For SFS and cladding contractors
Supply only
- We provide
- The frame, the brackets and the façade made to your drawings, delivered to site, with data sheets and fixing details
- You provide
- Installation
Rooftop floors in SFS
Airspace development: build up, not out
London has little land left to build on, so many buildings can only grow upwards. For a new floor on an existing roof, we design, make and install the frame and the façade: walls in MET-PRO SFS, our Express FS façade brackets, and aluminium rainscreen or metal cladding. Supply only, or supply and install.
- Frame
- MET-PRO SFS
- Façade
- Aluminium rainscreen
- Made in
- Rainham, Essex
- Buy
- Supply only or installed
Why build up
When a London site has no room to grow outward, the roof is often the one place left to add homes or workspace.
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No new land
The new floor sits on a building that is already there, on a plot that is already built on.
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A full new storey
The walls of the whole floor framed in MET-PRO SFS and clad in our metal façades, not a single room on the roof.
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One supplier for the envelope
The frame, the brackets and the façade come from one company, so the interfaces between them are ours to coordinate.
Ideas for a rooftop floor
Five typical London buildings, before and after new storeys in our cladding systems. Drag the line on each picture to compare.
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Victorian terrace with shops One storey in Express ALU Pro Plank, bronze -
1930s mansion block One storey in Express ALU Pro Fixed Cassette, RAL 9006 -
1960s concrete-frame offices Two storeys in Express ALU Pro Secret Fix, RAL 7035 -
Converted brick warehouse One storey in Express Standing Seam, RAL 7016 -
Modern residential block Two storeys in Express ALU Pro Plank, RAL 9006
Why build it light
An existing building was not necessarily designed to carry another floor. The structural engineer confirms what it can take; a frame of light gauge steel and a thin metal façade keep the added weight down.
- Our own steel frame. MET-PRO SFS (steel framing system) is our range of studs, tracks, cleats, angles and posts for loadbearing and non-loadbearing walls.
- Weathertight sooner. A lightweight frame and simple installation shorten build times and give early weather protection.
- Site or factory assembled. Choose what suits the roof, the access and the programme.
- Sized for your building. We do not publish load tables: send the structural and architectural drawings and we size the frame for the project.
- SFS studs
- 90 to 350 mm
- Galvanised steel
- 1.2 to 3 mm
- Aluminium panels
- 2 to 4 mm
- Standing seam
- From 2.87 kg/m²
What we supply for a rooftop floor
The envelope of the new storey, made by us: the frame, the brackets, the façade and the roof and wall sheets.
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The frame
MET-PRO SFS
The walls of the new floor: studs, tracks, cleats, angles and posts, loadbearing or non-loadbearing.
- Studs
- 90 to 350 mm
- Steel
- 1.2 to 3 mm
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The brackets
Express FS façade brackets
Carry the rainscreen rails off the frame at a set stand-off, clear of the wall for insulation and a ventilated cavity.
- Sizes
- 40 to 400 mm
- Types
- Single or double
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The façade
Aluminium rainscreen
Express ALU Pro Fixed Cassette, Secret Fix and Plank in any RAL colour or anodised, or Express Standing Seam.
- Panels
- 2 to 4 mm aluminium
- Finish
- Any RAL or anodised
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Roof and wall sheets
Express Pro profiles
Profiled sheets and planks in colour-coated steel, cut to length, for the roof and walls of the new floor.
- Material
- Coated steel
- For
- Roofs and walls
For developers and main contractors
Supply and install
- We provide
- Design, manufacture and installation of the frame, the brackets and the façade of the new floor
- One point of responsibility for
- The material and the fitting
Boarding and drylining inside the new floor: our sister company Express Group takes the wider package, with drylining by Express Group's own teams.
At roof level
Façades we have built on a roof
At Spelthorne Leisure Centre, for Willmott Dixon Construction, we designed, manufactured and installed the aluminium panel rainscreen on Core 3, the copper-coloured stair core at roof level, with timber batten rainscreen on Cores 1 and 2.
