Steve De Vial & Company Ltd
Chartered Architectural Technologist (MCIAT, since Oct 1997), self-employed since Aug 2004; L'Abreuvoir, La Rue des Landes, St Andrews. 20+ years designing alterations, improvements and new-builds for Guernsey clients. Not RICS-regulated. 28 applications as agent 2022-2025.
What they specialise in
Work types this firm files more often than the island does — "×3.9" means nearly four times the rate that type appears across all Guernsey applications. Ordered by the value of the work, not the ratio, so the jobs that actually pay come first: a rebuild at ×1.7 is worth far more than window replacement at ×2.5.
| Work type | Vs island rate | Jobs | Typical job | Est. value of this work |
|---|---|---|---|---|
| Single-storey extension | ×2.4 | 15 | £100,000 | £1,500,000 |
"Est. value of this work" is the typical job cost for that type multiplied by how many they filed — a rough sense of where the practice's money sits, not their fees or their turnover. Needs at least 12 applications on file and 3 in the category before a ratio is shown, so a small practice can't look like a specialist on two lucky jobs. Classified from each application's own wording, so a minority will sit in a category a human would read differently.
The properties they work on
Of 28 applications this firm filed, 12 are tied to a later recorded sale of the same address, and 11 of those carry a real price. The midpoint is £1,039,040, each carried forward to 2026 money at the island index. Most of their filed work is in Castel (5), St Sampson (4), St Peter Port (4).
1 matched sale recorded at a nominal £1–£100 was excluded — those are family or trust transfers, not market prices. Matching is by address and parish against the States register, not a shared ID, so a shared house name can mismatch. It tells you the value bracket this firm operates in; it is not their fee and not a claim about any individual job.
Work-type mix
Classified from each application's own description text, most common first — the same keyword model this site's planning cost estimates use. Select a type to filter the applications below.
Typical cost of work
£39,866–£71,875 average, estimated per application from its own description text using this site's planning cost model — a rough guide only, not a quote from Steve De Vial & Company Ltd or a reflection of what any specific job actually cost, and it does not include design fees. Each row below also carries an estimate at the prices of the year it was filed, deflated with the island house-price index — a proxy, since that index tracks house prices rather than construction costs and the two genuinely diverge (materials spiked in 2021–22 well beyond house-price growth). No Guernsey construction-cost index is published, so this is the best basis available, and it is an estimate on top of an estimate.
28 planning applications as agent — real cross-references
Success rate on decided applications: 100% granted (28 granted, 0 refused, of 28 decided — pending/withdrawn excluded)
| Application | Address | Description | Decision | |
|---|---|---|---|---|
| FULL/2023/1473 | Atlanta Route De La Passee St. Sampson Guernsey GY2 4TN | Demolish extension, extend and alter at ground floor level to south-east (rear) and north-east (side) elevatio… Est. £52,830–£88,050 at 2023 prices | Granted | Full record Decision notice (PDF) |
| FULL/2023/1495 | Viewfield 4 Courtil Colin St. Peter Port Guernsey GY1 1ZS | Partially demolish conservatory, erect single storey extension to south (rear) elevation. Est. £52,830–£88,050 at 2023 prices | Granted | Full record Decision notice (PDF) |
| FULL/2023/1607 | 12 Tropicana Bungalows Ruette De La Tour Castel Guernsey GY5 7TT | Install sun tunnels and alterations to fenestration. Est. £17,610–£46,960 at 2023 prices | Granted Later sold 2023-06-13 · £196,950 | Full record Decision notice (PDF) |
| FULL/2023/1749 | St Ives La Mare Road Castel Guernsey GY5 7AT | Extend outbuilding and alter fenestration to the south elevation and install rooflights to the west elevation. Est. £29,350–£52,830 at 2023 prices | Granted | Full record Decision notice (PDF) |
| FULL/2023/2294 | La Hougue Farm Rue De La Hougue Castel Guernsey GY5 7EA | Change of use of agricultural land (use Class 28) to use of dog secure field for 'off leash freedom and enrich… Est. £5,870–£17,610 at 2023 prices | Granted Later sold 2020-07-21 · £1,025,000 | Full record Decision notice (PDF) |
| FULL/2023/2344 | Tabula Rasa 4 La Mare Estate La Rocquette Road Castel Guernsey GY5 7BL | Demolish extension, erect 2 storey extension to north-west (side) elevation and alterations to fenestration. Est. £52,830–£88,050 at 2023 prices | Granted | Full record Decision notice (PDF) |
| FULL/2023/2482 | Grantley Woodlands Park Route Des Bas Courtils St. Saviour Guernsey GY7 9YE | Demolish conservatory, erect single storey extension and canopy to south (rear) elevation. Est. £52,830–£88,050 at 2023 prices | Granted | Full record Decision notice (PDF) |
| FULL/2024/0054 | La Petite Cloture La Mare Estate La Rocquette Castel Guernsey GY5 7AX | Demolish conservatory, erect single storey extension to south-east (rear) elevation and alterations to fenestr… Est. £54,863–£91,438 at 2024 prices | Granted | Full record Decision notice (PDF) |
