Ironstone Pre Mixed Lime Render

 

 

 

 

 

Our range of Natural Hydraulic Lime Renders are manufactured with NHL 3.5 binder from Heidelberg Materials Socli and blended with kiln dried sands. They are combined with carefully selected additives to improve the renders physical and mechanical properties, whilst maintaining all the virtues of a pure Natural Hydraulic Lime render.

Usage

For use externally in building conservation where the binder strength is appropriate for the host background / surface.

Advantages

  • Quality controlled production
  • Features the feel of a modern render
  • Significantly improved workability and reduced risk of shrinkage
  • Slower drying; better curing
  • Salt resistant

 Ironstone Basecoat Render 

Ironstone Basecoat Render is suitable for coarse render coats typically known as scratch and float coats. The addition of the alkaline fibres in the recipe provides reinforcement and improved tensile strength of the scratch and float coats, assisting to mitigate cracking on high suction backgrounds.

Ironstone Finishing Render 

Ironstone Finishing Render is suitable for finishing render coats externally. Do not use these products below 5 degrees or if freezing conditions are predicted over the following few weeks,  and do not use if temperatures exceed 30 degrees.

 

Coverage

After mixing, a 25kg bag will produce approximately 15 litres of mortar. A single 25kg bag will cover 1.5m2 at 10mm thickness onto a flat wall.

 Surface Preparation

Dense impervious backgrounds will require little to no dampening, whereas very porous backgrounds will require adequate dampening to prevent rapid drying. Ensure surfaces are clean and free of dust and other debris.

 

Colours

These products are entirely natural.

Ironstone Basecoat Render - made with an off-white sand which results in an off-white render whenfloated.

The Ironstone Finishing Render - made with a blended yellow sand which gives a light tan coloured render finish. This render gives a textured finish when floated with a plastic or wooden float, the finish is smoother when sponged but still moderately textured.

 

How to Mix

A 25kg bag of Ironstone Basecoat Render will require 4 to 4.5 litres of clean water. A 25kg bag of Ironstone Finishing Render will require 4 to 4.7 litres of clean water. Always avoid making the mix too wet, as this can promote shrinkage issues.

First add around 60-70% of the water followed by the Ironstone Basecoat Render / Finishing Render and
mix until the water is fully distributed, then add additional water to the desired consistency. Mix for 5 – 10 minutes. Ironstone Basecoat Render may be re-worked for up to 14hrs. Whisk mixers are also suitable for use.
Like most lime renders and plasters this blend will benefit from quenching. Allow the mix to stand for 10
to 20 minutes after mixing before use.

Ironstone Basecoat Render

Suitable for use onto masonry backgrounds with some suction. For application on to very smooth or highly porous backgrounds then a coat of Ironstone Bonding Coat should be applied first. Wood wool render carrying boards like Celenit are also suitable substrates. Ironstone Basecoat Render should be used as a minimum two coat system as a single coat application will ghost through the background.  

 

 

Always wet a substrate, including previous render layers, to control suction before use. However, you don’t want to be laying onto water sitting on the surface as this will act as a slip layer. Dub out the wall to bring it roughly flat by filling pockets, voids or missing pointing with a relatively stiff mix. After dubbing out a shallow scratch coat should be applied to areas filled. Allow 48hrs for this to stiffen sufficiently to take the scratch coat. Keep these areas damp by misting until scratch coat is applied.

The scratch coat should be applied at a target thickness of 10-12mm, this should be scratched using a crosshatch pattern scratch to approximately 1/3 of the depth of the render. The more common wavy line scratch used on cement renders is not suitable for this type of material. This coat should be left for 7 days to build up strength to take the float coat. During this time the render should be damp cured by mist spraying, and protected from direct sunlight / drying winds, preferably with damp hessian. The float coat should be applied at a target thickness of 8-10mm and should not be thicker than the scratch coat. This should be floated with a wooden or plastic float to compress the surface, lime renders should be stiffer than cement renders at time of floating and shouldn’t drag under the float. Optionally this can be sponged up after it’s stiffened to give a smoother surface of this is to be the topcoat.

If the Ironstone Finishing Render is to be applied, then this coat should be devil floated to give a light key and allowed to cure for 5-7 days. During this time the render should be damp cured by mist spraying, and protected from direct sunlight / drying winds, preferably with damp hessian.

 

Ironstone Finishing Render 

Our Ironstone Finishing Render is a topcoat render for application on Ironstone Basecoat Render, Cornerstone Insulating Render or Wood wool render carrying boards like Celenit. Always wet a substrate, including previous render layers, to control suction before use. However, you don’t want to be laying onto water sitting on the surface as this will act as a slip layer. 

Apply at a target thickness of 5mm and finish by floating plus optional sponging.
This blend is also suitable for scoring lines in to create a false ashlar blockwork appearance. If doing so aim for a target depth of 7-8mm to allow for 4mm scoring lines without pulling the coarse aggregate in the basecoat.

When applying to Cornerstone Insulating Render apply at a target thickness of 5mm and finish by floating plus optional sponging. When applying to render carrying Wood wool boards the suction from the board should be adequately
controlled before application. Apply two coats the first coat should be applied in a ‘two pass, one coat’ system. Applying the first pass at 5mm then embed 7mm render mesh with a trowel then immediately recoat to give a total thickness of around 7mm. Apply a scratch coat without pulling through the mesh.

Damp cure and protect for 7 days before applying a second coat at a target thickness of 5mm, finishing by float and optional sponging. After application the render should be kept damp to promote the cure by mist spraying, and protected
from direct sunlight / drying winds, preferably with damp hessian, for two weeks.