and/or is circulated to allow it to take the moisture from the primer. Warmth and airflow are the only routes to success here but do not try to force dry with direct heat, as this can cause them to skin too quickly and not be well bonded.
Smoothing compounds: Standard smoothing compounds have quite a controlled cure that is two-part. The first is reactivity of the cements / binders and the second is evaporation of the excess moisture used to make the smoothing compound flow. So, as with DPMs and primers, cold, damp conditions with poor airflow will delay the curing profile. If you cannot get the time to let the compounds cure and cannot get the site conditions improved then why not, where appropriate, select a rapid curing smoothing compound, such as Bostik’s Screedmaster Speed 30? These are generally designed for fast turnaround projects allowing flooring to be done in a day. The chemistry of the products differ, enabling the moisture levels to reduce much more quickly and for the strength build up to be much faster. The right products will give you the advantage in cooler conditions of still being ready for flooring the following day, which helps to minimise time on site.
epoxy, PU and MS type products, the argument is more akin to that of DPMs, albeit sometimes a hint of moisture in the atmosphere can benefit some of these adhesives.
“The small amount of solvent present in some
adhesives gives the ‘kick’ needed for them to tack off in colder weather,
but all the environmental and hazard concerns mean we are moving away from this style of adhesive.”
as 20o C, sometimes 23o
rule of thumb is that reactivity rates can halve for a drop of 10o
cure can well be doubled on sites at, for example, 10o
C to 12o
C. The general C, so the time to C compared to
that stated on the datasheet. However, the temperature of the substrate also has a major impact and can reach as low as 5o
C, so the curing time may be
increased even further. Suddenly an overnight cure can be more than 24 hours. The solution here is to utilise an accelerator or rapid curing system to counteract the temperature deficiency, but do not go below the minimum curing temperature or the product will not perform as expected.
Primers: Normally these are water- based and so the obstacle here is how quickly the water can escape to leave the primer film as desired. Damp as well as cold conditions will delay the drying of water-based products simply due to the fact that the air above the primer does not actually want any more moisture. You need to ensure the air above is warmer
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Floor coverings: This is where it gets a bit tricky. For floorcoverings to perform properly the manufacturers, particularly resilient manufacturers, know that ambient conditions are critical for the flooring to be sufficiently flexible to cut and to keep the end curl to a minimum. The recommendation always has to be to get at least to their minimum temperature requirements. It may not be so critical with textiles but from my experience they do suffer from high ambient moisture conditions, and in the case of fibre bonded, also cold temperatures. The key here is to get decent conditions.
This is not inclusive of all the issues that you may come across during the winter months but will hopefully get you thinking. If site conditions are poor can you use different products? If so are they technically suitable for your installation, or is it a case of fighting the main contractors for better working conditions?
Adhesives: The adhesive argument is pretty much the same as for primers with most adhesive now being water- based with minimal solvent. The small amount of solvent present in some adhesives gives the ‘kick’ needed for them to tack off in colder weather, but all the environmental and hazard concerns mean we are moving away from this style of adhesive. When it comes to reactive adhesives including
For further information on the extensive range of subfloor preparation and adhesive products available from Bostik, please email
flooring.uk@
bostik.com or call 01785 272625.
www.bostik.co.uk
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