Humidity is not just a present in our rainforests, it is also present in our homes
Humidity is basically moisture levels in the air.
Relative humidity (RH) is what we commonly talk about, and the ideal range is between 45-55% RH.
Why? Because at this level, it is not moist enough to for most mould, bacteria and other microorganisms to grow. Thus, this is our levels of “no concern” in our Building Biology Standards.
This image depicts different activity levels at different levels of RH (Arundel, et al).
The best way to know what the levels are in your home or workplace is to use a basic hygrometer, such as this one.
RH levels affect our comfort levels as well as our experience of temperatures
When RH levels are high, temperatures feel a lot more oppressive… Think “tropics” and “wet seasons.”
When RH levels are very low, we feel dry – our eyes, throat and mouth can become irritated as a result. Too, we may experience more static electricity.
Why is Humidity an Issue?
Humidity is an issue because when a material is cold enough, this moisture will condense out of the air and can result in the proliferation of mould. Read more about condensation here.
In a recent trip to far north Queensland, I witnessed first hand what regular high levels of RH were like. The temperatures remained stable in the high 20s (celcius) and the RH levels were around 86% night and day. The buildings I saw had the air conditioning running full pelt, and as a result, there was water streaming down all the windows.
On further investigation, it was apparent that the building materials had varying temperatures, and some were cold enough to be below dew point. The result? In technical terms: mould in the interstitial spaces of the building… hidden mould – aka “invisible mould.”
Discover more…
In the video below as I share with you how to manage humidity in our homes.
Understand the difference between desiccant dehumidifiers and refrigerant dehumidifiers and which one is best for you.
Condensation is an enormous issues in buildings, whether they be older buildings with single glazed windows and/or no insulation OR brand new buildings that are built to be energy efficient.
“My Building Is New, There is No Mould”
So I am told by many people when they call about at assessment of their home.
“I have NO MOULD, Everything is Dry Now…“
Others tell me. And I even hear:
“There is No Mould in My House… but There is a Musty Smell”
Mmmmm.
<<Picture me rubbing my chin and nodding slowly>>
All three of these cases do not preclude the presence of mould. The other thing to remember is that you cannot always smell mould when it is present.
Here is a video I did to explain about buildings built to code:
So why are we talking about mould when we started with condensation?
Mould has very basic needs: food and moisture.
Food is everywhere. Moisture can be controlled.
Condensation – Why is it an Issue? What is it? How Does it Form? Where Can it Occur?
It is an issue because it forms whenever a building material, or air, reaches dew point. What this means is that the material becomes cold enough to condense water out of the air – which is when droplets form… condensation. Condensation forms on the warm side of the material… Think about a bottle of cold water. The droplets of condensation form on the outside of the bottle.
In winter, a house that is warmed could have condensation forming under the metal roof or in the walls on the inner side of the sarking. As well, it often occurs on the inside of windows.
In summer, a house that is cooled could have condensation forming on the outside of windows, on the outer side of sarking and even within the building envelope where there are changes in temperatures.
This is a problem because it can result in building materials becoming wet enough to support the proliferation of mould (aka mould growth).
This can occur in roof spaces, wall cavities, window frames, and so on.
Research done by Dewsbury, et al, found that buildings built to code may be water damaged and mouldy within their first winter.
This is a big deal.
Condensation can be a large contributing factor to the mould burden in a building – so do take it seriously.
Essential oils can be used for many things – cleaning, mood enhancement, health, personal care products, perfumery, in your bath, in a burner, pest repellent, and on and on.
However, they do need to be used with care.
One drop of essential oil goes a very long way. When you put them in a burner, just use no more than 3 drops at a time.
Unless you are under the care of a qualified aromatherapist, NEVER EVER ingest any essential oil.
My Favourites
Two of my most regularly used oils are OREGANOand THYME.
This is because of the work that I do.
Of all the essential oils, oregano and thyme essential oils are the best at killing mould. Hence the regularity of its use.
When I have been in a mouldy house or workplace, despite wearing all my protective gear, I wash my clothes with a few drops of it.
Here is a video I did to explain what to look for, so that you get good quality ones.
* Please be aware that some people are very sensitive to essential oils.
