Posted on April 2, 2019April 1, 2019 by @wb_vixerFinishing and Sealing Failing Cinder Block Bulkhead. We created a Waterproof box out of Cinder block walls and thin poured concrete floor. Sealing top edge of Bulkhead at Bilco Edge. Bulkhead Wall and Floor Coated with Perma-Block Sealer System Sealing around Stair Cleats in Cinder Block Bulkhead. Message us on Facebook and we can look at your situation.