Road defects: the most common types

Road defects come in all shapes and sizes and will cause a range of issues for road users. They are mostly caused by water ingress, freeze/thaw and excessive usage from heavy traffic. Over time defects such as cracking, edge failure, subsidence or stress fractures may develop – all of which require specific road maintenance solutions.

It’s crucial that the UK roads are kept to a high standard and that any repair work is carried out using the correct solutions with minimum delays. A detailed understanding of the most common types of road defect is required before selecting the right road repair solution for you.

Types of road defect


Cracking is one of the most common types of road defect. It is often due to a failure of the layers due to age, using the wrong material mix during development or poor construction/previous road repair work. It is caused when there is an underlying movement in the structure or concrete bays below.

IKO Permatrack Inlaid Crack System can be used to repair damaged roads where cracking is present. This is a simple, effective solution that involves removing the damaged area and then filling with our durable Permatrack material. Inlaid cracking could go on for many miles, but for smaller areas, IKO supplies the IKO Permatrack Road Surface Patch Repair System.


Crazing is similar to cracking and occurs due to partial or total failure of the underlying structure. Whereas a crack may extend for many metres along the length of a road, crazing usually appears as a congregated series of cracks in one concentrated area. Crazing is treated using the same IKO Permatrack road repair solutions as cracking.

Edge failure

Edge failure is common in areas of road that have an unsupported structure underneath the road surface. It is often seen in passing places or for country lanes that do not have a curb. This is because the haunch is the weakest section of the entire road. Edge failure is also often seen around ironworks that have been poorly bedded into the road surface.

The IKO Pacopatch Ironworks Reinstatement System is a proven, dependable solution for edge failure road defects. This product is specifically made for reinstating ironworks that have become loose or damaged, which is a danger to road users when not maintained.


Subsidence is a frequent road defect that can develop on roads built on soft ground, such as peat moors. It affects larger parts of a road and will cause substantial areas of the surface to sink. As a result of this, subsidence will often lead to other road defects such as stress fractures or compression fractures. Stress fractures develop when the surface must stretch over the edges of the subsided area.

Stress fractures

Road movement is the main factor that leads to stress fractures and as we covered above, so is subsidence. They are particularly prevalent on roundabouts or bends that experience high amounts of heavy traffic.

This is caused by the tyres of the vehicles which over time will push the road surface outwards, stretching the material. This applies stress to the surfacing which will cause it to break up into smaller fragments. Like cracking and crazing, stress fractures can be treated using IKO Permatrack solutions.

Joint fractures

When work has been carried out it’s important to seal the surface joints from water ingress, but over time these joints will weaken. This splits the surface of the road and causes a joint fracture. If not properly dealt with it is common for a joint fracture to develop into a pothole as the surface becomes impacted by heavy traffic usage.

Joint fractures are more common in heavier utility works rather than road resurfacing. This is due to the deeper cuts into the underlying material which will cause greater levels of movement, especially if the cuts are parallel to one another. They are also often found when using rigid materials. The IKO Permatrack Inlaid Crack Repair System offers a valuable, durable solution for joint fractures.

Extra protection for road defects with mastic asphalt

Mastic asphalt repair is chosen because it offers a unique set of attributes that help to protect from the road defects listed above. It generally has a much longer wear because the material is waterproof. Road waterproofing is important because it helps to prevent water ingress and freeze/thaw. This means that even already cracked areas of road are better protected from wet and cold weather.

It is also a flexible material that can withstand heavy loads such as traffic, tram or train lines. Extensive use from heavy loads can lead to further damage being done, especially if cracks have already started to appear. Mastic asphalt is durable and malleable and will offer a greater level of protection than other surfacing materials.

The importance of investing in UK roads

It’s clear that maintaining UK roads is crucial for the socio-economic activity of the country, but there are many more reasons why it should be considered. Road users – whether drivers, cyclists or pedestrians – want high quality roads that are comfortable and safe to use. By maintaining roads to a high standard, you can help to alleviate the pressure of complaints from the public.

Here at IKO we are a firm believer in doing it once and doing it right. This ideology is always at the forefront of what we do as we understand how it can benefit you and road users. By using high-quality, long-lasting solutions for road networks, we can help to minimise time spent on repair work which means less interruptions for the public. Substantial infrastructure closures are also costly and should be kept to a minimum. Our long-term refurbishment solutions mean no costly second visits.

IKO products are suited to providing solutions for the present day. Full road resurfacing projects can be lengthy, complicated and costly, and may not always be the best option. By implementing any of our road solutions – such as our road surface patch repair, inlaid crack repair or ironworks reinstatement, or our Bridge Expansion Joint Systems – you can potentially add years onto the lifespan of a road which is often all that’s required.

IKO – maintaining UK roads

The IKO Road range offers high performance solutions for different road defects, such as crazing, edge failure and stress fractures. We have 50-plus years of experience in the mastic asphalt industry and can provide long term solutions with reduced delays. Our products provide great durability, even for high sear situations and standing traffic.

The IKO Permatrack Inlaid Crack System can be used to repair cracking and crazing in roads and is commonly used on damage between motorway lanes. The IKO Permatrack Road Surface Patch Repair System can be similarly used but on smaller areas of road.

For areas of road within proximity to metalwork, such as iron or steel, IKO provides two separate solutions. The IKO Permatrack Transition Joint Railway Lines System is used on sections of road on either side of a steel rail. A good example of this is inner city tram systems.

The IKO Pacopatch Ironworks Reinstated System is used on damaged areas of road with in-built ironwork. The ironworks are rebedded onto the chamber and then the surround is simply filled with pacopatch material.

If you are interested in any of our road and bridge maintenance solutions, contact a member of our expert team.

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