A while back I was contacted by a very nice lady living on the south coast of the country. She was very concerned about what appeared to be black mould covering approximately one third of the bedroom ceiling and extended onto one of the bedroom walls. We had a lengthy discussion about what it could be and I offered some advice about what to do if it indeed was black mould.
Lady has already cooperated with mould removal company which to mine believe once visited the place and removed the apparent mould. The black mould has returned in couple of months to the despair of the occupants.
She and loved ones have become increasingly concerned about the possible health effect of this mould. We have decided over the phone that she will send me a tape lift sample of the deposit so I can carry out microscopic investigation and confirm if it is a mould issue and what king of mould is she facing.
When the sample arrived I could not find any moulds in the sample but was able to observe fine black deposit, some sort of debris. I have advised the client that she is not actually facing a mould issue but something entirely else.
The case was then forgotten for couple of months when the lady in question called again and called me over to investigate and finally put the matter to rest.
When I visited the site I investigated the area which had uniform cover of fine black deposit to a specific rectangular area of the ceiling. There was a pattern of straight and lighter coloured lines across the ceiling copying the pattern of rafters in the roof. This pattern suggested that the relative coldness of the ceiling has some role in the patterning and overall deposition of the material. I have suspected that there has to be some sort of contaminant coming into the property and settling preferentially on this part of the ceiling.
I have investigated the entire house but could not fine one single thing wrong with it. The boiler has been recently tested and specifically checked for any leaks. House did not suffer from high humidity or water leak issues.
Just to be sure I have taken several samples for airborne mould and volatile contaminants to confirm and investigate the actual composition of the indoor air in this particular property. Just as I was leaving I have realised that during mine investigation whenever I had to move a piece of furniture I had to move a scented candle or two. The lady was a found lover of scented candles and had a fair supply if them in her room. I decided to investigate if they could possibly be the source of the black deposit. When I lit the candles some of them burned by releasing fine thread of smoke visible only under strong light.
I have taken samples of the smoke and the material deposited on the ceiling and mine microscopic investigation confirmed that the particle deposit from the candle smoke was identical to the one of the bedroom ceiling. Fortunately the house did not suffer from a mould attack just badly prepared scented candles. I this stage I closed mine investigation and recommend to call a decorator and use less candles in the future.
By Tomas Gabor