I was invited by DOC at Aoraki/Mt Cook to join an overnight hut maintenance visit to Empress Hut, NZ's highest building at 2530m.
I carried out a measure-up, visual inspection and some internal & external destructive investigation.
Next steps are to write it all up and look at options for remediation of the issues found during the visit.
Empress hut sites under the western face of Aoraki and South Face of Mt Hicks. The hut is used by elite climbers and is considered one of the Southern Hemispheres premier climbing areas.
The original hut was built by the Canterbury Mountaineering Club (CMC) in 1953 with all materials being carried in up the Hooker valley on the backs of climbers ferrying loads up to the builders who camped on site. The old hut now sites at the AMCNP Visitors Centre.
The current hut was built with CMC support to celebrate the 100th anniversary of the ascent of Aoraki/Mt Cook in 1994.
I stayed two nights in the old Empress Hut in 1985 when I climbed Mt Cook at the age of 21. To be able to return in my late 50’s with the ease of a helicopter was a real privilege.
The hut was designed in 1200mm sections consisting of floor, walls and roof which allowed off site construction and quick on-site assembly. The design was very clever in terms of prefabrication and structure but not so clever when it came to weathertightness and internal moisture and thermal bridging.
Each prefabricated section has two timber portals, the portals have a floor beam, two legs and two rafters forming the gable roof. The various timber members of the portal are fixed together with a continuous steel plate. When the sections of hut are brought together a flitch beam is formed with two timber plates sandwiching two steel plates which are then all bolted together. This provides bracing across the width of the hut.
There is wall and roof framing between the portals completing the 1200mm sections. Glass batt insulation between the framing and ply lining inside and structural ply bracing outside. The structural ply provides bracing along the length of the hut.
The 50mm thick flooring was installed on site in longer lengths and spans the full 1200mm between the portal frames. There is no floor insulation.
The windows are standard aluminium.
The cladding is flat galvanised sheet which is screwed onto the ply.
The hut has suffered from water leaks and condensation for some time demonstrated by the deterioration of the interior lining. Almost every piece of ply lining shows water staining. The window reveals have almost completely rotted. There is some black mould but not as much as you would expect given the amount of moisture. This is probably due to the high alpine environment.
