Our Services
Double Glazing for Sash Windows
About This Service
Reliable Double Glazing for Period Homes
One agreed price covering our free on-site survey, bespoke slimline units or timber rebates and aftercare, with a clear written quote and no hidden extras. RW Sash Windows install double glazing into original sash frames to improve thermal performance and reduce street noise while keeping original sightlines and mouldings intact. We work sensitively in conservation areas and with listed buildings, matching joinery detail where required. All installations are fitted by experienced joiners and backed by a workmanship warranty.
Our Process
How It Works
Free on‑site survey
A joiner visits to assess the existing sash, check cords, weights and frame tolerance, and recommend slimline, rebate or secondary options.
Clear written quote and specification
You receive a single, itemised quotation covering labour, materials and aftercare so there are no hidden extras and nothing to guess.
Craft-led installation and handover
Work is carried out by experienced joiners, finishing with draughtproofing, cord checks and a walkthrough covering maintenance and warranty.
Benefits
Why Choose us for Double Glazing for Sash Windows?
Conservation‑friendly approach
We adapt glazing methods to keep original profiles and sightlines, working with conservation officers and listed building constraints where required.
Improved comfort without visible change
Slimline units and timber rebates increase insulation and reduce noise while retaining the period character of your sashes.
Transparent process from survey to aftercare
Free survey, one agreed price and a written specification mean no surprises, and installed work is backed by a workmanship warranty.
How double glazing works: We fit slimline double glazed units into the existing sash or install a timber rebate to accept a slightly larger unit, depending on the original joinery. The aim is to improve U values and acoustic performance while keeping original sightlines, staff beads and mouldings visible from the street.
Options and conservation care: For conservation areas and listed buildings we offer bespoke timber rebates and like‑for‑like moulding profiles so repairs and upgrades sit hidden inside the box frame. Installations include draughtproofing, cord and weight checks and advice on long term maintenance to avoid condensation issues. Every job is measured and made to order by our workshop joiners, with a handover that explains care and warranty details.
FAQ
Frequently Asked Questions
Yes, in many cases. We work with conservation officers and can supply bespoke timber rebates or slimline sealed units that preserve original sightlines and profiles. We always recommend a survey first to confirm what conservation consent, if any, is required.
Double glazing replaces or adapts the sash to accept a slimline sealed unit, keeping a single glazing plane and original sightlines. Secondary glazing adds a separate glazed pane behind or in front of the existing sash. Both improve insulation and noise reduction, but the units retain the authentic external appearance.
When measured and fitted correctly slimline units are balanced to work with existing cord and weight systems or with sympathetic sash cord upgrades. Our survey checks frame tolerances and weight balance to ensure smooth operation after installation.
Slimline sealed units are made for joinery applications and typically last many years when fitted into sound timber frames. Regular sash maintenance, rubbing out paint build‑ups and keeping weights and cords serviceable will prolong performance. We cover workmanship with a warranty and advise on simple annual checks.
Upgrading to a sealed slimline unit reduces cold panes and can significantly lower visible surface condensation. Condensation within the home can also relate to ventilation and heating patterns, so we include advice on ventilation and draughtproofing as part of the survey and aftercare.