VELUX roof windows are one of the most cost-effective ways to add light and usable space to a Farnham home. The price range is wider than most people expect — partly because of window size and type, but mainly because the flashing kit specification varies by tile profile and significantly affects both cost and performance.
Standard VELUX Centre-Pivot Windows (GGL)
The most common VELUX installation — a centre-pivot opening window in standard or larger sizes.
- GGL MK04 (780×980mm) supplied and fitted: £600–£750
- GGL PK08 (940×1400mm) supplied and fitted: £700–£900
- GGL SK08 (1140×1400mm) supplied and fitted: £800–£1,000
These prices include the correct EDW or BDX flashing kit for most standard tile profiles. Interlocking tile profiles with unusual gauges may need a more expensive flashing solution.
VELUX Top-Hung Windows (GGU)
The polyurethane GGU range is recommended for bathrooms, kitchens and other wet rooms. Better moisture resistance than the standard GGL.
- GGU MK04 supplied and fitted: £700–£850
- GGU PK08 supplied and fitted: £800–£1,000
Fixed Rooflights
Fixed (non-opening) roof windows for rooms where ventilation isn't needed — hallways, stairwells, bathrooms with mechanical extraction.
- Fixed rooflight (600×900mm): £450–£650
- Fixed rooflight (1000×1500mm): £650–£900
Sun Tunnels
Rigid or flexible sun tunnels for rooms with no direct roof access.
- Rigid sun tunnel (250mm): £350–£500
- Rigid sun tunnel (350mm): £450–£600
- Flexible sun tunnel: £300–£450
Why the Flashing Kit Matters More Than People Think
The most common cause of VELUX window leaks is the wrong flashing kit for the tile profile. VELUX produces different flashing kits for different tile types — plain tiles, interlocking tiles, slates, and various profiles — and getting it wrong causes water to track under the surround and into the roof structure.
A correctly specified and installed VELUX window should be maintenance-free for 20+ years. An incorrectly flashed window will leak within a few years and require remedial work that costs more than the original installation. We always specify the correct flashing kit before ordering.
What's Included in Our Quotes
Our VELUX installation quotes include the window, the correct flashing kit for your tile type, all materials, installation labour, tile making-good around the perimeter, and internal plastering make-good if required. We'll confirm exactly what's included in writing before we start.
What Affects the Final Cost in Farnham
The prices in this guide are for standard installations on accessible roofs with common tile profiles. Several factors can move the cost upward from the base prices shown. Two-storey access requiring a scaffold tower or extension ladders adds cost versus a bungalow or single-storey roof. Unusual tile profiles requiring specialist flashing kits — some interlocking concrete tile profiles from the 1980s have non-standard gauges — add to the material cost. Internal plastering make-good if the room below has an existing ceiling that needs patching after installation.
Conservation area properties in Farnham may need a specific flush-fitting window type rather than a standard protruding frame — these are available from VELUX but cost more than the standard product. We'll flag any additional requirements at the survey stage before you commit to anything.
Getting the Most from a Roof Window
A roof window's value in a room depends heavily on its position on the slope. A window positioned high on a slope captures more sky and more light than one positioned low. On a south-facing slope, a high position also reduces direct summer sun glare. On a north-facing slope, position matters less for light quality but the higher the better for airflow. We advise on optimal positioning at survey stage — the difference between a well-positioned and poorly-positioned window in the same room can be significant.
Last reviewed: 19 July 2026
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