The full refurbishment and extension of a large detached house for clients with a young family. The south-facing rear elevation of the extension incorporates slender framed glass sliding doors set within a structural opening more than 12 metres wide. Solar shading to this opening is provided by customised louvres that we designed and had fabricated using concealed stainless steel fins clad in Accoya, a sustainable modified UK softwood which gives a durability greater than many species of hardwoods. By highlighting local precedents we succeeded in persuading the local planning department to accept our proposal for replacing the three original cramped dormer windows with two elegant large new ones - a key ingredient of the overall reconfiguration, and one that the case officer had initially wanted to resist.