Document ID: chunk:federal_register_of_legislation:F2013L01343:reg:16:p5
Version: federal_register_of_legislation:F2013L01343
Segment Type: reg
Provision Reference: reg 16 (pt 5/51)
Character Range: 209374–212140

integrity of the site. Such works programs need to be cautiously designed and assessed prior to their implementation in order to minimise these risks. This does not, however, preclude emergency intervention in the event of unanticipated threats to the structures. No major structural interventions of the scope and scale of the over-cladding of the roof of the workshop of the Main Hut (1998) and of the living section (2006) are however anticipated in the life of this plan.

Snow and melt water ingress into the Main Hut

The over-cladding of the Main Hut roof has largely prevented snow and melt water from penetrating the hut. This management action was designed to prevent further damage to interior structural members and fittings – including the collapse of shelves and bunks – caused by the melt-freeze cycles which had produced ice that encapsulated objects and stressed load-bearing features.

Although the over-cladding was designed to have minimal impact on the Main Hut's internal microenvironment, the additional buffering created by new air spaces, the additional layer of timbers, and the fabric membrane over the living quarters roof may alter the internal environment. The extent of potential impacts will be determined by continued environmental and corrosion monitoring. The monitoring plan will include the placement of monitoring sensors in high risk/high melt zones, such as walls and ceiling. The use of other sensors, such as gold grid sensors, will be investigated and incorporated into the monitoring plan (if deemed suitable).

Monitoring of snow and ice ingress into the Main Hut will help determine entry points and enable maintenance and internal patching to be undertaken to reduce ingress. In the longer term, careful monitoring is needed to assess the possibility of the build-up of snow and ice, particularly in wall and ceiling cavities, and to determine the effectiveness of internal patching.

The site is regularly affected by diurnal and seasonal freeze and thaw cycles. In winter, the Main Hut is typically buried to the top of the walls by drift snow. During summer seasonal melt cycles, the western and eastern walls often collect melt pools that abut the external timbers, with visible tide marks on the exterior cladding. This may increase the risk of melting of ice in the internal verandah and large melts may cause flooding under and possibly even in the Main Hut. The Oregon timber frame of the Main Hut, where it has been subjected to occasional exposure to water in these pools, shows no signs of damage to date but the potential impact of this activity needs to be monitored over time to identify any changes. In summer, when much of the external snow ablates and melts, melt water pools and streams sometimes form