Guide: Architectural Wrought Ironwork

Whilst every effort has been made to make this guide as informative and detailed as possible for owners of ornamental and architectural wrought ironwork this is not a definitive resource. This guide aims to provide an outline of the material, best practice maintenance and care along with signs to look out for which may indicate deterioration. If you are uncertain about anything concerning your wrought ironwork, it is advised to get in touch with Dorothea Restorations, who are more than happy to discuss best practices and a potential plan of action for your architectural ironwork.

Introduction

Wrought Iron became increasingly popular in the early 1700s widely used in architectural decoration. Wrought Iron is strong, versatile and durable which, whilst it was both plentiful and quite affordable, led to its widespread use. Georgian streets and squares in urban settings were increasingly enclosed by wrought iron railings and gates often finished with embellishments of pillars, scrollwork and urns.

There are two types of Wrought Iron – Puddled and Charcoal.  Charcoal Iron was predominantly used up until the early 1700s, so named because it was smelted in charcoal ore. Puddled Iron came about in the times of the Industrial Revolution,  essentially mass-produced in furnaces on a much larger scale this type of wrought iron had a slightly higher carbon content.

Both types have great tensile strength and high resistance to corrosion. For a more in-depth look into Wrought Iron production, its historical context and practical applications see our tech spec guide.

The most important thing to note is that new wrought iron is no longer produced in this country. It is only available as a recycled material and can currently only be obtained from a single producer in the UK. This has serious implications on the need to retain as much of the original material as possible. 

Identifying Wrought Iron

Wrought Iron can be mistaken for cast iron or mild steel in ornamental metalwork. Superficially, and to the untrained eye, they are easily mistaken for each other, but each has a distinct set of properties. Moreover, some metalwork may well be composed of a variety of types of iron so being able to correctly identify the type of iron used is an important starting point for maintenance and/or restoration.

Wrought Iron is most easily recognised by its architectural form, shape and type of design. Traditionally shaped by rolling and hammering whilst hot, wrought iron tends to be composed of several components fitted together. Furthermore, wrought Ironwork is often quite delicate in design with scrolls and foliage common motifs.
 
Since wrought ironwork is created by hand, variations in two seemingly identical elements can also aid identification differing from cast metals made to repeatable patterns in a mould allowing for identical castings. Another simple way of identifying wrought ironwork is by examining how the components of the ironwork have been joined to each other. Riveted, upset ends, collars, mortise and tenon joints and other traditional joinery techniques can all point to the existence of wrought iron.

 

Care and Maintenance

Before we get onto the subject of looking after your ironwork. There are some important safety notes to mention. 

 

SAFETY NOTE 1

Wrought iron can be coated with lead-based paints; often with a 75% lead content. Lead is a strong poison and there are serious health risks associated with it. Lead presence needs to be tested and then safety procedures must be followed when removing or disturbing lead-based paints in any way. 

 

SAFETY NOTE 2

Balconies, verandas, canopies, window guards, etc. are potentially very dangerous. Both from a working at heights perspective, and the risk of them falling on somebody below if there is a serious structural issue. This kind of maintenance work MUST be carried out by a professional.

 

Routine Inspections

The most important thing you can do to look after your ironwork is to regularly maintain it, repair damaged paint and inspect it periodically. You’ll be able to build up a conditional assessment and identify areas where your wrought ironwork may need intervention, if at all. 

 

Keep it Clean

Cleaning wrought ironwork should become part of a maintenance and care routine. That said, wrought ironwork is still relatively low maintenance requiring minimum intervention if cared for properly. By looking after the ironwork, you are likely to prevent serious issues from developing and you may save yourself future restoration works. Accumulated dirt can be removed by hand using water, or water with a little detergent, and a cloth or soft bristle brush. It’s important not to use an excessive amount of water, and definitely not a high-pressure power hose. Ironwork should also be thoroughly dried after cleaning to avoid trapping water.

Very small bits of corrosion can be removed using a chisel or bronze wire brush and sandpaper before repainting. Take care not to damage the ironwork and don’t use mechanical tools. Some levels of cleaning might not be suitable for certain historic ironwork, so if you are in any doubt about the appropriate methods seek advice.

Wrought Iron has a particular characteristic called “mill scale” a layer attributed to the rolling process which forms over the original material. This provides a certain level of protection and over-aggressive mechanical cleaning can destroy this. Furthermore, any decorative finishes your ironwork may have can provide historical information about your ironwork so samples should be taken and analysed, and records kept. Cleaning back to bare metal would destroy this history and should only be carried out when entirely necessary and by a skilled professional. 

 

Painting Ironwork 

The best approach should be decided on an individual case basis. Historical significance, your budget and performance requirements will vary. Larger-scale projects, bare metal restoration and serious corrosion should only be undertaken by a professional company. Minor patch repairs can normally be undertaken by the owner but it is essential to follow some basic procedures to ensure the paintwork doesn’t subsequently fail. 

 

• Remember Safety Note 1 – If original the existing paint is likely to be lead-based and very hazardous to breathe in. There are some useful safety guidelines available here
• Surface preparation is key - never paint over rust
• Clean, dry and well-prepared surfaces mean the paint will adhere to and protect your ironwork efficiently
• Check your paint is compatible with the existing paintwork and your ironwork. Most manufacturers will have a specified paint system you can use.
• When patching repairs, be careful to form a good overlap with the existing paintwork
• If painting over existing paint, key the surface by gently rubbing with sandpaper to ensure the paint has a good surface to adhere to
• Wait for optimum weather conditions for external works. Cold weather conditions can slow the paint curing, and create water droplets in the paint surface.
• Apply in several thin coats and always allow each coat to dry completely before applying the next.

