Guidance on concrete bases, foundations and groundworks for steel buildings — including our concrete base calculator to help estimate concrete quantities and costs.
STARTING WITH THE BASE
The Right Building Starts with the Right Foundation
The concrete base and foundations form a critical part of any steel building project. They provide a level, stable platform for the structure and transfer the loads from the steel frame safely into the ground.
There is no single foundation design suitable for every steel building. The appropriate solution depends on factors including the building size and structural design, site conditions, ground bearing capacity and intended use.
For some projects this may involve a reinforced concrete slab with thickened edges, while others may require individual column pads, ground beams or a separately engineered foundation design.
If you’re planning a new base, our concrete base calculator below can also help estimate the concrete volume required for common slab and foundation arrangements.
FOUNDATION DESIGN
What Determines the Right Base & Foundation?
The foundation requirements for a steel building are influenced by both the structure above ground and the conditions below it. Key considerations include:
BUILDING SIZE
Span, Length & Height
Larger spans, greater heights and different bay arrangements can change the loads transferred through the columns into the foundations.
GROUND CONDITIONS
What’s Below the Building
Soil type, bearing capacity, made ground and other site conditions can influence the type and size of foundation required.
STRUCTURAL LOADS
Wind, Snow & Building Loads
The frame and foundations need to work together to resist the forces acting on the building, including site-specific wind and snow loads.
BUILDING USE
What the Floor Needs to Support
A garage, workshop, warehouse or agricultural building may place very different demands on the concrete floor from vehicles, machinery, storage or other loads.
SITE & DESIGN
Every Project Is Different
Levels, drainage, boundaries and other site-specific constraints can all influence the final foundation and slab design.
READY TO GET STARTED?
Planning a Steel Building?
Tell us the size, location and intended use and we’ll help you develop the right building specification.
Although they are often discussed together, the concrete floor slab and the foundations supporting the steel frame perform different jobs. Depending on the project, they may form part of one integrated concrete design or use separate foundation elements.
CONCRETE SLAB
The Building Floor
The slab provides the finished floor area within the building and can be designed around its intended use, including vehicles, equipment, storage and general floor loading.
COLUMN FOUNDATIONS
Supporting the Steel Frame
Loads from the steel frame are concentrated at the column positions. Foundations at these locations need to transfer those loads safely into the ground.
INTEGRATED FOUNDATION
Designed to Work Together
A foundation design may incorporate thickened slab edges, local pads or ground beams so the slab and structural foundation elements work together as part of the overall base.
The steel frame should not simply be assumed to suit an existing slab without considering how the column loads will be supported.
FOUNDATION OPTIONS
Common Steel Building Foundation Arrangements
The appropriate foundation arrangement depends on the building design and site conditions. Depending on the project, a foundation solution may include one or a combination of the following:
REINFORCED BASE
Slab with Thickened Edges
A reinforced concrete slab can incorporate deeper or thickened sections around the perimeter and column positions to accommodate loads from the steel frame.
COLUMN PADS
Local Foundations at Column Positions
Individual reinforced concrete pads can be formed beneath the steel columns, providing additional foundation capacity where the structural loads are concentrated.
GROUND / EDGE BEAMS
Connecting the Foundations
Reinforced ground or edge beams can be used around or between foundation locations, depending on the structural design and site requirements.
The final dimensions, reinforcement and concrete specification should be determined for the individual project rather than taken from a generic foundation detail.
Already have the dimensions? Use our concrete base calculator to estimate the concrete volume for a slab, thickened edge, ring beam or column pads.
EXISTING BASES
Already Have a Concrete Base?
An existing concrete slab may be suitable for a new steel building, but its suitability should not be assumed from the slab thickness or concrete grade alone.
The existing construction needs to be considered alongside the new building dimensions, column positions, structural loads and ground conditions.
EXISTING SLAB
Check What You Already Have
Where possible, establish the slab thickness, concrete specification, reinforcement and details of any existing foundations or thickened edges.
COLUMN LOCATIONS
Additional Local Foundations
Where an existing slab does not provide the required foundation at a steel column position, it may be possible to locally cut out the slab and introduce appropriately designed column pads.
EDGE / GROUND BEAM
Strengthening the Perimeter
Depending on the project, another solution may be to introduce a reinforced edge or ground beam connected to the existing concrete.
An existing base does not necessarily need to be removed and replaced. Where suitable, a project-specific foundation solution can sometimes incorporate or adapt the concrete already in place.
FRAME CONNECTION
How the Steel Building Connects to the Base
Once the foundations and concrete base are in place, the steel frame must be securely connected to the supporting concrete at each column position.
The connection arrangement forms part of the structural design and needs to transfer forces between the steel frame and foundations.
BASE PLATES
Supporting the Columns
Steel columns are typically formed with base plates that provide the connection between the structural frame and the supporting concrete.
