Core Conservation
Contact
coreconservation banners floor banner109

Breathable Lime Floors

High-Performance Lime Cocciopesto Floors
Table of Content > Click to open

Lime Floors - Key Requirements

Breathable lime floors are the preferred floor choice for old and listed buildings.

Any floor must satisfy the following key requirements:

  1. Mechanical strength: a floor must be strong enough to support movement and the weight of furniture without cracking.
  2. Moisture control: a floor must be able to cope with liquid moisture to stay dry. It should be able to withstand soil moisture originating from water table variations and rainfall as well as the salinity of the soil.
  3. Thermal insulation: as many floors today are designed with underfloor heating, they should have a good thermal insulation so the generated heat is reflected and radiated upwards into the living space instead of being wasted in the underfloor area.
  4. Floor screed: the decorative or heat storage element under the finish should be thermally efficient.

This is usually achieved with the following structure:

floor-modern-core-conservation
Modern cement floor

In addition, traditional floors used in old and listed buildings should also be:

  1. Breathable: lime floors should be vapour permeable, able to regulate moisture.
  2. Traditional look and feel: lime floors should look traditional contributing to the overall aesthetics of the building.

Basic Lime Floors

Basic lime floors are composed of the following parts:

  • Subfloor aggregate: some porous aggregate – e.g. foam glass or light expanded clay aggregate (LECA) – which acts as both moisture control and thermal insulation layer in one.
  • Load bearing slab: a solid lime slab that performs multiple functions: it’s breathable, gives the floor strength and for underfloor heating also acts as heat storage.
floor-basic-core-conservation
Basic lime floor

Floor Improvement with Roman Limes

Roman lime plasters with special properties can bring several notable improvements to basic lime floors:

  • Improved water resistance: applying the Rinzaffo MGN Roman lime waterproofing plaster as a dedicated moisture barrier (DPM) and vapour control layer (VCL) allows lime floors to be laid in any damp (e.g. high water table) environment, protecting the floor structure from liquid water, high humidity and salts.
  • Improved thermal insulation: high-performance heat-reflective lime thermal plasters reflect the heat upwards. This reduces heat losses through the floor and improves thermal insulation while retains the breathability of the whole structure.
  • Improved energy efficiency: a high performance lime-cocciopesto floor screed can improve the energy efficiency of floors with underfloor heating. Cocciopesto floors, due to their high thermal mass, can retain more heat for longer or maintain the same floor temperature with less energy.

Roman limes make possible custom floor build-ups catering to a very wide set of requirements. Building lime floors of thin profile, or for high humidity environments, or lime floors on suspended timber base or on cement base all become possible.

floor-improved-core-conservation
Improved lime floor

Recommended Products

Here are the typical recommended materials / products for this solution. Other plaster variations are possible as we have different types of main coats (normal or thermal) and finishes (smoother, grainier, coloured etc.) depending on your needs or application. Please get in touch to discuss additional options.

Work Specifications

Here are the recommended work specifications for this solution.

rinzaffo category

Waterproofing, Base

Application Guide

Rinzaffo Controspinta MGN

[15-20 mm] ABOVE GROUND: Lime base coat, applied as:

  • â–ˆ [5-10 mm] Levelling / Repair: level, repair and point uneven walls first. The material consumption depends on how uneven the walls are.
  • â–ˆ [10 mm] Protective base coat: apply a 10 mm coat.

[25-30 mm] UNDER GROUND: Lime waterproofing coat or for very damp wall sections, applied as:

  • â–ˆ [5-10 mm] Levelling / Repair: level, repair and point uneven walls first. The material consumption depends on how uneven the walls are.
  • â–ˆ [10 mm] Waterproofing coat 1: apply a first 10 mm coat.
  • â–ˆ [10 mm] Waterproofing coat 2: apply a second 10 mm coat to complete the waterproofing.
betoncino-main-core-conservation

Consolidation, Base, Flooring, Building

Betoncino Consolidante MGN

[20-40 mm] Structural Consolidation lime plaster, in 20 – 40 mm or more thickness, applied as:

  • â–ˆ [10 – 15 mm] Consolidation plaster, coat 1
  • â–’ [Mesh] Structural reinforcement mesh (20 x 20 mm, 40 x 40 mm): embedded between coats for additional reinforcement and flexibility.
  • â–ˆ [10 – 15 mm] Consolidation plaster, coat 2. Etc.
IMG 20230908 091645 A1400x787

Thermal

Application Guide

TermoRasante AeroGel MGN

[10 – 30+ mm] Lime thermal super-insulation coat, breathable. Applied in 10 mm coats until the desired thermal performance is reached. E.g.

