Dampness, Condensation & Mould
There are several causes of dampness; rain soaking through a wall, leaking water pipe, leaking roof, ground water soaking up through a floor or wall. But one of the BIGGEST causes is CONDENSATION.
Commonly 'cold' and 'damp' rooms and buildings are associated with mould. What is the common factor? Moisture. H2O is a molecule that can be as a gas (vapour), liquid (water) or solid (ice). The difference is the amount of energy contained in each atom. It is relative to temperature. Therefore, the association with cold and damp.
However, a hot and humid room can have mould growing in it. Hot countries have mould problems so is it a 'cold and damp' issue?
As mentioned, the common factor is moisture. That is why very cold countries including the North and South Poles do not have mould. Why?
Moulds need moisture
Mould is part of the Fungi group of living things. As with all living things they cannot survive without moisture. Ice is not moisture therefore mould and other fungi cannot thrive. It is reported that the wooden hut used by Scott's expedition still remains 116 years later. There are no moulds or other fungi that can survive in such low temperatures. The air is dry.
Know your enemy
- We know it requires moisture
- We know various moulds can survive in hot or cold environment as long as there is moisture
- We know that moulds do not have seeds, they have spores
- We know that spores do not have any luggage. Seeds, pips and stones contain food for the initial germination and growth stage. Spores are just the initial 'spark' to start mould into life.
We need to know a bit more about the enemy though:
- How does it travel?
- How does it multiply?
- What does it eat?
- What does it prefer, or not prefer as an environment?
- Will it attack you? Or is it placid?
Moulds, like many fungi reproduce by spores. As there are over 100,000 different types of mould plus different fungi, and yeasts we will only consider those commonly found in the UK.
However, in the UK we so far do not have any 'toxic' moulds that will kill you. Websites that state that 'Black Moulds' will kill you are not true. They mainly refer to specific 'legal' cases that have gone through the Courts in certain North American States. Reading the published information, the occurances are 'reported' as being in property of 'run down' tenancy apartments in 'Downtown' areas. Another in a Mansion where there was a legal case suing for a very large amount of money. Both cases of death from black mould were not 'proven' though.
More later.
Let's look at the proven facts
How do they travel?
Mould spores are tiny. So small they are individually invisible without a microscope. Transported by floating in the air. Some travel on hosts such as fruit, grains, nuts and legumes. Some travel by the movement of 'goods': sacks, boxes, and timber. Others by animals, birds, and other live creatures. There isn't just one way.
How do they multiply?
Most, if not all mould spores multiply by division. The spore land on a moist surface and starts to swell. It then splits into two identical parts. (We won't go deeply into the biology - sufficient to say 'the spore divides to become two' identical life forms). It requires moisture to swell. No moisture, or insufficient moisture and the spore remains intact. Most can remain in a dormant state for years, even centuries.
When the spores come in contact with moisture it is absorbed enabling the spore to swell and split. As previously mentioned the spore carries no luggage so it exudes a now liquidised enzyme. The spore can then absorb nutrients from the host.
As the spore becomes established it produces fine tubelike roots termed 'hyphea'. The spore then uses the hyphea to transport the enzyme further afield and suck up the solution containing carbon. The enzyme breaks down the molecular structure of the host into a solution high in carbon that the mould can then feed on.
What does it eat? - What's on the menu?
'I think I'd like the carbon please'.
Most substances contain carbon. Plants contain sugars in the form of sap. The main fibres of most plants are made of cellulose. Cellulose (C6H12O5) is made from long chains of glucose (C6H12O6) that contains carbon. Therefore paper, cotton, hemp, timber are all good sources of carbon. That is why they often become covered in mould. It's the number 1 mould restaurant.
However, there are other sources of carbon. That mastic around the shower and bath contains carbon (some of the mould resistant mastics evidently either haven't got carbon in them. Or a chemical that the enzymes cannot convert. The black marks that appear to actually be in the mastic so cannot be wiped off are in the mastic. The black mark is the enzyme dissolving the carbon in the substance. The 'mould resistant' mastics have a limited timespan of about 5 years of stopping the enzymes.
The grouting between the tiles - yes it contains carbon as it has been made from calcium carbonate. (Limestone) It is one of the ingredients of Portland cement. Some grouts contain Portland cement. Others that are epoxy resin grouts contain carbon.
What about the mould growing on the gaskets around the PVCu windows? Again, yes neoprene (C4H5Cl) contains carbon.
Washing tablets and liquids contain carbon. So do the fabric softeners, and many of the washing up liquids.
We breath in and expel carbon molecules. Everything that burns contains carbon. We contain carbon. Most of the things we cook contain carbon. The splashes of fat on the cooker splashback, the sticky extractor surfaces, the brown sticky extractor filters, the shower curtain hems. Yes, we live in a carbon world. And what does mould feed on? Carbon.
There are even moulds that can live on metal and plastics. More specifically the enzymes can penetrate the substances to absorb the carbon content.
A page from
'House Buyer's Handbook'
What type of environment does it prefer?
Moulds prefer not to be disturbed. However, 'prefer' doesn't mean only. Mould growing on the hem of the shower curtains certainly gets disturbed. Hot water, soaps, body washes, shampoos, conditioners = being greatly disturbed.