Note that even though they are sourced from nature, and not synthetic, many people are very sensitive to them, particularly those with chemical sensitivities.
Also, everybody has individual nuances, and as such, even oils like lavender may not have the calming effect that they are traditionally known for.
As with everything, be slow and careful. I embrace the precautionary principle and encourage you to do the same.
One other important consideration is our pets – many pets are extremely sensitive so please consult your vet for advice.
Gutters – They Can Play a Large Role in the Health of Our Buildings
Gutters collect the water that come off the roof.
The roof is like a rain hat of our home.
Hidden Mould
I have been to so many homes that have water damage and mould because of poorly maintained gutters – and this is easy enough to avoid.
What happens when gutters are not maintained?
Generally, they overflow.
But not always.
In some cases, the water can run towards the house and end up in wall cavities! This is one cause of “hidden mould” and it can still affect your health – even if you can’t see or smell it.
This is situation where it is often hard to detect what the problem is. Often there are no obvious signs – to an unskilled eye.
So, what to do?
Simple – create a regular maintenance schedule.
How frequently this needs doing will depend on where you live.
Factors such as the amount and type of trees, how close they are, do they drop their leaves each autumn, and so on can all help to determine how often you should be cleaning the gutters.
I recommend starting with a quarterly/seasonal clean… and then during autumn/fall more often.
How Can I Tell If My Gutters Need Cleaning?
The most reliable way is to get up on a ladder and have a look.
Another way is to look for any signs of plant growth… I call this the “gutter garden.” When there is enough dirt and debris in the gutters, plants will begin to grow. It is pretty severely blocked at this point.
One final way is to observe what happens when it rains. Do you see water cascading over the sides? This shows that your gutters aren't coping with the rain. Often this will occur when they are blocked. It can also occur in extremely heavy rain, especially when there is hail.
So keep an eye out. Observing is a wonderful skill.
There are many ways to kill mould, but this does not make it safe for your health.
Dead mould is called “unviable” and alive mould is called “viable.”
Mould is everywhere, however only about 25% of the spores are viable. The rest aren't, which means they are dead.
In terms of health, mould, viable or not, is a problem.
Parts of mould break off, these are called hyphae.
There are spores released to start new colonies. Some contain mycotoxins and others contain microbial volatile organic compounds (mVOCs).
Some moulds are particularly irritating, allergenic or problematic for health.
Yet for people who are sensitive or sensitised to mould, ANY mould can be a problem.
Here's a video that I did… Mould Unwanted: Dead or Alive
Please excuse the start where the writing is mirrored – I hadn't realised it would do that. 🙂
In my years, I have assessed a lot of places (hundreds of them). In many I have found mould, dead and alive.
Mould is often not visible – and can also be hidden.
Remember, mould doesn't have to be alive to be an issue.
The first part of a water damage and mould Indoor Environmental Health Assessment is the visual inspection. My eyes are trained, and I can easily spot potential issues.
Role of the Health Practitioner in Mould and Health
With the growing awareness of the impact that mould has on our health, there is quite a lot of activity in many areas of the community. As someone who works in this field, it is exciting to see the burgeoning interest of the health practitioner (medical through to alternative health) and that they are getting on board to support people in reclaiming their health. However, it is also somewhat frustrating.
Why?
Because health practitioners are knowledgeable in their modality of understanding the health of the body and what to do to support it.
Where it gets frustrating is when health practitioners try to operate outside their scope and claim some mastery of understanding mould and the building, and then what to do.
As both a health practitioner AND a building biologist, I straddle both camps and deeply understand and appreciate the different perspectives.
The Problem is This…
Usually someone who is sensitive or sensitised to mould has done the rounds of health practitioners (medical to alternative) and has spent a good sum of money on tests. Many of these people are struggling to retain an income due to the health issues they face.
When health practitioners recommend testing that does not further the rectification of the issue, what happens is that more money is spent and often a wrong conclusion is achieved.
ERMI – its Role and its Limitations
ERMI (environmental relative mouldiness index) is a test that was developed as a quantitative indicator in settled residential dust of the presence and predominance of mould species associated with indoor fungal growth on building materials. The test was developed to use in scientific research, has been successfully used for this purpose, but is not optimised or recommended for use in individual houses.
