Cornerstone Heritage Mortar & Render

Description

Feebly Hydraulic Mortars

These mortars are made with a high calcium CL90 blended with selected pozzolans to give specific properties; they do not carry the EN459 designation “FL” as we are blending the materials as a mortar and not a binder, but in effect, these mortars are “FL” mixes. They are made at quite rich mix ratios to give a fatty and workable mortar with a high free lime content, this is common to many weaker historic mortars and allows for sympathetic repair of certain historic masonry types. These mortars do contain some modern additives, however, they have been tested in conjunction with multiple binder types to show a limited impact on mortar performance, especially with relation to capillary function and vapour permeability. If an “additive-free” mortar is required to meet a specification we do offer other products in our “Heritage Range” which are free from modern mortar modifiers.

The Argical M1000 modified mortars are highly vapour permeable and highly capillary active; their strength starts to develop around 2-3 days after mixing with water and 80-90% of the strength typically develops in the first month (depending on how well it’s cured). Typically final strength from the pozzolan is achieved within 2-3 months and only carbonation slowly allows the strength to increase over time.

The Rhine Trass modified mortars are more vapour permeable than NHL mortars, however, the Trass has the effect of reducing capillary function quite significantly. Trass gives a weaker strength than the Argical mortars typically starting to set at around 3-4 days with final strength achieved after approximately 4 months. Trass also imparts a warm buff colour to the mortar, giving a lovely aesthetic finish when used as a render.