Lime render

Composition

Pure natural hydraulic lime (NHL 5) + natural aggregates selected to grading curves suited to each use. Generic lime compositions (NHL 5 to EN 459-1). No synthetic additives.

Made in

Belgium

Unilit natural lime finishing coat on brick masonry, off-white with a slight grey tint: a section of wall framed tight and head-on, with no sky or openings (private house in Wingene-Zwevezele)

A range of 9 natural hydraulic lime (NHL 5) render mortars: Unilit 15 (bond coat), 20 (VOLCALITE thermal insulation), 25 (lightweight base coat), 30 (damp remediation), 35N/M (pointing/base coat), 35F (fine pointing), 40 (water-repellent finish), 45 (finish), 65 (repair/patching). Suitable for restoration and new build, with high vapour permeability.

The material

What is lime render?

Installation

Installation & uses

Close-up of the texture of an Unilit natural lime finishing coat, cream to light beige, fine to medium grain, with the brick courses showing through the finishing coat (Jezus-Eik site) — Close-up of the texture of an Unilit natural lime finishing coat.

Trowel application and smoothing of a light lime finishing coat on a test panel, during an Arte Constructo demonstration session — Trowel application and smoothing of a light lime finishing coat on a test panel.

Colour chart of Unilit lime render shades, twenty-four swatches — Colour chart of Unilit lime render shades.

About the producer

Arte Constructo is a long-established Belgian producer of mineral mortars, renders and limewashes, based in Schelle near Antwerp. The company develops the Unilit range in natural hydraulic lime, as well as the Coridecor and Keim decorative ranges, for restoration work and new build.

It works with a network of specifiers and restorers, and provides technical support before work starts on site. The Coridecor range extends Unilit into finishes, from Corical limewash to Marmolux and Venestuk Venetian stucco, with the same mineral approach.

See the technical data

Facade rendered in cream Unilit lime, white window frames — Facade rendered in cream Unilit lime.

Technical performance

Density

Range: 1,250 to 1,600 kg/m³ depending on variant…

Vapour diffusion μ

μ = 10 (Unilit 45, measured to EN 1015-19)

Reaction to fire

A1

Strength

Unilit 45 (finish): tensile strength ~0.35 N/mm²…

Binder: EN 459-1 (lime). Rendering mortar: EN 998-1. Strength: EN 1015-11/12. Density EN 1015-10. Grading EN 1015-1. Fire EN 13501-1. Vapour permeability EN 1015-19.

FAQ

What strength does the render reach?

Unilit 45, used as a finish, reaches around 0.35 N/mm² in tension to EN 1015-12. The range includes other mortars (Unilit 15, 25, 30, 35N-M, 35F, 40 and 65), each with a grading and strength suited to its use.

How does it behave in fire?

Class A1, non-combustible. The binder falls under EN 459-1 and the rendering mortar under EN 998-1.

Alongside

Same layer, same use · three materials to compare.

Float glass sheets stacked on edge, showing the green tint of the edges

Envelope EPD

Low-carbon glazing

Float glass with a high recycled cullet content. AGC · Seingbouse.

Envelope

Cork granules

Collected and crushed corks. De Vlaspit · Belgium.

Dry hemp-lime mix held in both hands, against a soft neutral background

Envelope

Loose-fill hemp-lime

Pre-dried hemp shiv and lime. Exie · East Flanders.