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GBE Overheating (CPD) G#15750

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GBE CPD Overheating CIOB 101119 S1 PNG

GBE Overheating CPD

GBE > Encyclopaedia > Files > CPD > G#15750

GBE Overheating CPD

  • Number of Slides:
    • 2019: 73 of __
    • 2017: 27 of 54
  • FileSize:
    • 2019
      • PDF Handout: 5mb
      • PDF Show: 15mb
      • PPTX: 15mb
    • 2017
      • 12.4 Mb (PPTX)
      • 13.3 Mb (PDF Show)
      • 3.2 MB (PDF Handout)
  • File Name:
  • File Format:
    • PPTX
    • PDF of PPTX
  • Scope: Overheating Issue paper CPD
  • Extract: none
  • Content: Overheating images and explanation
  • Created for: Construction Industry
  • Presented to: NET_Learning Erasmus+ Project 2017; CIOB Herts 2019
  • Author: BrianSpecMan aka Brian Murphy BSc Dip Arch (Hons+Dist)
  • © GBE NGS ASWS 2015 – 2019
  • Created: 12/09/2017
  • Revision: A01 & A02 & A03
  • Updated: 13/11/2019
  • Previously published on Scribd: N/A
  • Scribd reads: N/A
  • CI/SfB: (NN)
  • Uniclass: LNNNN
  • CAWS 2012: NN:NN:NN
  • Tags: GBE, Issue paper, Overheating, Problems Solutions, Images,
  • ProductSets: Methods of Construction, Materials, Properties, Building Elements, Building Performance,
  • UserGroups: Students, Architects, Assistants, Technicians, Structural Engineers, Constructors, Housing Providers

GBE Seminar Text

Build Light, Insulate Right, Solar Tight

  • Or why buildings overheat
  • © 2015-2019

If you are an educator or a student

  • If you want Architectural Education to embrace Climate Emergency
  • Call for Curriculum Change
  • Sign up now: Full name, School, Email
  • Join 2090 signatures 09/11/19
  • Use your mobile and join

This Presentation on GBE:


  • The Climate Emergency
  • Building Regulations
    • –SAP Standard Assessment Procedures
  • The Performance Gap,
    • –Airtightness, Thermal bridges and Psi values
  • Books to circulate.
    • –Passivhaus
    • –The Zero Carbon Hub
    • –The Buildings Hub
    • –Tom Dollard’s book Design to Perform
  • GBE Overheating
    • –Materials samples
    • –The right and wrong materials for overheating.
    • –Case studies
  • GBE Whole building calculators

Global awareness has risen

  • 1, 2, 3 or 4 decades late (never too late)
  • Trashed Film (to invited professionals and MPs 2013)
    • –If you have an audience get the CD to show
  • David Attenborough Blue Planet
    • –Ocean Plastics, straws in particular 2019
  • Greta Thunberg
    • –Started school strike for Climate 2018
    • –Behaviour Change campaign
      • Government, Business & Individuals
      • Unite behind the Science
    • –Embraced Globally 2019
    • –SchoolStrike4Climate
      • Asked the Adults to join them 20/10/2019
      • And we did in large numbers 4 million globally

Change is coming?

  • Architects Declare
    • –Starchitects signed (700+Practices signed)
      • But look at their portfolios
        • –Greenwash?
        • –Still accept holiday resort airport commissions
    • –Rejected me as a solution provider (not RIBA)
  • Construction Declare
  • Architecture Education Declare
    • –Accepted me (2090 signed by 09/11/19)
  • Architects CAN Carbon Action Network
    • –Architects Can’t, don’t have the know-how
    • –Education failed them

We do have the know-how

  • TGR The Green Register
    • –Membership and training group since 2000
    • –facilitating CPD by many specialists to many generalists
    • –PHT, TRA, BBA, AECB: CL CLR, ASBP, etc.
    • –To fill the knowledge gap