Why choose there then? The chemicals all contain carbon in an easy to consume liquidised form. Hair conditioners must be like caviar to mould. Doesn't need much, but 'oooo, it is so good to feed on'.
Drying yourself with those lovely soft cotton towels with the fabric conditioner to make them really soft and smell great. Yep - Although a Website that states that Lenor doesn't contain carbon. It is not true though
Several of the chemicals it does contain are made up of carbon:
- Benzyl benzoate C6 H5 CH2 O2 CC6 H5 and
- 4-tert-Butylcyclohexyl acetate C12 H22 O2
are both used as fragrance that remain in the fabrics for weeks. You've just made the towels damp and probably left them out to dry off.
As previously mentioned, mould must have moisture to live.
Humidity is moisture in gasious form. It is the amount of H2O in the air and can be measured as a percentage of dry air (Nitrogen, oxygen and a few trace gases).
When H2O has sufficient energy to become in a gasious state it will diffuse between the air atoms until the spaces are filled. At that point it is 'saturated air'.
The H2O molecules in vapour form eventually slow down and condense into the liquid state.
Where air movement is minimal, moulds can become established more easily. Air behind the curtains at the reveals, and in between the curtains and the wall is perfect. The air hardly moves, and is shielded from the main bulk of warm air providing heat for the occupants.
That is why mould is commonly found behind curtains and around the reveals of windows and doors.
As humid air tends to be slightly warmer than air in cupboards, drawers, wardrobes and under furniture it is another perfect place for mould. The humid air is pushed through even the smallest of gaps and enters drawers. If clothes have been washed, and contain cotton or leather they will absorb the condensing H2O molecules.
Enough moisture, plenty of carbon and being undisturbed = mould loves it. The 'musty' smell is the mould digesting the carbon and 'gasing off'.
This photo shows the wall at the back of fitted kitchen units. The cupboard doors have sufficient gaps allowing the humid air and mould spores to flourish mainly undisturbed.
The wall was continually cold as the main room air did not circulate in the cupboards.
Air in the kitchen had a high relative humidity and probably a high content of fat molecules from frying food
Will it attack you? Or is it placid?
There are Websites that state things like 'Toxic Mould!' and 'Killer moulds!' inferring they will kill you. It may be true in some Countries, but not in the UK. Do people die because of moulds. Indirectly yes. A University Hospital Consultant said that to the best of his knowledge no-one has died because of mould in the UK.
However, like cigarettes don't kill people, the smoke and other chemicals inhaled can cause diseases, cancers and other fatal symptoms. The same with moulds. Breathing in high concentrations of spores can trigger respiratory problems with some people and animals. They can die from complications such as pnuemonia.
This is the corner where two external walls meet. The living room had a large leather sofa about 100mm off the left hand wall.
Humid air was virtually stationary and warm air in the room prevented from flowing over a corner or close to the floor. The leather sofa had mould growth on the back surface and the end adjacent to the other wall.
Large furniture close to walls often are the main issue with mould.
Two 'specialist firms' had told the owner that the damp proof course had failed and quoted for injected DPC. Absolutely WRONG advice.
A similar cause where corners of external walls are colder than the rest of the wall (typically about 2°C cooler). The Council tenant was re-housed.
Although there are reasons for the wall being cooler, it could be said, and typically is: 'It's their lifestyle' that is the problem, not the property.
Another flat in the same tower block also having the WC room with two external walls - no mould at all. It was also noted that hygiene and cleanliness was also an issue with the tenant.
Under the microscope the fine complex matting of hyphea transports the nutrients back to the origin cell.
Some mould produce hair like tubes to attract moisture from the air
As calcite forms from soluble minerals in 'hard water' mould spores will colonise. An excellent source of carbon and moisture that are regularly rejuvenated.
Mould on a strawberry
Mould spore can in ideal conditions divide about every 20 minutes. When they waft into a room as a door opens the spores float in the air until they come into contact with moisture. So small that as individuals they are invisible with the naked eye.
An example of how fast they can colonise: 100 spores arrive and set up camp. 20 minutes later there are 200 spores. Then 20 minutes later there are 400 spores. Eight hours after they have arrived there will be 838,860,800 spores. And yes they will be visible. The photo of the WC above and the under the sink photos show how a surface can become covered.
How to get rid of mould
Timing is probably number 1 - attack as soon as spores are visible.
Bleach will kill mould spores. But not ideal. Bleach is only effective whilst it is fluid. When it is dry it will not do much other than take the colour out, or attack the substance.
White vinegar is said to kill mould. Sold as 'Cleaning Vinegar' or 'White Vinegar' it doesn't smell like you've been down the chippy.
If the mould is on paintwork Cleaning Vinegar on paper kitchen towel. Dispose of the soiled kitchen towels in a polythene bag, tie it off and dispose of in the bin outsde. Go over the area again with a cleaning fluid and kitchen towel. Keep an eye on the area as you are unlikely to have achieved 100% clearance.
Next
- Significantly reduce the humidity in the property.
For a lot more information about thermal insulation, condensation and many other home owning issues including what to do in a water, gas and electricity emergency situations.
