This new development in a conservation area required a traditional Collyweston slates covering, which Claude N Smith, winners of the Roof Slating category of the UK Roofing Awards 2018, delivered with great craftsmanship.
Marshalls Yard is a former car garage located in conservation area in the centre of Stamford and surrounded by Georgian listed buildings. The yard was made up of different semi-industrial buildings, which had become run down and eyesore. Harris McCormack, a well-known Stamford Architect was tasked by Burghley Developments to design twelve Georgian style local stone town houses in keeping with the conservation area. The site was cleared, and all reusable materials were salvaged, including the local Collyweston limestone roof slates.
Complexity of the project
Four of the 12 townhouses were built on the roadside and therefore required to fit into the surrounding conservation setting so Claude N Smith used the reclaimed Collyweston slates on the front roadside elevation. Dormer windows were designed to replicate the traditional local style, using a mix of laced valley Collyweston slates and lead flat roofing.
Likewise, the ridge tiles had clay hogs to replicate adjacent houses, with mortar bedded in place. However, this contradicted Part L of building regulations, which require all ridges on new building to be dry and mechanically fixed. After consulting the NFRC, a compromise was agreed between the different council departments that a long stainless-steel screw could be used through the top of each ridge tile, fixed to the ridge board, as well as keeping the mortar bedding in position.
Workmanship
All the reclaimed slates were transported to our premise in pallet crates so that the old mortar could be cleaned off each slate, re-dressed on three sides, and a nail hole drilled at the top of each slate where needed.
Every slate was then measured into 26 different length sizes from Long Tens (24”) to Outrules (5,1/2”) and re-pallet crated into each of the different sizes. TLX Gold breather membrane was used as to maximise the energy efficiency of the building as all third-floor rooms had vaulted ceilings.
Since there were 26 differently size slates and a rafter length of 6.1 m, Claude N Smith’s slaters had to calculate the quantity of each size of reclaimed slates in order to make a batten rod, which would include the correct number of slate courses of the same size slates. This would allow them to fix the battens on the roof in exactly the correct place for the head of the slate to be nailed into.
About Claude N Smith
We specialise in Collyweston slating and this is the only type of roofing we undertake. Collyweston slate is a historic stone slate that was traditionally split using the natural freeze thawing process, however, increasingly mild winters made this difficult and mining uneconomical. In 2017 we started mining new Collyweston slates using industrial freezers to split the stone so that Collyweston slating is no longer reliant on reclaimed slates.
What Claude N Smith says
Collyweston slate is an historic local stone slate roofing material that dates back to Roman times so we were pleased to be able to use it on this modern development and keep the tradition alive and well
Challenges
The relatively small size of site meant that strict safety needed to be implemented on every stage of the building process, limiting access to plant vehicles and materials brought in during a time pre-organised time slot. Being located in the centre of town, access and parking was very restrictive so all pallets of slates needed for the day had to be teleported onto the scaffold loading bay early every morning.
At a glance
- Project: Marshalls Yard Development
- Roofing Awards 2018: Winner of Roof Slating category
- Client: Burghley Developments
- Location: Stamford
- Roof covering: Collyweston Slate
- Architect: Harris McCormack
- Roofing Contractor: Claude N Smith
