L-shaped dormer loft costs in Worthing 2026: £55k–£75k. Perfect for Victorian back-addition terraces — master bedroom + ensuite in one build. This guide is written by PG Property Repairs and Renovations, an FMB and TrustMark accredited building company based in Worthing, using real costs and timescales from projects completed across Worthing, Lancing, Shoreham, Brighton and the wider West Sussex area.