitate for my old building?
• Structural work is rarely required, a notable exception being with heavily-saturated
earth-based construction.
• Lime plaster tends to dry out on walls intact, whereas daub, gypsum plaster and
plasterboard are more vulnerable to water damage.
• Floorboards and joinery items that are dried gently also usually survive flooding well,
unlike fibreboard, some insulation and certain other non-original materials.
• Electrical installations frequently need renewing but if retained should be inspected
regularly in the aftermath of flooding.
• Also check the building periodically for signs of structural movement and timber
decay.
• Salt deposits (‘efflorescence’) may appear during drying and can be brushed or
vacuumed off, although heavily salt-laden joints in stone or brick floors might need
re-pointing in lime.
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Evaluation
Your Name:
Event:
Retrofitting Buildings for Energy Efficiency – Day 1
Date:
11 Feb 2016
1. Why did you attend today?
 Business interest  Personal interest  Community interest
2. Have you attended any CAfS events before?  No
 Yes
3. Overall, how helpful did you find this event (Please circle 1-5)
Not Helpful << 1
2
3
4
5 >> Very Helpful
4. By how much has today's event increased your knowledge and understanding of the
topics discussed?
 Don’t know
 None
 A little
 A useful amount
 Greatly
5. Has the event made you closer to taking action in the energy efficiency field?
No
6. Did you find the event:
 Yes
 Inspirational  Informative  Neither
7. What further learning or information would you like on this subject matter?
8. Please let us know any other comments you have about the training.
9. Please let us know any other comments you have about the day - Venue, lunch
and refreshments catering, event organisation, booking or anything else.
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Thank you for taking the time to complete this evaluation.
The information you provide will be used for the purposes of monitoring effectiveness of our training
programme and used in relation to funders of this subsidised event.
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