  • â–ˆ [10 mm] Thermal insulation coat 1.
  • â–ˆ [10 mm] Thermal insulation coat 2.
  • â–’ [Mesh] Fibreglass fine mesh (4 x 4 mm): every 20 mm for consolidation and added flexibility.
  • â–ˆ [10 mm] Thermal insulation coat 3. Etc.
b40-main-core-conservation

Finishing

Rasante B40 MGN

[4 mm] Lime levelling coat and finish, applied as:

  • â–ˆ [2 mm] First half of the levelling / finish.
  • â–’ [Mesh] Fibreglass fine mesh (4 x 4 mm): embed a mesh into the finish for added flexibility.
  • â–ˆ [2 mm] Second half of the levelling / finish.
hdrpl

Flooring

Application Guide

Massetto Caldo MGN

[40 – 60+ mm] Lime-cocciopesto floor screed, applied as:

  • â–ˆ [20-30 mm] Lime floor screed, coat 1.
  • â–’ [Mesh] Structural reinforcement mesh (40 x 40 mm): embedded into the screed for additional reinforcement and flexibility.
  • â–ˆ [20-30 mm] Lime floor screed, coat 2.
pastellone-main-core-conservation

Flooring

Pastellone Veneziano MGN

[4-5 mm] Pastellone Veneziano floor finish, applied as:

  • â–ˆ [2 mm] Pastellone finish, coat 1, well compressed.
  • â–ˆ [2 mm] Pastellone finish, coat 2, well compressed.

Plaster Application

Here are some key application points about the application of each plaster, as well as links to the full application guides. Please have your plasterer read / watch the application instructions before applying the product. If any questions, please contact us, happy to help.

rinzaffo category

Waterproofing, Base

Application Guide

Rinzaffo

  • Clean the masonry: the plaster must be applied on a cleaned and uniformly wet substrate. All crumbling and loose parts must be removed by brushing so the masonry is free of dust, salts and oils. If possible, also wash the walls with a pressure washer; this will clean and wet the walls in one go. Close larger holes with lime mortar and pieces of bricks.
  • Must be the first coat: the Rinzaffo MGN plaster must be the first coat on any wall. It should not be applied on top of other parge coats or plasters because when those fail the performance of the Roman base coat will also likely to be affected.
  • Cement backgrounds: the Rinzaffo MGN base coat can be applied and will bond well to cementicios backgrounds. The removal of cement plasters is recommended for the vast majority of cases to restore the breathability of the wall fabric. However, in some (rare) cases, when the removal of cement would be too invasive, too costly or would not beneficial the underlying masonry, if the cement backing is stable, the Rinzaffo MGN can be applied over it for waterproofing purposes (e.g. to waterproof cement floor bases). 
  • Salt-inhibitors or PVA bonding agents are NOT needed and should not be used before the application of this plaster. This natural lime plaster bonds very well on its own.
  • Masonry paints should be removed (which occasionally can be challenging) so the plaster can firmly adhere to the underlying stones or bricks. Remove at least 50% of the existing paint – the more is removed, the better.
  • Mixing: mix the material with clean tap water only without adding anything else (no other material or additive), until a homogenous, creamy-consistency mix is obtained. 
  • IMPORTANT: Dry to wet mixing: plasters with hydraulic ingredients should always be mixed from dry to wet (workable) state. Add your powder to a bit of water, start mixing and gradually add more water till the right consistency is reached. This is the right way. Mixing the other way – wet to dry mixing – by starting with lots of water then gradually adding powder to the right consistency, is incorrect. Reason: excessive wetting weakens the plaster, alters its hydraulic set resulting in less performant, more friable and shorter lasting plasters.
  • Wet the wall fabric abundantly before applying the plaster, as well as in-between each subsequent coat. Lime plasters need moisture as they set slowly in a damp environment. If the walls are already damp, there is no need to wait to become drier, you can proceed with the application of this plaster. 
  • Level uneven surface first: very uneven walls (e.g. stone walls or crumbling old brick walls) are recommended to be patched up and levelled first before the application of a continuous coat, to ensure the consistency and required thickness of the base coat.
  • Application: apply the plaster in 10 mm coats.
  • IMPORTANT: Respect the thickness: do not under-spec the material. Apply min 10 mm (1 coat) for above ground level walls. Apply min 20 mm thickness (in 2 coats) for underground or extremely damp or salty walls. If more than one coat is applied, embedding a 10 x 10 mm fibreglass mesh is recommended between the coats – a standard practice in the industry.
  • IMPORTANT: Close all pores, no matter how small. Treat and apply the plaster as a tanking-grade material. Attention should be paid to compact it on the wall closing off all pores, no matter how small, leaving no gaps or holes where salts or liquid water could come through. Once an area has been completed, recheck that here are no missed holes, not even small ones.

