ICF Construction Ireland

What Is ICF Construction?

ICF stands for insulated concrete formwork. Each Amvic block is made of two panels of expanded polystyrene (EPS) insulation, 75mm thick, held apart by strong recycled polypropylene webs. The blocks measure 1200mm by 400mm and interlock along their edges, so a wall is stacked quickly and accurately without mortar.

Steel reinforcement bars sit in holders built into the webs, and once a storey of blocks is in place the hollow core is filled with concrete, giving a solid reinforced concrete wall of 150mm or 200mm depending on the structural requirement. The formwork stays in place permanently as the insulation. The outside is then finished in render, brick slips or stone cladding, and the inside is plasterboarded directly onto the webs.

The photographs on this page are from a recent ICF extension we built in Dublin: the first course set out on the foundation, the reinforced walls before the pour, and the completed shell tied into the existing house.

Why Build with ICF Blocks?

Faster than traditional construction

A cavity block wall is built in stages: inner leaf, cavity insulation, outer leaf, each waiting on the last. With ICF the insulation, formwork and structure go up together, and the wall is complete once the concrete has cured. The lightweight blocks are placed in most weather, so an ICF build is far less exposed to the delays that frost and rain cause for mortar work. The shell of a house or extension is weathertight and ready for the roof sooner, and the follow-on trades start earlier.

Warmer, with lower heating bills

The standard Amvic wall achieves a U-value of 0.20 W/m²K, and the thicker block options we use on new builds reach 0.16 to 0.17 W/m²K, close to passive house performance and comfortably inside the current Part L requirement for new dwellings. Because the insulation is continuous on both faces of the wall there are almost no cold bridges, and the monolithic concrete core makes the wall naturally airtight. Together these are what allow an ICF house to reach an A-rated Building Energy Rating without relying on heavy mechanical systems.

Stronger and quieter

A reinforced concrete wall is far stronger than two leaves of blockwork. The Amvic system is certified for buildings up to five storeys in Ireland, and the mass of the concrete core gives excellent sound insulation from traffic and neighbours. Concrete does not burn, so ICF walls also offer high fire resistance.

Less waste on site

ICF blocks are cut to size as they are placed, the webs are made from recycled material, and there is no cavity insulation off-cut or mortar waste. Site skips are noticeably emptier at the end of an ICF build.

ICF vs Traditional Cavity Block Construction

Most clients come to us comparing ICF against the cavity block wall they know. This is how the two compare on a typical Dublin project.

ICF is not the right answer for every project. Where an existing masonry wall is being extended by only a metre or two, or where a listed facade has to be matched in brick, traditional blockwork can still make more sense. We will tell you at survey which method suits your building.

ICF Houses Ireland: New Builds

For a new house, ICF gives you the thermal performance of a passive-style build with the solidity of concrete, on a programme that is shorter than blockwork. We build ICF houses on single sites and self-build plots across Dublin, Kildare, Meath and Wicklow, working from your architect’s drawings or with our own design team.

Because the ICF shell goes up so quickly, the roof, windows and first fix all start earlier, which brings the whole build forward. The completed house is airtight, well insulated and quiet, and it is built with a HomeBond-approved system, so it is treated as a standard construction method for mortgages, insurance and resale.

ICF Extensions in Dublin

ICF is particularly well suited to house extensions, which is where much of our ICF work is. The blocks are light enough to carry through a house by hand, the walls rise quickly on a small footprint, and the finished extension is warmer than the house it is attached to. We tie the ICF walls into the existing structure with steel beams and connectors detailed by our engineer, and the continuous insulation removes the cold junction that often forms where an extension meets the old wall.

Single-storey kitchen extensions, double-storey side extensions and garden rooms can all be built in ICF. See our house extensions in Dublin page for the full range, or garden room extensions for detached structures.

Commercial and Multi-Storey ICF Building

The same system scales to commercial buildings, apartments, care facilities and light industrial units. Amvic ICF is certified to five storeys (15 metres) under its NSAI Agrément certificate, and the speed of the build and the reduced heating load are strong arguments on any commercial project. Our commercial construction team handles design coordination, structural engineering and programme management for larger ICF builds.

The Amvic ICF System We Build With

We build exclusively with Amvic ICF, supplied in Ireland by Amvic Ireland. The system carries:

• NSAI Irish Agrément Certificate 07/0277, covering buildings up to five storeys under the Building Regulations 1997 to 2025
• British Board of Agrément Certificate 10/4809 for the UK and Northern Ireland
• HomeBond approval, so new ICF homes qualify for structural warranty cover
• Certified renders and finishing systems designed for the block

Amvic supplies the blocks and technical support. OS Holding designs, builds and finishes the building. If you have already spoken to Amvic about a project and need a certified contractor to build it, we can work from the drawings and block schedule you already have.

Our ICF Construction Process

1. Free site survey

We visit the site or house, discuss what you want to build, and confirm whether ICF is the right method for the project.

2. Design and engineering

We work with your architect or our own design team, and our engineer details the reinforcement, foundations and any steelwork needed to tie into an existing building.

3. Fixed quotation

You receive a written fixed price for the complete build, not just the ICF shell, with the specification and programme set out clearly.

4. Foundations and ICF shell

We pour the foundation, set out the first course, stack and brace the walls, place the reinforcement and pour the concrete storey by storey.

5. Roof, finishes and handover

Roof, windows, external render or cladding, internal plasterboard and all follow-on trades are completed by our own team, with a dedicated project manager from survey to handover.

How Much Does ICF Construction Cost?

The cost of an ICF build depends on the floor area, the number of storeys, the concrete core thickness required by the engineer, the external finish and the site access. On a like-for-like basis the ICF shell is usually close in price to a well-insulated cavity block wall once the separate insulation, labour and time on site are counted, and the shorter programme reduces the overall cost of the build.

Rather than quote a headline rate that will not survive the first site visit, we price every project individually. After your free survey we provide a fixed written quotation for the whole build so you can compare it directly against a traditional construction price.

Why Choose OS Holding as Your ICF Builders

• A complete building contractor: foundations, ICF shell, roof, finishes and services under one contract
• Building with the NSAI-certified, HomeBond-approved Amvic ICF system
• Fully insured and registered with the Construction Industry Register Ireland (CIRI)
• Member of the National Guild of Master Craftsmen and the Construction Industry Federation
• Free site survey and fixed written quotation for the whole project
• A dedicated project manager and our own trades from start to finish
• Honest advice on whether ICF or traditional blockwork suits your building

ICF Builders Serving Dublin and Leinster

We build ICF houses, extensions and commercial buildings throughout Dublin city and county and across the surrounding counties of Kildare, Meath and Wicklow. If you are also considering insulation upgrades to an existing house, our house insulation page sets out the options for older properties.