Elastomeric Coatings for Concrete

In terms of field applied,  they are now available in water-based, acrylics and thermoplastics with ultra-bonding, cross-linking chemistry and acrylic elastomerics  Bottom line is that the same solar reflective IR pigment technology is used and high levels of reflectivity are available, color-for-color as in the factory applied paints. These field-applied coatings clean up with water, are very low toxic and have a higher overall thickness once they are fully dried. However, in order to bond to failing, older Kynar coated metal roofs, some manufacturers are now making specialized “hot” primers,  that meet the VOC requirements and adhere very well to the older coated metal.  The acrylic colored IR coatings can be applied over this bonding primer and stick very well.  It is common with some manufacturers to also to have a clear sealer put on over the finished coloured reflective coating in order to protect the colour coat further, just like the similar purpose clear sealers commonly used on automotive finishes.  This clear coat or “glaze coat” further adds to the dirt shedding quality of the steep-slope, metal roofs.

When full water-proofing is also required for the metal roof, a class of flexible, waterproofing coatings called “elastomerics” is required to seal the metal roof as a whole system. 

How Do Thermal Roof Coatings Work?

One should also remember that roof tiles are laid in a certain way – to allow airflow under the tile.  Applying a coating to the exterior of the tile won’t stop that airflow, neither will it stop warm air from escaping through roof vents, soffit vents, through gaps between tile overlaps, around lead work etc. Even a roof without visible vents can be cold and breezy, that’s perfectly normal.

This is why the government and energy companies refuse to offer grants for thermal roof coatings - they simply don’t work.

It is much cheaper to increase the amount of loft insulation you have above the ceiling or to have cavity wall installation installed. 

So next time you see a website or leaflet boasting about how this thermal coating can reduce tile heat loss by 10-20%  etc just remember, very little heat goes directly through the tiles, most goes around it! And for good reason – to prevent condensation.

That is why your loft is always cold in winter, even if the house below is warm.

The purpose of protection is to keep the habitable part of the house warm that is why on most homes the insulation is placed above the ceiling, not on the exterior of the tiles.

Ensure that you have good quality insulation above the ceiling and you won’t have to worry about heat going through the ceiling, let alone through the roof tiles.