Mould treatment for Southport and Ormskirk Hospital NHS Trust

RTC were delighted to be instructed to carry out work for Southport and Ormskirk Hospital NHS Trust to complete a mould clean service within the endoscopy unit of Ormskirk District General Hospital.

Ormskirk District General Hospital had gone through some new construction, with nearly £2m being invested in a temporary, standalone endoscopy unit, which comes in addition to £500,000 for the upgrade of the existing unit in the main building.

Scope of inspection

During construction, the renovation project had to be paused. The building which is suspended timber and SIP panel construction, had been left empty since April 2023.

The site previously had water ingress due to drainage not being installed. We had been informed that the drainage had now been completed and there is no more water entering the building.

We were instructed to carry out an inspection of the proposed endoscopy modular to determine the remedial measures necessary to eliminate mould to the timbers which had built up, along with excessive moisture since the building had been left empty, resulting in excessive mould on the walls, ceilings and floor of the endoscopy unit.

Some areas at high level could not be inspected fully at the time of our inspection due to exposed engineered joists (I-Joists), and the lack of suitable flooring/walking bords.

The survey for Southport and Ormskirk Hospital NHS Trust included detailed testing with the aid of the following instruments:

SurveyMaster Electrical Conductivity Meter

The SurveyMaster uses electrical conductance principles to measure the moisture level of the material between two electrodes. The instrument also incorporates a ‘radio frequency’ mode where a radio signal is emitted that dismisses surface moisture and reacts to moisture approximately 10- 15mm beneath the surface. Readings were taken from wall surfaces unless otherwise specified. Data recorded is expressed as ‘%WME’ (Wood Moisture Equivalent) for plaster, masonry or concrete and ‘%MC’ (Moisture Content) for timber.

Hygrometer and Surface Temperature Readings

These determine humidity and moisture levels in the air at the time of the survey and also determine the temperature of walls and whether condensation is occurring or likely to occur.

Observations and conclusions

Visual inspections revealed the presence of hydro phallic fungal growth (mould) to sections of floor joists, timber boarding to walls and ceilings, and to sections of plaster boards throughout the ground floor.

Southport and Ormskirk Hospital NHS Trust
Southport and Ormskirk Hospital NHS Trust
Southport and Ormskirk Hospital NHS Trust
Southport and Ormskirk Hospital NHS Trust

Pictures 1-4: Hydro phallic fungal growth (mould) affecting timbers and plasterboards.

Although we were informed that no further moisture was entering the building, standing water was noted to various areas of the sub-floor which is a result of the previous drainage problem. Additionally, elevated moisture readings were obtained to sections of the timber floor joists.

Southport and Ormskirk Hospital NHS Trust
Southport and Ormskirk Hospital NHS Trust
Southport and Ormskirk Hospital NHS Trust
Southport and Ormskirk Hospital NHS Trust

Pictures 5-8: Moisture profiles taken to sections of timbers throughout the ground floor which revealed elevated moisture readings in various areas and visible areas of standing water on the oversite.

Mould spores are omnipresent in that they are widespread and ever present in the air. For mould spores to germinate a relative humidity of 70% or above for a sustained period of time is required. 

Relative humidity readings were taken at the time of our inspection which revealed humidity in excess of 71%.

Southport and Ormskirk Hospital NHS Trust

Picture 9: Relative humidity readings showing 71.5% which could allow new mould spores to germinate.

Mould and timber treatment

As requested by Southport and Ormskirk Hospital NHS Trust and their main contractors, we allowed for mould removal and sterilisation of all areas affected by mould growth using a proprietary mould treatment solution, which not only kills the mould, but also helps prevent the regrowth of the mould.

Owing to the elevated moisture content of the floor timbers, we also carried out the application of a water-based fungicide to help prevent the occurrence of decay occurring during the drying down of the timbers.

Additionally, and to help reduce the relative humidity within the building and to provide more suitable atmospheric conditions, we recommended the following:

• Remove the areas of standing water on the oversite still evident within the building
• Install the windows and doors as soon as possible
• Provide background ventilation
• Install dehumidifiers/drying equipment to help dry down the building

This treatment which is designed to not only remove, but to sterilise and help prevent the re-occurrence of mould growth in the future was completely successful.

For any queries, or to book a survey, please contact us.

Our staff will work closely with you from survey stage, right through to the successful completion of the contract.