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How To Identify Humidity and/or Temperature Issues

preventing a draft under doors

It is extremely important to make sure that you maintain the correct temperature for the chosen product. Be sure to check the datasheet or ring our technical line for confirmation as to any minimum / maximum temperature required, not only during the application process but also (as importantly) the curing process.

Cold Surfaces / Areas

Products applied at temperatures too low may never cure or at the very least will take far longer.  The fact that cold temperatures hold back the curing of the product may well mean that the product concerned may well never achieve the correct hardness.  Should this happen, this will inevitably reduce the longevity of the coating.

Most people simply take a temperature reading from the air temperature.  Whilst this does indeed give the general reading, don’t forget that hot air rises and the floor itself, assuming this is what you might be coating and/or repairing – may well be a lot colder.  It is therefore important to get a temperature reading of the floor itself.

A lot of our customers wish to paint the floor before moving into a building.  The building may well have been empty for a long time and warmth is required.  Again, remember that warm air rises and that whist ‘you’ may think the room is hot, the floor itself remains cold for a LOT longer.

We certainly advise heating the area for quite a period of time prior to carrying out the coating itself, in order to ‘warm up’ the fabric of the building.

Cold Spots!

It is also EXTREMELY necessary to identify cold spots as these are common reasons for failed ‘areas’!  Two places to check out are any perimeter walls that would be external walls where winter temperatures can transfer through from outside.  Another common place is to check for ill-fitting doors where freezing temperatures can be blowing through.  Again, these areas can be severely affected by this and guess where you need the strongest and hardest surface?  You’ve got it, I’m sure……right in the doorway.

External wall areas are harder to sort out but gaps under and/or around doors can be easily blocked, taped, sandbagged, etc, etc.  Of course, as you will undoubtedly be losing an incredible amount of heat through these areas, why not order some of our professional brush/rubber strips.  We even have roller shutter brushes and rubber bump strip – specifically for up and over roller shutters.

If you are applying next to fridges and freezers, the same thing can apply where the coldness of the room transfers through the substrate and can cause a lengthening of the curing process, even to the point of failure to cure.

Hot Surfaces / Areas

There is actually not much we can say here other than to identify the maximum operating temperature of the product concerned as products may well soften and affect their durability.

However, take great care when applying in hot temperatures as this will greatly reduce the pot life.  Should you be in awkward areas or in hot conditions, then it may well be advised to split the unit down but whatever you do, PLEASE make sure you split them correctly.  It is also strongly advised to stir the tubs thoroughly (individually) first BEFORE decanting into smaller units.

One very interesting point to note is that the surface temperature of the substrate to be treated can be A LOT HOTTER than the air temperature…!  We have known many a person to think a good warm day at 25°C is ideal to paint a surface, completely forgetting that the surface temperature in direct sunlight can be far, far higher.  This then means the coating gets too hot too quickly which in turn, means the applicant has an extremely difficult job of applying it quick enough…!

When in direct sunlight, it is important to remember that virtually all general building materials heat up, especially tarmac roads and paths and obviously, metal roofing and facades.  This may well mean that it would be better for the area to be covered to provide shade or indeed, that any treatment, repair or coating be completed early in the morning whilst the day/surface is still cool.

Relative Humidity (RH)

In ‘normal’ conditions, air contains water vapour, the amount however being primarily dependent upon the temperature of the air. In general terms, warm air can hold more moisture than cold air.

Therefore, as air temperature rises, its capacity to hold moisture also increases, so if air temperature rises and its moisture content remains the same, the RH decreases.

RH is calculated by the percentage of water vapour in the air in relation to the maximum amount of water vapour the air can hold.  For example, an RH of 60% means that the air contains 60% of the moisture it can possibly hold – at that particular temperature.  Should the moisture content reach 100%, the air is then referred to as ‘saturated’.

Humidity will not only facilitate the growth of fungi and mould but will also cause condensation to form on surfaces that are colder than the air temperature, hence why mould and fungus often proliferate on wall surfaces and condensation on the underside of roof surfaces – particularly metal.

The levels of humidity are primarily determined by the overall weather conditions and temperatures and these are obviously outside of our control.  However, water leakage from either rising damp or plumbing leaks, shower and wet room areas, swimming pools all contribute to the overall level of humidity.

High humidity levels cause a thin film of moisture (often so thin that cannot even see) to settle on the surface of the concrete.  The big issue when painting a floor is the sealing in of the moisture, which in turn causes the coating to bubble due to this trapped moisture rising through the coating.  When condensation settles onto uncured resin, this is when you will get what we call in the trade, an orange peel effect.  The ultimate problem of course is that it can cause complete delamination.

There is yet another issue with condensation onto the uncured resin and that is what is known as ‘blush’ or ‘bloom’.  This is where the water can also cause the colour to blush or a whitening of the surface.  This blushing may well not actually cause any great detriment to the coating other than the aesthetic appearance and can actually mostly be ‘washed off’ with warm soapy water.  However, whatever you do, please make absolutely sure the coating has had time to fully cure BEFORE washing.  Alternatively, if you can live with the appearance, the marks can often disappear through natural wear and tear.

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