Mould contamination due to building structural failure

Old period buildings often suffer from small structural failures due to ground subsidence, timber sagging or material deterioration. These common failures are usually quickly recognised and repaired by the property owners. The situation get sometimes a bit more complicated if properties are tied in long term maintenance contracts. Even though the maintenance companies are trying the quickly respond to any complaint it is in their nature only to repair the immediately visible and most pressing problem in the cheapest way possible. Very rarely a comprehensive investigation is carried out to ensure that the problem has been fully rectified.

In this case I have investigated a property where a distraught homeowner was tidied up in such a contract. The acting facility management company has repaired the first signs of mould appearing in the proper y but when the first problem reappeared the second visit was more difficult. Subsequent communication was even more difficult as the facility company was reluctant to spend more resources on the investigation. The property owner was required to obtain a proof of the facilities company’s improper conduct and failure to adequately investigate and repair property fault.

At the time I was invited to survey the building the property has already been unoccupied due to signs of significant mould contamination and strong unpleasant odours in the property. My investigation in the property has quickly identified the more visible signs of water damage problems. The most obvious problem was identified in one of the bedrooms and was caused by structural failure of the window construction. The window allowed the water to penetrate the building envelope and saturate the inner plasterboard panelling.  It flow down the window frame and saturated the carpeting and chipboard flooring. The water damage triggered a mould contamination of the adjacent wall and under the carpet. The window wall got mostly contaminated by cladosporium mould which is typically one the first mould ready to colonise damp surfaces. The presence of this mould on the wall surface indicated that the wall has not been wet for a long period of time , that the problem is recent or the wall has already started to dry out. The area under the carpet was contaminated by chaetomium moulds which is a mould requiring a longer time to grown and higher moisture content often provided by porous material that soaks up moisture.


Water entering the inner wall leaf in the corner of the balcony door


Mainly Cladosporium mould contamination to the door frame


Mainly `Chaetomium mould contamination to the floor under the carpet


Chaetomium mould

Second problem was identified in the master bedroom of the property where a brown stain has developed on one of the external walls at about 1.7 meters from the ground. The corner of the wall below the stain has developed a mould patch approximately 1 meter across. Laboratory analysis of the mould has confirmed the presence of cladosporium mould. My investigation showed that the stain was caused by a crack in the outer building envelope situated at the top of a bay window and penetrating the building envelope. Water most likely travelled across the cavity along some debris  or a cable tie. The mould contamination at the bottom of the wall was not directly link to the stain above but is as caused by water condensation in the cold corner of the building.


Structural failure of the outer leaf starting at the corner of bay window


Corresponding water stain on the inner leaf


Mainly Cladosporium muld contamination a the bottom of the wall caused by water condensation

By far the most serious problem was identified in the property lounge which suffered by bad odours and large water stain to double layer plasterboard ceiling. The presence of macroscopic fungi in the top corner of a wall immediately suggested a long term water damage issue.  The combination of odours, large extent water stain and the presence of macroscopic fungi provide enough justification for more aggressive and intrusive investigation. Opening of the ceiling cavity shows significant mould contamination, later confirmed to by predominantly stachybotrys chartarum, and significant wet rot deterioration of the structural timber.


Large water stain on the lounge ceiling


Macroscopic fungi indicating long term water damage


Wet rot of structural timber and stachybotrys mould contamination of ceiling plasterboard.


Stachybotys chartarum mould identified contaminating the plasterboard ceiling

The investigation provided enough indisputable evidence to start an insurance claim against the facility management company.

By Tomas Gabor

Link through to Sysco - Nationwide specialists in hazard exposure monitoring
Hi, I have been working in my job as an Indoor Air Quality Investigator for a number of years and decided to share my experience with you. You can find lot of related information on my website toxic black mould
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  • Martin

    Leaking bathroom , i’ve seen it before

    January 3, 2014, 7:45 pm permalink