UdiRECO, Back to Earth’s internal wall insulation, is a combination of a rigid wood fibre board on the front and a softer, flexible wood fibre wool on the rear of the board. This combination allows the board to mould itself to the shape of the wall surface, avoiding the need to render it flat first.
The board is supplied with a compatible and modified lime based plaster for use as an internal finish. The boards are manufactured from wood fibre which comes from the sawmill residue of sustainably produced European softwood timber.
This innovative and simple solution to the challenging problem of insulating internally whilst maintaining the breathability of the wall, combined with the sustainable raw materials, makes this product worthy of selection as ASBP’s Product of the Month.
Wood fibre is known to be effective as insulation. When used for internal wall insulation the ability to transport and disperse moisture is a particular benefit and reduces the risk of the build up of trapped moisture.
Back to Earth also state that evidence from in-situ testing strongly supports the view that walls internally insulated with wood fibre products will have a lower U-value than calculation suggests.
Back to Earth provide compelling evidence of this in a 10 year German study (conducted by the department of Building Climatology at the University of Dresden) that shows actual performance of wood fibre internal wall insulation as being 25% better than predicted.
This anomaly is almost certainly due to the hygro-thermal effect of the absorption and desorption of water and can be backed up by other studies on hygroscopic construction materials such as hemp and lime and straw bale.
When internally insulating pre-1930’s buildings the walls are usually uneven, whether they are brick or stone, making it extremely difficult to fix rigid insulation boards directly to the wall. The most common ways to insulate are to either render the wall flat and then fix the insulation or to build an insulated stud or block wall inside the original wall.
- Rendering the walls can add substantial cost and delay installation whilst render dries.
- Timber stud walls are low cost but tend to make the originally solid building sound hollow and insubstantial.
- The relatively high specific heat capacity of the wood fibre board, when combined with the avoidance of a cavity also helps to maintain the thermal mass of the original construction. Thermal mass is considered to be beneficial for thermal comfort and for the avoidance of overheating.
- Block walls overcome the thermal mass and acoustic issue but take up a lot of space and may require additional footings.
- The boards are mechanically fixed to the wall ensuring a tight fit and that there are no voids behind.
- The boards come in thicknesses ranging from 80 – 200mm, giving U-values down to 0.18 W/m2K.
- Above 100mm the boards can also be used to help level up uneven walls, should the customer want to straighten their wobbly walls.
About Back to Earth
Back to Earth was established in 1995 with a mission to help plan, retrofit and build high performance buildings. Back to Earth work with architects, builders and self-builders from across the UK and have a deep commitment to improving the efficiency and performance of buildings through the use of innovative, low impact and high performance products and methods.
To find out more about UdiRECO and other innovative and sustainable solutions for new build and retrofit projects, go to www.backtoearth.co.uk or, get in touch with Chris Brookman at firstname.lastname@example.org or 01392 861763.