History of poor indoor air quality
Our next project took us to Northampton where we were invited to a residential property and instructed to carry out an assessment of indoor air quality in relation to selected biological contaminants. The property itself is a two-storey residential property with external brick walls and a pitched tiled roof. The ground floor consists of a living room, a kitchen with a built-in utility cupboard and a toilet. The first floor consists of a bathroom and three bedrooms. The building is situated on a new housing development and is surrounded by properties of similar construction and use. The building has a small decorative yard to the front, a grass garden to the rear and tarmac driveway to the right side of the property. W were called to the property as the occupants had reported a history of intermittent odours in the first-floor master bedroom.
Sampling and analysis of airborne moulds and moisture mapping
In order to get an accurate result for our client we collected samples of airborne moulds onto Vesta Spore Trap cassettes using a High flow 1600 air sampling pump. Moisture mapping was carried out using a Hydromette HB30 moisture meter, a Tramex Moisture Encounter Plus and a Flir i7 infrared camera. We also measured the wind speed with a Rotating Vane Anemometer LCA301.
Results of moisture mapping
All the rooms on the ground and first floors were inspected for signs of elevated moisture in materials, water damage to decorative finishes and fungal contamination. However there was no evidence of elevated moisture in the construction or decorative materials. Nor was there any evidence of fungal contamination on exposed surfaces or behind installed cabinets. The infrared survey of the ground floor did not show any areas of significant temperature difference in materials or thermal bridging.
Recommendations to improve indoor air quality
Due to the results of microbiological sampling and moisture mapping our surveyor was able to conclude that the property is not affected by an elevated number of fungal spores as there is no evidence of fungal contamination within the property. This indicates that the property has adequate indoor air quality so the overall risk to health from exposure to fungal spores is likely to be low. It is our surveyor’s opinion that the intermittent odours reported by the property’s occupants are not caused by fungal contamination or fungal rot. It is possible that the reported odours are caused by off gassing of volatiles from the construction materials such as plaster. The concentration of these volatiles would be higher during periods of warm weather. However, we would expect that any significant off gassing should cease within the 6 months from the installation of the material.