The test provides a number associated with the “mouldiness” of a building, ranging from -10 to +20, permitting comparison with a database of 1,083 randomly selected US homes. Of the tested US homes, 25% exhibited an ERMI score of -4 or less, and 25% exhibited a score of +5 or more. A home measuring 0 on the ERMI scale would fall in the middle at the 50th percentile “mouldiness,” with half of all homes tested having values below that number and the other half having values above. A 90th percentile home would therefore be considered very mouldy compared with the average home, and a 10th percentile home, minimally mouldy.
ERMI is Limited
The ERMI metric looks at 26 species of mould more common in water damaged homes. As well, 10 species of mould commonly found in US buildings without water damage are also included.
The use of the ERMI metric has been validated in the US and several other countries, but not in Australia. This is important due the difference in building materials and design, construction techniques, climate and so forth. All of these factors can all influence the ERMI results.
People have an expectation that an ERMI test will be similar to a pregnancy test. That there's a 99% likelihood of telling you are pregnant when you really are. And a 99% likelihood of telling you that you aren't pregnant when you really aren't. In other words, that there will be very few false positives and very few false negatives. In Australia, we do not have any data with which to judge how accurate these results are. Many homes that are tested may be returning false negatives and false positives.
The ERMI test was originally done by vacuuming a large surface area of dust composited from the bedroom and living room floors, but now the methodology relies on the use of a swiffer cloth. This approach hasn't been validated.
Further, laypeople collecting samples themselves tend not to use the standardised methodology either, and can introduce positive and negative biases in the readings as a result, increasing false positives and false negatives.
Other types of mould samples (surface and air) identify hyphae and spores, fruiting bodies, and so forth. These potentially provides clues about nearby fungal growth. ERMI is looking at the total mass of genetic components. These details are absent, and therefore the clues are missed.
A Large Standard Deviation = Reduced Useful Information
The ERMI metric has a +/- 3 factor (standard deviation) as described by Vesper (2009). So given a final result of 3, the result is really somewhere between 0-6.
Mould is the most visible part of excess indoor dampness. There is a myriad of other components in the microbial stew initiated by excess indoor dampness. These include increased exposures to multiple allergens such as dust mites, cockroaches, and rodents. The results from ERMI only look at mould.
ERMI doesn't provide information that helps to pinpoint the cause or location of the moisture problem.
The ERMI test doesn't help with full identification and development of a remediation plan. A skilled assessor (Indoor Environmental Health Consultant or occupational hygienist) needs to step in and:
Conduct a thorough assessment to locate the problem and the cause
Address the cause – a mould issue is a moisture issue, after all
Do another set of testing that is accurate and useful
So, What Should a Health Practitioner Do?
First and foremost – recognising that there may be a problem with mould and referring onto the appropriate professionals.
What Else?
There are loads of ways that a health practitioner can support their client/patient.
I have offered a lot of really useful and practical ways that you can help your clients/patients in this webinar.
Understand mould and the important role it plays in our environment;
Become familiar with water damaged buildings and how they can impact health;
Become clear on your role as a health practitioner;
Introduction to a tool to assist in supporting clients to achieve greater wellbeing.
References
Tang, W (2007) Petition to EPA
US EPA Office of Inspector General (2013) “Public May be Making Indoor Mold Cleanup Decisions Based on EPA Tool Developed Only for Research Applications” in Report No. 13-P-0356 (22 August 2013): 1-13
Vesper, S (Feb 2009) “Understanding ERMI: How to Get the Most Value from the ERMI Scale” The Synergist (February, 2009): 40-43
Vesper, S, McKinstry, C, Haugland, RA, Iossifova, Y, Lemasters, G, Levin, L, Khurana Hershey, GK, Villareal, M, Bernstein, DI, Lockey, J & Reponen, T (Jan 2007) “Relative Moldiness Index as Predictor of Childhood Respiratory Illness” J Expo Sco Environ Epidemiol. (January 2007); 17(1): 88-94
Let's first explore humidity – to set the scene and give context to the rest of this post.
What is Humidity?