We told you so

  • 11,000 scientists
  • 153 countries
  • Declare
    • ‘we’re facing untold climate suffering’
  • Urgent action required
    • –Nov 2019
    • –40 years of disclosure ignored
    • –debate and inadequate Governance
    • –Problems
    • –Solutions

RIBA Plan of Work

  • Circular diagram
    • –Circular information-only flow
  • 0-7 = — Linear Building
  • 8 = Repurposing and Reuse of existing
  • 9 = Deconstruct, reclaim, reuse, reassembly
  • 0-9 = Circular Building

RIBA Education Committee

  • Out of touch with Climate Emergency
    • –Universities not leading the way
    • –Few unite behind the science
    • –Very few being taught science of building
    • –Considering dropping Part 3 Professional Practice
  • University Aspiration: Architectural Association
    • –Philosophical BS
    • –Fantasy Graphics
  • Never engage with reality
    • –let alone solve the problems
  • RIBA Sustainable Futures
  • –Campaign coming to challenge
  • –ARB & RIBA Education Committee
  • -On Health and Safety Grounds
  • -Not environmental Grounds

The Climate Emergency

  • Carbon Dioxide CO2 (since industrial revolution)
    • –Man-made
    • –Large scale, difficult, tinkered with, mostly Ignored
    • –Gov. Money invested in RE E&H (2015 withdrawn)
  • Ozone (1980s)
    • –Man-made
    • –Easy and 1st phase Semi-sorted
    • –2nd Phase still to follow
  • Methane CH4 (growing and became big problem 2019)
    • –21 x the global warming potential of CO2
    • –Decomposing Nature
      • Thawing of permafrost land, ice and ocean floor sediment
      • Ignite bubbling oceans, ponds, ice, tap water
    • –Unstoppable if global warming continues

Design & Detail Guidance

  • Building Regulations (legal minimum)
    • –SAP Standard Assessment Procedure
  • Principles of Element Design
    • –Performance (ignore thicknesses in diagrams)
  • Construction Guidance
    • –IBO Passivhaus/Eco
    • –NewBuild and Refurb books
  • Zero Carbon Hub/The Buildings Hub
    • –Briefing Design & Detailing Failures/Guidance
  • Tom Dollard Book: Design to Perform an illustrated guide to delivering Energy Efficient homes
  • Retrofit Guidance
    • –PAS 2030 Installation PAS 2035 Design
  • Energy Standards
    • –GBE Whole Building Calculators

Standard Assessment Procedures (SAP)

  • Building Regulations never set good targets
    • –Hopeless for meeting Carbon targets
    • –Focus on U values, not overheating and weak on airtightness
    • –Spec Housing Developers: Working to older versions
    • –Performance Gap falling way behind
  • SAP Never was good enough
    • –Just Building Regulations Compliance assessment
    • –AECB carried out a line by line comparison with PHPP
      • UKGBC published it on PinPoint
    • –Never understood low energy buildings well enough
    • –Retrofit for the Future: showed it was bad at Refurb too
  • Not a modeling tool
    • –Easy to assume your way into believing your building will be okay
  • Thermal bridging: easy to fudge your way through with false details and psi values, BCO unable to check
  • Overheating assessment: Easy to fudge

Passivhaus & PHPP

  • Based on Indoor comfort conditions
  • Correct U values to reduce heat loss
  • Glazing U values to feel no coolth
  • Eliminate thermal bridges, reduce risk of interstitial condensation, mould, structural failure
  • Mechanical Ventilation with heat recovery to not kill anybody by chemical off-gassing or carbon dioxide
  • Passivhaus PHPP software does a better job of overheating analysis
  • But:
  • MVHR installed in overheating attic will overheat house
  • MVHR with blocked filters will run inefficient and noisily and get turned off

Zero Carbon Hub ZCH

  • Funded by Government for 10 years
  • Find out how well we are doing
  • Set Targets
  • Discovered buildings do not perform to Building Regulations standards

The major weaknesses are:

  • Airtightness
    • –Designers do not design and specify it
    • –Red line it and and make it a site issue
    • –Builders can’t make building airtight
    • –Without spending money and time on materials they do not understand
    • –Won’t employ specialists
    • –Brown envelopes were known to be dished out
  • Thermal bridges & Psi values
    • –Complicated and time consuming process to work out accurate Psi values
    • –SAP calculations accept wildly inaccurate Psi values
    • –BCO do not understand them well enough to check them
    • –BCO need to have a specific education to do their job now
  • Overheating
    • –Found 20% of homes overheat,
    • –New homes worse %

The Performance Gap

  • ZCH coined ‘Performance Gap’ between designed and actual performance
  • Challenged Spec Housing to up its game
  • Developed many report and guides: ignored by designers
  • Developed Builders publications on good and bad details
    • –Finally something that designers could learn from
    • –Like hot cakes at EcoBuild exchanged for business cards

Zero Carbon Hub Publications

  • –Free to download PDFs
    • ZCH Builders’ Book
    • ZCH Thermal Bridge Guide
    • ZCH Services Guide
    • ZCH SAP untangled
    • ZCH Ventilation Guide

Zero Carbon Hub Success

  • They did understand overheating:
    • –Summer
      • Happens in top floors
      • On south-west elevations solar gain through glazing
      • Inadequate ventilation
      • Glazed stairs feeding solar heat into corridors to flats
    • –Winter:
      • Due to district heating pipe in corridors and insulation issues
      • Code of Practice conflicting flow and return temperatures
      • Domestic interface plumbing valves uninsulated
      • Inadequate consumer controls

Zero Carbon Hub failing

  • Despite everything they never got the bottom of one major issue:
    • –Solar radiation enters through opaque building fabric
    • –Not just glazing
    • –Lightweight roofs let in solar radiant heat through the tiles and slates and plasterboard
    • –Conventional insulation does not stop it
    • –Conventional included glass wool, stone wool, polystyrene
    • –Lightweight walls suffer as well

The Buildings Hub TBH

  • Government dropped Zero carbon target
  • ZCH was now redundant
  • The Building Hub set up to follow on
  • Free to download PDFs
  • TBH Designer’s Handbook

Tom Dollard Book:

  • Design to Perform an illustrated guide to delivering Energy Efficient Homes
    • –RIBA Publishing
    • –ISBN 978-1-8946-996-5
  • Brian Murphy proof read early draft
  • Builds on the work of ZCH
  • The Performance Gap: how to reduce it
  • How to Detail thermally efficient envelopes
  • Addresses services failures too

GBE Whole Building Calculators

  • GBE Green Building Encyclopaedia
  • GBE Calculator
  • Building Size: Lengths Areas Volumes
  • Regulations/Design standards:
    • –U value Set Selection
  • Winter Thermal Insulation Material Choices
    • –K values v U values = Thicknesses
  • But don’t forget Decrement Delay
    • –to avoid summer overheating
  • And acoustics, fire, moisture management, etc.

Many Energy Regulations and Design Standards compared

  • None address Overheating calculations

Decrement Delay

  • GBE Calculator

Energy and related design standards

  • Building Regulations Approved Document L
    • –Will eventually aim to meet carbon targets but not now
    • –Most new buildings will need to be retrofit by 2030-2050
  • Energy (exceeding Building Regulations)
    • –AECB Bronze, Silver, Gold and Platinum Standard
    • –Super E (Canadian; means to sell their softwood)
    • –Passivhaus (German) PHPP Software
      • Indoor Air Quality and Thermal Comfort conditions driven
      • Mimimise air leakage, minimise thermal bridges
      • EnerPHit (Passivhaus Retrofit)
    • –Minergie (Swiss)
    • –Carbon Lite (UK AECB)
      • Passivhaus interpretation for UK climate and energy mix
      • Carbon Lite Retrofit (CLR)

Materials > k values > U values > Thicknesses

GBE Issue Paper: Overheating

  • 2015 lots of internet chatter about overheating
  • Not understanding the whole truth
  • GBE joined in, it became clear a lot of misunderstanding exists
  • Started writing a GBE Issue Paper
  • “Build Light > Insulate Right > Solar Tight”
  • 124 pages later revision 14
  • Emptied my head of know-how
  • 111 pages and revision 11 published on GBE

