Outline specification : plastering, rendering, masonry, pointing

Product Description

Unilit 45 is a traditional, dry premixed mineral finishing mortar based on natural hydraulic lime as the binder and appropriate well-graded aggregates.

Unilit 45 is characterised by a slow but strong bonding, a high plasticity, a low content of soluble salts and an excellent water vapour permeability. 

The natural hydraulic lime mortar is inherently stable and designed to reduce problems of micro cracks along with premature drying out.

The natural hydraulic lime binder, used to prepare the preblend, conforms to the European Standard EN 459-1, NHL 5 for building limes.  The mortar Unilit 45 conforms to the European Standard UNI EN 998-1.

Application Area

Unilit 45 is a traditional natural hydraulic lime mortar, which has been applied for centuries in our cultural built heritage. Unilit 45 is, therefore, especially suited for all kinds of applications applying traditional building materials both in new construction, renovation as well as restauration. Unilit 45 can be applied as a finishing coat for both plastering and rendering, or as a bedding and/or pointing mortar in the case of traditional masonry constructions with thin mortar joints (joint widths up to 5 mm).

Thanks to its natural pore structure and low content of soluble salts, Unilit 45 regulates the moisture content within the masonry, eliminating practically all known problems related to frost, salt damage and lime bloom, providing that excessive damp and/or salt problems are not prevelant, and that the substrate is stable.


Prior to application, the substrate must be cleaned and freed of all traces of oil and grease. The substrate benefits from being slightly dampened. Saturation of the substrate is not recommended, as this will influence negatively impact upon the bond of the hydraulic lime mortar to the substrate as well as the aesthetic appearence.

The mortar is mixed with clean water at a ratio of +/- 4 litres of water to a bag of 25 kg ready mixed natural hydraulic lime powder. Mixing is undertaken with a slow speed electric paddle for a period of 3 to 4 minutes. A creamy workable mortar is obtained, which has approximately 2 hours of open time.

When used as a fine finish the mortar is applied in two passes, fresh on fresh, at a total thickness of about 5 mm and consequently sponged, flattened or polished with a trowel to achieve the desired finish. When used for thin (re)pointing  the mortar is applied with a small pointing iron and pressed firmly within the joint. At the end the masonry surface is cleaned with a soft brush in order to remove all excess mortar remains.

Unilit 45 may not come into contact with surfaces below ground level. 

If desired, a coloured finish can be applied afterward with a mineral paint, either a lime wash or either a silicate paint. A drying period of 1 to 2 days must be respected. 

The mortars must not be applied at temperatures below +5°C nor when a risk of frost exists. They should never be applied on to a frozen surface or in the case of thick fog. In hot, windy and dry conditions measures should be taken to prevent accelerated drying out of the freshly applied mortars. Applied mortars must be protected from frost and direct sunlight for 48 to 72 hours after their application.

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