Insulated Concrete Formwork

Insulated Concrete Formwork (ICF) construction is a simple thermally efficient way to build strong insulated walls for residential and commercial buildings.

Our insulated concrete formwork block brand, which is manufactured in the UK, is called WARMERWALL. Building with WARMERWALL ICF insulated building blocks provides self builders, contractors and design professionals with an energy efficient build solution which is strong, thermally efficient and quick to construct walls.

Our Clients

We supply our insulated block across the construction industry. Explore to find out more about WARMERWALL.


Looking to design and build a modern energy efficient home? Learn More

Property Developer

WARMERWALL is a fantastic method to create buildings faster. Learn More


WARMERWALL allows you to design buildings with straight lines and curves; single or multi-storey. Learn More

Structural Engineer

Our method provides structural engineers with a straight forward method to create retaining walls. Learn More


If you can build it traditionally, you can design it with WARMERWALL. Explore to see some fantastic projects achieved by our clients.


Looking to create a multi-storey building which is strong and energy efficient? Learn More

Self Builds

Explore the different types of homes self builders have achieved using WARMERWALL. Learn More


Looking to add extra space to your home. See what you can achieve. Learn More


Our 330mm wide block (200mm concrete core) is ideal for creating energy efficient retaining walls. Learn More


As a family run independent business, providing excellent service is important to us. How can we help?

Technical Hub

Our technical hub section has all the details to assist you in moving your project forward. Learn More


Our service section provides contact to tradespeople in the UK construction market who support the WARMERWALL build method. Learn More


Our products section provides contact to businesses that offer a product that works well with our build method. Learn More


For first time users of WARMERWALL, we offer an on site familiarisation training programme at the start of the job. Learn More

Insulated Concrete Formwork (ICF)

Our insulated concrete formwork (ICF) block WARMERWALL is made of up 2 panels of high-density graphite infused insulation with a strong steel frame which together form a rigid block that is light to carry (around 6kg) and easy to build with. The blocks have a tongue and groove design allowing the pre-formed corner blocks and straight blocks to interlock snuggly together.

Steel Fixing Points

The unique steel fixings every 150mm vertically, embedded within the insulation of the WARMERWALL block provides strong fixing points for wall coverings, cladding, brick slips, radiators and cupboards etc. without the need to fix back to the concrete. The steel fixings are much stronger than plastic and of course fire resistant.

Build Height

The WARMERWALL blocks are clipped together, cutting out door and window openings as you go. When a storey height is reached, typically between 2.4 metres to 3 metres tall, and with the door and window openings shuttered out, the blocks are then filled with ready mixed concrete to create an insulated concrete formwork wall with extraordinary (some would call magic) properties.

Thermal Mass

The building grade expanded polystyrene (eps) acts as shuttering in the first instance to mould the concrete into the shape of a wall. Afterwards, the polystyrene is left in place to act as insulation around the concrete. The insulation in conjunction with the concrete wall provides an excellent thermal mass benefit which means you can heat and cool buildings more efficiently.

Insulated Concrete Formwork Construction

Insulated Concrete Formwork construction provides excellent levels of energy efficiency due to the concrete sandwiched in between the two sheets of insulation producing superior levels of thermal mass within the buildings exterior envelope. This allows a self builder to create their dream family home or a design professional to create a commercial building with the confidence that the occupants of both building types will enjoy a cosy, draught free indoor environment. A building built using WARMERWALL ICF is quicker to construct and stronger than standard traditional methods.

Satisfaction Guarantee

A WARMERWALL building is quieter, cosy and strong.

A One-Stop Shop

As manufacturer of our insulated block, we can assist you with contacts in the trade for services and products that compliment and support WARMERWALL ICF.

Free Consultation

We provide free of charge supply estimate so if you have a build project in mind, get in contact to discuss.


Warmerwall is accepted as a standard build method by the Council of Mortgage Lenders.


Our pre-insulated building block Warmerwall is fully certified by the BBA.


Our build method is embraced by building warrantee providers such as NHBC, Premier & BLP.

