- Thermal Bridging – The blockwork substrate of ARKPRO is designed so that the insulation is external to the concrete core and wraps around the full envelope of the wall. The ARKPRO substrate has a selection of construction detail PSI values certified. Almost without exception these are far better than accredited which ensures a far simpler detail to build too and removes many of the requirements for renewables. To demonstrate this on request we can supply the required Linear Thermal Transmittance Junction Details.
- Thermal Mass – The Mass of the concrete within the ARKPRO wall creates an ideal heat store leveling out the temperature changes within a building.
- Acoustics – Woodcrete is a sound absorption material creating a very quiet house. Because the ARKPRO substrate absorbs sound this reduces echo. The D250 unit used as a party wall when wet plastered can be rated as high as 63DB or high 50’s with dot and dab plasterboard.
FABRIC EFFICIENCY AND SAP
Improved thermal performance of the walls reduces the amount of energy required to heat or cool buildings. This will directly cut the running costs of the space and the country’s reliance on expensive resource depletive fuel imports.
- U Values – ARKPRO walls have values without additional insulation down to 0.15 W/m²K. They can easily be reduced further by external cladding of extra insulation but this is only likely to be necessary if Passivhaus standards are required.
- Thermal Bridging – ARKPRO units are designed so that insulation is external to the concrete core and wraps around the full envelope even at the corners. Consequently average psi values in the range of 0.04 to 0.08 are usual depending on design. SAP calculations are far more sensitive to the movement in psi values compared to relatively large changes in wall, floor or roof U Values. At the Code for Sustainable Homes level 4 this will significantly reduce or remove the requirement for renewables.
- Thermal Mass – The internal face of an ARKPRO wall will be 40 mm of woodcrete followed by 120 mm of concrete helping a building to achieve high levels of thermal mass. The main benefit of this is in the smoothing of temperature movements through the walls and greatly enhanced acoustic properties.
- ARKPRO walls contribute to SAP with a BRE Green Guide A rating which reflects the low resource usage required to produce the product
We actively encourage discussion between our clients’ energy assessors and our own experts in order to achieve the lowest cost build package to meet the client specified targets.
In terms of resource depletion and carbon costs in particular Durisol’s net cost is broadly neutral. Although cement is used in the units and of course in the pouring of the walls, there are various compensating factors which reduce our Carbon count to below most traditional methods of construction.
- An average 3 bed semi-detached house built from ARKPRO will have 10 tonnes of recycled wood in the product. This wood is made up of old pallets and off cuts which would have been destined for Landfill and consequently would have released carbon back into the atmosphere. The mineralisation of the wood in our process and subsequent coating in cement locks up that carbon for at least 100 years, if not permanently.
- ARKPRO units are manufactured by moulding onto the factory floor and they then set at room temperature – there is no requirement for extra energy to warm the units.
- In the manufacturing process we use Cenin as a replacement for ordinary Portland cement, which greatly reduces the carbon content of the Durisol unit. This product can also be used in the concrete used to pour the walls to significantly reduce the carbon footprint.
We are currently calculating examples of the carbon footprint of our builds and this data will be available to customers shortly.
Sustainability is not just about energy efficiency, the use of natural resources and tonnes of carbon released back into the atmosphere. It also means producing buildings which provide a healthy and safe environment for people to live and work – indeed an environment which adds to the enjoyment of life rather than detracting from it. Durisol contributes to this in a number of ways:
- Acoustics – Durisol woodcrete panels are used across Europe and North America as sound barriers on motorways and railways and attain the highest possible European ratings for sound absorption. Combined with the thermal mass this produces a stunningly quiet and calm environment which has been particularly noticed in our schools and homes. A Durisol party wall unit has a db rating of 63, when wet plaster is used as a finish
- Breathability – The nature of the woodcrete is that the size of the air gaps will not encourage capillary action of moisture through the unit but does allow a high degree of breathability. When used with breathable skins the building can achieve impressively high levels of airtightness while still allowing the movement of air through the walls.
- Fire resistance – Durisol units attain European levels of fire resistance which are considerably higher than their UK counterparts. Durisol woodcrete will not burn or rot due to the mineralisation process during its manufacture. Durisol walls have maintained their integrity in heat tests of 1,100 degrees for over 4 hours without igniting?