| FULL/2024/0092 | Carfo Workshop Le Bouet St. Peter Port Guernsey GY1 2AW | Remedial repairs to west (front) and north (side) elevation (Protected Building). Est. £18,288–£48,767 at 2024 prices | Granted | Full record Decision notice (PDF) |
| FULL/2024/0250 | Maison Des Cartiers Les Poidevins St. Andrew Guernsey | Demolish utility/canopy, remove section of hedge and erect single storey extension. Est. £54,863–£91,438 at 2024 prices | Granted Later sold 2016-07-12 · £698,250 | Full record Decision notice (PDF) |
| FULL/2024/0414 | Capstan Cottage Sandy Lane St. Sampson Guernsey GY2 4RT | Erect single storey extension to east (rear) elevation, re-roof and install cladding to detached outbuilding. Est. £54,863–£91,438 at 2024 prices | Granted Later sold 2019-07-23 · £555,750 | Full record Decision notice (PDF) |
| FULL/2024/0638 | La Croute Mainguy Rue Mainguy Vale Guernsey GY6 8NL | Partially demolish extension, erect single storey extension to north (rear) and east (side) elevation, install… Est. £54,863–£91,438 at 2024 prices | Granted Later sold 2017-08-08 · £627,000 | Full record Decision notice (PDF) |
| FULL/2024/0719 | Neuf Courtil Rue Marquand St. Andrew Guernsey GY6 8RB | Alterations to fenestration to outbuilding to create a dower unit to east of site. Est. £30,479–£54,863 at 2024 prices | Granted | Full record Decision notice (PDF) |
| FULL/2024/0760 | Le Mottais Roncefer Road St. Sampson Guernsey GY2 4FP | Demolish conservatory, erect single storey extension to west (rear) elevation and alterations to fenestration. Est. £54,863–£91,438 at 2024 prices | Granted Later sold 2000-11-16 · £342,000 | Full record Decision notice (PDF) |
| FULL/2024/0807 | Fitzgerald Photo Services Les Caches St. Martin Guernsey | Replace windows and doors to (east) shop front. Est. £9,753–£24,383 at 2024 prices | Granted | Full record Decision notice (PDF) |
| FULL/2024/0897 | Les Prevosts Farm Les Prevosts Road St. Saviour Guernsey GY7 9UH | Infill existing vehicle access, relocate and create gated vehicle access and install hardstanding to south-eas… Est. £6,096–£18,288 at 2024 prices | Granted Later sold 2021-04-01 · £2,145,000 | Full record Decision notice (PDF) |
| FULL/2024/0910 | British Show Jumping Association Aeroplane Vinery Chemin Le Roi St. Martin Guernsey | Change of use of agricultural land to an Equestrian Recreation Facility (sui-generis) (37,150sqm). (Retrospect… Est. £18,288–£48,767 at 2024 prices | Granted | Full record Decision notice (PDF) |
| FULL/2024/1120 | Le Mottais Roncefer Road St. Sampson Guernsey GY2 4FP | Variations to previously approved plans to demolish conservatory, erect single storey extension to west (rear)… Est. £54,863–£91,438 at 2024 prices | Granted Later sold 2000-11-16 · £342,000 | Full record Decision notice (PDF) |
| FULL/2024/1249 | Orelle Route De La Croix Au Bailiff St. Andrew Guernsey GY6 8RY | Erection of cycle store to north (front) elevation. Est. £18,288–£48,767 at 2024 prices | Granted | Full record Decision notice (PDF) |
| FULL/2024/1394 | Petit Paradis La Rue Des Grand Marais Vale Guernsey GY3 5DX | Demolish extension, erect single storey extension to south (rear) elevation and alterations to vehicle access. Est. £54,863–£91,438 at 2024 prices | Granted | Full record Decision notice (PDF) |
| FULL/2024/1446 | Massabielle Les Nouettes Forest Guernsey GY8 0ED | Demolish outbuilding, erect single storey extension to south (side) elevation and alterations to fenestration … Est. £54,863–£91,438 at 2024 prices | Granted | Full record Decision notice (PDF) |
| FULL/2024/1639 | Maple Leaves Rue Colin Vale Guernsey GY6 8LA | Install dormer windows to west (front) elevation, alter existing dormer windows to south (side) and north (sid… Est. £54,863–£79,246 at 2024 prices | Granted Later sold 2024-05-16 · £911,625 | Full record Decision notice (PDF) |
| FULL/2025/0059 | La Fleuronne Route Des Bas Courtils St. Saviour Guernsey GY7 9YJ | Demolish extension, erect single storey extensions and alter at ground floor level to west (side) and south (r… Est. £56,694–£94,489 at 2025 prices | Granted | Full record Decision notice (PDF) |
| FULL/2025/0134 | Les Prevosts Farm Les Prevosts Road St. Saviour Guernsey GY7 9UH | Demolish conservatory, erect single storey extension, alter roof form and fenestration to north (rear) elevati… Est. £56,694–£94,489 at 2025 prices | Granted Later sold 2021-04-01 · £2,145,000 | Full record Decision notice (PDF) |
| FULL/2025/0219 | 3 Belmont Terrace Havelet St. Peter Port Guernsey GY1 1BA | Alterations to roof form of extension to north (rear) elevation and alterations to fenestration. Est. £56,694–£94,489 at 2025 prices | Granted Later sold 2025-09-18 · £2 | Full record Decision notice (PDF) |
| FULL/2025/0297 | Flat 2 Beaufort 6 Les Canichers St. Peter Port Guernsey GY1 2NE | Partially demolish and rebuild first floor bay window to south-east (rear) elevation (Protected Building) (Ret… Est. £18,898–£50,394 at 2025 prices | Granted | Full record Decision notice (PDF) |
| FULL/2025/0347 | Springfield Braye Road Vale Guernsey GY3 5PE | Erect covered store to east elevation (Protected Building). Est. £18,898–£50,394 at 2025 prices | Granted Later sold 2013-07-04 · £475,000 | Full record Decision notice (PDF) |
| FULL/2025/0368 | BSJA Show Ground Chemin Le Roi St. Martin Guernsey | Extend arena to south of site, install replacement arena surface and associated works. Est. £18,898–£50,394 at 2025 prices | Granted | Full record Decision notice (PDF) |