    The plaster application video below explains the concept in detail.

  • Light key: give the plaster a light key using a wet brush. Do not cut into the material with the edge of a trowel.
  • IMPORTANT: Dark patches. Allow the plaster to dry for 48 hours. Ideally, the whole surface should dry out uniformly to light brown, however you might notice some dark or damp-looking areas exhibiting surface condensation. Dark areas indicate insufficient thickness of the plaster in raport to the amount of moisture behind it. This occurs in areas where the underlying wall fabric is very damp, the intense evaporation causing surface condensation.
    The fix is easy: apply extra material over such dark areas increasing the thickness of the plaster, closing off all pores. The increased plaster volume dilutes the vapour flow allowing the surface to dry.
  • Additional coats can be applied in further 10 mm increments. Use an embedded fibreglass mesh for extra reinforcement over the recommended thickness.
  • Application conditions: ambient and wall temperatures must be between +5 to +30°C during application. Surfaces should be protected from rain and humidity until they have completely dried (approx. 3 – 10 days depending on weather conditions).
betoncino-main-core-conservation

Consolidation, Base, Flooring, Building

Betoncino

  • Clean the masonry: the plaster must be applied on a cleaned and uniformly wet substrate. All crumbling and loose parts must be removed by brushing so the masonry is free of dust, salts and oils. If possible, also wash the walls with a pressure washer; this will clean and wet the walls in one go. Close larger holes with lime mortar and pieces of bricks.
  • Salt-inhibitors or PVA bonding agents are NOT needed and should not be used before the application of this plaster. This natural lime plaster bonds very well on its own.
  • Mixing: mix the material with clean tap water only without adding anything else (no other material or additive), until a homogenous, creamy-consistency mix is obtained. 
  • IMPORTANT: Dry to wet mixing: plasters with hydraulic ingredients should always be mixed from dry to wet (workable) state. Add your powder to a bit of water, start mixing and gradually add more water till the right consistency is reached. This is the right way. Mixing the other way – wet to dry mixing – by starting with lots of water then gradually adding powder to the right consistency, is incorrect. Reason: excessive wetting weakens the plaster, alters its hydraulic set resulting in less performant, more friable and shorter lasting plasters.
  • Application: apply the plaster in 10 mm coats.
  • Light key: give the plaster a light key using a wet brush. Do not cut into the material with the edge of a trowel.
  • Additional coats can be applied in further 10 mm increments. Use an embedded fibreglass mesh for extra reinforcement over the recommended thickness.
  • Application conditions: ambient and wall temperatures must be between +5 to +30°C during application. Surfaces should be protected from rain and humidity until they have completely dried (approx. 3 – 10 days depending on weather conditions).
IMG 20230908 091645 A1400x787

Thermal

Application Guide

TermoRasante AeroGel

  • Mixing: mix the material with clean tap water only without adding anything else (no other material or additive), until a homogenous, creamy-consistency mix is obtained. 
  • IMPORTANT: Dry to wet mixing: plasters with hydraulic ingredients should always be mixed from dry to wet (workable) state. Add your powder to a bit of water, start mixing and gradually add more water till the right consistency is reached. This is the right way. Mixing the other way – wet to dry mixing – by starting with lots of water then gradually adding powder to the right consistency, is incorrect. Reason: excessive wetting weakens the plaster, alters its hydraulic set resulting in less performant, more friable and shorter lasting plasters.
  • Application: apply the plaster with a stainless-steel trowel in a 5-10 mm coat, just spreading and levelling it, without pushing the material around too much. Apply subsequent coats in further 10 mm passes. 
  • Finishing: for better mechanical protection thermal plasters should be finished with a dedicated finish (e.g. Megastuk MGN) – these are mechanically more resilient, longer lasting than ordinary lime putty finishes.
  • Painting: as this is a breathable lime plaster, wall surfaces should be painted with a breathable mineral paint. Wallpapers and modern emulsion petrol-based paints, with no or limited breathability, should be avoided.
  • Application conditions: ambient and wall temperatures must be between +5 to +30°C during application. Surfaces should be protected from rain and humidity until they have completely dried (approx. 3 – 10 days depending on weather conditions).
  • IMPORTANT: Please watch the plaster application video below before applying the material. Unmute the video if it plays without sound.
b40-main-core-conservation

