Can modules be stacked to two storeys?

Stacking is normal in volumetric construction and it is not the same job as placing a module on the ground twice.

Everything that changes, changes at design stage.

The load path is the first thing

A module at ground level carries its own weight and its own live load into the foundation.

A module with another above it carries that too, and the load has to pass through the lower module's structure into the foundation without relying on anything that was not designed to take it.

Which means the lower modules are structurally different to the upper ones. Same appearance, different design.

The connections between modules matter as much as the modules themselves, because they are what make the stack behave as one structure rather than as two objects sitting on each other. Lateral stability in particular depends on those connections.

Acoustics between levels

This is the item residents notice and the one most often underestimated.

Footfall from above, transmitted through the floor structure, is structure-borne rather than airborne, and it is not solved by insulation alone. It needs separation in the construction, so the impact does not have a direct path into the ceiling below.

Volumetric construction has an inherent advantage here, because the ceiling of the lower module and the floor of the upper module are separate assemblies with a cavity between them. That separation is difficult to achieve in conventional construction and it comes for free in a stack.

It still has to be detailed. The advantage is real and it is not automatic, and it is covered alongside fire and acoustic performance.

Fire separation

Separation between levels and between dwellings has to be continuous, and continuity is the whole question in a stacked assembly.

The junctions between modules, the cavity between floor and ceiling, and every service penetration crossing a separating element have to be detailed and fire-stopped so the rating is not broken at the join.

This is documented rather than left to the installer, and it is inspected.

Access and circulation

A two-storey dwelling needs a stair. A two-storey building with dwellings on both levels needs common circulation, and where accessibility applies, that circulation carries requirements of its own.

On accommodation designed to the Specialist Disability Accommodation standard, the accessible dwellings are generally at ground level, with the upper level serving a different purpose. That is a planning decision made from the accommodation brief, not a structural one.

Installation

The sequence is fixed. Lower modules first, set, levelled and connected, then the upper modules.

Which means the crane has to be capable of the reach and the load at the upper level, not just the ground level. Reach and capacity trade against each other, so a two-storey stack usually needs a larger machine and more standing area than a single storey on the same site.

That feeds straight back into the site assessment. A site that can take a single-storey installation may not have room for the crane a stack requires.

Weathertightness between the lifts matters too. The lower modules have to be protected between being set and being covered.

Why the frame handles it

The structural frame is powder-coated galvanised steel, over-engineered to survive road transport and craneage.

The loads a module experiences being lifted fully fitted out are substantial, and the capacity that provides is available for the in-service case, including carrying a module above.

That is the practical benefit of designing for the journey. The structure arrives with headroom.

Send us the project and we will work through the stack.

MADEmodular / MADEbetter.