Why should we address these areas because is doing something better than doing nothing at all?
The simple answer to this question is that it makes commercial sense to do the installation right first time and provide a continuous insulation layer.
Irrespective of the debates on what insulation materials should be used on different wall types, if these junctions are not addressed then the return on your investment is diminished as well as an increased after care cost of fixing the problems that arise by not addressing these areas in the first place.
It’s About Savings
A simple example – a EWI system is installed which should save you £500 per annum on your heating costs. This calculation assumes that all areas of the walls are insulated but obviously if they are not this saving will reduce. Let’s assume that it takes £5000 to install a EWI system without addressing the junctions and £6000 with the junctions addressed. We will look at 10, 20 & 30% percentage reduction in performance which would reflect how many thermal bridges could arise on particular properties – if the property has a deep soffit the then thicker insulation will reach the top of the wall as opposed to a property that has no soffit then the insulation will fall short by up to 150mm.
£5000 – so savings per year will be £450, £400.£350 reflecting 10,20,30% reduction so payback ranges from 11.12 years to 14.28 years and does not include any potential maintenance costs.
£6000 – £500 per year – 12 years and no maintenance costs