Historic Stone Portal Restoration at Momjan Castle

Restoring historic stone architecture rarely begins with complete drawings and perfectly preserved original elements. In many cases, only fragments remain — enough to understand part of the original construction, but not enough to simply put it back together.

This was the challenge we faced during the restoration of the historic stone entrance portal at Momjan Castle in Istria, Croatia.

For RockForm, the project was much more than producing replacement stone pieces. It involved understanding the original geometry of the portal, preserving the elements that could still be reused, recreating the missing components and helping bring a fragmented architectural feature back into a complete composition.

A Historic Castle on a Challenging Site

Momjan Castle, also known as Castle Rota, stands on a dramatic rocky position in northern Istria.

Its historic architecture, tower and defensive walls make it one of the distinctive heritage sites of the region. The entrance portal forms an important architectural element within the castle complex.

When work on the portal began, however, much of the original stone structure was no longer intact.

Only a relatively small number of original elements remained available for reconstruction.

Reconstructing a Portal from Surviving Fragments

The first major challenge was perhaps the most interesting:

What did the original portal actually look like?

Approximately 20% of the existing stone elements could be reused, while around 80% of the portal had to be newly produced.

The surviving elements therefore became an important physical reference for reconstructing the missing architecture.

Each remaining piece provided information about:

original proportions

stone profiles

radii and curves

column geometry

cornices and mouldings

connections between individual blocks

surface treatment and visual character

Creating replacements for historic architecture is very different from producing a new stone product.

The objective is not simply to manufacture something similar. New elements have to work together with the surviving original pieces so that the architecture can once again be understood as a complete composition.

Preserving Original Stone Wherever Possible

A fundamental principle in historic restoration is to retain original material whenever its condition allows it.

The surviving stone elements were therefore incorporated into the reconstructed portal rather than automatically replaced.

Approximately one fifth of the final portal consists of preserved existing elements, while the remaining elements were newly fabricated to restore the missing geometry.

This combination of historic material and newly manufactured stone is what makes restoration work fundamentally different from ordinary architectural stone production.

The new pieces have to complete the structure without erasing the history that remains.

Producing the Missing Stone Elements

Once the required geometry had been established, production of the new stone components could begin.

The portal includes a combination of substantial architectural forms:

bases

columns and half-columns

curved elements

arch components

cornices

moulded profiles

rectangular structural blocks

decorative stone details

Accuracy is critical.

A small dimensional error in one block can affect the position of several elements above it.

Modern stone-processing technology makes it possible to reproduce complex geometry with high precision, particularly when working with curves, profiles and repeated architectural components.

However, machining is only one part of the process.

Historic stonework still requires an understanding of how individual elements relate to the entire architectural composition, how surfaces are finished and how new pieces visually integrate with existing stone.

For projects like Momjan Castle, modern stone technology and traditional stone-working knowledge complement each other rather than compete.

The Second Challenge: An 18-Metre Cliff

Producing the stone elements was only part of the difficulty.

The location itself presented another major challenge.

Momjan Castle is not a conventional construction site with simple access for trucks, cranes and installation equipment.

The portal is located in extremely demanding terrain next to a cliff approximately 18 metres high.

Before the restoration could proceed, safe access had to be established and extensive scaffolding organised so that workers and heavy stone elements could reach the installation area.

Lifting and positioning architectural stone of this scale required careful logistical planning.

This is one of the realities of heritage restoration that is easy to overlook:

even a perfectly manufactured stone element is useless if it cannot safely reach its final position.

On historic buildings, access, scaffolding and lifting strategy can be as important as stone fabrication itself.

From Individual Blocks Back to Architecture

Installation is the stage when dozens of separate stone elements finally begin to read again as one architectural feature.

The bases, columns, profiled sections, arch stones and cornices had to be assembled accurately while incorporating the preserved historic pieces.

During production, every component exists as an individual block.

During installation, those individual blocks gradually disappear visually and become architecture again.

That transformation is one of the most rewarding parts of restoration work.

What had existed only as fragments can once again be understood as a complete stone portal.

What This Means for the Restoration of Old Villas in Istria

The Momjan Castle project also demonstrates something relevant to many private property owners.

Throughout Istria there are historic villas, traditional stone houses, estates and other older buildings whose architectural value depends heavily on original stone details.

For buyers considering the renovation of such properties, those historic elements can sometimes become one of the biggest concerns.

Typical questions include:

Can the original portal be restored?

What happens if some of the stone elements are missing?

Can an old arch, cornice or column be reconstructed?

How do conservation requirements affect renovation?

Who is permitted to carry out work on protected buildings?

These concerns can make buyers hesitant about purchasing older properties, particularly when conservation regulations and administrative procedures are involved.

However, damaged or incomplete historic stonework does not necessarily mean that the architectural element is lost.

With proper documentation, professional analysis and the involvement of the appropriate specialists, missing stone elements can often be reconstructed while retaining the surviving historic material.

Working with Conservation Specialists and Licensed Partners

Historic and protected buildings require a different approach from ordinary residential construction.

Depending on the status of the building and the scope of work, restoration may require conservation approval, specialised documentation and appropriately qualified or licensed professionals.

RockForm can participate in projects of this type in cooperation with experienced partners who have the necessary expertise and authorisations for work on historic and protected structures.

Our role can include the analysis, reconstruction and fabrication of architectural stone elements, while the wider restoration process is coordinated with the professionals required for the specific project.

This collaborative approach is particularly valuable for property owners who may understand the architectural potential of an old villa but are unsure how to navigate the technical and conservation requirements.

An Old Property Does Not Have to Be an Unmanageable Problem

Historic properties can appear complicated at first.

Conservation requirements, missing architectural elements and the uncertainty surrounding restoration costs can discourage potential buyers.

But the details that initially appear to be problems often become the features that give the finished property its greatest character.

An original stone portal, arch, window surround, staircase or cornice cannot easily be recreated through standard construction products.

These elements contain the proportions, material language and craftsmanship that distinguish historic architecture from a new building.

When part of an original architectural element has disappeared, the remaining fragments can sometimes provide enough information to reconstruct what is missing — provided that the project and conservation requirements allow it.

Momjan Castle is an excellent example.

From a relatively limited number of surviving stone elements, an entire monumental portal could once again be understood, fabricated and assembled.

Restoration, Technology and Stone Expertise

Projects like this require several disciplines to work together.

The Momjan portal involved:

analysis of surviving stone elements

reconstruction of missing geometry

fabrication of new architectural stone components

integration of new and existing material

complex access and site logistics

coordination between different specialists

precise installation within a historic structure

This approach is equally relevant to the restoration of historic villas, stone houses, hotels, estates and other architectural heritage projects.

For RockForm, stone restoration is not about making an old building look new.

It is about understanding what remains, preserving what can be preserved and carefully reconstructing what has been lost.

Planning the Restoration of a Historic Villa or Stone House?

If you are considering the purchase or renovation of an older property and damaged or missing stone elements are creating uncertainty, it is worth investigating the possibilities before assuming they cannot be restored.

Historic elements such as:

stone portals

arches

columns

cornices

window and door surrounds

staircases

decorative stonework

can often be restored or reconstructed depending on their condition and the requirements of the project.

Send us photographs, existing drawings or available project documentation.

We can help evaluate the stonework and, where specialist conservation involvement or specific authorisations are required, work together with appropriate professional partners.

Planning a historic stone restoration project? Contact RockForm to discuss what may be possible.