Data report · 1 October 2026

Guernsey's idle glasshouses: where they are and what they are worth

Guernsey has 150 glasshouse sites of 500 m² or more, covering 64.1 ha, and the States has never published where they are. This register lists every one; the land could hold about 2,245 homes, but at today's build costs its base-case value is −⁠£282m.

The headline figures

Measure	Figure
Glasshouse sites of 500 m² or more	150	mapped in OpenStreetMap
Glass on those sites	64.1 ha	about 391 vergées
Homes the land could physically hold	2,245	at 35 homes per hectare
Value of those homes once built	£1,160m	at today's sold values
Residual land value, base case	−⁠£282m	build at £4,000/m², 17.5% developer profit
Sites where housing pays for the land	6 (68 homes)	77 (992 homes) if build costs £3,500/m² and new homes sell at a 15% premium

Where the glass is

Half of the mapped glass is in Vale and St Sampson's (32.8 of 64.1 ha), and the 15 largest sites hold 27.0 ha of it.

Parish	Sites	Glass	Homes it could hold
Vale	46	21.3 ha	746
St Sampson's	23	11.5 ha	403
Castel	17	6.8 ha	239
St Saviour	23	6.2 ha	218
St Peter Port	5	6.2 ha	216
St Pierre du Bois	15	4.5 ha	159
St Andrew	4	3.0 ha	104
St Martin	6	2.0 ha	68
Torteval	7	1.9 ha	67
Forest	4	0.7 ha	25

Site size	Sites	Glass
1 ha or more	15	27.0 ha
5,000 m² to 1 ha	19	13.7 ha
2,000 to 5,000 m²	53	16.1 ha
500 to 2,000 m²	63	7.4 ha

Only 1 of the 561 OpenStreetMap objects is tagged as a ruin, so this shows where glass is, not its condition.

The official figures, and the gap

The States counts 460.7 vergées (75.5 ha) of redundant glass on about 250 sites, plus about 250 cleared sites.

Figure	Value	Source
Redundant sites with glass still standing (2018 survey)	about 250	Guernsey Press, 16 Aug 2018
Further cleared former sites, not counted above	about 250	same survey
Redundant glass area (2019 figure)	460.7 vergées	Bailiwick Express, 4 Jul 2024
The same area, as quoted by the planning president	75.5 ha	Guernsey Press, 14 Apr 2023
Glass mapped in OpenStreetMap, working and derelict	67.5 ha, 522 buildings	this register

The mapped total covers working and derelict glass together, yet sits below the official figure for redundant glass alone. Collapsed or overgrown glass is often not traced as a building, and official redundant-site areas can include yards and hardstanding. The roughly 250 cleared sites cannot appear in the map at all.

Would housing pay for the land?

Values come from this site's sale register. New build on Guernsey is quoted at £4,000 to £6,000/m², while St Sampson's homes sell for about £4,330/m², so private development in the north only pays if build comes in under about £2,350 to £2,860/m². Only St Martin clears the bottom of the quoted range.

Parish	Homes	Sales value	Land value, base	Land value, optimistic	Break-even build cost
Vale	746	£367m	−⁠£108.3m	−⁠£16.4m	£2,861/m²
St Sampson's	403	£166m	−⁠£84.7m	−⁠£39.0m	£2,350/m²
Castel	239	£144m	−⁠£13.5m	+£19.1m	£3,555/m²
St Saviour	218	£119m	−⁠£22.5m	+£5.7m	£3,191/m²
St Peter Port	216	£112m	−⁠£27.0m	+£0.3m	£3,020/m²
St Pierre du Bois	159	£93m	−⁠£11.5m	+£9.8m	£3,432/m²
St Andrew	104	£54m	−⁠£13.2m	−⁠£0.1m	£3,005/m²
St Martin	68	£48m	+£1.8m	+£11.9m	£4,205/m²
Torteval	67	£44m	−⁠£1.1m	+£8.5m	£3,874/m²
Forest	25	£15m	−⁠£1.7m	+£1.7m	£3,463/m²

Our reading: this gap is why the glass stays derelict and why the States ends up as the buyer. It paid £6.5m for Kenilworth Vinery in October 2021, £42k to £50k per planned home.

Homes average 95 m². Base build cost is £4,000/m² (pessimistic £5,000; optimistic £3,500 plus a 15% new-build premium), with 10% for roads and drainage, £100/m² of glass for clearance, 5% contingency, 10% fees, 6% finance, 2% sales costs and a 17.5% developer profit. Flood defence, drainage capacity and contamination are not costed.

