Temporary Works vs Permanent Works — Why It Matters Early

1. Defining the Difference: Stability vs. Substance

• Permanent Works: The final structure that remains after the project is complete (the beams, the walls, the roof).

• Temporary Works (TW): The “Engineered Scaffolding” required to keep the building standing while the permanent works are being installed.

• The Risk: If the permanent design assumes the building is inherently stable during the “strip-out” phase, it creates a massive safety and cost gap.

2. Why Early TW Design Reduces Cost

In many traditional tenders, Temporary Works are priced as a “provisional sum.” This is a gamble. By involving us early, we identify the specific engineering requirements:

• Needling and Propping: When removing a load-bearing wall, the “Needle” (temporary beam) must be designed to carry the specific dead loads of the floors above. Early calculation prevents over-engineering (which is expensive) or under-engineering (which is fatal).

• Facade Retention: For heritage projects like the Royal Albion, the “Temporary” steel frame required to hold the facade is often more complex and expensive than the internal “Permanent” steel. Identifying this at the PCSA stage ensures the budget is realistic.

• Façade Access & Loading: Designing scaffolding that isn’t just for access, but can actually handle the weight of heavy stone or steel being craned in.

3. Design Responsibility (BS 5975)

Compliance with BS 5975 (the Code of Practice for Temporary Works) is a statutory requirement under CDM 2015.

• The Interface Risk: A common point of failure is the “Interface” where the temporary support meets the existing building. Who checked the capacity of the ground to take the load of the prop?

• Our Approach: We provide a dedicated Temporary Works Coordinator (TWC) and Designer (TWD). We ensure that the temporary loads are checked against the permanent structure’s capacity, preventing “punching shear” or foundation settlement.

4. Programme Implications of Sequential Loading

Construction is a sequence of “Load Transfers.”

1. The building sits on its original walls.

2. We transfer the load to Temporary Works.

3. We install the Permanent Steel.

4. We “pre-deflect” or grout the steel to take the load.

5. We remove the Temporary Works. The Delay Risk: If the sequence is wrong, or if the permanent works haven’t reached full strength (e.g., concrete curing times), the temporary works cannot be removed, stalling the entire internal fit-out.

5. Ground Conditions and Propping

Temporary works are only as strong as what they are sitting on.

• Basements and Vaults: In Brighton, many buildings have hidden coal vaults or “soft” Victorian footings. Placing a high-load prop on a floor without checking what is beneath it is a major risk.

• Our Protocol: We perform “Load Path Analysis” from the roof down to the “Firm Ground,” ensuring that temporary propping doesn’t inadvertently collapse a basement or damage subterranean utilities.

The Bloomsbury Standard: As a Chartered Building Company (CIOB), we don’t view Temporary Works as a “means to an end.” We view it as the most critical engineering phase of a refurbishment. Our background in surveying allows us to identify the “weak points” in the existing fabric that a standard steel-fixer might miss, ensuring that the building remains static and safe throughout the transition.

View our Structural Stabilisation & Dangerous Structures Page

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