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Featured Project
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Bath Hotel Nevis, West Indies
S. Harris & Co. was recently retained to provide a general summary of the current physical conditions of the Nevis Bath Hotel, the prospects for the retrieval, recovery, and stabilization of the building, and the issues of preservation and restoration.
BUILDING DESCRIPTION The Bath Hotel is a Caribbean Georgian-style building which was constructed for visitors who came to the island to enjoy the health benefits of the warm natural mineral springs located adjacent to the hotel. The hotel was built by a local merchant in approximately 1787 and attracted visitors from throughout the Caribbean and Europe. This hotel was the center of the social life of the planter elite on the island from approximately 1787 to 1850 when the island was a primary supplier of sugar to the British Empire. The hotel also is part of the earliest stages of what would eventually become the tourism-based economy of the island and the Caribbean as a whole.
The lime-based mortar is derived from kilned coral and sand, with the inclusion of some darkening mineral or charred material to match the color of the stone. The stones are set in a coursed ashlar construction on the exterior walls with only a few rubble walls found on the interior. The ashlar walls are well-fitted and tightly jointed. The hotel is constructed into a hillside and was built in this location to take advantage of the natural hot spring which flows near and in front of the building. This spring is still active, and has a water temperature of 105º F.
PHYSICAL CONDITIONS ASSESSMENT
Drainage
Issues
The high roof is a porous material and is not water tight. This does not seem to present a serious problem as there is little evidence of water damage to the third floor rooms. The downspouts present a greater problem. They are disrupted, irregular, and clogged with vegetation, and are too small to handle the water capacity from the large expanse of roof, even if they were working properly. The upper roof drains and downspouts should be a minimum of 10 in.2 in sectional area.
The current method of removing the water from the site is to send it directly into the nearby spring. While it may be within current code requirements, this method may not be desirable if the spring is to be utilized as a tourist destination.
Masonry Issues The masonry issues can be divided into three categories: general deterioration, plant growth, and corrosion jacking.
The plant growth at the Bath Hotel is a problem. Not only is vegetation growing out of the drains as noted in the previous section, but it is also growing out of a number of joints and crevices throughout the building. This is one of the major reasons why there are joints that are opening up between the stones. The mortar is being disintegrated by root advancement. Plants can and do exert considerable forces on the stones causing cracks and shifting that is visible even when the vegetation is not.
The steel beams, posts, and railings on the North elevation are causing corrosion jacking of the stones where they enter the wall. This in turn causes cracking of the wall and damage to the surrounding stones. This will only progress as the corrosion builds within the wall until the stones give way.
Structural Issues
Pest Issues Besides the plant growth discussed in a previous section, the damage caused to the building by termites is highly destructive. The building is infested with sub-terranean termites. There is also some evidence of aerial termite damage. With the exception of the exterior wood shutters, all of the wood in the building has been replaced several times over the building’s history. With each renovation, new wood is installed and the damaged wood is removed. However, the remaining termites have been provided with a new food source and the cycle begins again. It is evident that the building is also continuously overrun by the local goats. There is evidence of the animals on every level of the building including the roof. This is not a serious detriment to the building due to its solid construction, but it does represent a health hazard to the occupants of the building.
Outbuildings To the west of the hotel there is the ruin of a later addition. A close inspection of this building was not conducted, but it is obvious that it has not been maintained and large trees are growing out of the ruin. The Bath House is an important building to maintain on the property as it is not only significant to the history of the property but is also potentially useful for future uses of the site. This building is in very good condition, however the metal roof is in danger of being pulled off in a high wind.
RECOMMENDATIONS
Drainage Issues While the porous nature of the high roof does not present an immediate problem, it is not a desirable feature. This could be addressed by applying an adhered, single ply, white membrane over the existing concrete roof. This membrane should be continued up the parapet and under the coping stones which require resetting to provide through-wall flashing. As a first step to the drainage issue, it is important to return the existing system to proper working order before analyzing whether it is able to handle the required capacity. The plants that are in the downspouts and drains on the upper and lower roofs are to be killed and the downspouts reconnected and repaired where required. An evaluation of where the water is directed once it is off the roof should be conducted. It may not be desirable to continue to empty the drain water into the spring although there may not be any alternative. The surface of the lower roofs needs to be addressed as well. The existing concrete flooring needs to be removed down to the existing structure. A new sheathing and adhered membrane roof should be installed to allow proper drainage. On top of the membrane, heavy stone pavers could be dry set in sand to provide a walking surface. These pavers would need to be of a size and weight to prevent shifting during high winds and borrowing by local residents. The total thickness of this new roof system would need to be coordinated with the existing thresholds.
