How does TESSA generate Cost Plans?
TESSA automatically generates Cost Plans by extracting metrics from the Design Options and applying these to the cost database produced and maintained by Modulous. Modular element rates have been developed in consultation with supply chain partners to establish detailed cost breakdowns for labour, materials, assembly, and transportation across the full Kit of Parts. Base build unit costs are supplied by the Modulous in-house Quantity Surveyor team.
The cost plans follow RICS NRM and are split into two sections: the base build and the modular elements of the buildings. Elemental summaries go down to NRM Level 2. TESSA provides cost certainty for 30% to 40% of the construction cost (the modular elements) and benchmarked cost estimates for the base build at feasibility stage.
Default Values
The default values and calculation methods currently used in TESSA for Prelims, Overhead & Profit Allowance and Contingency are included in the table below.
| Line item | % or Flat Rate | Applied to |
|---|---|---|
| Modules | - | |
| Fit Out | - | |
| Base Build | - | |
| Total Construction | = | Modules + Fit Out + Base Build |
| Prelims | 10% | (Construction Total) |
| Contingency | 3% | (Construction Total + Prelims) |
| OH&P Allowance | 5.5% | (Construction Total + Prelims + Cont.) |
| Total | = | Construction Total + Prelims + Cont. + OH&P |
The Total Construction is divided by the GIA (Gross Internal Area, see Design Options) to obtain the cost values per sqm or sqft, which therefore exclude Prelims, Overhead & Profit Allowance and Contingency unless otherwise stated.
Tall Buildings Implication & Methodology
To account for expected changes in building systems as a result of building height increases, we adjust our assumptions for costing line items in the default element list against the following storey categories:
>8 Storeys
9 – 12 Storeys
<13 Storeys
Building characteristic changes such as the size and quantity of circulation, amenity, technical and service spaces because of increased building height are reflected in building level area and quantities. Some of the changes allocated from a costing perspective are reflected below.
Base Build
1.1 – Substructure: Changes in rates and substructure methodology as result of transitioning between more robust substructure solutions associated with taller buildings (i.e. Deep piled foundations required for buildings 12 storeys and above)
2.1 – Frame: Increased tonnage and complexity of frames, supports/restraints and connections necessary for changes in building height across non-modular areas of the buildings
2.1 – Frame: Increased fire protection requirement on structural frames for changes in building heights (60mins, 90mins, 120mins) across non modular areas of the buildings
2.5 – External Walls: Increases in façade and balcony costs for taller buildings associated with loading and additional operational/access requirements for install
2.5 – External Walls: Increases in cavity barriers and fire protection measures for taller buildings (60mins, 90mins, 120mins)
- 5.10 – Lift Installations: Increased quantity, size and speed of lifts to facilitate taller buildings
Modules
- 6.1 – Prefabricated Structures: Module Frame: Increased tonnage and complexity of frames, supports/restraint and connections necessary for changes in building height
- 6.1 – Prefabricated Structures: External Walls: Increased fire protection measures in wall build ups for changes in building height (60mins, 90mins, 120 mins)
- 6.1 – Prefabricated Structures: Ceiling Panels: Increased fire protection measures in ceiling panel build ups for changes in building height (60mins, 90mins, 120mins)
- 6.3 – Prefabricated Structures: Party Wall: Increased fire protection measures between units for changes in building height (60mins, 90mins, 120mins)
- 6.3 - Prefabricated Structures: Deployment: Increased cost associated with installation of modules on site with longer periods of lifting and operational/access requirements
Project On Costs
- Preliminaries: User can manually adjust for an increased allocation of preliminaries associated with additional operational/access requirement, site management and construction timelines for taller buildings (Default % in Cost Settings - 10%)
- Contingencies: User can manually adjust for an increased allocation of contingency associated with increased risk of taller buildings (Default % in Cost Settings - 3%)
Assumptions & Clarifications
1 Substructure
2 Superstructure
2.1 Frame
Base Build
- Structural steelwork as the primary structure of the building to cores and corridor locations
- Structural steelwork tonnages based on allocation of either 65kg/m2, 80kg/m2 and 105kg/m2 dependant on building requirement
- Structural steelwork to be painted with a factory applied intumescent coating to provide the appropriate fire resistance dependant on building requirement
- Stair and elevator cores will be formed from structural steelwork and core walls infilled with SFS framing
- Podium – If podium is selected as an option within Design Brief, structural steelwork is included to this location and appropriate fire resistance applied consistent with the above
Modular
- Hot rolled steel frame and columns incorporating the Modulous floor panel system
2.2 Upper Floors
Base Build
- Upper floor construction to corridor and core areas consist of composite structural trapezoidal metal deck with lightweight concrete infill up to 150mm thickness.
