Whilst during the course of House Inspections, all due care is taken in respect of Thermal Imaging and Non-invasive Moisture scans, it is not practically possible, to be certain that moisture related problems do not exist, even though, no visual sighs of water ingress (stains, damage), or no elevated moisture readings were recorded during the inspection.
Therefore, including a list of Particular attributes and Risk factors is Extremely Important.
It will point to architectural details and application / installation faults which have been identified as problematic with conventional / monolithic cladding allowing moisture ingress.
Including them in the report could dramatically reduce your risk of buying the house with inherited moisture problems.
With regards to monolithic clad (plaster) houses, especially build with no cavity and questionable timber treatment (usually 1998-2004) the full Weathertighness report done by certified Assessor is highly recommended.
IMPORTANT: Please also refer to other sources of information and your legal aid to learn more about this subject as risk associated with moisture damage to the dwelling is very high and cost of remediation could be very substantial. Remember - your general pre-purchase/ pre-sale inspection is not a Weathertightness Assessment.
Why we include list of Particular Attributes and Risk Factors in the report?
Up to 1992, most timber used for house framing in New Zealand was radiata pine treated with boron. From the early 1990s, a range of alternative timber framing treatment options for radiata pine became available.
From 1998 to April 2004, homes were often built with untreated kiln-dried radiata pine framing.
If the framing used is untreated or has a preservative treatment only effective against insects, it is more likely decay will be both severe and widespread in a leaky building.
Elements and details that Inspector can't see but might cause a leak
Mitre Jonts in joinery (windows and doors) - Manufacturing fault, Installation fault, Movements (temperature, Settlement, Quake).
The window mitres could open up quite easily (mitres are very fickle and vulnerable to loosing their seal due to the leverage applied to the joint when movement occurs), letting the water directly down onto the sill plate and studs which supports the window. Water damage could be very substantial, especially when the building doesn’t have a cavity system installed.
Photo: an extensive damage to timber with humongous fungus growth.
No visual signs of moisture ingress, stains or damage in inner GIB liner is present. Only INVASIVE inspection can reveal it. If no elevations in moisture readings noted - a pre-purchase inspector will "pass" this area.
Head flashing construction - even in event of this element is visually looking well constructed, it is not possible to determine the watertightness of an area as some important installation elements are hidden from the view (as for example - a fault with flashing installed over wall underlay).
Therefore in a general pre-purchase/pre-sale inspection only visual and visible appearance is inspected and commented on - the presence of top flashing, how it extends over the opening and general condition.
More info: http://www.wanz.org.nz/.pdf
"Harmless" baluster - no visual damage. Issues: flat top, top railing fix. Result - damage, rot - total replacement.
Enclosed balcony. Issues: drain penetrations are often causing leak due to poor waterproofing or/and workmanship. Result - extensive damage.