Roundtower Marine P50 Mortar
Roundtower Marine P50 Mortar is a ready-mixed natural cement mortar developed for masonry exposed to marine, tidal, and water-bearing environments. Manufactured using Natural Cement and 5mm down sharp washed flint sand, it provides rapid strength development, high adhesion, and excellent resistance to washout, making it suitable for coastal and submerged conditions.
Positioned between Marine P15 and Marine P60 within the Cornerstone Marine range, Marine P50 offers a balance of workability and high strength for demanding marine repairs, harbour structures, seawalls, bridges, and tidal masonry. Unlike lime mortars, it does not rely on carbonation to harden and can therefore perform in permanently damp or underwater environments.
Technical Data
| Property | Value |
|---|---|
| Product Type | Ready-Mixed Marine Mortar |
| Binder | Natural Cement |
| Aggregate | 5mm Down Sharp Washed Flint Sand |
| Mix Ratio | 1 : 2 |
| Colour | Natural Tan |
| Application | External |
| Workability Time | Approx. 30–40 Minutes at 17°C |
| Yield | Approx. 14.5 Litres per 25kg Bag |
| Coverage | Approx. 1.5m² Pointing @ 10mm Depth |
| Compressive Strength | Approx. 50 N/mm² |
| Fire Rating | A1 |
| Standard | BS EN 998-2:2016 |
| Packaging | 25kg Bags |
Source: Cornerstone Marine P50 Technical Datasheet & Cornish Lime Product Information.
Key Benefits
Designed for Marine Environments
Suitable for masonry exposed to saltwater, tidal action, coastal weathering, frequent wetting, and submerged conditions.
Rapid Strength Development
Develops strength quickly, helping reduce the risk of washout in exposed marine locations.
No Carbonation Required
Hardens hydraulically, making it suitable for permanently damp and underwater applications.
High Adhesion & Durability
Provides strong bonding and long-term durability in aggressive coastal environments.
Sulphate Resistant
Suitable for marine and salt-laden conditions where conventional mortars may deteriorate.
Portland Cement Free
Contains no Portland cement, synthetic polymers, or pigments.
Typical Applications
| Application | Suitability |
| Sea Walls | ✓ |
| Harbour Structures | ✓ |
| Quay Walls | ✓ |
| Lock Walls | ✓ |
| Bridge Masonry | ✓ |
| Coastal Pointing | ✓ |
| Tidal Zone Repairs | ✓ |
| Submerged Masonry | ✓ |
| Conservation Projects | ✓ |
Why Use Marine P50?
Marine P50 is designed for projects requiring greater strength and durability than Marine P15, while maintaining sufficient workability for general marine construction and repair works.
Its combination of rapid set, high compressive strength, sulphate resistance, and underwater curing capability makes it particularly suitable for coastal infrastructure, tidal masonry, and exposed marine environments where long-term performance is essential.
Installation Overview
1. Surface Preparation
Substrates should be clean, sound, and free from loose material.
2. Mixing
Mix with clean water or clear seawater free from biological contamination, silt, and sand.
3. Application
Suitable for pointing, building, bedding, and masonry repairs in marine and water-bearing environments.
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 and frost.