Finishing

Rasante B40

  • Mixing: mix the material with clean tap water only without adding anything else (no other material or additive), until a homogenous, creamy-consistency mix is obtained. 
  • IMPORTANT: Dry to wet mixing: plasters with hydraulic ingredients should always be mixed from dry to wet (workable) state. Add your powder to a bit of water, start mixing and gradually add more water till the right consistency is reached. This is the right way. Mixing the other way – wet to dry mixing – by starting with lots of water then gradually adding powder to the right consistency, is incorrect. Reason: excessive wetting weakens the plaster, alters its hydraulic set resulting in less performant, more friable and shorter lasting plasters.
  • Recommended thickness of the finish: 3-4 mm. For best results, the finish should be applied in two “half-coats” of 2 mm each, with a fine 3-4 mm fibreglass mesh embedded in-between. The mesh makes the finish more flexible, minimizing the appearance of fine cracks.
  • Various textured finishes can be achieved, depending on the finishing technique used:
    • Coarse finish: by finishing the surface with a sponge or wooden trowel.
    • Smooth finish: by using a stainless steel trowel, compressing and smoothing the semi-dry surface, the sand granules are pushed into the material, resulting in a smooth finish.
    • Washed finish: by finishing the surface with a sponge trowel. After the surface has hardened, the surface is washed with water and blotted with a sponge to bring out the aggregate, its specific texture and colour.
  • Painting: as this is a breathable lime plaster, wall surfaces should be painted with a breathable mineral paint. Wallpapers and modern emulsion petrol-based paints, with no or limited breathability, should be avoided.
  • Application conditions: ambient and wall temperatures must be between +5 to +30°C during application. Surfaces should be protected from rain and humidity until they have completely dried (approx. 3 – 10 days depending on weather conditions).
hdrpl

Flooring

Application Guide

Massetto Caldo

  • Mixing: mix the content of the bag with clean tap water only without adding anything else (no other material or additive), until a runny slurry is obtained, as shown here.
  • Application conditions: ambient and wall temperatures must be between +5 to +30°C during application. Surfaces should be protected from rain and humidity until they have completely dried (approx. 3 – 10 days depending on weather conditions).
  • IMPORTANT: Please watch the plaster application video below before applying the material. Unmute the video if it plays without sound.
pastellone-main-core-conservation

Flooring

Venetian Pastellone Floor

  • Mixing: mix the material with clean tap water only without adding anything else (no other material or additive), until a homogenous, creamy-consistency mix is obtained. 
  • IMPORTANT: Dry to wet mixing: plasters with hydraulic ingredients should always be mixed from dry to wet (workable) state. Add your powder to a bit of water, start mixing and gradually add more water till the right consistency is reached. This is the right way. Mixing the other way – wet to dry mixing – by starting with lots of water then gradually adding powder to the right consistency, is incorrect. Reason: excessive wetting weakens the plaster, alters its hydraulic set resulting in less performant, more friable and shorter lasting plasters.
  • Application conditions: ambient and wall temperatures must be between +5 to +30°C during application. Surfaces should be protected from rain and humidity until they have completely dried (approx. 3 – 10 days depending on weather conditions).

Videos

Here are some videos related to this solution. Please unmute the videos when playing them.

Showing videos: 1 - 4 of 4 total.

Any Questions? Need Technical Advice?

If you have any questions about a project, a problem, a solution, or any of our plasters - please get in touch.

We understand that each project is unique. Using the contact form below feel free to ask us any questions. Give us as much detail as you can about your project so we can get back to you with more relevant answers. 

Are you in the process of buying / selling the property?
Preferred time for the survey? (tick all that applies)