Roofing in Dominica

Dominica, a steep volcanic island between Guadeloupe and Martinique, lost almost all of its roofs when Hurricane Maria passed over it in 2017. Its recovery became a regional test case for building back roofs to a higher standard.

Climate and hazards

Hurricane Maria made landfall on 18 September 2017 as a Category 5 storm with winds above 277 km/h (172 mph). The Post-Disaster Needs Assessment put damage at US$930.9 million and losses at US$380.2 million, together equal to 226% of 2016 GDP. Housing was the worst-hit sector, with 38% of all damage, and about 90% of the housing stock was damaged. A shelter-sector review reported that over 90% of buildings and 98% of roofs were damaged; the building damage assessment recorded 23,488 damaged houses, of which 5,961 were completely destroyed. Dominica also faces earthquakes, volcanic hazards and flooding.

Roofing history

Throughout the Eastern Caribbean, older timber houses typically have steep hip or gable roofs clad first in wooden shingles and later in corrugated iron. Hip roofs, sloping on all four sides, are self-bracing and lack tall gable ends that catch the wind, and slopes of about 35 degrees or more are often preferred in hurricane regions because shallower roofs are more prone to uplift.

Roofing today

After Maria, roof repair programmes used corrugated roofing sheet, galvanised ridge capping, treated timber and metal straps, ties and angle brackets. One programme repaired 670 roofs averaging 35 m² (377 ft²) at an average cost of US$3,700 (US$2,550 materials, US$1,150 labour), and trained 180 people in basic carpentry and Build Back Safer techniques. Underestimated structural damage, code requirements and material shortages raised costs, and many houses needed structural strengthening before they could carry a code-compliant roof.

Codes, standards and regulation

The Organisation of Eastern Caribbean States (OECS) developed model building codes and guidelines for small buildings with support from UNCHS and UNDP, based on the Caribbean Uniform Building Code (CUBiC). The USAID-funded, OAS-executed Caribbean Disaster Mitigation Project helped Antigua and Barbuda, Dominica, Grenada and Saint Lucia prepare national codes from these models, and published construction diagrams covering hip and gable roof framing, rafter-to-ring-beam and wall-plate connections and hurricane straps for houses under 3,000 ft² (279 m²). A revised OECS Building Code was issued in June 2015, reviewed that year for Grenada, Saint Vincent and the Grenadines, Saint Lucia and Montserrat, and drew on the codes of Jamaica and the Cayman Islands. National consultations on administering it were held across the sub-region in 2017 under the EU-funded iLand Resilience project. Dominica's draft national code was awaiting legislation under the Development Planning Act in the late 1990s. After Maria, a revision of the Dominica Housing Standards was completed on 15 January 2018, chiefly increasing purlin and rafter sizes, and published as the Guide to Dominica Housing Standards 2018.

Sources and gaps

Published accounts of island-specific historic and Kalinago roofing: published information is limited.

Pre-Maria roofing history, Kalinago building and material statistics: published information is limited.