What has happened to glass sites so far

Site	Parish	What happened	Scale
Belgrave / Fontaine Vinery	St Sampson's	Affordable housing; framework approved 2025	6.26 ha
Kenilworth Vinery (Parc Le Lacheur)	Vale / St Sampson's	Housing: 131 planned, now about 154	17 vergées; £6.5m
Les Abreuveurs	St Sampson's	Ground-mounted solar, about 2.95 MW proposed	glass on about 80% of the site
Domarie & Avondale Vineries	St Sampson's	15 storage units and 2 yards for trades	12 vergées
GROW, Les Petits Quartiers	St Sampson's	Charity horticulture, glass rebuilt on site	£2.5m to £3m project
Les Nicolles Vinery	Vale / St Sampson's	Bought by the States for a school or housing	22.5 acres; £1.7m
Rue des Mares vinery	St Pierre du Bois	Clearance plus one house: refused	1.2 ha

Our reading: housing and industry approvals cluster in the north near the Bridge; rural western sites get refused and stay derelict.

Planning policy

Island Development Plan (2016): outside the centres, where most sites sit, redundant glass may be reused for small-scale industry, storage and distribution, a property's curtilage, renewable energy, or camping and outdoor recreation (Carey Olsen, 8 Jun 2018).
The Strategic Land Use Plan rules most redundant glass out of housing; in 2024 it was not due for review for about seven years (Guernsey Press, 5 Jul 2024).
Affordable-housing policy GP11 is set to 0% until 31 May 2029 (Collas Crill).

All 150 sites

Largest first. Homes at 35 per hectare; land value is the base-case residual. Each link opens the site on OpenStreetMap.

