Henry

SF311 Synko-Flex Primer

Solvent-based primer · US · manufacturer-sourced

Check your container: This countdown is for the Solvent-based primer variant. Similar-looking versions may have different times.

How long does Henry SF311 Synko-Flex Primer take to dry?

Short answer

Set / hardened: 1 day after application.
Safe to touch: 3 hours after application.
Roof coatings and roofing sealants

Weather-window plan

Rain-ready comes long before fully cured

  1. Apply the Solvent-based primer to a dry, clean roof surface
  2. Keep rain off for the stated period
  3. Allow foot traffic only at the stated time

This product’s stated stages Quoted at 66°F and 50% humidity

  • Safe to touch3 hours
  • Set1 day

Worth noticing: Safe to touch at 3 hours; set at 1 day.

Common mistake: Starting a coat when the afternoon forecast turns wet.

Roof coatings and roofing sealants

Coat timeline

Plan the next coat and final use separately

  1. 1
    ApplyUse the Solvent-based primer directions and prepare for primer.
  2. 2
    Next coatUse the listed recoat milestone; do not substitute touch-dry time.
  3. 3
    Normal useWait for the applicable handling, water or cure milestone.

Plan around the weather

When did you apply the coating?
Conditions that affect drying
Where?
Thickness

Stated times

  • Safe to touch3 hours
  • Set / hardened1 day

From Henry data sheet · checked 2026-10-25. Anything not listed isn’t stated by the manufacturer.

Manufacturer website: henry.com

Conditions & fine print
  • Stated conditions: 66°F (19°C) and 50% relative humidity
  • Roof coatings need a dry surface and a rain-free window. Dew, fog, cold nights and thick coats all lengthen the times. Follow the current data sheet.
  • Apply at 50°F or above
  • Region US. Formulas can differ between countries; check your container.
  • Safe to touch: At 66°F and 50% relative humidity.
  • Set / hardened: At 66°F and 50% relative humidity.
  • Entered from the cited manufacturer documentation. Check the current label for the exact formula and region. Report outdated information
  • Actual results depend on preparation, thickness, ventilation, temperature, humidity, mixing and substrate.

Confirm this is your product

Closely named formulas, colors and regional versions can use different times. Match these details to your container before starting a countdown.

Exact listing
Henry SF311 Synko-Flex Primer
Variant
Solvent-based primer
Region
US
Listed use
primer
Timed stages recorded
touch, set
Source checked
2026-10-25

Documentation: Technical data sheet · Revision Date 10/10/2025

Condition attached to the stated time: At 66°F and 50% relative humidity.

About this product

A solvent-based primer. The numbers match HE910, 3 hours to touch and 24 to set, but they are measured at 66°F rather than 68°F, and the sheet wants 50°F and rising for application.

Using this specific product

Henry SF311 Synko-Flex Primer is listed here as the Solvent-based primer version for primer. For coating or sealing a roof, the useful question is not simply whether the surface looks finished—it is whether the exact next-action milestone shown above has been reached.

Before you start

  • Confirm the package says Solvent-based primer; related versions can use different timing.
  • For primer, pay particular attention to roof temperature, dew, rain in the forecast, film thickness and how many coats are needed.
  • At 66°F and 50% relative humidity.

How to check readiness

Check that the surface is dry and that no rain or dew is forecast inside the stated window. Touch only a hidden edge first; a dry surface can conceal a soft layer underneath. The data sheet gives a set time of 24 hours.

Avoid this mistake

Rain resistance and walkable are earlier milestones than the full cure the roof system is rated for.

Compare with similar products

Keep going

Questions

How long does this product take to dry?

Henry states: The data sheet gives a touch time of 3 hours. Conditions: At 66°F and 50% relative humidity.. The data sheet gives a set time of 24 hours. Conditions: At 66°F and 50% relative humidity.. These are the manufacturer’s stated times, not a guarantee.

Is SF311 the same as HE910?

The drying numbers are the same, touch 3 hours and set 24 hours, but they are measured at 66°F on SF311 and 68°F on HE910. They are separate data sheets.

How long until this product is safe to touch?

Henry states: The data sheet gives a touch time of 3 hours. Conditions: At 66°F and 50% relative humidity.. These are the manufacturer’s stated times, not a guarantee.

What affects how long this product takes to dry or cure?

Roof coatings need a dry surface and a rain-free window. Dew, fog, cold nights and thick coats all lengthen the times. Follow the current data sheet. Follow the product label for your conditions.

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