ANCHOR FIXINGS
Securing the Frame
Structural anchor fixings secure the column base plates to the concrete. The type, size and arrangement of the fixings will depend on the building and connection design.
SETTING OUT
Getting the Positions Right
Accurate setting out is important. The concrete base, foundation positions and finished dimensions need to correspond with the approved building drawings before erection begins.
The base should be constructed from the approved foundation and building information — not simply from the nominal external dimensions of the steel building.
BEFORE POURING CONCRETE
Get the Building Design Confirmed First
Where possible, the concrete base and foundations should be constructed after the steel building design and relevant dimensions have been confirmed.
This allows the foundation layout to correspond with the actual frame, column positions, openings and agreed building dimensions rather than relying on preliminary or assumed measurements.
BUILDING DESIGN
Confirm the Specification
Agree the building dimensions, structural arrangement, doors and other principal openings before finalising the base.
APPROVED DRAWINGS
Work from the Right Information
Use the approved building and foundation information when setting out the concrete works, checking dimensions and column positions before construction begins.
CONCRETE WORKS
Build the Base Accurately
The base and foundations can then be constructed to suit the agreed building, ready for the steel frame to be erected once the concrete has achieved the required condition for installation.
Already have a base?
Don’t worry — an existing slab may still be usable or adaptable. Tell us what is already on site when requesting your quotation so it can be considered as part of the project.
Typical steel building foundation arrangements shown for guidance only. Final foundation design should be confirmed for the individual building and site conditions.
PROJECT INFORMATION
From Building Design to Groundworks
The steel building and its foundations need to work together. Once the building design has progressed, the relevant dimensions and structural information can be used by your groundworks contractor or engineer to develop and construct the appropriate base.
Planning your groundworks? Tell us early in the project if you need building information for your engineer or groundworks contractor.
BUILDING DIMENSIONS
Confirmed Building Layout
Approved drawings establish the building dimensions, bay positions, column locations and principal openings required for setting out.
STRUCTURAL INFORMATION
Loads & Building Design
Relevant structural information can be provided to support the design of the foundations for the building and site.
FOUNDATION DESIGN
Designed for Your Site
Foundation requirements should take account of the structural loads together with the ground conditions and intended use of the completed building.
GROUNDWORKS
Ready for Construction
Your engineer or groundworks contractor can use the agreed project information to set out and construct the base and foundations before erection of the steel building.
BEFORE YOU START
Plan the Base Around the Building
Avoid committing to final concrete dimensions until the steel building design and relevant foundation requirements have been established.
If you already have a slab or foundations on site, let us know at quotation stage and provide as much information as possible about the existing construction. This can then be considered alongside the proposed building design.
Remember:
Ground conditions vary from site to site. The final foundation design should be appropriate for both the structural loads from the building and the conditions on which it will be constructed.
CONCRETE CALCULATOR
ESB Steel Building Concrete Base Calculator V3
Easy Steel Buildings
Steel Building Concrete Base Calculator
Estimate concrete quantity and indicative material cost for a slab, thickened-edge base, ring beam, slab with column pads or column pads only.
Concrete quantity estimator
Calculate Your Concrete Requirement
Enter the building size, choose the base arrangement and we’ll calculate the estimated concrete volume.
1. Building size
Use the actual proposed building dimensions.
m
m
2. Base / foundation arrangement
Choose the arrangement you want to estimate.
3. Slab thickness
mm
4. Thickened edge
Use a typical ESB edge example?Available for spans up to 12m and selected automatically from the entered span.
mm
mm
Typical ESB example: suitable ground is assumed. Ground conditions and bearing capacity must be verified for the individual site. The calculator uses the example only to estimate concrete quantity; it is not a foundation design.
3. Ring beam dimensions
mm
mm
4. Column pads
Enter pad dimensions from your own foundation design. For pad-only estimates, the calculator can also estimate the number of main-column pads from the building length. In this example, we have assumed a 4.00m bay rule.
mm
mm
mm
Pad sizes are user-entered. The correct pad size depends on the project, column reactions and ground conditions. For the automatic quantity example, we have assumed a 4.00m bay rule and two main columns per portal frame. Actual bay layouts can vary. Gable posts, internal columns, lean-tos or other supports may require additional foundations. If you know your proposed layout, choose “Enter number of bays” or “Enter pad quantity”.
5. Cost & ordering allowance
£/m³
%
How to calculate a concrete slab
Multiply length × width × slab thickness, converting the thickness from millimetres to metres.
How to calculate a ring beam
This calculator uses the actual perimeter band area, avoiding double-counting the four corners.
Using your own foundation dimensions
If your engineer has supplied pad, beam or edge dimensions, enter them directly for a quantity estimate.
PLANNING A STEEL BUILDING
Start with the Building. Plan the Base Properly.
Tell us the dimensions, location and intended use of your proposed building and we'll help establish the building information needed to progress your project.
