#MAPEITechTip: Do I have to wait until Spring? —Tiling tips for cold weather climates

It’s that time of year again when you have to get up just a little bit earlier in the morning —as you go through the morning ritual of scraping the windshield and warming up the pickup.  Since Winter is in full swing, taking the extra time to prepare for work is just a necessary part of living in the colder climates.
 
Installing tile or stone in cold weather requires adjustments too to ensure proper product handling and installation procedures. Most industry specifications only recommend setting tile or stone between 50°F and 95°F. When you are no longer setting tile in 85°F weather, understanding how cold, dryness and wind affect setting mortars, grouts and adhesives will ensure a better installation.
 
Since these conditions can prevail at months on end both in the Northern and Western parts of the United States and typically all of the ‘Great White North’ in the Canadian Territories, it’s important to consider not just the ambient temperature, but more importantly the temperature of the substrate, along with all of the subsequent installation layers—tile or stone, mortar and grout.  Typically room temperature is the ideal setting scenario, 72ºF-74°F and an relative humidity 30%-50%, whenever temperatures drop below 60°F and the relative humidity is higher than 70%—allow for extended periods of curing time. 

For example in cold weather, the water in the mortar or grout can freeze, particularly near the surface. The resulting small ice crystals can expand, separate the sand and cement particles, and completely destroy the internal structure of the mortar or grout. This can cause loss of strength and ultimately bond failure.  Since cold weather slows the strengthening process of cement-based mortars and grouts, it is important to allow more time for the curing process.  As the temperature drops from 50°F to 35°F, the curing process slows until, at 35°F, the hydration process slows dramatically.  When the temperature is between 40°F and 50°F, no grout should be installed until the tile or stone mortar is sufficiently set (typically after 72-96 hours). 

It is important in these conditions to look at all the components—the latex additives when exposed to freezing conditions can affect, spoil or destroy certain freeze/thaw-sensitive latex additives.  So it is crucial to carefully read each product’s set of instructions, especially the requirements for freeze/thaw protection.  MAPEI’s tile setting additives such as Granirapid ® System (powder & liquid additive must be used together as a system), Keralastic™, and Keraply™ are freeze/thaw-stable down to 0°F.  Even so, during freezing conditions, it is important to ship setting materials in heated semi-trucks and keep them in dry, heated, even on the jobsite.  Leaving these products in the pick-up truck over night or until they are needed, alleviates any good shipping practices and could compromise the performance of the mortar during application.
 

When working in cold weather climates there are some advantages when using polymer-modified single component mortars—as long as the bags are kept dry, they can be transported over long distances without the need for special protection against freezing.  During the production of these Dried Latex Polymers—all the moisture is removed by a high-speed spinning process, leaving only the dried polymer powder.  This powder is then blended with the sand and cement into a single component, polymer-modified mortar.  When you add water to the mix on the jobsite these are then reconstituted to create a polymer-modified mortar (ANSI A118.15, A118.4 & A118.11) offering excellence performance in various climates, including mild cold weather applications.

When cured, two-component mortar systems like Kerbond T/Keralastic™ System, Keralastic™, the latex (in place of the water) mixes with the sand and cements particles as they begin to grow and expand—creating a stronger more deformable mortar.  Due to the high polymer content in these two-component mortars and increased flexural strengths (ANSI A118.15, A118.4 & A118.11) these mortars are a great choice in severe cold weather climates, especially as the temperature plummets below zero for months at a time.

In addition to the polymer added to mortars to improve bond and deformability, another feature that helps in cold weather applications is rapid-setting mortars and by extension rapid-setting grouts.  These rapid-setting products, like Granirapid® System, Ultraflex™ LFT Rapid and Ultracolor® Plus grout can substantially reduce curing time—reaching initial cure in just 3 to4 hours.  This is achieved using calcium aluminate technology in place of traditional Portland-based cements—significantly reducing the hydration time and exposure to the elements.  Always keep in mind that whenever you have the potential for increased ‘cycles’ of movement due to extreme cold and freeze/thaw, selecting the right mortar and grout will greatly increase the success of the installation.  

In addition to selecting the right mortar and grout for the project, there are some preventative measures that can be taken on the jobsite to ensure that the installation materials are within manufacturers’ guidelines for storage on-site.  It is also key to make sure that all on-site materials are delivered, stored and acclimatized at least 24 hours before work begins.  Maintaining an adequate temperature level in the working environment may require building a temporary shelter and using indirect auxiliary heaters. Electric heaters work better than fossil-fuel-burning heaters in providing a more even, constant temperature and in preventing surface chalking, carbonation, and weakening of the fresh mortar and grout.   When using a blower heater, make sure that the tile area directly in front of the heater is shielded to prevent rapid drying. (Always follow all federal, state and local laws governing safe practices for auxiliary heating).  In addition, keep substrate surface and ambient temperatures in the tiling areas at no less than 50°F during installation and for at least 7 days after work is completed or 72 hours for rapid-setting mortars and grouts.  It is important to remember, that even on interior projects like walk-in coolers and freezers, these same principles apply to maintain the ambient air and substrate at 50°F or warmer.

Following these basic principles will eliminate the need to shut-down all your exterior tile and stone projects until Spring, keeping you profitable all year round!