Lime Mortar in WA - Why, Where & When To Use It

Lime Mortar

Bricks Fix WA specialises in limestone repair, mortar repointing and heritage brickwork restoration across Perth, Fremantle, and Western Australia. In this guide, we explain why lime mortar is essential for historic and coastal buildings, when to use it, and how to choose the right type for the job.

History of Lime in Western Australia

Lime mortar has been a key building material in Western Australias colonial history, particularly in heritage structures like:

  • Fremantle Prison

  • The Perth Mint

  • Historic limestone buildings in Fremantle and East Perth

Early builders used lime from local limestone, producing breathable, flexible mortars that are still protecting walls over a century later.

Where Lime Comes From

  • Locally quarried limestone (burnt to make quicklime)

  • Imported Natural Hydraulic Lime (NHL) from Europe (used for restoration work)

Suppliers include Lime WA Inc, Saint-Astier, and WA Limestone.

Types of Lime for Heritage Brickwork

1. Lime Putty (Non-Hydraulic)

  • Made by slaking quicklime in water

  • Carbonation set absorbs CO from the air to harden

  • Ideal for historic lime rendering and repointing

2. Natural Hydraulic Lime (NHL)

  • Reacts with water to set (hydraulic set)

  • Comes in different strengths:
    - NHL 2 Soft (interior or sheltered work)
    - NHL 3.5 General-purpose external repairs
    - NHL 5 Stronger, for exposed and marine environments

3. Hydrated Lime (Builders Lime)

  • Often sold in bags at Bunnings

  • Not suitable on its own for heritage work

  • Sometimes added to cement but not a substitute for lime mortar

Lime vs Cement Mortar: Why Lime is Better

Lime is the correct material for old brickwork and coastal homes.

Advantages of Lime Mortar:

  • Breathable: Allows moisture to escape

  • Flexible: Prevents cracks caused by building movement

  • Self-healing: Microcracks reseal naturally

  • Softer than bricks: Prevents damage to heritage masonry

Why You Should Never Use Cement Over Lime

  • Traps moisture, leading to rising damp

  • Causes bricks to spall and crumble

  • Creates rigid, incompatible joints

  • Can cause long-term structural damage

Coastal Brickwork: Lime Mortar Near the Sea

In suburbs like Fremantle, Cottesloe, and Rockingham, salt damage is common. Lime mortar is perfect because it:

  • Resists salt efflorescence

  • Allows walls to breathe and dry out

  • Matches the softness of limestone and heritage bricks

Bricklaying, Repointing & Restoration with Lime

At Bricks Fix WA, we use lime mortar for:

  • Repointing historic brickwork

  • Restoring lime render on limestone walls

  • New builds using traditional techniques

  • Heritage-listed site repairs

Projects we've completed with NHL and lime putty include:

  • Fremantle Prison restoration

  • Perth Mint conservation

  • Heritage repointing across Subiaco, Albany, and Perth CBD

Does Lime Mortar Need to Be Replaced?

Yes, but lime mortar is designed to weather naturally over decades. It:

  • Wears down before bricks do (sacrificial)

  • May need replacing after 80 to 100 years

  • Is easier to repair than cement joints

Lime repointing restores your walls strength and breathability without harming original materials.

How We Mix Lime Mortar at Bricks Fix WA

Every job is unique, but here's how we typically mix mortar:

  • NHL mix: 1 part NHL 3.5 or NHL 5 to 2.53 parts sand

  • Lime putty mix: Matured for 3+ months, fine washed sand

  • Additives: Sometimes we use pozzolans for faster set or strength

Colours are carefully matched to the original mortar for invisible repairs.

Lime Safety & Storage

Lime is alkaline and must be handled with care:

  • Always wear gloves, goggles, and a mask

  • Avoid contact with skin and eyes

  • Keep bags sealed and dry

  • Let lime putty mature in airtight tubs

We follow strict safety guidelines to protect workers and buildings.

Storage Tips for Tradesmen & DIYers

If you're storing lime for later use:

  • Keep NHL in a cool, dry area

  • Use within 6 months of opening (ideally)

  • Lime putty can last years if kept airtight and covered with water

Final Words

Lime isn't old-fashioned if it's just done properly. Using the correct lime mortar protects your building, keeps it breathing, and ensures long-term integrity.

Whether you're restoring a Federation-era home, a limestone cottage, or repointing a heritage wall, Bricks Fix WA has the skill and experience to do it right.

Need Help With Lime Mortar or Heritage Repointing?

Get in touch with Bricks Fix WA today:

  • Heritage Specialists

  • Lime Repointing Experts

  • Serving Perth, Fremantle, and Regional WA