Further Information on AMVIC ICF

The Code for Sustainable Homes

Following a fundamental review of technical housing standards, the government has withdrawn the Code for Sustainable Homes, aside from the management of legacy cases.

View further information on GOV.UK.

AN A+ GREEN GUIDE TO SPECIFICATION RATING

The Amvic ICF system has also been awarded an A+ by the BRE under its Green Guide to Specification assessment scheme.

To quote the BRE, ‘In the Green Guide, materials and components are assessed in terms of their environmental impacts, within comparable specifications, across their entire life cycles. This accessible and reliable information will help all those involved in the design, construction and management of buildings to reduce the environmental impacts of their properties.’

An A+ demonstrates that the Amvic ICF system is one of the most environmentally friendly and sustainable ways that you can build today and is completely compliant with the code for sustainable homes.

SO HOW IS AMVIC ICF SUSTAINABLE? EMBODIED ENERGY

Concrete, a major element of ICF construction, hasn’t traditionally faired that well in ‘Eco’ terms because of the high amount of energy needed to produce cement. However, recent developments in concrete technology has changed this, for example, a typical structural concrete mix using 50% ground granulated blast-furnace slag as a cement replacement now has embodied CO2 in the order of just 12% of what would have been the original 100% cement figure.

Similarly, expanded polystyrene (EPS), a natural by-product of the petroleum refining process and the other major element of ICF construction, when used for insulation purposes will recoup the CO2 generated during its production within the first week of the building’s operation, simply by reducing occupant heating/cooling demands. EPS is also HCFC and CFC free.

THE CODE FOR SUSTAINABLE HOMES

As can be seen, if you are looking to engage in a construction project in within the area, the Amvic ICF is completely compliant with the code for sustainable homes. As mentioned earlier, sustainability decisions must consider the lifetime of a building and not just the initial impacts.

In the UK, 10% of our CO2 emissions come from the construction of our built environment. But a massive 50% comes from actually using our buildings, 27% of which is residential use.

And this is where ICF construction really comes into its own, both in terms of its durability and its energy efficiency, proving that it is a truly sustainable modern method of construction (MMC).

LIFETIME SAVINGS

The following points are considered as key aspects to consider when developing sustainable construction:-

  • Thermal Mass

  • Durability

  • Fire resistance

  • Acoustic performance

  • Flood resistance

  • Maintenance

  • Security

  • Air tightness

The way in which polystyrene and concrete is combined in ICF construction means this system provides outstanding performance levels for each of these key points.

THERMAL MASS

Concrete construction naturally has a high thermal mass, which is the ability of a material to store excess heat energy during the day. This heat energy is then released back into the building at night as it begins to cool. The strength of an ICF construction allows for concrete elements to be used internally throughout, including all floors and internal walls, maximising the thermal mass available.

DURABILITY

An Amvic ICF structure is built to last. Concrete is inherently durable, and when cast within the Amvic ICF system, it cures without suffering exposure to extreme temperature variances. This results in a far higher strength of set initially, but the insulation provided by the polystyrene also permanently reduces the stress on the concrete caused by thermal expansion and contraction, enhancing its lifetime well beyond standard masonry construction.

FIRE RESISTANCE

Concrete construction is extremely resilient to fire damage. Amvic ICF walls have fire-performance ratings of up to 3 hours.

SOUND INSULATION

The mass of the concrete within the Amvic ICF system makes for amazing sound absorption with typical sound reduction of 52 dB across the finished wall.

FLOOD RESISTANCE

Neither concrete nor expanded polystyrene rot or suffer from water damage, making ICF construction extremely resilient to flood damage. The monolithic structure is much better at resisting water ingress.

MAINTENANCE

The physical and chemical constancy of both concrete and EPS in an ICF building means there is practically no maintenance required to the structure at all.

SECURITY

The inherent strength of the solid concrete core makes an Amvic ICF structure safe and secure. This can be further enhanced by reinforcing the concrete where necessary.

AIR-TIGHTNESS

Amvic ICF is extremely airtight, with a typical structure experiencing less than 1 air change per hour (ACH). Because this is a poured concrete method of construction the structure is effectively monolithic, thus air-leakage is reduced to an absolute minimum.

RECYCLABILITY

Even though an Amvic ICF structure has a very long lifespan, at the end of the building’s lifetime, both the polystyrene and the concrete can be fully recycled, along with the plastic bridges which are already made from 100% recycled plastic.

FURTHER INFORMATION

You may also find the following websites of interest regarding sustainability:- These also apply for the code for sustainable homes.

The Sustainable Concrete website

Concrete Centre and Sustainability

AMVIC Case Studies & Media


Frequently Asked Questions on AMVIC ICF

 Q. How wide is the concrete core inside the Amvic system?

A. There are two thicknesses available, 150mm (the 280 system) and 200mm (the 330 system).


Q. How high can you concrete the Amvic ICF system in a single pour?

A. Up to 3 metres high of concrete can be placed in any single concreting day, so building and concreting a full storey height at a time is quite convenient.

Q. Does the concrete core require steel reinforcement?

A. In the UK, as a rule of thumb steel reinforcement is only required over the top of window and door openings for low rise structures. However, retaining walls (basement shells and swimming pools) and structures taller than 3 storeys high are always reinforced throughout.

Q. Does the concrete need to be vibrated once poured?

A. Whilst not strictly necessary for above ground construction, for basement and swimming pool shells, we routinely vibrate the concrete in the Amvic system to ensure full compaction around any steel reinforcement.

Q. Can you render onto the Amvic system?

A. Yes. Acrylic or polymer modified render systems are available that have been designed to be applied onto polystyrene (EPS). With this type of render system no supporting eml (expanded metal lathing) is required. These systems are also ‘through-coloured’ and so do not require painting.

Q. How is a brick or stone finish achieved?

A. There are two ways of achieving a masonry finish – either by building a full brick or stone skin around the Amvic shell, or by applying brick/stone slips directly to the surface of the Amvic blocks. The brick /stone Wall ties are cast into the Amvic concrete core to support the full masonry skin option, whereas slips are bonded to the face of the Amvic system using a high adhesive bonding mortar over a supporting eml which is pinned back to the Amvic concrete core.

Q. How is the internal finish applied?

A. The plastic webs within the Amvic system have been specifically designed to provide a fixing strip which runs the full height of the block to which plasterboard can be fixed using coarse threaded dry-lining screws.

Q. Can curtain rails / shelves / heavy items be hung on an Amvic wall?

A. The plastic webs to which we fix the plasterboard (see above) can also be used to support light to medium weight loadings. Alternatively, for heavier items such as kitchen cabinets, fixings can either be drilled or precast into the concrete core.

Q. How are internal services accommodated?

A. Electrical conduits and water pipes can be recessed into chases cut into the polystyrene at the time of installation. SPECIAL NOTE: PVC cables should be kept from direct contact with polystyrene by placing it inside plastic conduit. This is to stop the cable sheathing reacting with the EPS and becoming brittle over time. However, low-smoke cable and plastic plumbing can remain in direct contact with EPS without issue.

Q. How do Amvic ICF build costs compare to traditional building?

A. Amvic build costs, including materials and labour, are on average about the same as traditional construction. However, the Amvic ICF system provides far better levels of thermal and acoustic insulation for that same cost. Indeed, to match the performance of an Amvic home, a cavity wall construction would cost around 40% more to build, and take significantly longer to erect.

Q. How does fire affect the Amvic system?

A. The polystyrene bead used in the production of the Amvic system is a flame retardant grade. If the Amvic forms are exposed directly to a naked flame the polystyrene will burn, but once the flame is withdrawn or the Amvic burns clear of it, the polystyrene will self-extinguish, i.e. the Amvic system will not contribute to the spread of the fire. Add to that the fact the solid structural concrete core cannot burn and you can appreciate just how safe and robust Amvic homes really are.

Q. Is condensation ever an issue with Amvic?

A. The internal surface temperature of the Amvic wall will be within one or two degrees of the room air temperature, preventing condensation from forming on the internal wall face. Amvic is a vapour permeable method of construction, so in theory the occurrence of interstitial condensation is possible during the winter months. However, this will then quickly disappear during the rest of the year. In fact, to date interstitial condensation has never been detected in an Amvic ICF wall.


Q. Can Amvic be built to dimensions based on traditional construction?

A. Amvic is a fully metric system based on a 50mm modular size. However, it’s relatively easy to build to any dimension required simply by cutting ‘off-module’ through one block in the same wall position on each course. To support the vertical co-incidence of the cut joints we then simply screw plywood across the joint into the plastic webs of the Amvic system either side until the concrete has been placed.