Can polyurethane sealant be used for water immersion?
Filling with water? Check whether the exact product allows that exposure and how long you must wait before filling.
For Vulkem 116, water immersion needs a separate suitability check. Tremco lists it for certain water immersion applications, but excludes chlorinated, potable, heavy and waste water. It’s approved for exterior use only. Get confirmation for your submerged joint before specifying or buying it.
Read the exact product sheet first. If it leaves your underwater exposure unclear, ask the manufacturer to confirm it’s suitable for that use. Polyurethane chemistry alone isn’t enough to choose a sealant for underwater service.
Start with the water and the location
A chlorinated pool or drinking-water tank? Vulkem 116’s exclusions rule it out. The sheet also prohibits use inside an occupied building, even when nobody is present during application.
Have another exterior immersion job? Tell Tremco whether the joint stays submerged or is periodically drained, and send the water type, any treatment chemicals, water temperature and expected depth. Give them the joint dimensions and both bonding surfaces too. Get written confirmation that the product suits the job, along with instructions for installing it.
You can’t confirm that Vulkem 116 suits your particular submerged joint just from its listed uses. It’s designed for poured and precast concrete, masonry, window and door perimeters, and similar construction joints.
Set the filling date before you start
Before you promise a filling date, get the waiting time confirmed for the conditions on your job. Neither the wait before immersion nor the full-cure time is given in the supplied sheet.
It lists a typical skin time of 6 hours. The tack-free time is 30 hours at 23°C and 50% relative humidity. Neither entry states when the joint can go underwater. Don’t use either number as permission to fill.
Check the surface condition too. Tremco says not to apply Vulkem 116 over damp, green or contaminated surfaces. Don’t schedule application onto a wet joint.
What to settle before ordering
Ask the manufacturer to confirm the product, water exposure, surface preparation, any primer, joint backing and bead dimensions, plus the required cure period before immersion. Keep those instructions with the job specification.
You can’t use this sheet as a full set of instructions for installing a submerged joint. It allows immersion only under certain conditions, so don’t recommend the product for underwater use in general.
Get the immersion approval settled before you order. Check the [Vulkem 116 product details](/vulkem-116/) first. Still need help choosing what to buy? Send Cranco your joint size, substrates, water type and planned filling date.