Site	Parish	Glass	Homes	Land value, base	Map
1	St Peter Port	38,019 m²	133	−⁠£16.6m	Map
2	Vale	29,269 m²	102	−⁠£14.8m	Map
3	St Pierre du Bois	25,882 m²	91	−⁠£6.6m	Map
4	Vale	22,372 m²	78	−⁠£11.3m	Map
5	Vale	16,965 m²	59	−⁠£8.6m	Map
6	Castel	15,983 m²	56	−⁠£3.2m	Map
7	Vale	15,955 m²	56	−⁠£8.1m	Map
8	St Andrew	14,830 m²	52	−⁠£6.6m	Map
9	Vale	14,801 m²	52	−⁠£7.5m	Map
10	St Sampson's	14,352 m²	50	−⁠£10.5m	Map
11	St Sampson's	14,346 m²	50	−⁠£10.5m	Map
12	St Peter Port	12,712 m²	44	−⁠£5.5m	Map
13	St Sampson's	12,410 m²	43	−⁠£9.1m	Map
14	St Saviour	11,311 m²	40	−⁠£4.1m	Map
15	Vale	10,527 m²	37	−⁠£5.4m	Map
16	Vale	9,978 m²	35	−⁠£5.1m	Map
17	Castel	9,848 m²	34	−⁠£1.9m	Map
18	St Sampson's	8,897 m²	31	−⁠£6.5m	Map
19	Vale	8,712 m²	30	−⁠£4.4m	Map
20	Vale	8,317 m²	29	−⁠£4.2m	Map
21	St Sampson's	7,984 m²	28	−⁠£5.9m	Map
22	Torteval	7,954 m²	28	−⁠£0.4m	Map
23	St Andrew	7,894 m²	28	−⁠£3.5m	Map
24	St Sampson's	7,669 m²	27	−⁠£5.7m	Map
25	Castel	6,988 m²	24	−⁠£1.4m	Map
26	St Sampson's	6,623 m²	23	−⁠£4.8m	Map
27	Castel	6,570 m²	23	−⁠£1.3m	Map
28	St Martin	6,311 m²	22	+£0.6m	Map
29	Vale	5,928 m²	21	−⁠£3.0m	Map
30	Vale	5,875 m²	21	−⁠£3.0m	Map
31	St Peter Port	5,610 m²	20	−⁠£2.5m	Map
32	St Sampson's	5,288 m²	19	−⁠£4.0m	Map
33	St Saviour	5,181 m²	18	−⁠£1.9m	Map
34	Torteval	5,041 m²	18	−⁠£0.3m	Map
35	Castel	4,866 m²	17	−⁠£1.0m	Map
36	St Sampson's	4,809 m²	17	−⁠£3.6m	Map
37	St Saviour	4,580 m²	16	−⁠£1.7m	Map
38	St Sampson's	4,368 m²	15	−⁠£3.2m	Map
39	St Peter Port	4,326 m²	15	−⁠£1.9m	Map
40	Vale	4,259 m²	15	−⁠£2.2m	Map
41	Castel	4,184 m²	15	−⁠£0.8m	Map
42	St Andrew	4,130 m²	14	−⁠£1.8m	Map
43	Vale	4,017 m²	14	−⁠£2.0m	Map
44	St Martin	3,964 m²	14	+£0.4m	Map
45	St Sampson's	3,911 m²	14	−⁠£2.9m	Map
46	Vale	3,691 m²	13	−⁠£1.9m	Map
47	St Sampson's	3,688 m²	13	−⁠£2.7m	Map
48	Castel	3,636 m²	13	−⁠£0.7m	Map
49	St Saviour	3,615 m²	13	−⁠£1.3m	Map
50	Vale	3,516 m²	12	−⁠£1.8m	Map
51	St Martin	3,454 m²	12	+£0.3m	Map
52	Vale	3,404 m²	12	−⁠£1.7m	Map
53	St Saviour	3,187 m²	11	−⁠£1.1m	Map
54	Vale	3,165 m²	11	−⁠£1.6m	Map
55	St Pierre du Bois	3,092 m²	11	−⁠£0.8m	Map
56	St Saviour	3,074 m²	11	−⁠£1.1m	Map
57	St Saviour	3,058 m²	11	−⁠£1.1m	Map
58	Castel	3,004 m²	11	−⁠£0.6m	Map
59	St Sampson's	2,904 m²	10	−⁠£2.1m	Map
60	Vale	2,886 m²	10	−⁠£1.5m	Map
61	St Sampson's	2,872 m²	10	−⁠£2.1m	Map
62	St Andrew	2,852 m²	10	−⁠£1.3m	Map
63	St Martin	2,837 m²	10	+£0.3m	Map
64	St Saviour	2,740 m²	10	−⁠£1.0m	Map
65	St Sampson's	2,718 m²	10	−⁠£2.1m	Map
66	Vale	2,542 m²	9	−⁠£1.3m	Map
67	Vale	2,482 m²	9	−⁠£1.3m	Map
68	St Sampson's	2,475 m²	9	−⁠£1.9m	Map
69	St Saviour	2,447 m²	9	−⁠£0.9m	Map
70	St Pierre du Bois	2,404 m²	8	−⁠£0.6m	Map
71	St Saviour	2,401 m²	8	−⁠£0.8m	Map
72	St Pierre du Bois	2,378 m²	8	−⁠£0.6m	Map
73	St Saviour	2,365 m²	8	−⁠£0.8m	Map
74	Forest	2,289 m²	8	−⁠£0.5m	Map
75	Vale	2,274 m²	8	−⁠£1.2m	Map
76	Castel	2,250 m²	8	−⁠£0.5m	Map
77	Vale	2,227 m²	8	−⁠£1.2m	Map
78	St Sampson's	2,220 m²	8	−⁠£1.7m	Map
79	Castel	2,196 m²	8	−⁠£0.4m	Map
80	Forest	2,189 m²	8	−⁠£0.5m	Map
