MOULD IN BUILDINGS
New Plymouth Conference – November 2013
Philip O’Sullivan, Director
Typical Buildings Affected
• Residential
• Educational
• Healthcare
• Accommodation
• Offices
All You Need Is:
Dampness
Cellulose
Air
Spores
Cellulose is common in many building products:
• Timber
• Reconstituted wood panels e.g. particle board
• Plasterboard (paper faced)
• Kraft-based building papers e.g. black building paper
• Fibre cement e.g. Hardiflex
• Carpet with jute backing
And in all types of construction:
• Light timber framed
• Light steel framed
• Reinforced concrete masonry
• Reinforced concrete
• Structural Steel
Typical causes of dampness
• Leaking roofs
• Leaking walls
• Plumbing leaks
• Air-conditioning – condensate drain leaks
• Subfloor dampness – often poor ventilation
• Flooding
Reinforced Concrete Masonry
Inside View
Steel Framing
Timber Framing
Symptoms
• Health issues (Adrienne to discuss)
• Internal evidence of mould in walls – not common
• Most often no obvious symptoms
Best to obtain information BEFORE
remediation commences
• Sample collection - Adrienne to explain
• Prendos prefers air sampling – helpful diagnostic tool
• AVOID removing internal linings - if no choice then cover
and seal opening
Diagnostic Techniques
Example from
air sampling in
concrete
building with
light steel
framed walls.
Colour coded to
mould type and
anticipated level
of dampness.
Comparing spore levels with possible levels of
dampness
Retaining Wall
Leak
Balcony
Leaks
Damp
subfloor
Options if high spore levels encountered:
• Eliminate –takes time to remediate
• Isolate – only if parts of building can be closed and sealed off
• Minimise – improve ventilation or use recirculating air filters
• Fixing or preventing the leak, without mould removal, often
leads to increased spore levels.
• Need to undertake on-going air testing if building is to remain
occupied.
Remediation - localised
• If leak localised then possible to seal off affected area and
remediate.
• Need H&S plan
• Provide negative pressure – extract fan to outside
• Provide separate access from outside to prevent
contamination
• Check spore levels after decontamination and re-clean if
necessary.
• Check again as may have missed some contaminated
material.
Remediation - global
• If leakage affecting a substantial part, or all of building then
usually best for occupants to vacate during repairs.
• If mould in external walls then leave lining on, remove
cladding and remove other materials while damp.
• If mould from located internally (roof or services leak):
1. Provide negative pressure – extract fan to outside.
2. Remove mould affected material.
3. Check spore levels after decontamination and reclean if necessary.
4. Recheck as may have missed some contaminated
material.
Severely decayed timber and mould spore levels
were very high
Decayed untreated timber, very limited mould
growth.
Thank You
Any Questions?