Ironstone Pre Mixed Lime Mortar 

Our range of Natural Hydraulic Lime Mortars are manufactured with NHL 3.5 binder from Heidelberg Materials Socli and blended with kiln dried sands. The sands are prewashed to remove sediment before being dried.

The Ironstone mortars are natural and highly workable, combining long term durability with breathability for building and re-pointing. The range has been developed to ensure a traditional heritage finish and is available in a range of 12 colours with various aggregate sizes as specified - just add water.

Ironstone premixed mortars are batch blended for consistency and naturally coloured from a range of sands to give the desired finish and texture.

Masonry walls built with Ironstone Lime Mortar provide:

  • Improved breathability
  • Protection of masonry from frost and damp damage
  • Long term durability
  • Reduced susceptibility to sulphate attack
  • Naturally flexibility reducing the chance of cracking
  • Environmentally friendly - Lime mortars actively absorb CO2 from the atmosphere.

 

 

Usage

Suitable for applications in building conservation where the binder strength is appropriate for the host background / surface.

Coverage

After mixing, a 25kg bag will produce approximately 14.5 litres of mortar sufficient to repoint 3 - 5m2.

Advantages

  • Quality controlled production
  • Consistency of mix ratio
  • Significantly improved workability and reduced risk of shrinkage
  • Improved and even cure which offers an improved bond with the substrate.
  • Extended working and finishing time.
  • Can be used on high suction backgrounds
  • Suitable for use in listed and heritage building

Surface Preparation 

Before pointing or building , clean and remove all dust and loose material from joints and masonry.

Where necessary the background should be adequately dampened to promote adhesion/ bond with the host surface

How to Mix

Slowly add 25kg of Ironstone Mortar into a drum mixer. Add only 4 to 5 litres of clean water. Pour the water in slowly as the product mixes, using just enough to achieve the correct workability. Mix for 5–10 minutes. Lime mortars benefit from being left for 15 mins to fatten after mixing and can be reworked. Ironstone mortars may be re worked for up to 8hrs.

Always avoid making the mortar too wet as this can promote shrinkage. Whisk mixers are also suitable for use.

It is possible for settlement to occur in the bag in transit, hence if mixing a part bag ensure the contents are thoroughly blended prior to mixing with water. If you don’t use the full amount of mortar, just seal the remaining in a tub or bag.

How to Apply

Apply using a hawk and appropriately sized tuck pointer. Ideally pull back on fresh mortar when applying i.e. if you’re right handed apply from the right side and work towards the left or vice versa if left handed. Leave sufficient time to finish with a churn brush the same day or the following day in cooler periods.

How to Finish

To ensure good compaction and adhesion the mortar should be tampered firmly with a bristle brush as it starts to firm up, normally after 2-4 hours. This process also brings the sharp aggregate to the surface creating a lovely textured finish. The mortar will benefit from a further brush the next day before continuing with fresh pointing.

 

Curing and Why

 

Natural Hydraulic Lime (NHL) mortars do not set as quickly as modern cement based products. NHL starts to set once water is added and hardens by reacting with carbon dioxide which is a slow process. Strength and long term durability are achieved over months, not days. Protect the mortar against the effects of drying winds, strong sunlight, rain and frost. In warm weather gently mist spray with water over a few days after application and cover if required with damp hessian. In cold weather cover fresh mortar with protective layers of hessian to help avoid frost damage.

As soon as the mortar is applied it will start to do its job of sucking excess moisture out of the surrounding stone and brick work. Where the masonry is particularly wet then the mortar may well look patchy over the first few days until all the moisture has been passed out to the atmosphere, and the mortar has had chance to cure. Then the colour will become consistent. In cold conditions this process can bring lime to the surface which appears as small specs, these can be just brushed away