Timber Sash Windows and Casement Windows

historc windows restoration

Our restoration protocol on timber sash windows and casements includes:


  • WOODWORK: all repairs are carried out using Accoya Radiata certified timber (Douglas Fir), that is treated using preservatives and properly primed prior installation.
  • SCREWS AND FIXINGS: we only use silicone bronze or 316 stainless steel screws and fixings outdoor, brass fixings indoors
  • DRAFT-PROOFING: we provide a full draft-proof refurbishment in order improve insulation performance on all casement parts (parting beads, battens, sash rails)
  • GLAZING IMPROVEMENT: we upgrade window thermal performance by re-glazing original units (where possible and after authorities’ consent) using ultra-fine double-glazed units. We install slim double glazed units (Slimlite) and high performance vacuum units such as Fineo (starting from 6mm thickness). Fineo units provide insulation U factor that is comparable to triple glazed units (see specifications here).
  • SASH WEIGHT BALANCE: we calibrate sash weight after new glazing installation
  • DECORATION: we decorate timber windows to last during time. We start with detailed surface preparation, priming, undercoating and final finish. We use linseed oil-based paint (such as Allback) and anti-fungi priming products in order to guarantee long lasting finish.
  • SAND MASTIC: we seal window openings using traditional sand mastic, a mix of kiln dried sand and linseed oil

If you need more information about our restoration protocol on timber windows, you can find more information about the workflow HERE.