Green building is all about making structures as efficient as possible in terms of the resources used to build them and the energy they consume during their lifetime. Whether it’s a house or a hospital, if you use sustainable materials you will achieve a higher sustainability rating for the finished building. But as a professional builder you may be worried that ‘going green’ will mean higher material costs, more labour intensive methods, or having to use unfamiliar products that are tricky to work with. These are all valid concerns which we were keen to address in the development of Durisol.

Firstly, let’s look at how Durisol qualifies as a ‘green’ building product. Durisol interlocking wall units have very low embedded energy, are fully recyclable and Part L compliant. They are manufactured from at least 80% FSC recycled waste softwood bonded with a proprietary cement/PFA (Pulverised Fuel Ash) mix. This mix dilutes the environmental impact of cement which is a practical and unavoidable ingredient because of its reliability.

Ease of use and speed of installation are equally important considerations for the busy builder. Durisol scores highly here too, as the modular units are simply dry-stacked, with no need for mortar or bricklaying skills. They are then filled with concrete to create solid walls with excellent thermal and sound insulation. The use of Rockwool mineral fibre insulation, a green material in itself, further enhances Durisol’s green credentials and enables U-values as low as 0.23 without additional insulation. Indeed, as the insulation is located on the exterior of the concrete core, the thermal mass benefits make it viable to use low energy heating systems.

As the units are stacked, reinforcing bars are placed as required and concrete is poured into the built-in voids. Drylining and fittings are attached with screws straight into the Durisol material, and the open surface texture provides an ideal substrate for plaster or render. The Durisol wall system offers thermal performance up to twice that of a conventional wall and the high thermal mass reduces the need for cooling in summer and heating in winter. Each unit is inert, dimensionally stable, non-combustible and inhibits growth of fungus and mould.

Key guidelines when using the Durisol wall forming system

Foundations

Prepare foundations for a Durisol building exactly as you would for walls using traditional bricks and blocks. Because Durisol is dry stacked it is important to get the foundations as accurate as possible. We recommend using a chalk line to mark out the walls, corners and door openings on the foundations before you start stacking.

Laying the first course

Always lay the wallforms so that the insulation is on the outside of the wall. Start from the corners of the building. Accurate horizontal and vertical alignment on the first course helps to ensure an easy build and depending on the accuracy of the foundations, it may be necessary to set this into mortar.

Cutting

Anything that cuts wood - a hand-held circular saw with a wood blade is ideal - can be used to cut wallforms to size and after the core has cured, to ‘chase out’ for services. Durisol material can also be core drilled with a traditional saw bladed hole saw.

Stacking

Durisol wallforms should be dry stacked in a stretcher bond. Always ensure that wallform mating surfaces are clean as even slight contamination can compromise a level stack. Check for level and correct if necessary by inserting wood wedges before the concrete pour.

Pouring concrete

Standard concrete mixes with a high slump (180 - 220mm) and a maximum aggregate size of 10mm are used and can be poured by hand from a bucket, placed from a concrete skip or pumped. Clean up any spills and if more wallforms are to be stacked, leave around 100mm of the top form empty so that the next pour keys into the previous pour.

Lintels

Construction of window and door lintels is usually carried out using Durisol face units. These can be cut to size on site, arranged to suit the width of the opening and supported by formwork to prevent movement during filling.

Floor systems

All current flooring systems can be used with Durisol walls, including block and beam flooring and poured floors.

In the bid to get greener, more and more professional builders are recognising the benefits of using Durisol in terms of its sustainability, durability, and last but not least, the speed and ease with which walls can be built. This overview provides an introduction to what this unique system can offer the modern building trade - more detailed planning and construction guidelines are available, and our technical team is happy to advise on specific building applications or to provide on-site support if required. For further information and contact details visit www.Durisol.net.