Domestic ground floor slabs
- New build houses, bungalows and extensions with solid ground floors.
- Slabs with insulation, DPM and screed ready for finishes and underfloor heating.
Menu
Ground bearing slabs • Ground floor structural design
Ground floor slab design for domestic, commercial and light industrial buildings
Ground floors carry people, traffic and equipment every day. If the slab is too thin or sitting on weak ground, you get cracking and settlement. We design ground bearing slabs and ground floor slabs so they work with the ground and pass Building Control checks.
This service is for floors that are mainly ground bearing. For heavy forklift traffic and high bay racking we use our separate industrial concrete floor slab design service.
- Ground bearing and part suspended slabs for houses, extensions, small warehouses and workshops.
- Slab thickness, mesh, joints and edges set from loads, ground conditions and floor build up.
- Fixed fee calculation packs with clear drawings and notes your builder can follow on site.
We work with homeowners, developers and business owners across the UK, providing ground floor slab designs that suit the use of the space and the ground conditions on site.
Ground floor slab design for domestic, commercial and light industrial buildings
This page is for slabs that are mainly ground bearing. Heavy forklift and high bay warehouse floors are covered by our industrial slab design service.
Light commercial and trade units
- Shops, trade counters and small warehouses with vans and pallet trucks.
- Focus on slab thickness, joint layout and crack control for regular use.
Garages and workshops
- Domestic and small commercial garages with cars, light trucks or 4x4s.
- Local thickening or pads under vehicle ramps and machinery bases.
Slabs on improved ground
- Slabs over engineered fill or ground treated with vibro stone columns.
- Designed to work with the geotechnical solution as one system.
Slabs with underfloor heating
- Ground floors with heating pipes within the slab or screed build up.
- Allowance for thermal movement, insulation and service zones.
Replacement and remedial slabs
- New slabs where existing floors have cracked, settled or failed.
- Designs that account for the existing structure, ground and services.
Ground conditions we often see with ground floor slabs
The behaviour of a ground floor slab depends as much on the ground and hardcore as on the concrete and mesh above.
Firm natural ground
Trial pits show firm natural soil at shallow depth.
A simple ground bearing slab may be suitable.
We set thickness and mesh for the loads and panel sizes, with edge thickening where needed.
A simple ground bearing slab may be suitable.
We set thickness and mesh for the loads and panel sizes, with edge thickening where needed.
Made ground and old fill
Mixed fill from previous buildings, backfilled basements or services.
We may suggest ground improvement or deeper excavation.
Slab may be treated as partly spanning between better areas.
We may suggest ground improvement or deeper excavation.
Slab may be treated as partly spanning between better areas.
Clay, trees and movement
Shrinkable clay close to trees can move with changing moisture.
We look at tree size, distance and depth of firm strata.
Slab type and detailing are chosen to manage volume change.
We look at tree size, distance and depth of firm strata.
Slab type and detailing are chosen to manage volume change.
What our ground floor slab design covers
We treat each slab as a full structural element, not just a thickness taken from a table.
Load cases
- People, storage, vehicles and pallet truck traffic.
- Point loads from columns, posts, racking legs and machinery bases.
Slab thickness and reinforcement
- Thickness based on bending, punching and serviceability checks.
- Mesh type and spacing chosen for crack control and durability.
Sub-base and support
- Hardcore and sub-base specification and compaction guidance.
- Bearing checks on the underlying soil and any improved ground.
Movement and cracking
- Joint layout and joint types to manage shrinkage and thermal movement.
- Edge thickening at external walls, door thresholds and upstands.
Build up and details
- DPM, insulation and screeds with allowance for service routes.
- Falls to drains or thresholds where these sit within the slab build up.
Coordination with others
- Coordination with architect, contractor and ground specialist.
- Designs suitable for Building Control and warranty provider review.
Information we need to design your ground floor slab
Good information keeps fees sensible and reduces queries during construction.
Architect or designer drawings
- Plans and sections showing footprint, openings, levels and build up.
- Architect PDFs are fine; DWG can also be used if preferred.
Ground information
- Site investigation report if you have one.
- Trial pit photos and notes on soil type, depth and any existing slabs.
Load information
- Intended use of the space and any heavy equipment or storage.
- Locations of racking lines, machinery bases and vehicle routes.
Project details
- Address, postcode and whether Building Control or a warranty provider is involved.
- Target dates for design and construction so we can plan delivery.
Recent ground floor slab projects
A few examples of how we apply ground floor slab design in real projects.
Trade counter unit – Romsey
Ground bearing slab with vans and pallet trucks
We designed a reinforced slab on compacted hardcore with joint layout, edge thickening and mesh specification. The contractor reported a smooth pour and Building Control accepted the design without queries.
Warehouse extension – South East
New slab tied into existing floor
Our work covered checks on the existing slab, new slab thickness and joint details at the construction joint. The client was able to phase the pour while keeping part of the warehouse in use.
House refurbishment – Wiltshire
Replacement domestic ground floor slab
An old slab on mixed fill had cracked and settled. We proposed a new insulated slab with defined build up, trial pits and clear notes for the builder. The new floor gives a level base for finishes and underfloor heating.
Ground floor slab design – frequently asked questions
Short answers to the questions we hear most often about ground bearing slabs and ground floors.
What is the difference between a ground bearing slab and a suspended slab?
A ground bearing slab sits directly on compacted hardcore and soil and passes loads into the ground. A suspended slab spans between walls, beams or piles and does not rely fully on the ground for support. This page focuses on ground floor slab design where the slab is mainly ground bearing.
How thick should a ground floor slab be?
There is no single thickness that suits every project. Many domestic slabs end up around 100 to 150 mm thick with mesh, but this can increase where loads are higher or ground is variable. We set the thickness from loads, ground conditions and the full floor build up.
Do I always need mesh reinforcement in a ground floor slab?
Mesh is usually recommended to control cracking, even where loads are modest. The mesh type depends on slab thickness, panel size and expected movement. In some light slabs fibres may be used instead, but we review this case by case.
Can you design a ground floor slab without a site visit?
Often yes. With clear drawings, trial pit photos and basic ground information we can design the slab remotely. If the ground conditions are unclear or the project is complex we will say so and confirm if a visit is needed.
Can you coordinate joints and detailing with my architect or contractor?
Yes. We often coordinate joint positions, falls and build ups with the wider team so the structural design, drainage and finishes all work together.
Request a structural engineer quote for your ground floor slab
Use this form to outline your project. Your enquiry goes straight to an engineer, not a call centre.
Tell us about your ground floor slab
Share a few details so we can review the drawings and ground information and confirm the right slab type, thickness and a fixed fee for your ground floor slab calculations.
This form connects to our central SECalcs email. You will usually hear back from a structural engineer within one working day.
Ready to move your ground floor slab design forward?
If you are planning a new ground floor slab or replacing an existing slab, send us a few details and we will review the project, recommend a slab approach and confirm a clear fixed fee for the design work.
- Head Office: Corwell Lane, Uxbridge, England, UB8 3DE.
- 07359 267907
- info@structuralengineercalcs.com
- Company No: 12653163