GBE CPD: Overheating

  • GBE Issue Paper CPD
  • © 2015-2017
  • 124 pages reduced to 34 slides that follow

Battle Of Weather Fronts

  • Ever changing competing weather fronts keep UK average mild, wet and windy
  • Not normally the same weather for prolonged periods
  • But high level jet stream having greater variation and influence

House + Loft Envelope

  • House+Attic
  • 20th century construction
  • Has its fair share of problems: inadequate insulation, airtightness, acoustics, etc.

Overheating Of Buildings

  • Top floors and south facing rooms get sunny and overheat
  • Not just through the glass, but through the opaque fabric too
  • Roofs and walls
  • Air Conditioning is not the answer

General Approach

  • Winter: Small windows to the north, big windows to the south
  • Summer: Small windows to the south or solar shading needed

Back To Back Housing

  • Back to back
  • 19th Century design relic
  • What is it still doing here in the 21st C?
  • Fiduciary Rules?
  • Cheap and profitable
  • Very common in multi-storey flats

Passive Hub Norwich

  • South facing for winter solar gains
  • And summer overheating?
  • Needs summer solar shading and winter solar penetration

Learning from termite mounds

  • Building termite mounds above ground subjects the colony to summer sun
  • Facing N-S means the mound avoids midday sun but also exploits cooling
  • Offices can do that too

Internal Heat Transfer

  • Keep heat in its place of arrival
  • Maintain safe refuge on the cooler side
  • Insulate internal floors and partitions
  • Close doors
  • Promoted by BedZED

Roof Top Extensions

  • Planners insist on top floor additions set-back
  • Structure needs lightweight construction
  • Comes with with wrong insulation
  • Will overheat
  • Needs air-con

New Penthouses

  • Roof Top extensions
  • Usually overheat
  • Try as hard as you like with bits and pieces
  • ‘Comfort Cooling’ sounds cool but its still air-conditioning bad for the planet

Radient v Conductive

  • Radiant verses Conductive heat flows
  • Insulation needs to resist both or overheating occurs

Radiant v Conductive

  • Thermal Insulation:
  • Once radiant heat gets in it warms the space and the warmth cannot get out through conductivity insulation

Radiant v Conductive

  • UK Government funded insulation programmes
  • Refurbishment and retrofit
  • Cavity insulation
  • Attic insulation
  • Cheap materials: glass and stone wool or polystyrene: all conductive insulation
  • Will overheat top floors

Roof Insulation

  • Wrong, right and no insulation
  • Some work some do not
  • Choose carefully
  • Roof Insulation

Building Integrated Renewables

  • Is it really a good idea?
  • I don’t think so
  • Non-BIR ventilate below and perform better
  • BIR radiate below into a hot attic

Solar Panel Layouts

  • Solar panel layout to avoid overshadowing by one panel on another
  • Winter is worse
  • Get your angles right
  • Solar Panel Layouts

Solar tracking: 1

  • Universal joint on pedestal supporting frame and panels
  • Motors and levers adjusts the frame angle
  • Allows panning to track the sun during day
  • Allows adjustment to keep panel orthogonal to the suns rays through the seasons of the year
  • PVs pick up sunlight and daylight
  • Solar Tracking Panels

Solar tracking: 2

  • Hinge on pedestal supporting frame and panels
  • Panel tilted to be orthogonal towards sun at mid-day summer facing south
  • Motors and levers adjusts the panel angle
  • Allows swivelling on hinge to face sun facing east in morning, south mid day and west in evening

Corrugated Fibre Cement or Metal Roof

  • Thin lightweight coverings offer no protection from solar radiation heat gains
  • And rainstorm water noise

Profiled Metal Roofing

  • Profiled Metal roof cladding
  • No insulation or plastic sandwich panel
  • Both ineffective against solar gains

