Mansard Roof of Old Tainan District Courthouse

Last updated on September 28th, 2017 at 11:08 pm

Old Tainan District Courthouse was built in 1914 during the Japanese Occupation period in Taiwan.

It was designed by Japanese architect Matsunosuke Moriyama in the resemblance of the French Baroque style.

The building was closed in 2003 and reopened in November 2016. During this closing period of time, a full-scale restoration work was carried out.

The site was categorised as the second class historical monument by the Ministry of the Interior.

On this post, I shall describe the design and structure to my best of knowledge.

Please also watch the unscripted replay video I have recorded on my visit to Old Tainan District Courthouse at Section 1 Fuqian Road.

In Taiwan, as far as I know, almost all the national heritage buildings with French Baroque architecture do not permit or expose the framing works of the roof for public viewing.

At Old Tainan District Courthouse, it is the best opportunity to have a close-up view of the mansard roof; well-preserved and fully restored.

Based on the framing structure, there are two inclined parts of the roof.

The steeper roof is supported by lower rafters, having ratio of rise to run is 60:12. On top, a much gentle slope of ratio 3:12 is supported by upper rafters.

Due to the steep incline of the upper roof, the ridge line will be out-of-sight from ground floor.

The roof is reinforced by vertical web that raises from the floor joists up to the curb where the two roofs meet on each side.

Following that inwardly from both sides, another pair of inclined cantilever webs connects to the collar tie which is attached together with the ceiling joist.

Inside the framework, the floor joists made up the nominal span of the roof.

The design of the horizontal floor joist, the pair of vertical webs and the ceiling joist established the rectangular roof structure for interior framing.

This interior frame supports the two sides of rafters and curbs of two inclined roofs.

Right at the middle of the framework, it consists of a short king-post joining perpendicularly up to ridge beam at the pinnacle of the rooftop.

All the joints are securely strapped and bolted with metal gussets.

Some of the wooden beams are restored by joining new fabricated wood. Joints are tailored carpentry to match the original part.

You can see the difference in colors where the darker color shows the original old wood and whiter ones are new material.

In addition, the old wooden materials are ‘injected’ with epoxy consolidants to prevent further wood-rotting and insects infestation, such as termites.

At a closer inspection of wood surface, small drilled-burrows are visible and to necessitate the flow of penetrant.

The design of ox-eye windows or oeil-de-boeuf on the roof are the distinct characteristic of grand architecture of France Baroque.

These round windows are beyond the reach from the suspended service alley retrofitted at the center.

The suspended service alley is a unique integration to the entire mansard roof. Locally, there called it as the cat’s walkway.

The narrow walkway is retrofitted for engineering purpose, such as inspections, maintenance and repair work.

A similar structure of the service alley, can also be found at Former Tainan Public Meeting Hall located at Section 2, Minquan Road, West Central District.

At Former Tainan Public Meeting Hall, there is no public access to the attic roof. Only able to view from the hall at ground floor. Therefore, one has to look up to see the service alley.

Roof Framing, Mansard roof, Suspended Service Alley
Roof Framing, Mansard roof, Suspended Service Alley

The wooden back-wall at the entrance are laminated with thick planks. In-between each planks is reinforced with white elastic epoxy shown therein.

According the explanation from the tour guide, this elastic material helps to absorb stress from horizontal seismic events.

Interior wall of the entrance to mansard roof
Interior wall of the entrance to mansard roof

The guided tour to the roof is catered to very small group at two specific time slots per day. Plus, it limited to first 15 -20 pax of the queue due to resource.

It’s a very local tour and the drawback is that tour guide speaks Chinese Language. I was given permission by the staff on my second visit for video recording.

On the next post, I shall write about the missing west tower with the tapering conical roof called the spire.

Replay video of Old Tainan District Courthouse

On Google Map, This place is named Tainan Judicial Museum.