I was a Machinist Mate in the Navy and thus almost all of my training was mechanically focused. One class I had was Electrical Theory for Mechanics. The quick summation by the Senior Chief instructor for it was "Electricity is magic and when the smoke comes out the show is over." Being on a submarine it was deemed a good thing to keep water and electricity separate. My first time ever using polyurethane chemical grouts was on a group of sixteen conduits entering a below-grade mechanical room. While electricians may understand the "magic" of electricity they often fall short as waterproofers. Combined with the fact the numerous electrical cables coming through a conduit can be notoriously hard to waterproof and it is a recipe for leaks and electrical problems. In this post, I'll share step-by-step instructions, along with a couple of photos from a recent job one of our customers completed in a San Francisco condo complex.
Oakum soakem is a kindergarten-skill level procedure that makes waterproofing these types of penetrations easy. I refer to this as fingerpainting with chemical grouts.
- For PVC and HDPE pipe roughing the surface will increase the mechanical bond and is recommended.
- Wet the application area.
- Soak oakum in either Spetec F400, GT500, or GT380 resin until saturated.
- Pack soaked oakum into pipe joint to be sealed. If necessary, pack multiple layers. Ensure it is under compression.
- Allow grout to cure.
Often this is all that needs to be done, but it can be followed up with injection to fill the conduit if required.
- Stab injection needle through the cured grout and oakum plug.
- Inject grout.
Photo: Contractor on a recent job in San Francisco, addressing multiple conduit leaks with electric injection pump, a pail of Spetec PUR F400, and Oakum.