How Long Do You Have to Let Mortar Set Before Grouting?

Written by tim anderson | 13/05/2017
How Long Do You Have to Let Mortar Set Before Grouting?
Different thinset mortars have different drying times. (Thinkstock Images/Comstock/Getty Images)

Thinset mortar is a cement-based product used to adhere ceramic tiles and natural stones to substrate surfaces such as floors and walls. Thinset is manufactured in a range of types, with varying chemicals depending on the type of material the mortar is designed for and whether it is a rapid setting mortar, an epoxy mortar or just a standard cement mortar. Each type has a different curing time associated with it before you can safely grout your tile or natural stone installations.

Fortified Thinset Mortars

Fortified thinset mortar is the standard thinset mortar used in man-made tile installations such as ceramic and porcelain. A latex-modified thinset, this mortar has additives already mixed into the mortar to fortify it; all you need to do is add water according to the manufacturer's instructions to use it. As a standard rule, 24 hours is required before light traffic or grouting can be allowed, although temperature and humidity can change the drying time.

Multipurpose Mortars

Thinset mortars that are designed to be used for tiles or stones, such as slate, granite, marble or travertine, are multipurpose mortars. Medium-bed (thick) thinsets, multipurpose mortars have additional additives to help them hold up under the weight of natural stone as well as adhere to additional substances, such as plywood, which regular thinset cannot. As with regular fortified thinset, a minimum of 24 hours set time is generally recommended by the manufacturer, although climate can affect the drying time.

Rapid Setting Mortars

Rapid setting mortars are those mortars that are specifically designed to cure over a period of just a few hours in comparison to traditional mortars. A special blend of quick-setting polymers, rapid setting mortars are ideal for repairs or small areas in commercial settings, such as bathroom floors, that need to be completed within a certain amount of time. Grouting can generally be performed roughly two hours after setting your tile or natural stone.

Epoxy Mortars

Special mortars designed for commercial applications, epoxy mortars are also used for areas where improved chemical resistance is required, such as in hospital bathrooms, restaurant kitchens and cafeterias. Epoxy mortars are not cement-based mortars; rather, they are two or three-part chemical mortars designed specifically for heavy-duty and chemical-resistant applications. Curing time is based upon temperature and can range from 16 hours to 72 hours before grouting is allowed.

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