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Retrofit RetrofitGreenDeal RisksGreenDeal Risks

R ti l Rh t i R t t iRational, Rhetoric, Restructuring, Risks & Risk Management,

Rev 10

This & contained presentations

• Scribd: www.scribd.com/brianspecman• > collection > • SusCon Retrofittingg• http://www.scribd.com/collections/2401889/SusCon-Retrofitting

• Refurbishment• http://www.scribd.com/collections/2426007/Refurbishment-See-

also-SusCon-Retrofitting

• SMARTLife Hive• SMARTLife Hive• http://www.scribd.com/collections/3311795/SMARTLife-Hive-Low-

Carbon-Centre

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R t fitRetrofit:GreenDealGreenDeal

RisksRisks 6

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Risks

• Inadequate survey– Using limited knowledge & guesswork– Bats & Birds not expected

• Lack of understanding of physics– Poor design & choice of materials

• Interstitial or surface condensation– Mould: asthma– Toxic mould

• Death by Insulation

• Destruction of Historic Fabric

Risks: Inadequate survey

• Inadequate surveyor– Using limited knowledge & guesswork– Energy Performance Certificate (EPC)– EPC have shown how bad this can get

• Limited access to tools– Limited extent of surveys

• Bats & Birds not expectedp– Tell tale signs missed– Difficult to detect unless a BAT expertp

22/02/2012 8

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Risks

• Assumption: – About existing construction– About existing insulation measures

• Inaccurate:– Guesswork on thicknesses – based on normal construction

• Estimation– About benefits of improvements

• Inappropriate proposalsInappropriate proposals22/02/2012 © NGS GreenSpec 2010 BrianMurphy 10

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Current Research

• Cambridge University & SIG• Attempt to be more accurate with

surveys/visual inspectionsy p• Develop the tools to do surveys

– Non-destructiveNon destructive– IR T, X-Ray, Acoustic/Echo, etc.?

• One piece of kit to do all• One piece of kit to do all– accurate analysis

22/02/2012 © NGS GreenSpec 2010 BrianMurphy 11

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Risks: Bats

• Protected species– Avoid £5000/bat fines

• Avoid changing roof or wall conditions– temperature/humidity/air flow/light level

• Avoid excluding batsg• Avoid trapping /entombing bats• Avoid replacing bituminous felt• Avoid replacing bituminous felt

– BRM Breathing Roofing Membranes• Avoid replacing sheathing boards• Avoid replacing sheathing boards

– BRM Breathing Roofing Membranes 12

Bat DetectionBat Detection techniques include:techniques include:

• Sign surveys:– Faeces and urine particularly at roost entrances.

B t f l k lik d i b t i d d– Bat faeces looks like mouse droppings but is dry and powdery, containing insect exoskeletons

• Food remains; – with some species the wings of butterflies moths and other– with some species the wings of butterflies, moths and other

food may be found• Visual location:

– bats may be seen at dusk and dawn entering and exiting y g groosts, but many bats are timid and may not be seen

• Audible location:– some bats emit audible social calls

• Building occupants;• Building occupants; – often building occupants are aware of bats and may provide

useful data• Ultrasonic location:Ultrasonic location:

– detectors are available which make the inaudible ultrasound emitted by bats as echolocation audible to humans22/02/2012 13

Lack of understanding ofLack of understanding of physicsphysics

• k, R, E & U valuesCondensation checks• Condensation checks

• Decrement delay• Hygroscopicity over time• Hygroscopicity over time• Hydrophobicity over time• Capillary attraction• Capillary attraction• Moisture transport• Thermal movement over time• Thermal movement over time• Hydro-thermal moisture movement• Thermal massThermal mass• Cavity, Gap or Contact 14

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Poor design

• Not using a designer or software• Not understanding the existing

– Guesswork• Not understanding the physics• Not understanding the materialsNot understanding the materials

– Limited pallet not able to make right choice• Not applying the knowledge• Not applying the knowledge

– Compromise

22/02/2012 © NGS GreenSpec 2010 BrianMurphy 17

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Analysis

• U value• Condensation check (static) BS 5250 • Heat and humidity transports (dynamic) y p ( y )

to BS EN 15026• WUFI:• WUFI:• Computer assisted simulation

programme for heat and humidityprogramme for heat and humidity transports (dynamic) to BS EN 15026

• www.wufi.de

Interstitial or surfaceInterstitial or surface condensationcondensation

• Inadequate performance:– Conventional materials

• performance diminished when moist

M ld th• Mould: asthma• Toxic mould: ‘Death by Insulation’• Condensation, spores, wet or dry rot• Vulnerable structure: early failure,Vulnerable structure: early failure,

