Q&A With the Experts at Sika

Q&A With the Experts at Sika

Following are some of the frequently asked questions regarding Sika roofing systems:

Is 28 days an acceptable amount of time to install a Sika roofing system over a new concrete pour?

The 28 day “cure time” is not related to the amount of time before the roofing system may be installed. The 28 days is the amount of time by which a concrete deck meets its specified structural strength. It has no correlation to moisture content or drying time required. Sika’s position is that the decision for timing of roofing over the concrete is best left to the project designer, general contractor, concrete contractor and suppliers since they have more knowledge of the concrete formulation and moisture release rates. These parties should advise the roofing contractor when to proceed, but the roofing contractor makes the final decision as he is ultimately responsible for accepting the substrate condition

What concrete curing agents are acceptable when installing a Sarnafil roof?

Sika does not have a list of approved curing compounds for concrete. Per Sarnafil guide specs, roof decks shall be installed and cured in accordance with industry standards. The surfaces shall have a smooth and level finish and shall be free of dust, excess moisture, oil-based curing agents and loose debris. Under no circumstance shall a sealer be used in lieu of a curing agent. If the Sika roofing assembly includes insulation boards and is being mechanically attached over the concrete substrate, the compatibility is of no concern. If the insulation is being adhered with one of Sika’s insulation adhesives, then an adhesion test shall be completed. It has been our experience that a typical concrete curing compound (NOT a sealer) that does not contain petroleum distillates does not create any compatibility or adhesion issues.

What is Sika’s minimum distance requirement between pipe penetrations?

As an industry standard, the typical distance required between pipe penetrations in order to properly flash with Sarnafil flashing membrane is 12 inches. This allows the installer of the flashing boots enough room to properly weld the flange to the base membrane. However, if an installer can flash penetrations that are closer than 12 inches apart and is able to properly hot air weld enough flange to the base membrane so that it passes the Sika technical rep’s inspection for warranty purposes, it is acceptable to Sika. This situation typically occurs with field fabricated flashings, rather than molded pipe boots.

Photo: Courtesy of Sika. Ranck Mill Road Real Estate, LLC, Adhered EnergySmart Roof using 60 mil Sikaplan membrane

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