Surbiton Build Blog 004 — Transfer Deck Installation

Following the completion of the strip-out works, the project moved into one of the most critical phases, installation of the transfer deck.

The transfer deck forms the structural interface between the host building and the new development above. It redistributes loads enabling additional storeys to be constructed safely.

This stage required a high level of accuracy and coordination, as all subsequent works, particularly the light gauge steel frame (LGSF), rely on the precision of this installation.

Setting Out & Fabrication Measure

The process began with the accurate setting out. This is a critical stage, as the entire transfer structure is built from these positions. Survey control points and grid lines were used to ensure all locations aligned precisely with the project grid .

Any inaccuracy at this stage would impact the installation of both the steel frame and the LGSF system that follows. Once our team fully set-out the Structural Grid and made the measurements, we could put the Transfer Deck order into fabrication.

Steel stub locations were carefully set out to align with the structural grid and future works.

Fin Plates and Coordination with the LGSF Manufacturer

Fin plates were pre-fabricated and welded to the hot rolled steel members prior to delivery.

These plates are designed to receive the LGSF joists, meaning early coordination with the LGSF manufacturer was essential to ensure all connections aligned with the off-site fabricated system.

This level of coordination reduces site adjustments, improves installation speed, and ensures the accuracy required for MMC construction.

Pre-fabricated fin plates were coordinated with the LGSF design to ensure accurate installation of the floor system.

Craning of the Hot Rolled Members and the Stubs

Once the Transfer Deck was fabricated, it was craned into position. Careful coordination between the lifting team and installation crew ensured that each element was safely manoeuvred into place .

The sequence of installation was planned in advance to maintain stability and efficiency as the structure was assembled.

Hot rolled steel members were craned into position to form the primary transfer structure.

Levelling Using Timber Wedges to Level Datum

Once installed, the structure was levelled to the project 'Level' datum.

Timber wedges were used to make fine adjustments, ensuring that each steel member sat at the correct level. Achieving the correct datum is essential, as it directly impacts the installation of all subsequent structural elements.

Timber wedges were used to level the structure accurately to the project datum.

Lining Up with Grid Lines

Following levelling, the structure was Lined with the project grid lines.

This ensured that all elements were positioned correctly in Grid , maintaining consistency with the design and allowing future works to proceed without complication.

Grid alignment is particularly important for ensuring that prefabricated elements such as LGSF components can be installed without modification.

The structure was aligned to grid lines to ensure accuracy across the frame.

Drilling & Grouting of Base Plates into the Roof Slab

To secure the structure, drilling works were carried out into the existing roof slab.

Mechanical fixings were installed to anchor the steel stubs and ensure a robust connection between the new structure and the existing building.

These connections are critical in transferring loads safely into the host structure.

High-strength SIKA grout was used to provide full bearing between the steel base plates and the existing structure. This ensures effective load transfer and long-term stability.

Grouting completes the installation process and locks the structure into its final position.

Base plates were grouted to ensure full load transfer and structural stability.

Looking Ahead

With the transfer deck complete, a stable and accurate structural platform is now in place.

This enables the next phase of construction, the installation of the light gauge steel frame floor system.

At this stage, the development is (in traditional development terms) out of the ground! Marking a major step forward in the project.