– Rotting timber– Frost damaged masonryFrost damaged masonry

22/02/2012 27

Changing Historic Fabric

• Moisture permeability• Both internally and externally• For summer and winter conditions

22/02/2012 © NGS GreenSpec 2010 BrianMurphy 29

Risks: Historic fabric

• Must permit it to continue to breathMoisture flow from ground to wall surfaces• Moisture flow from ground to wall surfaces

• Moisture flows from inside to out and visa versaversa

• Heat flows from inside to out and dries the fabricfabric

• Adding insulation cools the outer face and make it vulnerable to frost damagemake it vulnerable to frost damage

• Avoid risk to historic fabric– Add insulation to avoid internal condensationAdd insulation to avoid internal condensation

risk and no more– Avoid mould growth inside

22/02/2012 30

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R t fitRetrofit:GreenDealGreenDeal

Risks MethodsRisks Methods 33

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Mechanisms

• Rain and other precipitation cools buildings• Sun’s rays heat the building externallySun s rays heat the building externally• Solar gains through windows heat internally• Exposed thermal mass can absorb heat from

solar gainssolar gains• Evaporation draws heat from building

– Condensing can put heat back ing p• Heat flow dries fabric

– Absence of heat: the fabric cools• Moisture and coolth can lead to frost damageMoisture and coolth can lead to frost damage• Spores are ever present• Moisture, spores and coolth can lead to mould

growthgrowth• Mould can lead to ill-health and death

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Approaches

• External insulation: – wraps up thermal masswraps up thermal mass– heat keeps fabric warm – minimises thermal bridges

Insulate cavities:• Insulate cavities:– inadequate insulation

• Internal insulation:Internal insulation: – separates thermal mass from heating– cools the external fabric

stops heat flow from drying external fabric– stops heat flow from drying external fabric– external fabric vulnerable to frost– internal fabric vulnerable to mould

C bi d i l ti E t / C it / I t• Combined insulation: Ext +/- Cavity +/- Int– Risk of interstitial condensation

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Barriers & Risks

• Planner & Conservation officer dictate– Ornate and historic façade and/or interiors– Prevent some buildings being insulated

Prevent details changing so can’t insulate• Cavities invented to ventilate & keep

external moisture in cavity & drain it out– Filling them removes those functionsg

• Solid walls traditionally were moisture permeablepermeable– Insulation can change their permeability22/02/2012 39

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Complications

• Every building type/era is different– Construction, materials, breathability– Ventilation, windows, fireplaces– Services

• Every occupier has different habits:– Heating, cooling and ventilation– Water use, cooking and bathing habits– Care for the building fabric– Money to spend on all of the above– Understanding of their impacts

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How do you choose

• Guesswork v Analysis• GreenDeal Approved Advisors

– Trained but in conventional thinking• or better?

• GD Approved Measures• GD Approved Products

– Limited pallet p– Will they solve all the problems?– CESP & CERT approved measures will notpp

22/02/2012 41

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R t fitRetrofit:Materials &Materials &

MethodsMethods 42

1

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Retrofit M t i l &Materials &

M th dMethodsGreenDeal Risks & Risk Management,g

Rev 10

Another GreenSpec CPD file to downloadAnother GreenSpec CPD file to downloadSee www.scribd.com/brianspecman

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R t fitRetrofit:GreenDealGreenDeal

Risk ManagementRisk Management 44

Delegate’s ProposalDelegate s Proposal and my reactionsand my reactions

• Risk Management:Go ahead with unproven solutions– Go ahead with unproven solutions

• but monitor and inspect • Inspection access compromises integrity

– Go ahead but make it undoable• Like EA’s Sacrificial Construction in flood plains

– Don’t do it to too manyDon t do it to too many• Too many to correct if it goes wrong• People have to live in your experiments

and put up with your error correcting exercises– and put up with your error correcting exercises– Do many different experiments

• to a few buildings at a timeD d t d d i d t t thi t– Do understood, designed, competent things to many buildings at the same time

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© GreenSpec

• Brian Murphy BSc Dip Arch (Hons+Dist)• Architect by Training• Specification Writer by Choice• Greening up my act since 1999• Founder of www.greenspec.co.ukg p• E BrianSpecMan@aol.com• Twitter: http://twitter.com/brianspecmanTwitter: http://twitter.com/brianspecman• Scribd: www.scribd.com/brianspecman• Facebook:

http://www.facebook.com/pages/GreenSpec/77375462337

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