WA: Mould and moisture in a ground floor apartment: Investigating the cause and responsibility

This article discusses strata mould moisture responsibility investigation and how to find the cause of dampness and determine who must fix it.

Question: Over the past two years, I’ve experienced problems with moisture and mould in a ground floor apartment. How do we resolve this?

I own and live in a ground floor apartment of a block of 12 units, 2 storeys high and built 5 years ago. I purchased into the complex 2 years ago.

Over those two years I have had a mould and dampness issue plus water dripping from the light above my alfresco area from the upstairs balcony. The Strata Manager arranged for a building inspector who has advised the following:

• The dripping light needs to be investigated and rectified immediately. The Strata Manager has agreed the strata company will do this.
• A reading of 38% moisture in an external bedroom wall on 29.12.21 – the unit had been vacant for 6 days prior with temps ranging between 38.6-43.5 degrees. The Strata manager has agreed to another moisture reading in a few months.
• The exhaust fans need to be replaced with more efficient ones. This would be my responsibility. The building inspector further advised that he doesn’t believe these vents are vented externally and an electrician needs to investigate if they are or not. This needs to be done prior to replacing the fans.

If the existing air vents are not vented externally, is it up to the strata company to have this rectified? Should we be taking anything else into account?

Answer: You should engage a building consultant to attend the site and complete forensic investigations to identify the cause of the issue and make recommendations as to a remedial course of action to resolve the problem.

In the circumstance described in your alfresco area, it sounds like there may be a waterproof membrane issue relating to the balcony above that requires further investigation. A plumber would be able to conduct a flood test to further identify the source of the water ingress.

A reading of 38% is a high reading. The dry standard of plasterboard is no greater than 17.9%. The relative humidity should be checked and a further investigation carried out in the form of a moisture survey and mapping.

Some of the additional questions that should be asked are:

• What is on the other side of the adjoining wall that is 38% (e.g. a bathroom)?
• Does the wall have pipes?
• Is there a garden bed or the like?
• How high up is the 38% Moisture Content?
• Is it isolated to only one small area?
• Is there shade from trees or other buildings in the area in question?
• There are many factors that should be considered when trying to determine the true extent of the issue and address both the underlying cause. Once this has been identified an informed course of action can be implemented to resolve this and any resultant damage.

If the exhaust fans are not being vented externally then the question needs to be looked at as to where high moisture air is going? In the case where it is simply recirculating in the room similar to that of range-hood, there is the potential for relative humidity to be high within the unit. This can be due to lack of airflow which can produce moisture issues, in such situations venting fans externally where possible is highly recommended and preferred with supporting mechanical components.

A potential option to assist in mitigating the issue in the short term may be through the installation of a dehumidifier if the problem is localised in a single/small “location”, to further compliment this the other alternative that can’t be understated is to keep windows open whenever possible to allow air exchanges in the instance where this is not a larger building related issue.

Sedgwick would recommend in this instance engaging a building consultant to attend the site and complete forensic investigations to identify the cause of the issue and make recommendations as to a remedial course of action to resolve the problem. To further compliment this we would also recommend a restoration consultant to assist with identification and/or monitoring of relative humidity levels, this may include the use of thermal imaging. This combined approach will ensure a complete identification of the issues and provision of a complete solution.

This post appears in the February 2022 edition of The WA Strata Magazine.

Ryan Richards
Sedgwick
E: Ryan.Richards@au.sedgwick.com
P: 0420 961 402