Thurso · Highlands & Islands
Sash Windows in Thurso
If single glazed sashes in Thurso stream with condensation every winter, double glazed replacements with draught seals can make rooms warmer and quieter.
- KW14
- Guide from £1,495
Replacement sash windows in Thurso: what to know
Sash windows can be supplied as complete new frames, or as new double glazed sashes fitted into an existing sound box frame. Keeping the box retains original linings and architraves and reduces disturbance to plaster, but only works when the frame is free of rot and still square.
Slim double glazed units let sash windows keep fine glazing bars and traditional proportions while improving thermal performance. Bars can be true divisions with individual units, or bars bonded to both faces of a single unit with a spacer bar between the panes, which looks very similar from a short distance.
A traditional box sash hides cast-iron or lead weights inside the side boxes of the frame, connected to each sash by cords running over pulleys. Modern sash windows often use spiral or spring balances instead, which take up less depth and suit uPVC and some new timber designs without weight pockets.
Security on sash windows comes from keyed sash locks at the meeting rails, sash stops that limit the opening for ventilation and child safety, laminated glass, and close-fitting staff and parting beads. Ground-floor sashes in older houses are often the weakest point, so locks are worth upgrading during replacement.
What a typical job includes
- Weights or balances set for smooth, even sliding
- Removal of old sashes or frames and disposal
- Survey recording mouldings, horns, bars and box condition
- Double glazed units, with safety glass where required

Local details for Thurso
- Postcodes covered
- KW14 and the surrounding area, including Kirkwall
- Coast
- Thurso is about 2 km from the coast or a tidal estuary, so salt air and wind-driven rain are worth planning for. Salt-laden wind and driving rain shorten the life of paint on exposed sashes, so coastal timber windows benefit from durable timbers, good factory coatings and regular inspection. Brass or stainless sash furniture resists corrosion better than plated steel near the sea.
- Daylight and sun
- In Thurso the midwinter sun reaches about 8° above the horizon at noon, with roughly 6.0 hours of daylight, rising to about 55° and 18.0 hours in midsummer. Glazing bars and deep frames reduce daylight, so slimmer bars and high light-transmission low-E glass help north-facing rooms. Tall south-facing sashes can let in strong summer sun; the top sash can be lowered to vent warm air out at high level.
- Access and setting
- Older rural houses often have sash openings that are out of square, with soft stone or lime plaster around them, so each window is measured individually and fitted gently. Exposed sites benefit from draught seals and robust weatherboards on the bottom sash.
- Rules in Scotland
- Section 4 (Safety) of the Scottish Technical Handbooks covers glazing that people could collide with, such as glass in and beside doors and low-level glazing, where safety glass is needed.
Guide prices in Thurso
| Typical job | Guide price inc VAT |
|---|---|
| uPVC sliding sash, 900 × 1500 mm | £1,495 – £1,995 |
| Timber-effect uPVC sash, 900 × 1500 mm | £1,795 – £2,295 |
| Painted timber sash, 900 × 1500 mm | £2,595 – £3,295 |
Get a guide price for your size
Listed buildings in Scotland need listed building consent for most changes to historic windows; Historic Environment Scotland publishes guidance on traditional windows.
Options to choose between
Replacement sashes only
New double glazed sashes fitted into your existing sound box frame, keeping original linings, architraves and plasterwork.
uPVC sliding sash
Low-maintenance uPVC frames with sculpted profiles and optional woodgrain foils, suited to homes where planning rules allow uPVC.
Spring-balanced timber sash
Timber sashes running on concealed spring balances, giving a slimmer frame where weight pockets are not needed or space is tight.
Sash Windows in Thurso: questions
How long does it take to replace sash windows?
Fitting a single sash window usually takes most of a day, longer where the box frame is removed or plaster disturbed. A whole house typically takes several days on site. The windows are made to order first, and timber sashes with special details take longer to manufacture; the lead time is confirmed in writing with your quote.
How secure are sash windows?
New sash windows can be secure when fitted with keyed locks at the meeting rails, sash stops, laminated glass and tight-fitting beads. Older sashes often rely on a single catch, which is easily forced. Upgrading ground-floor and easily reached windows first makes sense, and the glazier can recommend locks that suit the sash and frame.
Will double glazed sashes be too heavy for my existing frame?
Double glazed sashes are heavier than single glazed ones, so the box frame, pulleys and weights must cope. When new sashes go into an existing box, the glazier checks the pulleys and adds or replaces weights so each sash balances. If the box is weak or rotten, a new frame is the better option, and the survey will tell you.
What guarantee comes with new sash windows?
Manufacturer guarantees apply to the joinery, finish, sealed units and hardware, and the terms are confirmed in writing. Cover on the paint finish often depends on regular maintenance, so check the conditions. Guarantee terms for the installation are set out in writing with your quote, so you know what is covered before agreeing to go ahead.
Do you cover Thurso for sash windows?
Yes. We can quote for sash windows across Thurso and the surrounding Highlands & Islands area, including postcode districts KW14, and nearby Kirkwall. Start with your postcode on the quote form and a glazier will arrange a free survey before giving you a written quote.
Get a written quote in Thurso
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.