- Stair landings and half landings utilise the same system and build up
- Optionality – User may choose to select utilising the Modulous floor panel system to corridor locations
Modular
- Modulous floor panel system includes infill light gauge steel studs, thermal insulation, mesh and metal decking sheet
2.3 Roof
Base Build
- Roof Structure & Build up - Warm flat roof system incorporating plywood roof deck, vapour control layer, 200mm rigid insulation and single layer waterproof membrane allowed for to roof areas
- Roof Structure – Parapet structure incorporating rigid insulation, external sheathing board, flashings, waterproof membrane to internal face and copings to finish
- Roof Finish – Photovoltaic panels provisionally included to cover roof area to 25%
- Roof Finish - Gravel ballast to roof area
- Roof Features – Mansafe and Maintenance Equipment allowance included
Modular
2.4 Stairs
Base Build
- PPC metal stairs, mild steel handrails and balustrades included
- Concrete infill to metal treads
- Slip resistant vinyl flooring finish with nosings
Modular
2.5 External Walls
Base Build
- External wall finish – Brick Slip system with rails, secondary steel support and bracketry, rainscreen thermal insulation and vapor control layer used across residential façade area
- Lift and stair core walls constructed out of SFS framing. External wall finish above fixed to SFS framing system for facade where applicable
- Single skin blockwork walls to service locations including forming openings and penetrations. External wall finish above fixed to single skin blockwork for facade where applicable.
- Podium – If podium is selected as an option within Design Brief, external wall to be built out using single skin blockwork walls for external wall finish to be applied to where applicable.
- Includes all associated detailing and finishing costs for penetrations, openings, articulations and abutments in the external wall
- Horizontal fire barrier separation between floors and vertical fire barrier separation at party walls included within external wall cost
- Balconies, balustrading and floor finish provided to each residential unit
- Entrance enhancement allowance for canopies and features to main building entrance
- External/entrance signage allowance
Modular
- Modulous external wall system comprising of light gauge steel studs, mineral wool insulation, external sheathing board and vapour permeable air barrier.
- Includes all associated detailing and finishing costs for penetrations, openings, articulations and abutments in the Modulous external wall system
- Firestopping is not included (Allocated for within MEP BWIC)
2.6 External Windows & Doors
Base Build
- Mild steel PPC entry & exit doors included to core, service, commercial and amenity locations on the ground floor where required with associated ironmongery and frame
- Podium – If podium is selected as an option within Design Brief, triple glazed aluminium framed windows will be included to the shown locations.
Modular
- Solid wood core entrance doors included to each unit with architraves, thresholds and ironmongery
- Tripled glazed aluminium framed windows installed to Modulous external wall panel system.
- Glazed balcony/patio doors included to each unit
2.7 Internal Walls & Partitions
Base Build
- Plasterboard finish and insulation to interior side of lift and stair cores
- Plasterboard finish to exterior of module walls on corridor side
- Single skin lightweight blockwork walls to service locations including forming openings and penetrations
Modular
- Unit internal metal studs partition walls built out with light gauge steel, mineral wool and plasterboard
2.8 Internal Doors
Base Build
- Single and double fire rated doors to escape, circulation and communal spaces where required with timber architraves, thresholds and aluminium ironmongery. Doors painted off site.
- Fire doors to services risers in corridor spaces with architraves, thresholds and ironmongery
Modular
- Single solid core doors to bathrooms and bedrooms
- Double cupboard doors to utility rooms
3 Internal Finishes
3.1 Wall Finishes
Base Build
- Mist coat and emulsion finish to internal walls in corridor and core locations
- Blockwork walls to service locations to be exposed with no finish
Modular
- Mist coat and emulsion finish to internal walls in apartment units
- Ceramic wall tiling to internal walls of bathrooms where shown
3.2 Floor Finishes
Base Build
Non structural lightweight screed included to all services, corridor and core flooring areas
- Basic carpet finish included to all corridor and core flooring areas
Resin paint finish included to all service locations
Painted MDF Skirtings to all internal walls
Entrance matting to main building entrance
Modular
Non structural lightweight screed included to all unit flooring areas
- Basic carpet finish included to all unit flooring areas
- Slip resistant safety flooring included to bathroom areas
- Painted MDF Skirtings to all internal and external walls
3.3 Ceiling Finishes
Base Build
MF suspended ceiling system with service void included all corridor locations with tape and jointed plasterboard finish
- Allowance for access hatches/panels
Modular
- Modulous ceiling panel system comprising light gauge steel studs, mineral wool insulation, GIFA board and fire resistant plasterboard.
- Allowance for access hatches/panels
4 Fittings, Furnishings and Equipment
4.1 Fittings & Furnishings
Base Build
- Residential Letter Boxes
- Interior Wayfinding Signage
Modular
- Kitchen fit out including appliances, worktops and cabinetry
- Bathroom fit out including sanitaryware and vanity units
5 Services
Base Build
Modular
- Sanitary installations
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