Black spot mould will commonly form on the internal wall surface due to a combination of moisture, poor ventilation and a lack of insulation. Because bay windows in older properties usually have less insulation than other walls this will often create cold surfaces where the warm and humid air condenses, making the perfect conditions for mould growth. This is the typical construction of most bay windows in older properties around Wakefield and the Yorkshire area.

There are a range of different internal wall insulation options we can specify to suit the various types of bay window and wall thickness. Timber framed bay windows can be insulated using PIR plasterboard, which gives a higher thermal resistance and the foil backing gives an additional vapour control layer to the insulation. In rooms where loss of floorspace is an issue, there are a few TIWI (Thin Internal Wall Insulation) options we can recommend. These products can still reduce heat loss by 30% and offer similar benefits to the thicker PIR boards such as condensation prevention. The installation of TIWI products is faster and can often be a more cost effective option 

After completion of the internal wall insulation, a smooth and flat plaster finish is applied ready for decoration.