RICS Level 2 Survey Tresco, Isles of Scilly

The housing stock on Tresco differs markedly from typical mainland UK properties. Many homes are constructed from granite, reflecting the island's geology which forms part of the late Variscan Cornubian batholith dating back approximately 290 million years. Properties such as the late 19th-century Blockhouse Cottages and traditional terraced houses throughout the settlements feature solid granite masonry walls that require specialist assessment by surveyors familiar with traditional island construction methods. Our inspectors have direct experience evaluating these properties and understand how granite construction behaves differently from modern cavity wall systems.

The entire Isles of Scilly, including Tresco, is designated as both a Conservation Area and an Area of Outstanding Natural Beauty. Sixteen listed buildings grace the island, including the Grade II* King Charles's Castle and Cromwell's Castle, the Grade II Tresco Abbey, and numerous historic cottages such as Dolphin Cottage, Rose Cottage, and Ivy Cottage. Properties in these categories often have unique construction features and may require more detailed assessment than a standard Level 2 survey provides. Our team advises purchasers on whether a more comprehensive RICS Level 3 Building Survey would be appropriate for listed properties.

Coastal exposure presents another critical factor for Tresco property owners. The island's position in the Atlantic means properties face ongoing challenges from salt-laden air, increased storminess, and potential coastal erosion. Our inspectors examine how this marine environment affects roof conditions, external joinery, and the overall structural integrity of buildings. The granite bedrock provides excellent stability, but the interface between structures and the rocky terrain requires careful evaluation. We specifically assess drainage patterns and how water migrates across the granite surface toward the coast.

With limited new development on the island, most properties available for purchase will be either historic homes dating back to the late 19th century or renovations of existing estate properties. Planning permission granted in 2021 for the Blockhouse Cottages replacement dwelling and in 2024 for the Bottom Staff Annexe demonstrates that any new construction or significant alteration requires careful consideration of the island's unique character and conservation requirements. Our surveyors are familiar with these recent developments and understand how they may affect neighbouring properties.

Properties on Tresco predominantly use granite as the primary construction material, reflecting the island's geology. Buildings such as Tresco Abbey and its gatehouse showcase coursed granite with ashlar dressings, while traditional cottages typically feature rough-faced granite rubble masonry. Our inspectors understand how these traditional construction methods perform over time and what defects to look for in granite-walled properties. The solid nature of these walls provides excellent thermal mass but requires different assessment criteria compared to modern cavity wall construction.

Many historic properties on Tresco, including the terraces at Norrard and the old Blockhouse Cottages, were constructed in the late 19th century using traditional techniques that predate modern building regulations. Pointing between granite stones is often lime-based rather than cement, which allows the walls to breathe but can deteriorate over time. Our surveyors examine pointing condition carefully, as failed pointing allows water penetration that leads to internal damp problems. The interface between different construction elements, such as where timber floor joists bear onto granite walls, requires particular attention.

Roofing on Tresco properties typically uses local slate or imported stone tiles, with some properties featuring traditional thatch. The age of these roofs varies considerably, with some dating back to the late 19th century when Blockhouse Cottages and similar terraces were constructed. Our inspectors assess slate condition, the effectiveness of hip and ridge pointing, and the condition of roof void ventilation. For properties with thatched roofs, we identify any deterioration or signs of past water ingress that could indicate underlying problems.

Windows and doors in traditional Tresco properties are typically timber-framed, often with single glazing that does not meet modern energy efficiency standards. The salt air environment accelerates decay in timber frames, particularly at the bottom rails where moisture collects. Our surveyors examine frame conditions closely, checking for signs of rot, insect activity, and the effectiveness of existing decorative coatings. Many period properties will require window replacement or significant renovation as part of any purchase decision.

Properties on Tresco face distinct challenges that our surveyors are trained to identify. The salt-laden Atlantic air accelerates corrosion of external metalwork including gutters, downpipes, and any exposed steel lintels. What might appear as minor staining on a mainland property could indicate significant metal deterioration requiring immediate attention on an island home exposed to constant maritime weather. Our inspectors examine metalwork carefully, looking for signs of rust staining, pitting corrosion, and structural weakening that may not be visible without close inspection.

Many Tresco properties feature traditional roof construction using local slate or imported stone tiles. The age of these roofs varies considerably, with some dating back to the late 19th century when Blockhouse Cottages and similar terraces were constructed. Our inspectors assess slate condition, pointing quality, and the effectiveness of roof ventilation, which is crucial in properties with solid granite walls where moisture management differs from modern cavity wall construction. We specifically look for slipped slates, deteriorated hip ridge pointing, and any signs of past water ingress in the roof void.

Given the granite geology, traditional solid wall construction predominates. These walls offer excellent thermal mass but can suffer from rising damp if ground levels have been raised over the years or if existing damp-proof courses have failed. Our surveyors use moisture meters and visual inspection techniques to assess wall conditions comprehensively. The granite bedrock provides excellent load-bearing capacity, reducing subsidence risk, but the interface between buildings and the rocky terrain requires careful examination. We assess how surface water drains away from buildings and whether any retaining structures are performing effectively.

The limited number of recent property transactions on Tresco means that comparable sales data is scarce. Your survey report includes a valuation based on available market evidence, including the substantial £4,375,000 sale of Watch House in October 2024, providing you with realistic expectations for the property investment. We also consider the broader Isles of Scilly market and any relevant planning permissions that might affect value, such as the recent approvals for the Blockhouse Cottages replacement dwelling and Bottom Staff Annexe.