Secure the Notched Capstone
At 0:14 in
Such a small detail, makes all the difference. #hardscape 
What happens here
Once the notched capstone fits perfectly, it's time to permanently secure it to the retaining wall. Apply a generous bead of landscape adhesive (a strong, weather-resistant construction adhesive designed for masonry) to the top surface of the retaining wall blocks where the capstone will rest. Alternatively, if using mortar, apply a consistent layer with a trowel. Carefully lower the notched capstone into its final position, ensuring it aligns perfectly with the adjacent blocks and the wall's edge. Press down firmly to seat the capstone into the adhesive or mortar. Use a rubber mallet to gently tap the capstone into place, ensuring it's level and well-bonded. Immediately wipe away any excess adhesive or mortar with a damp sponge before it cures. Allow the adhesive or mortar to cure for the time recommended by the manufacturer, typically 24-72 hours, before applying any pressure to the capstone or continuing with further landscaping.
Goal: Permanently install the notched capstone for a finished look.
Tools and materials
- Caulking Gun DAP — Applying landscape adhesive
- Damp Sponge — Wiping away excess adhesive or mortar
- Level — Checking the horizontal alignment of the capstone
- Rubber Mallet Estwing — Gently tapping the capstone to ensure proper seating and level
- Trowel Marshalltown — Applying mortar if used instead of adhesive
- Landscape Adhesive Loctite PL S30 — Securing the capstone to the retaining wall
- Mortar Mix Sakrete — Alternative to adhesive for securing capstones
- Water Tap water — Mixing mortar and cleaning