Featured Projects

Detached Home

A detached home built using our Warmerwall ICF blocks to create the exterior envelope to the build. This property was finished to the outside in a mixture of both facing brickwork and acrylic render to the outside of the build.


An apartment block in Scotland was successfully built using Warmerwall insulated blocks to form the exterior and party walls to this 4 storey build. Externally, a coat of acrylic render was applied to the outside to provide a finish.


In this project, a standard semi detached residential street development had a basement level added using Warmerwall insulated blocks for simplicity, in conjunction with a structural reinforced steel design and waterproof solution.

ICF Ancillary Products and Services

We focus on manufacturing and supplying our insulated concrete formwork block WARMERWALL. It is what we do best. We also like to provide fantastic support through introducing our clients to third party independent suppliers who understand the insulated concrete formwork (ICF) build method and can assist you in moving your project forward.

We have a list of builders who are familiar installing our WARMERWALL Insulated Concrete Formwork Block.

View ICF Installers

We have a list of third party independent architects who are familiar designing with WARMERWALL Insulated Concrete Formwork (ICF).

View Architects

We have a list of third party independant structural engineers who are familiar designing projects using WARMERWALL Insulated Concrete Formwork (ICF).

View Structural Engineers

Over the years, we have built up knowledge supplied to us by our clients of products that we are told work well with WARMERWALL Insulated Concrete Formwork (ICF).

View Products

Tell us about your building plans.

Our icf block will provide you with a simple way to create an energy efficient building envelope. Stock is generally available within a couple of days, delivered directly to site. Contact us to discuss your plans.

Call Us: 01242 692335


Find out our latest news and information.

Build your own house with extraordinarily low energy bills

Wanting to build your own house? A house built using WARMERWALL blocks will provide you with extraordinarily low energy bills. This particular home costs on average £20 per month for both heating and hot water. The WARMERWALL build method allows you to achieve these...

read more

Warmerwall New Website

New Website PolySteel UK Ltd is pleased to announce the launch of to promote our insulated building block - Warmerwall. Our block is suitable for forming the walls for residential and commercial buildings. Please give us a call to discuss your...

read more

Frequently Asked Questions

Is Warmerwall ICF insulated block certified?

Warmerwall ICF has a BBA certification.

£20 a month for heating and hot water achieved - How?

By way of an example of what is possible, we have continually monitored a home in Cheltenham which was built using our Warmerwall block.

The house is a 3 storey semi detached property on a residential street with useful living space of about 100m2. It has a full height basement (the basement walls was constructed using the Warmerwall 330mm wide icf block).

The external walls are made of the standard 280mm wide Warmerwall block with dot and dab plasterboard to the inside and externally is finished in a mixture of render and brickslips.

Inside the property, there is a MVHR system to assist with mechanical ventilation as the air tight result achieved was less than 3 air changes an hour. Windows are standard A Rated Double Glaze. Gas Mains supplied for heating and hot water via a combi boiler. A Family home which is also used for work.

Average Gas Bill of circa £20 a month, heating and hot water, fantastic performance.

What is the U-Value of a Warmerwall block?

A Warmerwall ICF block has Neopor added to the EPS insulation which increases the energy efficiency of the block. A fully finished rendered wall achieves a U Value of 0.22. However the thermal mass effect of the concrete trapped between 2 sheets of insulation is what brings the magic to the true performance of a building when constructed from Warmerwall.

Our Lead Times?

We manufacture our block in Newport, South Wales and supply directly to our client building site. We generally have available stock in the Warehouse, with supply lead times influenced by the time it takes to clear payment and arrange transport, typically 2 to 3 days. At times of heavy demand for our product, lead time are typically up to 2 weeks.

Can I get a mortgage and insurance on a home built using Warmerwall?

We are members of the ICFA. As a member, the Council of Mortgage Lenders views Warmerwall ICF as a standard build method.

Have a different Question?

Get A Free Consultation & Estimate

Interested in building with WARMERWALL? Looking to find out more information about our insulated block or have a set of building plans and you would like a supply cost. Get in contact to discuss your proposed build project with us.

01242 692335

27 Libertus Road, Cheltenham, GL51 7EJ