ICF is a building system consisting of twin-walled expanded Polystyrene (EPS) separated by a patented structural web system to create a 3D cube which is interlocked with the adjacent cube to create the walls of a building.
The formwork system is then reinforced and filled with ready mixed concrete to create a superstructure ready to accept the roof and floors. Proprietary finishes – render, brickwork, plasterboard etc. – can be applied to the ICF to complete the process.
The ICF system naturally provides:
The ICF system has been used extensively for basements, residential solutions, industrial, retail and commercial applications, as well as education and healthcare buildings


Features & Benefits of ICF
Design flexibility: A variety of standard block shapes and components creates almost limitless design opportunities.
System integration: The ICF solution is compatible with all other building elements – foundation, flooring, roofing, internal walling and other structural features.
Finish flexibility: The exterior of the building can be finished in any conventional cladding solution.
Rapid installation: ICF systems require a degree of training and skill to install, but this is much less a factor than with other comparable modern methods of construction.
Programme predictability: ICF can be installed in wet or freezing condition (although concrete may not be able to be poured).
Reduced site interfaces: With less labour on site it is possible to create a safer and cleaner site environment in which to work.
Regulation compliant: The IntegraSpec® ICF system provides an efficient means of achieving compliance with Building Regulations in England, Wales and Scotland.
Exceptional in-service performance: Occupants of our ICF building will see reduced running costs, improved acoustic performance due to the heavy mass construction, and a healthier indoor environment with highly controllable air quality and internal temperatures due to minimal thermal gain.
Insurable innovation: All mortgage lenders, insurance companies and building control authorities approve the use of ICF construction methods.
Building Process
Footing and Pad Preparation
Checks are carried out to ensure the footing or pad is level, uniform, and wide enough for the Lock-Form panels and Base Plate to rest on.
Wall Form Assembly
Half ties are inserted in every slot (200mm apart) along the bottom of the form. Full ties are inserted into the top of panels (also 200mm apart). This allows the next course of panels to be placed.
Horizontal Rebar Placement
The horizontal rebar rests on a row of spacer ties. Bar is wire-tied to the ties every 200mm to prevent the rebar from shifting.
Window/Door Block Out and Bracing
Blockout is constructed by placing any sturdy material matching the required hole dimension. Blockouts are securely anchored at head and jambs. Sill blockout is not added until during pour when concrete has reached sill height.
Utility Cutouts
Holes for water, gas, etc. are cut into the form wall with a saw. These cutouts are made when the wall has been fully assembled.
Wall Bracing & Scaffolding
Vertical braces are placed at 600mm centres, horizontal bracing (running across vertical braces) are placed at 1000mm centres while lateral braces are fixed to every second vertical brace at 2/3 up wall height.
The Bracing and Scaffolding system is integral to the Lock-Form process. It provides a safe and easily accessible working surface during the pour.
Pre Pour Checklist
Before concrete is poured we check that:
plastic ties are inserted every 200mm
ties are on both sides of the Lock-Form panel
corners are plumb
rebar is inserted and tied every 200mm
vertical braces are wire-tied every 200mm
every second vertical brace has a lateral brace and that all lateral braces are adjusted and anchored
all window/door casings are reinforced
all utility holes have been cut and blocked
final alignment has been checked
scaffold planking is safely anchored and supported
Concrete Mix and Pour Guide
The Lock-Form system uses:
7mm smooth aggregate
100mm slump
Strength specified by an engineer for each project
Concrete is placed in 1200mm lifts and does not exceed 2000mm per hour.
Electrical / Plumbing Services
A path for utility lines is cut by saw, electric hot knife or router and concealed within the styrene Lock panel. Wiring is protected by a conduit anchored to the concrete wall.
Stripping ICF Lock-Form
If ICF Styrene Lock-Form panel on a curved wall is to be stripped off after concrete pour, panels will be treated with an approved release agent prior to all assembly.