The SROH reinstatement specification, explained

The Specification for the Reinstatement of Openings in Highways (SROH) is the statutory code that sets how a road, footway or verge must be put back together after street works in England. It tells whoever opened the ground which materials to use, how deep each layer must be, how hard it must be compacted and how the finished surface must perform, and it gives a highway authority the legal right to make a failing reinstatement be dug up and redone.

For anyone commissioning utility or civils work, the reinstatement specification matters because it decides whether the surface lasts the life of the surrounding road or starts to sink, crack and pond water within a couple of winters. Reinstatement to the SROH is the core of McFadden’s reinstatement works, from backfill and sub-base through to the final surface course, so this guide explains what the specification actually requires, which edition is current, and the parts that most often catch people out.

What the SROH is, and the law behind it

The SROH is published by the Department for Transport and prepared with the Highway Authorities and Utilities Committee (HAUC). It is not an Act in its own right. Its force comes from the New Roads and Street Works Act 1991 (NRSWA), which is why following it is a legal duty rather than best practice.

Two sections of that Act do the work. Section 70 places the duty to reinstate on the undertaker, the organisation that carried out the works, and requires them to tell the street authority whether each reinstatement is interim or permanent. Section 71 then sets the standard, requiring compliance with the prescribed specification of materials and standards of workmanship, and conformity with performance standards for a set period after the work is done. Failing those duties under section 71 is a criminal offence.

One common error is worth correcting. The SROH is sometimes described as being published jointly by utilities through a utilities group. The publisher is the Department for Transport, issuing it as a statutory code of practice under section 71. HAUC is the technical forum behind it, not the publisher.

Which edition is current

The current edition in England is the fourth edition of the SROH. It was released in 2020 and became statutory guidance on 10 May 2021, replacing the third edition that had been in force since 2010. A December 2024 addendum was later added, covering the reinstatement of footways after cable channels are installed for electric vehicle charging. You can reach the current documents through the gov.uk reinstatement page.

There is a genuine source of confusion here. Some booksellers list the document as a fourth edition dated May 2010, which leads people to think the 2010 version and the current version are the same. They are not. The 2010 document was the third edition. The fourth edition is the later one that came out of a 2020 review and took statutory effect in 2021. If a specification or method statement still references the 2010 edition by number, it is pointing at superseded guidance.

The edition picture also changes the moment work crosses a national border.

What the specification actually requires

At its core the SROH rebuilds the road in layers, and it sets a different recipe depending on how the road is constructed. The specification recognises four construction types, and the reinstatement has to match the existing build, not just fill the hole.

On top of construction type, the SROH grades roads by category, from Type 0 for the most heavily trafficked routes down to Type 4 for the lightest, and the material and layer requirements get more demanding as the category rises. A surface course suitable for a residential footway is not acceptable on a busy junction.

The shape of the opening matters too. The specification treats small openings and narrow trenches differently from larger excavations, sets out rules for shallow or aborted digs so they cannot undermine the surrounding structure, and now includes a formal specification for micro trenching, the narrow slot-cut method used to lay fibre, which previously needed separate agreement with each authority.

Underneath all of this sits compaction. Air voids in the bound layers are the single biggest cause of early failure, because voids let water in and the reinstatement loosens, so the SROH sets compaction requirements and air void limits for each material and layer. Most reinstatements that fail an inspection fail on compaction that cannot be seen from the surface.

The guarantee period and the 150 rule

The reinstatement is not signed off the day it is finished. The SROH sets a guarantee period during which the undertaker stays responsible for how the surface performs. It runs for two years from completion of the permanent reinstatement, or three years for deep openings.

The trigger catches people out. The guarantee period starts when the permanent reinstatement is completed, not when the authority is told it is completed. Notifying late does not delay the clock on performance, although failing to notify is a separate breach in its own right. If remedial works later go beyond a set extent, that section can be treated as a fresh reinstatement with a new guarantee period.

The 150 rule is one of the most searched questions about reinstatement, and it refers to a specific requirement for modular surfaces. Where the units are 300 mm or smaller, such as block paving or small slabs, the reinstatement has to extend to a line drawn 150 mm outside the edge of the excavation on each side, rather than stopping at the dig. The reason is structural. A narrow strip of relaid units along the cut line would rock and settle, so the specification forces the reinstatement wide enough to lock the new units into the existing surface.

What changed in the fourth edition

The fourth edition kept the structure of the third but updated it for newer methods and materials. The headline changes are worth knowing if you are reading older guidance alongside it.

New reinstatement methods were brought in to cut how long the road is occupied. Large diameter coring was introduced, letting a contractor cut and reinstate a single core rather than open a full trench, which can turn a week of occupation into roughly a day. The narrow trench definition was rewritten and the small opening definition was widened. Overbanding requirements were confirmed, and a route was added for introducing new materials and methods, the A9 process, so the specification can take on innovation without a full rewrite.

Materials moved on as well. The fourth edition added materials aimed at hitting the air void and compaction targets more reliably in the small, awkward excavations that utility work produces, and later updates clarified when cold applied materials are acceptable as a permanent reinstatement rather than only as a temporary measure.

What this means on a live job

On the ground, the SROH is the difference between a reinstatement that is signed off and one that comes back as a defect. The practical aim is to reinstate to a permanent standard at the first visit wherever the road type allows it, because every return visit means more traffic management, more disruption and another opening in the same stretch of road.

This is the standard McFadden's reinstatement teams work to every day, across backfill, sub-base, binder and surface course, tarmac and modular surfaces, and the ancillary details such as road markings and ironwork that the specification also covers. Getting the compaction and the layer build right first time is what keeps a reinstatement inside its guarantee period rather than back under the saw. If you are planning works that will open the highway, our reinstatement works cover the dig and the reinstatement to the current SROH, so the surface is handed back compliant.