The Difference Between Temporary Works and Permanent Works

• Permanent works are built to last for the entire lifespan of the structure.
• Temporary works support the construction process but are typically removed once the project is finished.
• Permanent works include foundations, drainage systems, retaining walls and roads.
• Temporary works include scaffolding, formwork and shoring.
• Sometimes, temporary works become part of the permanent structure.
• The Building Regulations 2010 and CDM Regulations 2015 set safety and design rules for both types of work.

Permanent works are the parts of a structure that remain in place once construction is finished. In other words, they’re the final product – what people use, live in, work in or drive on after the job is done.

Permanent works are designed to last for many years. Engineers and architects must plan them carefully to make sure they’re safe, strong and able to carry the right loads.

Some common examples of permanent works include:

• Foundations and retaining walls
• Underground drainage systems or water mains
• Concrete lift shafts and stairwells
• External cladding and roofing systems
• Pile caps and structural floor slabs

Temporary works are structures made to enable the building of the permanent works. They’re removed when they’re no longer needed, so they aren’t part of the final structure.

Temporary works support construction activities. They provide safety, shape, access or support during building.

Some examples of temporary works are:

• Scaffolding around a building
• Formwork to shape concrete
• Temporary bridges or roads for construction vehicles
• Shoring to support a wall during building
• Access platforms and walkways

Temporary works are used to support the building process and are removed after they’re no longer needed.

Permanent works are the structures that stay when the project is finished.

Both play an important role in construction and are needed to complete the project successfully.

Different people design temporary and permanent works.

Permanent works designers are usually architects, civil engineers and structural engineers. They focus on making a building or structure safe, useful and long-lasting. They think about things like weather, load limits and lifespan.

Temporary works designers are often specialist engineers. They focus on short-term needs. Their job is to:

• Create structures that support loads safely during construction
• Allow workers to move around the site safely
• Protect the public and nearby structures
• Provide the right shapes for concrete

Permanent and temporary works designers often need to work closely together. Temporary works may interact with permanent structures or affect how they’re built. For example, a deep excavation next to an existing building may require temporary support that prevents ground movement or collapse. In that case, the temporary works must be carefully coordinated with the permanent design to ensure both the safety of nearby structures and the integrity of the final construction.

Below are three examples that show how temporary and permanent works are used during different stages of construction:

In high-rise construction, temporary works like formwork systems shape concrete floors and core walls while they set. Scaffolding and edge protection provide safe access during the build.

Once the concrete has cured, the temporary works are removed. What remains are the permanent structural elements, such as floors, lift shafts and external walls.

Building a bridge generally involves falsework and temporary props to support spans during assembly. These help hold the structure in place until it can support itself.

After the bridge deck, piers and abutments are completed, the temporary supports are dismantled, leaving the permanent load-bearing structure.

Tunnelling typically starts with access shafts and temporary supports to keep the excavation stable. These allow workers and equipment to safely reach the tunnel area.

Once the final tunnel lining is installed, the access shafts are backfilled or sealed. The permanent tunnel structure is what remains in use.

Yes – temporary works are sometimes reused as part of the finished structure. When this happens, they must meet the same standards as permanent works: strong, safe and built to last.

One example is foundation piles. These may be installed to support the ground during excavation, then later reused to carry the weight of the structure above. Another is diaphragm walls, which can hold back earth during deep excavations and later become the permanent basement walls.

Reusing temporary works requires careful planning. Contractors, temporary works designers and permanent works designers must coordinate to ensure that reused elements are fit for long-term use and meet all building regulations.

Below is a breakdown of the most relevant legislation and guidance for both temporary and permanent works.

Permanent works are subject to a range of laws, including:

• Building Regulations 2010 – Governs structural safety, fire performance, energy efficiency and accessibility in buildings.
• Town and Country Planning Act 1990 – Sets out requirements for planning permission and land use.
• Construction (Design and Management) Regulations 2015 (CDM Regulations) – Outlines legal responsibilities for the safe design, planning and execution of construction works.

Temporary works are mainly governed by:

• CDM Regulations 2015 – Requires temporary works to be properly planned, managed and coordinated as part of the wider construction process.

Construction sites are a workplace, so are subject to the Health and Safety at Work etc. Act 1974.

If you’re working in or around any temporary or permanent structure, the employer has a legal responsibility to protect you from work-related harm. This duty is reinforced by the Management of Health and Safety at Work Regulations 1998, which make it necessary for employers to carry out and act on risk assessments for their work sites.

CDM 2015 also has implications for health and safety. Each duty holder must take steps to prevent harm by planning work carefully and coordinating with others.

Permanent works designers must follow established standards to meet safety and performance expectations, including:

• British Standards – Such as BS EN 1990–1999 series, covering structural design.

Temporary works are guided by:

• BS 5975 – The principal code of practice for temporary works procedures. It covers design checks, risk management, and requires the appointment of a Temporary Works Coordinator (TWC) to ensure proper control.

If you’re new to construction or want a clearer understanding of how temporary works differ from permanent ones, training is a great place to start.

Temporary works play a critical role in site safety. When they’re not properly planned or understood, they can lead to accidents, delays and serious structural risks.

Our online Temporary Works Awareness Training course introduces the key principles behind temporary works, including why they matter, how they’re used and the safety responsibilities involved.

Start the course today and gain a solid understanding of temporary works and their safety requirements.