Updated November 2026 · Will Brain, technical lead
Senini’s name for it
Natural breathable render, sponged and trowelled.
HERITAGE LIME RENDER · NATURAL HYDRAULIC LIME
A true natural hydraulic lime render, ready-mixed in the bag. Just add water.
Few suppliers in Australia stock a plain natural hydraulic lime render. SNT Plus is one. It’s a premixed mineral render of natural hydraulic lime and graded limestone aggregates, made to protect and restore old lime plasters while keeping them breathable. Use it for heritage restoration, on any traditional brick, stone or block wall, and on our hempcrete blocks.
$54.76 a 25 kg bag + GST · about $6.57–$10.95/m²
Technical datasheet (PDF)
MADE IN ITALY BY SENINI · SUPPLIED BY RESPIRABUILT
NHL
Natural hydraulic lime binder with limestone aggregates.
BREATHABLE
A vapour diffusion resistance of μ 10.
2–8 MM A LAYER
Finished sponged or trowelled.
A1 EUROCLASS
European reaction to fire class, not an Australian rating.
SNT Plus, finished
Senini’s sample blocks: sponged and trowelled panels side by side.
Sponged and trowelled
Front view
Natural light hazel beige
SNT Plus on Senini’s sample blocks
with the note they wrote on each
SNT lamato acciaio · spugna · grezzo spatola rovescia
SNT Plus steel-trowelled, sponged, and left rough with a reversed trowel.
SNT strappo · NB500 giallo lamata · NB500 materico · SNT a spugna
SNT Plus torn texture, Venezia in yellow trowelled, Venezia textured, SNT Plus sponged.
Where this lime render goes
three kinds of job, one bag
MINERAL WALLS
Heritage, any masonry, and hempcrete
SNT Plus goes onto mineral walls: lime plaster, brick, stone and block. The wall needs to be stable, sound, clean and dry.
Heritage restoration
Protects and restores old lime plasters while keeping the wall breathing. Its natural colour suits heritage buildings.
Any traditional masonry
Non-hemp jobs too: over lime-based and other traditional mineral plasters on brick, stone and block walls.
On RespiraBlock
Over a lime base on hempcrete blocks, and with mesh as the band at junctions, doors and windows.
Not for gypsum (including plasterboard), fibre-cement or expanded panels. For board walls, see our other finishes.
Made for old walls
why heritage work calls for lime
VENICE: CENTURIES OF LIME RENDER, STILL STANDING.
Photo: Jorge Franganillo, CC BY 2.0, via Wikimedia Commons
Lime, like the wall
Old houses were built with lime. Soft brick, stone and lime plaster let moisture move in and out of the wall, and the render on top needs to do the same.
Breathable
SNT Plus is made for high permeability to water vapour, with a vapour diffusion resistance of μ 10, so the wall behind it keeps drying out.
Ready in the bag
No slaking or batching on site. The natural hydraulic lime and graded limestone are premixed; you add clean water and paddle it.
Heritage overlays and approvals
Victoria and New South Wales
If your house sits under a heritage overlay in Victoria, or is heritage-listed in New South Wales, your council or heritage adviser usually has a say on materials and colour. Send them the SNT Plus datasheet. We’re happy to answer their technical questions.
SNT Plus on our hempcrete blocks
RespiraBlock walls, ready for render
Openings like this door get a meshed band of SNT Plus at the junctions.
Over a lime base, SNT Plus can also be the finished surface.
How it goes on
every wall has its own recipe, so ask us before you start
1. Check the wall
Stable, sound, clean and dry.
2. Mix
One 25 kg bag with 7.0–8.0 L of clean water, low-speed paddle. Rest 3 minutes, stir, use within 90 minutes.
3. Apply
2–8 mm per layer, between +8 and +30 °C. Finish sponged or trowelled.
4. Protect
Keep off frost, rain and fast drying for the first 24 hours.
Technical data
the figures, and where they come from
By the numbers
μ 10
vapour diffusion resistance
2–8 mm
per layer
3.0–5.0 kg/m²
approx. consumption, so 5–8 m² a bag
1,200 kg/m³
hardened density, approx.
A1
European reaction to fire class
25 kg
bag, 63 per pallet
Maximum aggregate size
1.0 mm
Capillary water absorption (EN 1015-18)
Class A1
Thermal conductivity (EN 1745)
λ = 0.47 W/m·K (tabulated)
Compressive / flexural strength (EN 1015-11)
1.0 (CS I) / 0.4 N/mm²
Adhesion (EN 1015-12)
0.40 N/mm² (FP) B
Colour
Light hazel beige, varies by batch
Shelf life
12 months, dry and unopened
Technical datasheet (PDF)
The fire class is the manufacturer’s European class (EN 13501-1), not an Australian rating. Figures from Senini’s Stabilitura Naturale Traspirante Plus datasheet (November 2025).
Heritage lime render questions, answered
the ones people ask first
What is natural hydraulic lime (NHL) render?
A render whose binder is natural hydraulic lime, a lime that sets with water as well as with air. SNT Plus uses an NHL binder with graded limestone aggregates and comes premixed in the bag, so you only add water.
Can I put SNT Plus over old lime plaster?
Yes. It’s made to protect and restore lime plasters while keeping them breathable. The old plaster needs to be stable, sound, clean and dry first.
Does it work on brick and stone that isn’t hempcrete?
Yes. It goes over lime-based and other traditional mineral plasters on brick, stone and block walls.
Can I use it on plasterboard or fibre-cement?
No. It isn’t for gypsum (including plasterboard), fibre-cement or expanded panels.
How thick does it go on?
2 to 8 mm per layer, at temperatures between +8 and +30 °C.
How much will I need, and what does it cost?
About 3.0 to 5.0 kg per square metre, so a 25 kg bag covers roughly 5 to 8 m². At $54.76 a bag + GST that’s about $6.57 to $10.95 per m². Send us your wall sizes and we’ll work it out.
What colour is it?
A light hazel beige. Being a natural product, the colour varies a little between batches.
Is it fire rated?
SNT Plus has a European reaction-to-fire class of A1 (EN 13501-1). That is the manufacturer’s European class, not an Australian rating.
How does it compare with your other lime finishes?
SNT Plus is the plain natural hydraulic lime render. For hemp you can see, there’s Venezia; for a smooth interior hemp plaster, Canaposo; for colour wash, Lime Wash; and for the classic Rockcote lime finish, Lime Plaster. See every finish on Natural wall finishes.
How long does a bag keep?
12 months, dry and unopened.
Talk to us about SNT Plus
Restoring an old house, or rendering a new hemp one? Send us the wall and we’ll give you the build-up. We host people for a coffee at our spec house in Richmond, Melbourne. Email info@respirabuilt.com.au.