Humidity is the amount of water vapour in the air. It is important to know and understand this, particularly if you have any water damage or you live in a humid environment.
Humidity is commonly measured and discussed in two ways.
Firstly, there is relative humidity – this is the one we hear about a lot. When you think of being somewhere tropical, where you feel clammy despite having just showered, these areas will have a high level of relative humidity. The level is given as a percentage, for example 62%.
Relative humidity is the measure of how much water vapour is in the air and varies according to the temperature, in that it is relative to the temperature. The warmer the air, the more water vapour can be held and thus the relative humidity level will be higher.
Specific humidity is a different measurement and does not vary with temperature. It is expressed as gpk (grams per kilogram) or gpp (grains per pound).
Ideal Levels of Humidity
There are no ideal levels for specific humidity. As a building biologist, the different readings in different rooms can show me where to look further for water damage, and this requires quite specialised equipment.
Relative humidity is the one that is easiest to measure and changes can be quite noticeable in the way it feels. This is the one more closely related to comfort. Relative humidity is easily measured using an inexpensive hygrometer, such as this one.
Most people generally feel comfortable when the temperature is between 18-24oC and the relative humidity is between 35-75%, beyond this people generally feel uncomfortable.
When relative humidity levels are high, the air is uncomfortably moist – you may feel hot and clammy, sticky or just damp.
When relative humidity levels are low, you may feel quite dry – dry eyes, dry throat, dry skin, “parched”; you may even experience more static electricity.
The optimum level for relative humidity is between 40-60%.
Bacteria, viruses, fungi and house dust mites all are less active; and these biological contaminants can be highly problematic for health, and form part of the microbial stew.
Occupant Activity and Humidity
Humidity can result in water damage.
In our homes, there are four main ways for water damage to occur. The first is a disaster of some sort, eg flooding. The second is damage to the building, eg a burst pipe, tiles coming off the roof, a leak. The third is poor building design or poor workmanship, such as not having an exterior vent on an extractor fan, having bedrooms with no opening windows, running the downpipes to the underneath of the house… And the fourth (which can often be overlooked) is occupant activity.
Occupant activity can cause a lot of water damage. Some examples are:
not using the extractor fan when bathing
using a clothes dryer
spilling liquids and not cleaning them up quickly
Examples of Moisture Created from Occupant Activity
The following is from Elkink and Pringle's 2012 book Building Basics: Internal Moisture – and these levels, I am sure, will amaze you!
Activity
Creates
Showering and bathing
Varying levels of moisture depending on temperature of shower, length of time, ventilation.
People in a room
Awake we exhale 200ml of water vapour per hour. Asleep we exhale 20ml per hour. This is roughly 3L of moisture per day.
Unflued gas heaters
0.5-1L of water per hour.
Cooking
Varies depending on method (e.g. boiling and steaming), if the heat source is gas; and includes kettles, microwaves, dishwashers and washing dishes.
Clothes washing and drying
Up to 5L per load can be released if clothes are dried inside on a rack.
All produce enough heat and water vapour to require additional mechanical ventilation systems.
Humidifiers
Increase the humidity in a room and can result in condensation.
Accidental floods
Overflowing baths, sinks and laundry tubs can all create problems if not dried within 24-48 hours.
Roof space ventilation
This is important particularly if extractor fans are flued into the roof cavity, and not vented externally. Changes in pressure can cause moisture and other contaminants to enter the building.
Steam cleaning
A potential problem is created if the materials are not completely dry within 24-48 hours.
Leaking pipes and appliances
A very large problem, which will vary depending on what, where, how much, and how long before it is rectified.
A normal subfloor
Evaporation from a 93m2 subfloor is 45L of moisture per day, and up to 180L per day if there is standing water on the subfloor soil.
Ventilation
As you can see, there are a lot of ways that we can fill our homes with moisture – inadvertently, which is one reason why ventilation is important. My ideal would be for every home to exchange all of the air every few hours, and yet reality brings us back to at least once a day.
My favourite thing to do is to open windows and doors in the morning until I feel the temperature change, and I know that all of the air in my home has been exchanged.
