deleterious materials - 3cpd · 2020-06-14 · deleterious materials what do building surveyors...
TRANSCRIPT
Deleterious MaterialsJo Williams MRICS
Partner at Sanderson Weatherall
Deleterious Materials
Agenda
• What is a deleterious material
• Historic context
• Some examples and misconceptions
• What to watch out for in the future
Deleterious Materials
What is a deleterious material?
It means different things to different people
A Lawyer will say:A prohibited material - Blacklisted
The HSE will say:A material that has the potential to cause harm
Building Control will say:A material that’s not used in accordance with Regulations
Deleterious Materials
A Building Surveying definition is:
Deleterious materials are those materials which are capable of
causing damage or harm to the individual, the environment or to
buildings and infrastructure
Deleterious Materials
The Historical Context
Blacklists in legal documents such as leases or development agreements
Once a material has had negative publicity it was blanket blacklisted
Kneejerk reaction
Minimal intelligent consideration on the correct use of the material
Deleterious Materials
Some Examples of Deleterious Materials
• Can you recognise them?
• Do you know how to report on them?
• What do you specify repair?
Deleterious Materials
Asbestos or asbestos containing products
Deleterious Materials
High Alumina cement or concrete
Pre-stressed AND structural
1950’s to 1970’s then banned
Calcium aluminate
Structural collapse
Poor detailing
Water ingress and chemical changePhoto Credit: Sandberg
Deleterious Materials
Woodwool Slab
As permanent formwork• Voids• Compaction• Water degradation
As insulation materials• Water degradation
Stramit Board or StrawboardPaper lining
Deleterious Materials
MMMF
Materials which are generally composed of mineral fibres either man made or naturally occurring which have a diameter of 3 microns or less and a length of 200 microns or less which contain any fibres not sealed or otherwise stabilized to ensure that fibre migration is prevented
• Precautions on installation
• Saturation/detailing
Deleterious Materials
Mundic Blocks
Marine or beach dredged aggregates
1900’s – 1950’s but some up to 1960’s
Mostly residential in South West
Loss of strength
Mortgagability
InsurabilityPhoto Credit: RICS.org
Deleterious Materials
Black Ash Mortar
Waste product from power stations
Corrosive to mild steel wall ties
Can contain un-fired particles
Mortgagability
Insurability
Photo Credit: DIYNot.com
Deleterious Materials
Trussed rafters and truss plate connectors
EN IOS 1461 Hot dipped galvanising
1960’s design, technology and workmanship
1976 Roof collapse at Birkenhead school sports hall
Moisture changes in roofs can change life expectancy of galvanised plates
Deleterious Materials
Polyisocyanurate foam (PIR)
Used in Grenfell Tower
Hydrogen Cyanide
PIR and PUR flame retardance tests small scale only
Post-Grenfell mock-up failed fire tests
Photo Credit: Sealle - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=48128386
Deleterious Materials
Polystyrene and Extruded Polystyrene
Good thermal properties
Not water or vapour resistant
Gives off carbon dioxide and water when burnt
Does not Biodegrade and limited re-use
More uses outside the building industry
Photo Credit: InsulationExpress
Deleterious Materials
Urea Formaldehyde
Insulation blown into cavities
Binder for particle boards, mdf, plywood, laminates
Also used in clothing and textiles
Health issues as breaks down
Photo Credit:TombKonrad
Deleterious Materials
Other Examples of Deleterious Materials
• Lead or any materials containing lead which may be ingested, inhaled or absorbed
• Lightweight or air entrained concrete bricks or blocks
• Vermiculite plaster
• All tropical rain forest hardwoods
• Any product which contains or uses Montreal listed CFC gases in its manufacture
Deleterious Materials
• Marine dredged aggregates
• Concrete or mortar additives containing calcium chloride
• Calcium silicate bricks or tiles
• Slipbricks
• Light bulbs, batteries, Building Services disposals
Deleterious Materials
What to watch out for in the future
• Mild steel welding and associated fumes
• MDF (92% wood and 8% urea formaldehyde resins)
• Breathable felts and geotextiles
• Expanding foam fire stopping
• Oil-based products
Deleterious Materials
What do Building Surveyors need to do
• Understand the material, not just the marketing material• Think about how you’re specifying the material• Use manufacturers guidance• Use published research and guidance
RICS Practice Notes and CodesBRE DigestsBBA CertificatesBritish standards and CE standards Building Regulations – Materials and WorkmanshipBCO ‘Good Practice in Selecting Construction Materials’
• Common Sense
sw.co.uk
Any Questions?