Seattle, WA

The owners of the 41st Avenue Condo located in Seattle, WA were in need of a waterproofing solution for the over occupied, plywood penthouse deck and plaza deck over the parking structure other than the typical deck coating system. The local Sika sale representative and Sika LAM Tech Service worked with J2 to design and specify the RoofPro system to fit the high moisture climate of the Washington area. Sikalastic 621 TC system was able to be successfully installed by Charter Construction and Trinity Waterproofing over the existing urethane deck coating on the plywood decks without complete removal. The ability of the Sikalastic Moisture Triggered technology made working in the damp Seattle environment much easier for the applicator.

Project Success

The project was a win for all parties. After discovering the benefits of Sikalastic 621 TC, Charter Construction went on to use Sika's RoofPro system for future applications. Trinity Waterproofing continues to be one of the valued applicators in the Seattle area with many successful projects completed.


  • Engineer: J2
  • General Contractor: Charter Construction
  • Contractor: Trinity Waterproofing