St Patrick's College Chapel Silverstream

Board of Proprietors St Patrick's College Silverstream
Construction value: 
Scope of Works: 

This project was the renovation of an early 1970’s catholic chapel situated in the heart of St Patrick’s College in Upper Hutt. Since its beginnings the chapel has been integral to the special character of their school. It was crucial this chapel was finished in time for graduation type events held in the Hall Atrium. The aim of this project was to strengthen the chapel, repair water damage and retain as much of the original building as possible.

Restrengthening of the chapel included the main atrium, entrance foyers, aisles and roof. The essential structural strengthening of the roof required removing the roof and inserting steel bracing, before installing the original roof back in place. It was challenging as the project was carried out over winter. To combat severe weather, a substantial amount of scaffolding was used to fully tent the chapel with shrink wrap. The size of this roof was – span – approx. 35m wide and 20 metre deep = 700m2 in total.

The existing ceiling in the main chapel roof is no longer manufactured. To keep this chapel in its original condition Armstrong Downes Commercial preserved the roof in situ and retained the feature Rimu timber ceiling shiplap. The main chapel roof was completed with diamond deck and clip lock metal cladding.

Renovations involved removing a vast amount of water damage in the structure and ceiling lining. To combat this, the structure was replaced with a Rimu shiplap and polyurethane stained feature wall lining.

To preserve the architectural and special aesthetic character of the building once all the restrengthening work was completed the Chapel was completely returned to the original look and function with all steel bracing and restrengthening work completely concealed.

Special Info / Challenges: 

One of the main challenges of this project was the practicalities of installing the steel bracing into the building while it was fully tented and scaffolded. This required a staged sequence as the existing structure was so unstable. There was a threat that precast wall panels would have fallen outwards, collapsing the whole building. To mitigate the risk, the interior of the chapel was internally scaffolded and the entire roof propped up throughout this complex process.

The roof was taken off in sections to retain the structural integrity of the building at all times. This involved taking a section of roof off, applying structural steel, reinstating the roof and moving to the next section. This was achieved in 7 distinct stages.

Stages 1 - 3 happened initially on the  left hand side of the building while stages 4 - 6 took place on the right side and the final stage, 7 was to secure the centre of the atrium. Due to the weight of steel, large sections came in under the tent and were placed underneath the purloins, fixed in place and then moved to the next section. This unusual and carefully planned programme ensured the integrity of the building and minimised the risk on site.

The elements were also a hazard as, in effect, the shrink wrapped building could act as a massive wind sail.  A specialist scaffolding engineer was employed to design the external and internal shrink wrapped scaffolding to minimise risk. To alleviate this potential danger, several interesting techniques were employed to ensure the safety of the site and integrity of the building during the strengthening process. 12 * 1 tonne weights were placed around the perimeter of the site to keep the scaffold tied down. In addition 25 *2.5 tonne strops tied the plastic shrink wrap and scaffolding back to the main building structure.  

Award Winning Project

St Patrick’s College Chapel Silverstream (1977) won an award for Enduring Architecture at the NZIA 2017 Wellington Architecture Awards.