Roundtower Marine P30 Mortar
Roundtower Marine P30 Mortar is a ready-mixed natural cement mortar developed for building, bedding, and pointing masonry in marine and water-bearing environments. Manufactured using Prompt Natural Cement and natural sands, it provides rapid strength development, high durability, and excellent resistance to tidal washout.
Positioned between Marine P15 and Marine P50 within the Cornerstone Marine range, Marine P30 offers increased strength while maintaining good workability, making it suitable for coastal structures, tidal masonry, harbour works, canals, lock walls, and conservation projects. Unlike lime mortars, it does not rely on carbonation to harden and can therefore be used in permanently damp or submerged conditions.
Technical Data
| Property | Value |
|---|---|
| Product Type | Ready-Mixed Marine Mortar |
| Binder | Prompt Natural Cement |
| Aggregate | Natural Sands |
| Colour | Natural Tan |
| Application | External |
| Workability Time | Approx. 45–50 Minutes at 17°C |
| Yield | Approx. 14.5 Litres per 25kg Bag |
| Coverage | Approx. 1.5m² Pointing @ 10mm Depth |
| Performance | Water Resistant |
| Fire Rating | A1 |
| Standard | BS EN 998-2:2016 |
| Packaging | 25kg Bags |
Key Benefits
High Strength Marine Mortar
Developed for marine and water-bearing environments requiring greater durability than lower-strength marine mortars.
Water Resistant
Suitable for masonry exposed to saltwater, freshwater, tidal action, and repeated wetting and drying cycles.
Rapid Set
The Prompt Natural Cement binder develops strength quickly, helping reduce the risk of washout in exposed locations.
No Carbonation Required
Hardens hydraulically, making it suitable for permanently damp and underwater applications.
Sulphate Resistant
Suitable for aggressive coastal and marine environments.
Portland Cement Free
Contains no Portland cement or synthetic polymers.
Typical Applications
| Application | Suitability |
| Sea Walls | ✓ |
| Harbour Structures | ✓ |
| Lock Walls | ✓ |
| Canal Structures | ✓ |
| Coastal Masonry | ✓ |
| Tidal Zone Repairs | ✓ |
| Marine Pointing | ✓ |
| Water-Bearing Masonry | ✓ |
| Conservation Projects | ✓ |
Why Use Marine P30?
Marine P30 is designed for projects where a robust, high-strength mortar is required but where the highest-strength marine mortars may be unnecessary. It provides a balance between strength, durability, workability, and water resistance, making it suitable for a wide range of coastal and marine masonry applications.
Its rapid set, sulphate resistance, and ability to cure in damp conditions make it particularly useful where masonry is exposed to regular wetting, tidal movement, or aggressive environmental conditions.
Installation Overview
1. Surface Preparation
Substrates should be clean, sound, and free from loose material.
2. Mixing
Mix with clean water in accordance with the manufacturer's guidance.
3. Application
Suitable for pointing, building, and bedding in marine and water-bearing masonry applications.
4. Protection
Do not apply below 5°C or above 30°C. Protect fresh work from frost, heavy rain, direct sunlight, and drying winds.
5. Storage
Store dry, covered, and protected from moisture, frost, and ground contact.