Concrete Flat Roof

  • Concrete and Asphalt Flat Roof
  • No Insulation
  • High Decrement Delay concrete
  • No overheating
  • Well eventually

Timber Flat Asphalt Roof

  • Old timber and asphalt roofs keep you roasting in summer well into the evening as they cool down

Victorians knew a thing or two: water is good solar protection

  • Strengthen your roof to carry the load
  • Raise upstands to hold the water and have enough height for an overflow
  • Flood your roof with water
  • Keep it topped up on evapourative sunny windy days
  • Solar protection
  • Resists uplift
  • Finds leaks if there any

An Assortment Of Cavity Walls

  • Cavity masonry walls
  • 20th century construction
  • Its on its last legs or is it?
  • 1919-2019?

An Assortment Of Cavity Walls

  • Since its forced introduction and demise of the solid brick wall in 1919 the cavity wall has served a purpose.
  • It kept the weather out
  • I stopped the suns radiant heat
  • As regulations started to stop us wasting heat, insulation was introduced into the cavity with varying levels of success
  • But for the 21st century its on its last legs
  • 300 mm of full fill cavity wall insulation is at the upper limit
  • Lintels, Cavity tray DPCs, cavity closers and wall ties are struggling to keep up
  • That won’t stop us using it though

An Assortment Of Cavity Walls

  • Cavity masonry walls
  • 20th century construction
  • Its on its last legs
  • 1919-20??

An Assortment Of Cavity Walls

  • Cavity masonry walls
  • 20th century construction
  • Its on its last legs
  • 1919-20??

Flexible Living Space

  • The sun moves around the building
  • In big buildings you can move away from the heat to cooler parts on extreme days

Overheating Of Glazed Offices

  • 100% Glass facades
  • 20th century construction
  • Fuel poverty (cooling) or Wellbeing might stop it
  • We need 100% solar shading or 100% air conditioning
  • Agile working might help share the burden

Consider the external landscape around a building

  • Hard landscape can be light in colour reflect some heat or dark and absorb it
  • It will then reheat the air in the vicinity and may pre-warm air entering via windows
  • Soft landscape can cool the air with shade and moisture
  • Wet landscape can cool the air by moisture evapouration
  • Reflections off water will be dappled

Trees can cool air passing by and shade buildings directly

  • Trees are an essential part of cooling urban areas
  • The stop sun from reaching hard paving preventing it being heated and pre-heating air
  • Trees also shade windows and roofs to prevent direct overheating
  • Deciduous trees drop their leaves and permit winter sun to reach the building

Moving Solar Gain Heat to Cold Areas

  • Hot floor slabs fitted with under floor heating pipes can move heat to the colder parts and visa versa
  • Suffolk CC in Ipswich

Moving Solar Gain Heat to Cold Areas

  • Heat Transfer from Glazed Entrance stairs, to corridors, to flats
  • Glazed communal stairs and corridors serving apartments student accommodation
  • Everything overheats

Badly insulated buildings squander heat

  • Hospitals require 24 hour heating
  • Windows need to be triple glazed for thermal comfort of patients in jimjams
  • Building should be so well insulated that they do not need heating
  • Radiators on external wall below windows squanders heat 24 hours of day/night

Stair wells and rooflights can provide passive cooling using stack effect

  • With fresh air inlets at ground floor and vents at roof level, stair wells can permit heat build ups to dissipate upwards
  • But in winter they cool the building

Passive ventilation via atrium is obvious with easily overcome problems

  • Opening at floor perimeters and rooflights over atrium is easy enough
  • But some floors will overheat for no apparent reasons
  • Lower floor hot air buoyancy may create a barrier to upper floor air entering atrium
  • Controlled perimeter vents will balance the floors to ensure equal access to atrium

Winter sun traps need to be well ventilated in summer

  • Sun spaces at BedZED are on the south side to get maximum exposure in winter
  • Internal glazing is shut to keep heat in sunspace
  • When there is enough heat then open doors to let heat in to warm the rooms
  • Top floor does not have enough shading and can overheat

