AIA Tasmania CPD Seminar

Australian Institute of Architects, Tasmania CPD Presentation 

Launceston Thursday 26th April

Hobart Friday 27th April

For those attending the CPD Seminars in Launceston and Hobart in April we include here more details about condensation, and for further reading, a list of resources used in the writing of the presentation.

Outline

Building envelope design is no longer just about keeping out the rain and wind. We are now faced with the challenge of balancing the need to keep out or keep in, and let in or let out cool and warm air, daylight, fresh air, contaminated air, sound, fire and moisture as appropriate for all seasons and all times of the day.

The drive for energy efficient buildings with improved air tightness and insulation has changed the dynamics of the building envelope as insulation, whilst keeping some surfaces warm, also keeps other surfaces cold. Sealing up the building can also prevent the safe passage of water vapour, resulting in potentially damaging condensation on these cold surfaces.

Tasmania, with a climate more akin to New Zealand than Brisbane, has seen an increase in the occurrence and severity of condensation problems. Following presentations in Tasmania as part of the AIA Refuel National Seminar Series in 2011, Andy looks at specific challenges for designing for the Tasmanian climate.

Foot through ceiling

 

Download presentation slides

Download CPD suggested answers

The Problem

The drive for energy efficient buildings is leading to improved air tightness, the installation of bulk insulation and a failure to consider the building envelope holistically is leading to roof space and interstitial condensation.

Failure to consider condensation within your roof space and walls can have serious consequences.

  • unseen mould growth
  • saturation of insulation
  • sick buildings
  • corrosion
  • timber decay
  • loss of structural integrity
  • ghost leaks
  • expensive rectification

  

The Theory

"Higher levels of insulation may introduce unforeseen problems where they are incorporated into construction styles which have previously been relatively immune to condensation. This is because insulation, whilst it keeps some surfaces warm, also keeps other surfaces cold."

A simple example is domestic roof spaces.High levels of ceiling insulation mean that roof spaces are colder as they are not heated to the same extent from below." (CSIRO, 2001)

 

 

 

 

Our Solution

Unlike foil and perforated foil products, the high water vapour permeability of the Proctor Roofshield and ProctorWrap breathable membranes allows for the escape of high volumes of vapour from within the building at the same time as restricting the ingress of moisture.

  • protection against wind-driven rain, snow and dust during construction and for the life the building
  • highly durable, strong and lightweight textile membranes
  • quiet when exposed to wind
  • non corrosive for coastal environments
  • vapour resistance no greater than 0.26MNs/g
  • complete range of AS4200.1:1994 compliant products for walls and roofs
  • a system approach including window surrounds and tapes

 

Description How much vapour can 
pass through 10m²/day?
How long would it take for 1,000mL
vapour to pass through 10m²?

    Proctor Roofshield

    ProctorWrap HP

             6,500 mL                   3 hours + 45 minutes

    ProctorWrap AT

    ProctorWrap HT

    ProctorWrap BL

   

         3,100 mL             

    7 hours + 45 minutes
    Typical perforated "breather foil"       120 mL                 7 days + 15 hours
    Perforated "breathable" reflective
    insulation
      30 mL                32 days + 1 hour

 

Avoid Costly Mistakes

Before specifying a vapour permeable building wrap, be sure to check the vapour resistance data and make sure you are confident that it really does breathe. With a 20 year track record around the globe select a Proctor breathable membrane for your next project and let your building breathe.

  • For more information on the Proctor membranes and installation details please browse the construction membranes area of our website. 

Technical Advisory Service

Proctor Group Australia (PGA) work tirelessly to pre-empt future thinking across a wide product range in response to the needs of the building and costruction industry, thus consistently delivering innovative solutions at the top end of the performance spectrum.

PGA and Dynamic Composite Technologies (DCT)  support all of their products with a comprehensive Technical Advisory Service, assisting Architects and Contractors in specifing the right type and thickness of insulation for your buiding project. Calculations can be carried out to provide R-Values, plus condensation and dew point risk analysis. Thereafter any number of permutations can be provided to help you achieve your desired target.

To access our free Technical Advisory Service simply visit Dynamic Composite Technologies:  www.dctech.com.au/design and register your company details.


 Technical Advisory Service Link

Condensation Risk Analysis Service

We use independent software to conduct condensation risk analysis. This software is available for download at www.techlit.co.uk If you purchase this software and need assistance we are happy to share our database of Australian climate data from the Bureau of Meteorology and common material properties.