I'll come back to this a little later, but it is important to note that moisture moves to where levels are lowest… So, if there is less humidity outside, then opening your windows can allow the moisture to dissipate out of your home. If the relative humidity is higher outside, then it could be better to open your windows and doors when this has changed over.
How to Use a Dehumidifier
A dehumidifier takes the water vapour out of the air and it can be used to bring relative humidity levels back into the optimum zone – between 40-60%.
I like people to have them, particularly when the cause of the moisture is occupant activity or a lack of ventilation (such as a rented property with no extractor fan in the bathroom).
Here is a general step-by-step guide for how to use a dehumidifier for the initial deep-drying. Please note that every house is different, so this is merely a guide.
If you have pets, like birds, etc, please take them out of the room first.
Close the windows and doors of the chosen room.
Open cupboards and drawers in this room.
Set your dehumidifier to 30% relative humidity.
If temperature of the room is low, turn on the heater (or the heater on the dehumidifier) for optimum drying.
Run the dehumidifier for 24-hours a day for 1-3 days.
A good dehumidifier will automatically turn itself off when its water tank reaches capacity – so you should be able to run it while you are at work (they are a bit noisy, so this is preferable to running them overnight).
After this initial drying phase, you can use it periodically to dry the room.
NOTE: If there is water damage and/or mould, I recommend that a) the source of the water is addressed and b) if anything is wet for more than 48 hours that the resultant mould be addressed first.
When Else a Dehumidifier is Useful
A dehumidifier, as mentioned is great for moisture caused by occupant activity.
My #1 use for a dehumidifier, in an ongoing way, is to use it in the bathroom or ensuite when bathing. Despite using it regularly, it always astonishes me the amount of water vapour that a shower can produce.
It can also be used when you are exchanging the air in your home, and the outside relative humidity is higher than the indoor relative humidity.
If you get a good one, it will also have a heater on it. This is beneficial as you now have a clothes dryer – that doesn't add moisture to the air! Simple hang your clothes on a rack and run the dehumidifier nearby (wishing I had one when I lived in the Blue Mountains, where it took weeks to dry my laundry!)
Which One Do I Recommend?
I have sought out one that I like (I stock it for this reason) – I personally own this model and use it every day.
This is the New Wide Tech All Seasons 35L Dehumidifier.
Basically, bigger is better, it does the job more efficiently and has a greater water capacity.
What else to look for?
variable humidity settings
the water tank will automatically signal when it is full and the dehumidifier will stop working
a ceramic heater to help dry more quickly and allow it to work well in cooler climates
option for continuous drainage
When a Dehumidifier is Not Enough
As much as I am a fan of the dehumidifier (pun not intended) – there are times when one is not enough. My biggest concern with recommending them is that someone may have water damage to their property with resultant mould.
Mould spores are everywhere and just need water as the spark of life… anything that is wet for longer than 48-hours can be a problem – even if it is dry now.
Read more about mould here and mould, water damage and health here.
A dehumidifier is fabulous for occupant activity, but not ideal (without professional assessment) when there is something more going on, eg structural damage…
So, these factors would give you an indication that you should look beyond just drying out the room with a dehumidifier:
You (or someone in your household) is unwell, and generally, your health improves when away from the home
You have mould
Your home (or parts of it) smell musty, mouldy, damp, dank or earthy
Your clothes are always damp
There is a history of water damage in your home
You have a leak
There is water under your house
Obviously, the above list does not cover everything. Mould is a serious problem, and it is a moisture issue. Addressing the source is paramount to resolving the issue.
(This post is intended to be informative, and not an infomercial. Given the gravity of biotoxin/mould-related illnesses, please understand that I do need to point out the limitations, and how you can action the situation.)
References
Aderholdt, J (3 August 2011) The Insulation Lab (Online) Available at http://www.ntcinsulation.com/the-insulation-lab/moisture-_psychrometrics_and_relative_humidity_-_their_effect_on_structure_and_air_quality (accessed 28 November, 2016)
Elkink, A and Pringle, T (2012) Building Basics: Internal Moisture Building Research Association of New Zealand, Porirua, New Zealand
ProAir (2011) Indoor Air Quality (Online) Available at http://www.proair.ie/the-technology/indoor-air-quality/3/ (accessed 28 November 2016)
