Building Pathology Flashcards
What is Dry Rot?
Serpula lacryamans
Spore - strands - hyphae - fruiting body
East cellulose and hemicellulose leaving lignin
Need to clear 1 meter from affected area
20-30% on the Damp meter
Dry docks
Breathability of property construction
Attracted to lime/calcium, lime mortar / plaster.
But using lime mortar an plaster to make it more breathable helps prevent the issues as ventilation is an issue.
Discuss Structural Movement
Settlement - when a house ‘settles’ after construction. Largely due to settling of temperatures and different building components characteristics. Use of expansion joints to prevent issues.
Subsidence - more to do with the changing ground / soil substrate conditions due to changes in water content. Changes in water content can be brought about due to roots and changes in temperature, as well as faulty foundations / sites.
Heavy - similar to subsidence but the upward movement of the ground.
What are the issues regarding Sprayfoam?
Breathability of timbers.
Allow for moisture to collect with no escape.
Limited lending opportunities.
What are the defects associated with cavity walls?
Wall tie failure - due to older wall ties that have corroded due to water ingress. Can be identified due to cracks roughly 400m apart.
Cavity wall insulation - insulation being put in the cavity of brick and allowing for water to ‘bridge’ the cavity. This is prevalent in the west coast of Scotland. Also an issue when put into timber cavity as it allows timber defects to spread.
Tell me about 3 Non-Trad houses, construction and defects?
Dorran - Houses built from pre-cast concrete panels (40mm wide un-finished) with metal rebars. Built during the 1950s. Property is only mortgageable if it had been upgraded by the appropriate PRC scheme, no contractors left in Scotland to do this. Identified by unusual timber structures in the loft, thickness of walls, and by checking with the local area.
Athol Steel - there are different kinds of Athol steel based on when they were built. Pre 1926 consists of metal panels riveted together. Later construction only has the tubular steel frame, which can go into the walls, or imbedded near the top of the walls. Walls cold be cavity/ solid brick or concrete panels with or without brick. Issues are again with metal corrosion causing structural issues.
Wimpey No Fines - ‘no fine aggregates’ resulting in a honeycomb look. Issues are again with corrosion to metal rebars.
Non-trad can be identified visually, due to external wall insulation, circular vents, curves in the corner of internal walls. etc.
Discuss cladding and legislation.
Cladding - external wall systems. Issues arose after the Grenfell Tower Fire where it had been found that combustible materials had been used. These materials are now banned, and an EWS1 form has to be commission upon the sale of properties that meet specific requirements as set out by RICS. Can have metal sheets, as well as timber.
Requirements for EWS1 form - properties above 4 stories with multiple occupancy. Properties below the four stories will still require the form if one wall has more than 25% cover of cladding, especially if this is over the only exit. Another factor is stacked balconies - 4 or more.
The legislation that came out after the fire has been relaxed, however changes to Scottish legislation have happened. The Buildings (Scotland) Amended Regulations 2022. The ban is to properties 11m or higher which contain a dwelling, building used as an assembly place, entertainment or recreation, hospital, or residential care building or sheltered housing or shared occupancy.
Discuss housing acts in relation to defective housing.
The housing act of 1987 in Scotland listed defective housing. They owner of said housing could apply for a grant to have the house reinstated or purchased.
Now, this has be repealed by the Housing Act (Scotland) 2014.
What is sulphate attack?
Sulphate attack occurs when moisture gets through a concrete floor to the red ash below. Sulphate in the red ash reacts to the moisture and penetrates the concrete, which expands and makes the floor ‘heave’ and ‘crown’.
What is the Home Survey Standard (2020).
Is the best practice benchmark, enabling consistency of services and contributing to delivering trust in the home survey market across the UK.
Purpose:
- establishes a clear framework that sets minimum expectations
- provide mandatory requirements for RICS members and regulated firms in the UK who deliver any level of residential property survey
- replace and harmonise previous RICS publication relating to residential surveys
