Having decided to proceed with a pilot project to construct a 'gable warmer', my first thoughts were to investigate what permissions might be needed. Such cladding works on an elevation not facing the highway are generally 'permitted development' in planning terms. Obviously the nature of the cladding will have a visual impact and consideration should be given to your neighbours and anyone passing by who may have to look at it.
With Listed buildings and within Conservation Areas the rules are generally tighter and consents will be needed. These works will also require clearance under Building Regulations to ensure both the adequate performance of the insulation and fire protection where the house adjoins a neighbour's property, the latter not being needed where a gable is some distance from the property boundary.
I have recently constructed my gable warmer using mainly 4"x2" and 3"x2" timbers, infilled with 4" of Thermal fleece wool insulation, covered with a breathable membrane and then a cladding of fire retardant treated feather-edged timber boarding, a traditional Suffolk building material. I chose to stain mine a brick red colour and line up the joints with the brick courses, so that at a glance it looks much as it always did.
I have now had two winters with the insulation in place and have enjoyed a marked rise in comfort levels inside the house especially through the colder spells, which used to be miserable times each year. Comparison of my energy bills before and after the gable warmer was constructed bears out my calculations. I have achieved a 15% average reduction in my energy bills, nearly matching the predictions, which might have been achieved had I completed the timber cladding and not had two colder than normal winters to contend with.
Such a gable warmer is the biggest and most efficient energy saving measure that can be applied to an end terrace (or semi-detached) house, especially as a gable usually has no windows and therefore requires no special detailing other than at the edges. There remain several choices of insulation material and cladding finish that should suit a variety of situations and finances available.
A short walk around most neighbourhoods will reveal many older houses that are either end of terrace or semi-detached to which such a gable warmer could be applied. If promoted (or even encouraged with grant aid) this idea could provide a significant reduction in this country's energy footprint.
Patrick Taylor, Conservation Architect