Pictured: Core 3 in our aluminium panel rainscreen, beside the roof terrace at Spelthorne Leisure Centre. A leisure centre roof, not an airspace development.
Before you build: what a site needs
Every building is different. These are the questions a rooftop floor usually raises. Your structural engineer, architect, planning consultant, building control and solicitor answer them for your site.
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Structure
Can the existing frame and foundations carry another floor, and what strengthening would it need? A structural engineer checks. We size the SFS to the project from the drawings.
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Stairs, lifts and escape
The stair, and any lift, usually has to reach the new floor, and the fire strategy has to cover it.
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Access and lifting
How materials reach the roof (crane, hoist or scaffold), where deliveries stop, and how people in the building below are kept safe.
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Planning
A new floor needs planning permission, or prior approval where permitted development rights apply. Conservation areas and listed buildings add their own rules.
Permitted development, Part 20 (legislation.gov.uk) (opens in a new tab) -
Building safety
Adding storeys can make a building higher-risk: 18 metres or seven storeys, with at least two homes. The Building Safety Regulator then approves the work before it starts.
Higher-risk buildings (gov.uk) (opens in a new tab) -
Neighbours and ownership
Work on a shared wall needs notices under the Party Wall etc. Act 1996. The freehold, the leases and any covenants decide who may build on the roof.
Party walls (gov.uk) (opens in a new tab)
How a rooftop floor runs with us
Send the drawings at any stage: we give estimating and specification support, then detail, make and install the frame and the façade.
Enquiry
Send the architectural and structural drawings, the façade and the finish. We come back with a quotation.
Design
We detail the frame and the façade and produce CAD drawings for approval. Bracket layouts come with structural and thermal calculations.
Samples and colour
Samples in your chosen RAL colour or finish, for sign-off.
Manufacture
The frame and the façade are made in the UK.
Delivery
Delivered to site, ready for installation.
Installation
For supply and install, our teams fit the frame, the brackets and the façade.
Handover
System guarantees are available on request for the Express ALU Pro systems.
Airspace development FAQs
What is airspace development?
Building new floors on top of an existing building, in the space above its roof. Where there is no land to build on, it adds homes or workspace without a new plot.
Why use SFS for a rooftop floor?
SFS (steel framing system) is light gauge galvanised steel: studs and tracks that form the walls. MET-PRO SFS frames loadbearing and non-loadbearing walls, can be site or factory assembled, and its light frame and simple installation shorten build times and give early weather protection.
Can MET-PRO SFS carry the new floor?
MET-PRO SFS is made for loadbearing and non-loadbearing walls. Whether loadbearing SFS suits your floor depends on the structural design. We do not publish load tables: send the structural and architectural drawings and we size the frame for the project.
Which façades can go on the new floor?
Our aluminium rainscreen systems (Express ALU Pro Fixed Cassette, Secret Fix and Plank), Express Standing Seam and our Express Pro wall profiles. The aluminium panels come in any RAL colour, or anodised.
Do I need planning permission?
Usually you need planning permission, or prior approval where permitted development rights cover the building. The rights are set out in Part 20 of Schedule 2 to the General Permitted Development Order 2015. Your planning consultant or the local planning authority confirms the route for your site.
Does a new floor change the building safety rules?
It can. If the building will be 18 metres or more, or seven storeys or more, and has at least two homes, it becomes a higher-risk building, and the Building Safety Regulator approves the work before it starts. See the government guidance on building control approval for higher-risk buildings.
Can I buy supply only?
Yes. MET-PRO SFS, every rainscreen system and the Express FS façade brackets are available supply only, made to your drawings and delivered to site. Or our teams install them.
Send us the drawings for the new floor
Send the architectural and structural drawings. We will price the frame and the façade together, supply only or supply and install.
Illustrative renders and computer-generated images, not photographs of completed projects.