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Commissioner’s House restoration
by Ian Coles
Preserving our past
Commissioner’s House verandah restoration maintains the original aesthetic and conserves its historic value
Commissioner’s House dominates the Dockyard skyline and since it was built two hundred years about four inches thick and were prestressed. When they manufacture these in the factory, they have reinforcing wire ago, has become an icon of the West End. However, with its location exposed to the harsh Bermuda elements, the building requires constant care and conservation.
Most recently, the dark red columns, hand railing and concrete floor of the wrap around verandah have all been repaired or replaced.
“The reason the floor needed rebuilding”, says Michael Tatem of contractor Crisson Construction, “was that the existing verandah was a precast system of concreate slabs that were laid in between steel beams. They were running through the slab. And then they cut the slab to the size you want, and the wire that’s prestressed in slab is exposed at the end.” “What should have happened when the building was restored in the 1990’s”, explains Tatem, “is the end of the slab needed to be sealed where the rebar sticks out, otherwise it rusts.” Although a four-inch topping slab was put over the pre-cast slab, over a period of time, rainwater ingressed through that slab into the precast slabs and rusted the rebars that were prestressed.
When rebar rusts, it expands and the concrete falls away. This was happening at Commissioner’s House, it was becoming unsafe, and big pieces were dropping away.
Tatem says the four-inch slabs were jackhammered off the top, and then the pre-cast slabs were removed, all the way around the verandah.
“Once all the concrete was removed, the supporting steel beams were exposed. We then removed the rubber membrane from the steel beams and had them sandblasted. The handrails and columns were sandblasted at the same time. Then a 3-part paint system was used — primer, rust proofing and topcoat.”
On inspection of the exposed steel beams, Crisson Construction found that some of the connections were not supported properly. Tatum points out that “the engineer had to redesign some of those connections. Each one of those
connections had to be modified and a new plate, shims and other work had to be undertaken on the beams. There are 39 of those beams that all had to be repaired.”
“In order to replace the floor slabs, we had scaffolding all around the building so that we could create the concrete forms. Then we installed two layers of rebar. The slabs are now eight inches thick instead of four — we poured them right in place, as opposed to pre-formed.”
The entire project took six months, and the Commissioner’s House verandah is now well-prepared to withstand several more decades of salt spray and hurricane strength winds.
KEY CONTRACTORS
• Crisson Construction Limited • Brunel Engineering
Consultants