If you prefer, we offer a free condensation risk analysis available through the Technical Advisory Service of the Dynamic Composite Technologies website. Alternatively please send us send us the following information preferably by e-mail to technical@proctorgroup.com.au

  • a basic cross section of proposed wall/roof as a pdf file
  • the thickness and type of insulation and other materials proposed
  • details of construction type and proposed building use
  • location of the project

 

 

 

Links for background reading or sites referenced in the presentation

There is a wealth of information on the web about condensation and global sick house/building issues. Just googling "sick building", "mouldy/ moldy home", "roof space condensation" will keep you busy for days

Building Science Information

One site that is well regarded in the building science community is www.buildingscience.com. There is a lot of free information on this website which although there is a North American slant, is equally relevant to Australia. The following articles make reasonably light reading and go into greater depth, some of the issues raised during the presentation and the Q&A:

  • BSD-106: Understanding Vapor Barriers 
    The function of a vapor barrier is to retard the migration of water vapor. Where it is located in an assembly and its permeability is a function of climate, the characteristics of the materials that comprise the assembly and the interior conditions
  • BSI-009: New Light In Crawlspaces  
    Think of the good old days—the Civil War, WWI, the Great Depression, WWII—crawlspaces were uninsulated. They were ventilated and they didn’t have ground covers—and they didn’t have problems. Why?
  • BSD-007: Historical Development of the Building Enclosure  
    This digest provides a brief overview of the development of the building enclosure and can serve as an entry point into a deeper historically-informed study of buildings and building science.
  • BSI-005: A Bridge Too Far  
    One of the big ideas of the past couple of decades or so is to keep the heat out during cooling and keep the heat in during heating.  The better we are at this the less energy we need to use to condition the interior.  If an alien from another planet looked at our construction practices he would conclude that we have too much heat in buildings and we want to reject that heat to the outside. We expose our concrete slab edges and our concrete frames.  We build our structures like heat exchangers with protruding fins that transfer every last available BTU across them—like huge concrete “Harleys” with air-cooled structural frames.
  • R-0302: Roof and Attic Ventilation Issues in Hot-Humid Climates
    A presentation examining the requirement for roof/attic venting in hot-humid climates.
  •  Ontario Association of Architects (OAA) Mould Control Practice Guide
    "Moulds are a natural part of our environment. While in most cases they cause no harm, some can cause health problems, such as allergic responses and even asthma, in some people. Perhaps all have this potential in specific individuals. Dampness in buildings has been associated with health problems. Although moulds do not justify a hysterical response, their growth should be avoided and mould should be removed, along with the source of moisture, when observed.

    "Mould control is not about selecting materials or applying biocides. Mould spores exist everywhere. Hence, mould control is primarily about controlling moisture to levels and durations appropriate for the material used. The general strategy is to construct and operate buildings in such a way that materials do not get wet enough to support mould growth or to ensure that those materials that get wet will dry quickly and do not provide sufficient food value to support mould growth."
  •  At Harvard U., the Culprit Is Moisture, and the Cure Is Demolition
    "Harvard University’s big art-museum overhaul will entail demolishing Werner Otto Hall, an addition to the Fogg Art Museum that’s only 17 years old—and that was designed by Gwathmey Siegel & Associates Architects, one of the most prominent firms in business today. Now Robert Campbell, the architecture critic for The Boston Globe, has written a fascinating article about Werner Otto Hall for Architectural Record. He says the addition’s problem isn’t that it no longer meets the museum’s needs—the problem is that its walls have rotted from the inside."
  •  Condensation, Building Technology File 03, CSIRO
    This Building Technology File (BTF) deals with condensation. Condensation on internal surfaces is the cause of unsightly mould growth in houses and of water collecting under and dripping from factory roofs. However, it often occurs within the building fabric where it may not be so obvious. This may be of greater consequence, leading to decay of timber and otherwise threatening the structural integrity of the building. Ironically, this interstitial condensation can be the result of incorrect use of thermal insulation intended to stop surface condensation.
  • Insulating roofs at rafter level: Sarking insulation
    Publisher: BRE (Building Research Establishment)

    This Guide highlights a system of roof insulation where the insulation material is laid between and over inclined rafters: it is sometimes referred to as sarking insulation. Sarking insulation provides an effective solution to satisfying the thermal requirements of building regulations. It allows complex roofs to be more effectively insulated with a reduced risk of thermal bridging and condensation problems as the roofing timbers are kept at or near internal environmental conditions. This Guide provides advice on specifying sarking insulation and on avoiding the associated technical risks. Available at the BRE Bookshop  http://www.bre.co.uk/
  • Condensation in Buildings
    Publisher: ABCB & AIA 

    This Non-Mandatory Handbook is intended to assist architects, designers and builders in the assessment and the management of the risk of condensation and its consequences in the contemporary industry environment and should be read in conjunction with the BCA provisions relating to Damp and Weather Proofing, and Energy Efficiency in all classes of buildings.

    Appropriate detailing of buildings ensures they remain serviceable, the occupants remain healthy and that the design life of the building is not compromised. The outcome of failing to adequately detail for moisture control is a common underlying cause of many reported building failures. The rectification of the side-effects of condensation can result in costly repairs and in the case of related fungal and mould infestations, prohibitively expensive repairs.

    Traditionally our buildings were not airtight and had little or no insulation. However, as a result of changing occupant practices and the introduction of mandatory energy efficiency requirements, building practices are changing, requiring a change in detailing so that moisture related problems are adequately managed.

    While a common cause of moisture related problems is due to water ingress, the focus of this Handbook is controlling moisture within the building’s fabric resulting from condensation.

    Handbook is available for free download here.

    ABCB Condensation in Buildings

 
 
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