Repair Systems — 03 — Facade & External Envelope
NHL 5.0 natural hydraulic lime repointing mortar
Supplier reference for NHL 5.0 (eminently hydraulic) natural lime repointing mortar — the stronger NHL grade for repointing moderately hard historic brick and exposed parapets on Class 2 strata building facades where NHL 3.5 would erode prematurely. Compares Parex, Limemortar.com.au, and specialist heritage lime suppliers by distribution, technical performance, and suitability.
What is NHL 5.0 natural hydraulic lime repointing mortar?
Natural hydraulic lime (NHL) 5.0 repointing mortar is an eminently hydraulic lime mortar used for repointing moderately hard historic brick and exposed parapets on Class 2 strata building facades where the original mortar was lime-based. NHL 5.0 produces a mortar compressive strength of 5–15 MPa — stronger than NHL 3.5 and better suited to wind-driven rain zones and exposed locations. It remains breathable and softer than Portland cement mortar.
Product Reference
3 products — 3 suppliers — NHL 5.0 natural hydraulic lime repointing mortars — scroll to view all
Parex NHL 5.0 Natural Hydraulic Lime Mortar
NHL 5.0 natural hydraulic lime repointing mortar — exposed masonry — Parex
System Description
Parex natural hydraulic lime mortar — NHL 5.0 grade — for repointing moderately hard historic brickwork and exposed parapets on Class 2 strata buildings. NHL 5.0 (eminently hydraulic) is the strongest NHL grade, producing a mortar compressive strength of 5–15 MPa — stronger than NHL 3.5 but still breathable and softer than Portland cement mortar. Used where NHL 3.5 would erode in exposed or wind-driven rain environments, and where the brick is hard enough to accommodate a stronger mortar without face spalling. Confirm NHL 5.0 is appropriate for the brick compressive strength before specifying — a harder mortar than the brick will cause brick face spalling under thermal movement. Rake joints to minimum 15mm depth, clean, dampen, apply in layers not exceeding 10mm per pass, moist-cure 3–7 days, and protect from rain, frost and rapid drying during cure.
Technical Properties
- NHL 5.0 binder — eminently hydraulic — compressive strength 5–15 MPa — stronger than NHL 3.5 but still breathable
- Moderate–high vapour permeability — better breathability than Portland cement mortar; suitable for damp masonry management
- Better freeze-thaw resistance than NHL 3.5 — suitable for southern states with regular frost and exposed parapet locations
Limitations
- Stronger than NHL 3.5 — can cause spalling of very soft or mechanically weak historic brick if over-specified
- Still softer than Portland cement mortar — not suitable for joints in highly loaded structural masonry without engineer confirmation
- Colour matching to original mortar requires aggregate selection — confirm aggregate colour with specialist before ordering
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Limemortar.com.au NHL 5.0 Hydraulic Lime Mortar
NHL 5.0 natural hydraulic lime repointing mortar — specialist supply — Limemortar.com.au
System Description
Limemortar.com.au is an Australian specialist heritage lime supplier offering NHL 5.0 natural hydraulic lime mortar with custom aggregate blending to match the colour and texture of original mortar on heritage buildings. This approach is suited to significant heritage buildings where standard pre-blended products do not achieve the required colour match, or where heritage authority requirements necessitate demonstrated aggregate provenance. Confirm current product range, lead times, and state delivery availability before specifying. Supply is specialist and lead times may be longer than standard trade products.
Technical Properties
- NHL 5.0 binder — eminently hydraulic — compressive strength 5–15 MPa — specialist-confirmed grade for the specific application
- Custom aggregate blend — aggregate type, colour and grading matched to original mortar for significant heritage buildings
- Moderate–high vapour permeability — breathable mortar suitable for heritage damp masonry management
Limitations
- Specialist supply — longer lead times than standard trade products; confirm availability and lead times before scheduling work
- Higher cost than standard pre-blended NHL products — specialist supply and custom aggregate blending increases cost
- Requires experienced lime work contractor — poor application or mix proportions will compromise durability
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Heritage Specialist — NHL 5.0 Custom Mortar Specification
NHL 5.0 natural hydraulic lime repointing mortar — heritage specialist — authority-grade specification
System Description
Heritage specialist lime suppliers offer a full specification service for NHL 5.0 repointing mortar on significant heritage buildings — mortar analysis of original fabric, NHL grade selection, aggregate matching, trial panel commissioning, and application specification. This level of service is required where a heritage authority (Heritage NSW, Heritage Victoria, etc.) has oversight of the works, or where the building is listed and requires demonstrated material compatibility. Confirm the specific specialist supplier and their service offering in your state — specialist heritage lime consultants operate in most Australian states but supply, analysis services, and lead times vary significantly.
Technical Properties
- NHL 5.0 binder — eminently hydraulic — compressive strength 5–15 MPa — grade confirmed by analysis of original mortar fabric
- Full mortar analysis service — original mortar sampled and analysed for NHL grade, aggregate type, and colour before specification
- Custom aggregate blend — aggregate type, colour and grading specifically matched to original mortar on building
Limitations
- Longest lead time and highest cost — mortar analysis, custom blending, and trial panel add significant time and cost to the programme
- Requires specialist engagement before tendering — cannot be specified from a standard TDS alone
- Availability varies by state — confirm specialist availability before commencing design or tendering
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Comparison
Side-by-side comparison of NHL 5.0 lime repointing mortar suppliers. Confirm all product selections against the current manufacturer TDS before specifying.
| Supplier | Product | Distribution | NHL grade | Strength | Key feature | Primary use |
|---|---|---|---|---|---|---|
| Parex Australia | Parex NHL 5.0 | National (distributor) | NHL 5.0 | 5–15 MPa | Pre-blended, standard colour range | Exposed parapets, moderately hard brick |
| Limemortar.com.au | NHL 5.0 custom blended | Specialist (national) | NHL 5.0 | 5–15 MPa | Aggregate colour-matched to original | Heritage buildings, colour-match required |
| Heritage lime specialist | Custom mortar specification | State-based specialist | NHL 5.0 | 5–15 MPa | Full analysis, trial panel, authority spec | Listed heritage buildings — authority oversight |
Do not confuse NHL 5.0 lime mortar with:
- NHL 3.5 natural hydraulic lime mortar — softer grade (2–7 MPa) — use on soft, friable historic brick where NHL 5.0 would be too strong — listed on the NHL 3.5 mortar page
- Lime putty gauged mortar — non-hydraulic, softest available option (0.5–2.5 MPa) — reserved for very soft, friable historic masonry — requires heritage specialist specification — listed on the lime putty gauged mortar page
- GP cement + hydrated lime mortar — a cement-based mortar — contains Portland cement and is significantly harder and less breathable than NHL mortar — not suitable for soft historic brick
- Pre-mixed masonry cement mortar — contains no natural hydraulic lime — not a heritage-compatible product for soft brick
- Polymer-modified cement repointing mortar — high-bond cement mortar — not suitable for heritage soft brick masonry
Disclaimer
This page provides general technical information only. NHL grade, aggregate selection and compatibility with existing masonry must be confirmed by a qualified remedial practitioner with heritage masonry experience against project-specific conditions and AS 3700. Supplier availability and product ranges change — confirm with supplier before specifying.