Masonry Issues It is very important that a high lime mortar similar to the original is used rather than the cement mortar. This mortar should be colored to match the original mortar and injected into the thin joints between the stones. With the specified high lime mortar, stone or mortar dissolution should not be a significant issue in the long run. The plant growth is the top priority in the preservation of this structure. It is one of the most destructive forces which is presently at work. Herbicides should be applied on both vertical and horizontal surfaces. It is important to not only kill the existing vegetation but to include the prevention of plant growth as part of the ongoing maintenance schedule. The corrosion jacking can be eliminated by removing the steel from the walls. The railings could be attached solely to the cement floor so that there is no need for the steel to contact the stones. Alternative ways of supporting the spandrels, such as stone corbels, could be adopted. Where it is not possible to remove the steel from the wall, an air space between the stones and the steel should be provided. This allows the corrosion to build without being crowded by the stone. It also allows water to escape, thereby slowing the build-up of corrosion. Until a solution is found, it would be desirable to remove the entire third floor porch roof framing.
Structural Issues
As the hotel does not exhibit any
structural issues other than those related to seismic activity, there is little
concern for its structural integrity. The porch roof on the south façade
is a possible concern during hurricanes and should be secured. The prior
seismic damage should be addressed, in particular the pier shown in Figure 11
which needs to be reinforced with straps and reintegrated into the structure.
As a precaution, a quantitative analysis of the building relative to seismic
activity needs to be completed in order to be able to address these issues
before they may arise.
Pest Issues
Since the replacement of the wood
pieces in the building has not solved the termite issue, a program of chemical
termite eradication is recommended. This treatment should not be
undertaken only once with the idea that the problem will then be solved.
The inspection of the building for evidence of termite damage should be added to
the maintenance program. Any signs of damage should be followed up with
additional chemical treatments. The goat infestation should be curtailed as much as possible. At the very least, they should be kept from entering the building and leaving deposits in areas that are to be occupied. It would be beneficial if the grounds were to be upgraded and landscaped to keep the goats off the property entirely as they cause much destruction to plantings.
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The hotel, constructed of a
locally derived volcanic rock, is three stories high with intermediate levels
located in the side pavilions. The volcanic rock is of a type known as ejecta rock and is somewhat like
pumice in form and structure, although more dense and less porous. The
individual mineral composition of the ejecta has characteristics of granite.
By virtue of being blown into the air and deposited on the ground before it has
cooled, there is a certain amount of trapped air which reduces the density
(weight per cubic foot) of the rock. In more hostile environments, this
characteristic could jeopardize the integrity of the rock. In the mild
climate of Nevis, however, the trapped air does not have a significant impact on
the quality of this rock as a building material.
There
are two other significant structures on the site. The first is the Bath
House which was built over the spring and was used for guests to take the waters.
The second is a significant addition to the west of the hotel. This
structure is currently in a significant state of collapse.
The
hotel building essentially has a flat roof. The roof over the main body
of the hotel is divided into three segments which correspond to the partitioning
below. The central portion drains to either side due to a slight curve.
This water runs onto either of the side segments. These side segments
pitch from north to south and contain drains at the outer corners of the
southern side. From these drains, downspouts exit through the wall and
carry the water down to the ground.
The
lower roofs, used as roof decks on the third floor, have drains which lead to
short lengths of pipe that simply eject the water out onto the ground. The
drains appear to be clogged since discoloration of the walls below indicates the
water is not entering the pipes but is washing straight down the wall.
There
are very few cracks in the stone walls of the hotel. There is some
cavitation and surface weathering of the stone which has to do with the presence
of soluble minerals. Most visible mortar loss is from water dissolution, some of
which will be addressed with effective reactivation of the drainage system.
A particularly obvious problem is the recent use of high portland cement
pointing which has not only been applied in a haphazard manner but is also too
hard for the softer volcanic stone. When the two surfaces meet, the cement
does not give way to the stone as it expands and contracts, so the stone is more
likely to crack. This cement mortar is also not the appropriate color and does
not create the unified appearance of the original stone wall.
The
Bath Hotel is a well-founded, solidly built structure with few structurally
related issues. The building has withstood hurricanes and other natural
forces quite well over its more than 200 year history due to its mass and size.
There is, however, evidence of past seismic damage and movement. Visible
cracks and shifting are found in piers and exterior walls. There does not
appear to have been any recent damages of this nature, but there is no way of
knowing when another such event will occur.