Lime Structural Consolidation

Roman Lime as Structural Consolidation Material

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Structural Consolidation and Repair

As a result of the ongoing long-term decay of the old historic fabric, sometimes some structural consolidation of old walls or rebuilding the damaged masonry becomes necessary.

The structural consolidation of older walls and buildings is often done with cement-based mortars or concrete, for a number of reasons:

Low cost: being produced in large quantities, cement mortars are cheap.
Mechanical strength: cement has the mechanical strength to withstand large loads which can be advantageous in some situations.
Wide-spread use in the building industry: particularly in new-build applications.
Not being aware of the damages cement can cause to old structures: as mentioned earlier, cement-based materials can damage old buildings in a number of ways. Not being aware of these opens the door to such damages.
Not being aware of building-friendly alternatives: the de-facto construction material today is cement.

However, there is more to structural consolidation than just cement.

The Romans have developed lime-based alternatives, building some impressive buildings that have lasted hundreds of years using lime mortars. The Colosseum or the Pantheon in Rome are just some examples of Roman architecture fully built with lime about 2,000 years ago that still stand today.

structural reinforcement of old walls — The Colloseum in Rome, built around 80 AD. It has been standing for 2,000 years on a 6 metre thick lime foundation

So the right types of Roman limes are definitely suitable for all sorts of structural works, and they are breathable.

Lime Structural Consolidation and Crack Repair

The Betoncino Consolidante MGN Roman mortar can be used as a lime structural consolidation and reinforcement mortar for all sorts of consolidation and repair works. It can also be used as a bedding or building mortar during various construction works.

This mortar is also highly salt and water resistant, being able to withstand harsh environments, offering long-lasting, durable, sympathetic repairs. It is part of a certified lime structural consolidation system suitable for any old or listed building. The video below demonstrates the concept.

Here is an application example - crack repairs on a 1930s building with Roman structural lime.

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.

Betoncino

Lime Structural Consolidation Mortar

Consolidation

Base

Flooring

Building

Work Specifications

Here are the recommended work specifications for this solution.

Consolidation, Base, Flooring, Building

Betoncino Consolidante MGN

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

█ [10 – 15 mm] Consolidation plaster, coat 1
▒ [Mesh] Structural reinforcement mesh (20 x 20 mm, 40 x 40 mm): embedded between coats for additional reinforcement and flexibility.
█ [10 – 15 mm] Consolidation plaster, coat 2. Etc.

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.

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).

Completed Projects

Here are some of our projects using this solution:

Listed Farm House Complete Restoration

Full Restoration & Thermal Insulation

Residential

Photo Galleries

Here are some photos demonstrating this solution. Click on any image to open the photo gallery.

Structural Reinforcement of an Old Barn with Betoncino MGN

Here is an application example of the Betoncino Consolidante MGN structural reinforcement mortar used on an old barn with damaged, weakened masonry.

Timber-frame Farmhouse - Full Refurbishment & Thermal Insulation

1600s timber-frame listed farmhouse undergoing full refurbishment from top to bottom addressing sympathetically many problems including: new roof, lime pointing, timber infill panels, thermal insulation, replastering, structural reinforcement with lime and lime floors – just to name the most important aspects of the project.

Structural Crack Repair and Consolidation with Lime

Some Roman lime mortars are great structural consolidation materials as they are breathable, flexible, of adequate mechanical strength, yet softer than the bricks or stones it consolidates – conforming to all aspects of building consolidation. This 1930s residential building had some structural cracks that have been repaired with the Betoncino Consolidante MGN Roman structural consolidation mortar.