Is the plaster falling off the old wall? On a smooth substrate with different absorption, there is nothing to grip. Rinzaffo applies a rough, salt-resistant base layer to the wall — the plaster grips onto this. NHL 3.5 pure lime — breathes, does not trap moisture. This is Kerakoll Biocalce Rinzaffo.
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Plaster falls off old walls: the next layer grips — rough, rustic base layer, ≥ 0.7 N/mm² adhesion on hollow brick
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Part of the system: the base layer of Biocalce breathable plasters (Zoccolatura, Benesserebio) — without it, the plaster absorbs the substrate unevenly
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Patchy, streaky finished plaster: evens out wall absorption — provides a uniform base on all wall types
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Wet, saltpeter wall: salt-resistant mortar — sulfate resistance certified (ASTM C 1012-95a), works even under rising damp
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Mixed masonry (brick, tuff, stone, adobe): one base plaster for everything — partial coverage on brick, full coverage on tuff and non-absorbent walls
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Pure lime, no cement: breathes, does not trap moisture — μ ≤ 20, only natural raw materials
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By hand and machine: easier application than traditional base plaster — spray in one layer
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Finish: the Biocalce salt-blocking (Zoccolatura) or thermal insulation (Benesserebio) plaster provides the actual protection — Rinzaffo alone is not a finished surface
| Product family |
Biocalce moisture-proofing system (Rinzaffo + Zoccolatura + Benesserebio) |
| Type |
general plaster mortar, GP (EN 998-1) |
| Function |
base plaster / adhesion promoter under breathable plasters |
| Adhesion (hollow brick) |
≥ 0.7 N/mm² |
| Material requirement |
≈ 15 kg/m²/cm |
| Minimum achievable layer thickness |
≈ 5 mm |
| Packaging |
25 kg bag |
| Storage |
≈ 12 months |
What is it suitable for?
Substrates: Hollow and solid brick, tuff, stone, adobe, and mixed masonry. Walls affected by moisture, saltpeter, and rising damp. Worn, river gravel substrates in monument restoration.
Function in the system: Base plaster (adhesion promoter) before applying Biocalce breathable plasters — Biocalce Zoccolatura and Benesserebio — for exterior and interior use.
Not suitable for:
- On dirty, loose, dusty substrates — clean first
- On old paint or existing leveling
- As a standalone, finished plaster surface (without Biocalce plaster)
- On surfaces covered with salt deposits — remove first
The Biocalce moisture barrier system
Rinzaffo is the first layer of the system — adhesion-promoting base plaster under breathable plasters. On damp, salty walls the full build-up:
Which layer / product is needed?
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Base plaster (adhesion promoter): Biocalce Rinzaffo — this product
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Salt-damaged base, wall section: Biocalce Zoccolatura — salt blocker, μ ≤ 3
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Energy saving, mold-free warm wall: Benesserebio — thermal cell, λ 0.14 W/(mK)
Frequently Asked Questions
Why does plaster fall off old walls?
Because on a smooth or differently absorbent substrate, there is nothing for it to grip onto. A rough, salt-resistant base plaster (e.g., Kerakoll Biocalce Rinzaffo) creates a bonding bridge on the wall and evens out absorption — allowing the next layer to adhere.
What is base plaster (rinzaffo)?
Base plaster is the first rough lime layer on the wall that acts as a bonding bridge under the plaster. It provides an even base and absorption so that the breathable plaster does not stain or peel.
Is a base plaster needed under Biocalce plasters?
Yes. Rinzaffo is always recommended under Biocalce Zoccolatura and Benesserebio plasters — it increases adhesion, regulates absorption, and prevents salts from entering fresh plaster.
Is it good for damp, saltpeter-affected walls?
Yes. Rinzaffo is salt-resistant — its sulfate resistance is certified (ASTM C 1012-95a), and it is highly breathable. Suitable as a base plaster for walls affected by rising damp.
What kind of wall is it for?
For hollow and solid bricks, tuff, stone, adobe, and mixed masonry. Apply partially overlapping on brick, fully overlapping on tuff and non-absorbent walls.
What do GP and CS III mean?
GP means general-purpose plaster mortar (EN 998-1). CS III is a strength category — the 28-day compressive strength, which provides a stable, load-bearing base layer under the plaster.
How many square meters does a 25 kg bag cover?
Material requirement is approximately 15 kg/m² per centimeter. For a thin base layer of about 5 mm, a 25 kg bag covers approximately 3 m².
When should I NOT use it?
Do not use on dirty, dusty, loose substrates, old paint, or leveling layers. Remove salt deposits first. Special preparation is needed for cellular concrete panels — please consult with us.
Can I apply it myself?
Yes, it can be applied by hand or machine, more easily than traditional base plaster. However, repairing damp, saltpeter-affected walls requires expertise — we also provide full system installation.
Can it be purchased separately?
Yes. You can buy it separately if you already have the finishing Biocalce plaster and paint, if you are repairing an existing base layer, or if you underestimated the surface. However, on its own, it is not a finished plaster surface — Biocalce plaster is required on top.