 

Typical Repair Techniques

As I’m sure you have surmised, the majority of repair work should be carried out by qualified and experienced professionals using traditional materials and techniques. Since wrought iron is now only available as a recycled material, its retention and sympathetic restoration are even more important. Some of the techniques and processes we use to restore wrought iron can be found here in the technical specification guide in more detail. Below, you’ll find details on the types of corrosion your ironwork is likely to suffer if unmaintained and typical issues that arise with particular pieces. 

 

Types of Deterioration, Decay and Corrosion

Despite a high resistance to corrosion, wrought iron is not invincible. The two most common causes of deterioration are corrosion (either chemical or galvanic) and mechanical action. Chemical corrosion occurs when iron oxidises (rusts) caused by moisture and oxygen in its surroundings, whilst galvanic corrosion is caused by two different metals in contact reacting with each other. One of the two metals will suffer and become sacrificial to the other. For example, this might occur at a joint between a cast iron finial and a stainless steel pin or where repair works have previously been carried out using stainless steel.

Mechanical action pertains to the unsettling of the ironwork or some kind of impact. It may be that stones have settled slowly over time causing ironwork to bend out of shape or fracture. Worst case scenario, your heritage railings have been hit by a vehicle.

 

Contributing Factors to Deterioration

With an understanding of the types of deterioration that occur, factors that can contribute to wrought ironwork’s decay are as follows:

 

• General Neglect
• Flaking paint exposing bare ironwork
• Insufficient protective coating or preparatory cleaning methods applied to the ironwork
• Poor workmanship to start with! Badly worked iron and design flaws can lead to areas where water can settle easily. (this also applies to poorly carried out restoration works)
• Plants, particularly the sort that binds and has damaging roots.
• Unstable or subsiding masonry works

It’s also worth noting that as wrought iron corrodes it expands. By volume, rust can take up an area many times that of the original material. This can cause distortion forcing the components of your ironwork apart making early intervention important. 

Signs of Ironwork in Need of Intervention

Deterioration isn’t always immediately visible but there are tell-tale signs to look out for which might indicate your ironwork needs intervention. 

• An uneven surface to the ironwork is termed “pitting”. This is often a sign of corrosion beneath the paintwork
• Rusty-coloured staining to supporting masonry
• Blistering to the paintwork – another sign of corrosion beneath

Common Issues with Particular Items of Wrought Ironwork

Dependent on the application of ironwork it will suffer in different ways. The most common problems are outlined below with a brief indication of likely repair techniques and the definite don’ts when dealing with their degradation. 

 

Corrosion to Decorative Scrollwork

Unfortunately, the levels of craftsmanship executed in the embellishments of wrought ironwork are often lost under corrosion and excessive paint. Left to weather, the likelihood of corrosion is compounded by their intricate shapes, acting like water traps. Often it is the centre point or nose of the scrollwork that has eroded the most, along with other water-trapping areas leaving the rest relatively intact. As such, restoration and repair work rarely require the replacement of the whole item. In line with conservation policy, as little of the corroded section as is necessary should ever be removed. 

 

Missing or Broken Cast Iron Finials or Collars

Since these embellishments act like water traps, they are particularly susceptible to corrosion over time. Eventually, they will fall off. Normally, these can be replaced by matching architectural patterns, of which Dorothea holds a selection. Alternatively, a new pattern can be made to fit with the existing design.

 

Distortion to Ironwork 

As rust develops it can cause distortion to the existing ironwork. Sometimes, dismantling the ironwork is necessary to successfully clean, reshape and paint it, but this can be problematic. 

 

Sections of Ironwork Dismantling

This can be caused by either corrosion of the ironwork itself or its fixings corroding over time causing joints to come apart. The joints can normally be re-secured using new pins, though these should be in keeping with traditional techniques. 

 

Corrosion of Ironwork

Whilst minor pitting and corrosion will not necessarily compromise the structural integrity of your ironwork, if left alone, it may accelerate the corrosion process. Where the corrosion is particularly bad, it may be necessary to replace areas with recycled wrought iron. 

 

Missing or Broken Fixings

Over time it is quite natural for the original wrought iron fixings to have corroded away. When replacing, phosphor bronze or iron fixings are recommended.

It’s worth noting, fixings have changed over the years - threading standardisation for example has altered considerably. The shape and style of the originals should always be matched to keep within the historic style.

 

Backstays, Loose or Detached From Railings

Normally made from cast or wrought iron, the problem arises due to the fracturing of the cast iron or corrosion. Welding is not advised when attempting to reattach backstays since this is not a traditional technique.

Where the backstay is cast iron, and it has fractured, a proper inspection should be carried out to find out why the failure occurred as the issue may be structural.

 

Fractured Coping Stones

Railings can be fixed into the masonry by pouring hot lead into sockets within the masonry. As corrosion occurs (and the volume of the rust expands) the masonry can become susceptible to damage and crack. Masonry restoration is normally carried out and the railing is cleaned, repainted and then reattached to the socket.

The original fixing techniques are still best practice, and, as you might imagine, pouring molten hot lead into sockets to reaffix railings, is best carried out by a professional company.

 

Seized Mechanics ( most likely gates)

There are a number of reasons why wrought ironwork mechanics, particularly in gates, are likely to fail. Rising ground levels, leaning gate pillars, wearing to the heel cup (pintel) or distortion through use are all common. Identification of the primary issue is the first port of call before planning any repair work.

It’s worth mentioning, inappropriate repairs or maintenance will often result in reduced value and if not, a reduction in the overall appeal of the gates. So think carefully about retaining the original features before embarking on any work.

Click below for guides on other architectural metalwork features: 
 

• Caring for architectural cast iron
• Cast iron rainwater system care
• Maintaining metal casement windows
• Traditional leaded light maintenance