Limelite NHL 3.5 Natural Hydraulic Lime

Tarmac Limelite NHL 3.5 is a moderately hydraulic general-purpose lime suitable for use in lime mortars and renders




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Natural hydraulic lime for building conservation

Limelite NHL 3.5 is suitable for conservation and restoration of historic buildings that were built with lime mortar.

NHL 3.5 natural hydraulic lime for lime mortar

Limelite NHL 3.5 can be mixed with a suitable sharp sand to make a lime mortar for repointing brick and stone walls built with lime mortar

Natural Hydraulic lime for internal plaster and render

Limelite NHL 3.5 can be used to make a lime render for internal or sheltered external use

Medium strength NHL 3.5 natural hydraulic lime

Limelite NHL 3.5 is ideal for standard brickwork above damp proof course

Technical Data Sheet (pdf)
Safety Data Sheet (pdf)
Safety Data Sheet Annex A (pdf)

Product Description:

Matching existing lime mortar aesthetic

Using lime mortars helps to maintain and complement the general colour and aesthetic when renovating or extending historic buildings of constructing new buildings in historic locations or conservation areas.

Porosity and breathability of lime mortars

Lime mortars offer better vapour permeability to allow moisture to leave the building. This also helps to reduce the risk of freeze thaw damage when trapped moisture freezes and expands.

Flexibility and reduced strength of lime mortars

Lime mortars are slow to harden and remain more flexible than modern sand-cement mortars, with lower compressive and flexural strength, which helps to accommodate movement such as settlement or thermal expansion without causing stress to other building materials like brick or stone.

Quality assurance

Our products contain no additives, mineral additions or Portland cement and are quality assured to EN 459-1: Natural Hydraulic Limes with independent third-party certification. They also carry a CE Mark.

Technical Data

Mortar Mix Proportions
NHL 3.5: Sand Typical Application
1.1 - Walls below DPC
- Chimneys
- Earth retaining walls
1.2 - External walls
- Copings and cappings
- Parapets and sills
1.3 - Facing to solid construction
1.4 - Internal Walls

Render Mix Proportions NHL 3.5: Sand (By Volume)
Substrate Basecost Finish Coat
Weak or porous (soft brick) 1:2 1:2.5
Medium strength 1:2.5 1:2.5
Impervious or dense brick 1:2.5 1:3
Plasterwork 1:2 1:3

Note: As a general rule, each successive coat should be weaker and/or thinner as you move away from the substrate

Batching and Mixing

Sand for lime mortars and renders should be sharp sand, clean and well graded, free of clay or silt. Building (soft) sands, or sands containing clay and silt, can cause excessive shrinkage.

Mixing water should be clean and potable. Adding too much water should be avoided as it leads to a reduced strength and an open structure susceptible to frost attack.

Mortars and renders containing natural hydraulic lime should always be batched by volume using batch boxes.

Sufficient mixing is required to ensure that the lime is uniformly dispersed throughout the mortar or render. Mechanical mixing is preferred and mixing times should be significantly longer than for cement-based mortar. The workability of the mortar improves with increased mixing time (however, avoid over mixing in hot weather). Allowing the mortar to stand in the mixer drum for a short period of time (10-15 mins), before a final remixing will also improve workability.

Use of Admixtures and Additions

Many proprietary admixtures (especially air-entraining admixtures) can be used successfully in natural hydraulic lime mortars. However, attention should be paid to the admixture manufacturers instructions and trial mixes are always recommended.

The use of proprietary admixtures with natural hydraulic lime is not usually necessary as the workability and frost resistance of mortars or renders based on natural hydraulic lime is usually adequate for most applications.

In certain circumstances however, the addition of materials such as pozzolans or ground blastfurnace slag may be used to increase the mortar strength. The addition of Tarmac Hydralime (hydrated lime) can also be used to improve the plastic properties of the mortar and/or reduce its strength. Trial mixes are always recommended.


Natural Hydraulic Lime should be stored in unopened bags clear of the ground in cool dry conditions and should be stacked in a safe and stable manner. Information on the maximum storage period can be found on the bag.

Contact us to order Limelite NHL 3.5 Natural Hydraulic Lime: