Building climate Resilient homes in an era of climatic uncertainty in the Caribbean
by Daniel Campbell
Director / Civil Engineer
Caribbean Engineering and Design Consultants Ltd (CEDCO)
The multi-island Caribbean nation Saint Vincent and the Grenadines is one of the most vulnerable countries to the effects of climate change and natural hazards. Tropical storms, hurricanes, torrential rainfall, coastal and beach erosion, sea-level rise, storm surges, landslides, flooding, volcanic eruption, and seismic activity such as earthquakes are natural hazards that threaten our lives, livelihoods, and property. The chances of these hazards contributing to devastating physical damage and loss of life increase due to deficient house design, inappropriate building practices (both construction methods and materials), and improper site selection. A climate resilient home should be located in a relatively low flooding and landslide hazard zone and be able to keep persons inside the house safe from the high winds and violent rainfall of a category 5 hurricane, moderate floods, and earthquakes, without the house being destroyed beyond manageable repair. What can be done by homeowners, contractors, architects, draftspersons, engineers, planners, and legislators to ensure that climate resilient homes are built in SVG?
The development and implementation of a revised building regulatory system (building codes, guidelines, land use and physical development plans and integrated spatial plans for climate change and biodiversity) is critical to the development of truly resilient housing. Better data to guide isolated house construction, housing development and relocation will help communities adapt to the reality of a changing climate. Everyone involved in the home building process must be trained and sensitized on what actions they can take contribute to the building and retrofitting of safer homes. The following guidelines are some of the practical ways to build better houses in SVG:
1. Consult with a qualified architect and structural engineer, especially if the house you want to build will be more more than 2,500 square feet;
2. Developments should adapt to natural site contours as much as possible and construction on natural drains should be avoided. As much natural vegetation should be left undisturbed. Grading large flat terraces on hill side sites should not be allowed. Homes should be constructed on solid ground and not on backfilled areas. Standard soil studies and geotechnical investigations should be mandatory for new developments.
3. All new land developments should integrate an effective storm water management system.
4. Erosion and sedimentation control measures with plants such as vetiver should be used as much as possible, especially to stabilize slopes;
5. Use isolated reinforced concrete foundations in hilly terrains with tie beams;
6. The ground floor level of homes should be raised as much as possible;
7. Building Shape Houses should be rectangular, square, hexagonal or circular in shape. Avoid irregular shaped houses (such as “T” and “L” shaped as well as long rectangular shapes (the length should not be more than triple the width). If extensions to the houses would cause an irregular shape, it would be best to build the extension as a separate structure and join it by a footpath or walkway;
8. Steel bars should extend beyond foundation walls/columns and tie into the structure above ground. Houses in flood plains should be designed to resist dynamic water force, floating debris and scouring;
9. Ensure that columns, beams, reinforced concrete blocks, studs and all other materials are properly braced to withstand high winds as well as flooding;
10. Use hip shaped roofs with minimum 30 degrees slope or if possible, reinforced concrete slab roof. The overhang (eaves) should be less than 8 inches (horizontally) or maximum of 18 inches when enclosed. Galvanized sheets should be no thinner than 26 gauge (24 gauge is ideal). They should also be nailed at the top of every corrugation at eaves and the ridge board, and every second corrugation and a wooden fillet to the purlin/lath. The ridge should be capped nailed at every corrugation and in general. Hurricane straps should always be designed and used;
11. Porch/veranda roof should be separate from the house roof so that it can break away without badly damaging the main house roof and structure;
12. Water Tanks, cisterns, rainwater harvesting systems and renewable energy powered pumps should be utilized as much as possible.
13. Solar power and other forms of renewable energy as well as backup power generators and battery tied PV systems should be used whenever feasible.
14. Invest in hurricane shutters that can be installed and rapidly closed when necessary or make shutters that could be nailed in place quickly before a storm;
15. The members of the household should be trained to keep all entrances closed during a storm and/or open entrances on opposite sides of the house to neutralize air pressure.
Our nation has many willing and able professionals and an international network of Vincentians and foreigners who can contribute to upgrading our housing sector. Likewise, present and future homeowners are eager to learn and contribute to building a safe and comfortable homes in an era of climatic uncertainty in the Caribbean.
Caribbean Engineering and Design Consultants Ltd may be contacted at:
Email: [email protected]
Telephone: +1784 533 1101 or +1784 527 0101
Facebook page is @cedcoltd.vc