Exposed Thermal Mass in floors and roof

  • When the doors are opened between dwelling and sun space the heat is permitted to enter the rooms
  • Any excess heat will be absorbed by the exposed thermal mass floors, walls and roof

Office Buildings need thermal mass to absorb excess heat

  • But the thermal mass must be on show and exploitable
  • Raised Access floors and ceilings prevent its use
  • Metal trough deck floors exclude use of thermal mass

Lightweight building ‘fabric’ cannot stop solar gains

  • It will be unbearably hot on sunny days
  • But as soon as the sun sets they will rapidly cool down and be suitable for the evening ‘Show’

Light weight cladding may not be enough thermal mass to stop solar radiant heat

  • Stone fibre, glass fibre, plastic thermal insulation will not stop solar radiation heat gains
  • So the interior could overheat
  • However the blockwork wall behind will stop the heat getting in

Thermal bridges will ruin any choice of insulation material performance

  • Thermal bridges will let conducted heat out, conducted coolth in and solar radiant heat in
  • Eaves details are most vulnerable
  • 300 mm of insulation reduced to 50 mm is asking for trouble
  • Risking interstitial condensation, surface condensation, mould, structural failure, asthma, toxic mould and death

Materials samples

  • The right and wrong materials for overheating:
  • Use of high decrement delay thermal insulation materials at:
    • –rafter level will delay radiant solar heat gain from entering the attic.
    • –ceiling level will delay radiant solar heat gain from the entering the rooms below.
  • Using low conductivity insulation at:
    • –ceiling level will stop heat in attic air from conducting down to the rooms below.
    • ceiling level will stop heat getting out via the attic.
  • Very hot attics in summer will provide sufficient heat to overcome the resistance of thermal conductivity insulation and heat the rooms below.
  • Solar heat gains via windows will heat the upper floor rooms
  • Use of only:
    • –low conductivity thermal insulation in attics will help upper floor overheating in summer.
    • –high decrement delay thermal insulation in attics can prevent upper floor overheating in summer.
  • The thickness of the high decrement delay thermal insulation will determine the period of delay, 10-12 hours is sufficient to avoid all overheating.
  • The same issues can affect lightweight construction walls if not protected by masonry outer leaf or some form of solar protective rain-screen cladding, which does not reradiate inwards.

Case studies


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  • It’s the front end of the file with the middle and rear end deleted
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  • These files are created by generalists with a big dollop of green flavour
  • These files are updated from time to time
  • We are not experts so from time to time these file may get out of date or may be wrong.
  • If you feel that we have got it wrong please let us know so we can put it right

© GBE 2015-2019

© GBE NGS ASWS Brian Murphy aka BrianSpecMan *
13th September 2017 – 13th November 2019

GBE Overheating CPD

CIOB Event

BrianSpecMan At CIOB Hemel Hub Hatfield TGR GreenRegister on ScreenBRM At CIOB Hemel Hub Hatfield With Samples

Cover Slide

GBE CPD Overheating CIOB 101119 S1 PNG

GBE CPD Overheating CIOB 101119 9H1 PNG

First Audience

NET Learning Students 1

NET Learning Students 1

Handout Cover

GBE Images:  Overheating

© GBE NGS ASWS Brian Murphy aka BrianSpecMan *
13th September 2017 – 16th November 2019

GBE Overheating CPD
See also:

GBE Past Event


GBE CPD Satisfied Customers

GBE Checklist

GBE Jargon Buster

  • Conductivity
  • Conservatory
  • Decrement Delay Decrement Factor (Jargon Buster) G#14043
  • Density
  • Overheating
  • Radiant heat
  • Solar gain
  • Solar radiation
  • Specific heat capacity
  • SunSpace
  • Thermal lag
  • Thermal Mass
  • WinterGarden

GBE Overheating

GBE Defects

GBE Issue Papers

GBE Slogan

© GBE NGS ASWS BrianMurphy aka BrianSpecMan
13th September 2017 – 13th November 2019

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