81	St Saviour	2,162 m²	8	−⁠£0.8m	Map
82	St Saviour	2,118 m²	7	−⁠£0.7m	Map
83	Forest	2,117 m²	7	−⁠£0.5m	Map
84	St Martin	2,113 m²	7	+£0.2m	Map
85	St Saviour	2,060 m²	7	−⁠£0.7m	Map
86	St Saviour	2,053 m²	7	−⁠£0.7m	Map
87	Vale	2,000 m²	7	−⁠£1.0m	Map
88	St Saviour	1,924 m²	7	−⁠£0.7m	Map
89	Vale	1,897 m²	7	−⁠£1.0m	Map
90	St Saviour	1,866 m²	7	−⁠£0.7m	Map
91	Vale	1,843 m²	6	−⁠£0.9m	Map
92	Vale	1,836 m²	6	−⁠£0.9m	Map
93	Castel	1,811 m²	6	−⁠£0.4m	Map
94	St Sampson's	1,797 m²	6	−⁠£1.3m	Map
95	Vale	1,795 m²	6	−⁠£0.9m	Map
96	Castel	1,790 m²	6	−⁠£0.3m	Map
97	Castel	1,702 m²	6	−⁠£0.3m	Map
98	St Pierre du Bois	1,680 m²	6	−⁠£0.4m	Map
99	St Saviour	1,642 m²	6	−⁠£0.6m	Map
100	Vale	1,572 m²	6	−⁠£0.9m	Map
101	St Pierre du Bois	1,543 m²	5	−⁠£0.4m	Map
102	Vale	1,522 m²	5	−⁠£0.7m	Map
103	Torteval	1,515 m²	5	−⁠£0.1m	Map
104	Vale	1,492 m²	5	−⁠£0.7m	Map
105	Vale	1,490 m²	5	−⁠£0.7m	Map
106	St Sampson's	1,433 m²	5	−⁠£1.1m	Map
107	Vale	1,419 m²	5	−⁠£0.7m	Map
108	St Pierre du Bois	1,413 m²	5	−⁠£0.4m	Map
109	Torteval	1,401 m²	5	−⁠£0.1m	Map
110	Vale	1,353 m²	5	−⁠£0.7m	Map
111	Vale	1,342 m²	5	−⁠£0.7m	Map
112	Torteval	1,328 m²	5	−⁠£0.1m	Map
113	Torteval	1,285 m²	4	−⁠£0.1m	Map
114	St Pierre du Bois	1,248 m²	4	−⁠£0.3m	Map
115	Vale	1,203 m²	4	−⁠£0.6m	Map
116	Vale	1,190 m²	4	−⁠£0.6m	Map
117	Vale	1,176 m²	4	−⁠£0.6m	Map
118	St Peter Port	1,166 m²	4	−⁠£0.5m	Map
119	St Sampson's	1,156 m²	4	−⁠£0.8m	Map
120	Vale	1,118 m²	4	−⁠£0.6m	Map
121	Vale	1,101 m²	4	−⁠£0.6m	Map
122	St Saviour	1,097 m²	4	−⁠£0.4m	Map
123	St Sampson's	1,068 m²	4	−⁠£0.8m	Map
124	St Sampson's	1,065 m²	4	−⁠£0.8m	Map
125	St Pierre du Bois	1,060 m²	4	−⁠£0.3m	Map
126	Castel	1,014 m²	4	−⁠£0.2m	Map
127	St Saviour	968 m²	3	−⁠£0.3m	Map
128	Vale	918 m²	3	−⁠£0.4m	Map
129	St Sampson's	915 m²	3	−⁠£0.6m	Map
130	Vale	889 m²	3	−⁠£0.4m	Map
131	St Pierre du Bois	882 m²	3	−⁠£0.2m	Map
132	St Martin	872 m²	3	+£0.1m	Map
133	St Pierre du Bois	812 m²	3	−⁠£0.2m	Map
134	St Pierre du Bois	806 m²	3	−⁠£0.2m	Map
135	Vale	777 m²	3	−⁠£0.4m	Map
136	Castel	776 m²	3	−⁠£0.2m	Map
137	St Saviour	773 m²	3	−⁠£0.3m	Map
138	St Pierre du Bois	770 m²	3	−⁠£0.2m	Map
139	St Pierre du Bois	738 m²	3	−⁠£0.2m	Map
140	Castel	718 m²	3	−⁠£0.2m	Map
141	Castel	700 m²	2	−⁠£0.1m	Map
142	Torteval	650 m²	2	£0.0m	Map
143	St Saviour	649 m²	2	−⁠£0.2m	Map
144	St Saviour	615 m²	2	−⁠£0.2m	Map
145	Forest	603 m²	2	−⁠£0.1m	Map
146	St Pierre du Bois	565 m²	2	−⁠£0.1m	Map
147	Vale	548 m²	2	−⁠£0.3m	Map
148	Vale	546 m²	2	−⁠£0.3m	Map
149	Vale	519 m²	2	−⁠£0.3m	Map
150	Vale	505 m²	2	−⁠£0.3m	Map

How to read this

Glass is from OpenStreetMap (ODbL), 1 October 2026: buildings within 25 m merged into one site, sites under 500 m² dropped, parishes from OpenStreetMap boundaries. It shows where glass is, not its condition.

The appraisal is physical capacity, not what planning would allow; the realistic yield is a fraction of it. Values come from this site's sale register.

Explore moreSold prices Where new housing is built Where extending pays Property with land Extremes