Outline specification : flooring, plastering, roofing, lime slurry

Product Description

Unilit 15 is a traditional, dry premixed multi purpose mineral bonding layer based on natural hydraulic lime as the binder and appropriate well-graded aggregates.

Unilit 15 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 15 conforms to the European Standard UNI EN 998-1.

Application Area

Unilit 15 is applied as a bonding bridge when the background is unable to guarantee an optimum bonding of the subsequent base and finishing coats. Therefore, Unilit 15 is applied in the case of unstable backgrounds such as reinforced concrete, old deteriorated masonry, old lime washes, etc.

Unilit 15 prevents undesirable spots from occuring within the finishing coat due to differences in material properties in the background. Unilit 15 can also be applied as a preparatory treatment for completely saturated backgrounds.

Unilit 15/P0 can be applied as a fine egalising filler when old lime renders are removed.

Unilit 15/P1 can be applied either in a slorry layer as a lime wash using a brush, either as a 2 to 4 mm thin finishing layer using a trowel.

Unilit 15/P2 can be applied as a keying or priming coat in a maximum layer of 5 to 8 mm. Hence, Unilit 15/P2 is applied as a base coat for the Limetics external thermal insulation composite sytem with lime rendering.


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 5 to 6 litres of water to a bag of 30 kg ready mixed natural hydraulic lime powder (25 kg in case of Unilit 15/P1). Mixing is undertaken with a slow speed electric paddle for a period of 3 to 5 minutes. A creamy workable mortar is obtained, which has approximately 2 hours of open time.

When used as a fine egalizing render the mortar is applied either manually or by mechanical means at the required thickness. When used as a lime wash the mortar is applied in two layers, fresh on fresh, with a soft brush, with particular attention paid to the filling of fissures, cracks and gaps.

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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