Cornerstone Marine L4 Mortar

Product Description

Cornerstone Marine L4 is a dry ready mixed hydraulic lime mortar designed for exposed marine applications above the water level. Among the marine range, the Marine L4 stands out as the lowest strength and slowest setting, yet it enables a more capillary-active and vapour-permeable marine mortar, with a set time of approximately 8 hours at 17°C. Available in the colour buff.

Engineered with precision, using natural hydraulic lime and natural sands to create a high-performance mortar for freshwater and saltwater applications, allowing for a more capillary active marine mortar with a slower setting time and additional flexibility. Further, a longer open time makes this mortar undemanding to apply and finish. Available as standard with Saint-Astier® NHL5.

Well-suited for fresh or saltwater environments above the water level, where a fast-set is not required, or the project requires the absence of Portland Cement.

• The lowest strength of the marine mortar range
• Roughly 8-10 hours of working time at 17°C
• Features an attractive off-white natural finish
• Contains no Portland Cement
• Contains no synthetic polymers
• Designed for flexibility and an aesthetic natural finish
• No pigments to prevent colour fading
• Maintains the natural colour of the sands
• Features an attractive off-white natural finish

Area of use

Suitable for external use, where the binder strength is appropriate for the host background or surface.

Relevant for marine building and pointing work applications, including freshwater and saltwater environments above the water level, where tidal washout poses minimal risk. For a faster setting time or for areas submerged underwater, explore Marine LP6. Appropriate for various project types, including conservation or renovation.

While Marine L4 is entirely natural in colour and absent of any pigments, the environmental conditions and curing process will affect the final colour achieved. For colour-sensitive projects, our team can provide guidance on curing methodology.

A 25kg bag will produce approximately 14.5 litres of mortar and fill roughly 1.5m² of joint at a depth of 10mm. The width and depth of the joint will influence this estimation. On-site trials are advised for the best yield indication for your specific project.

Supplied in 25kg polythene-lined and colour and batch-code paper bags for easy identification on-site and palletised for ease of transport, storage, and handling. FIBC tonne bags are also available.