Following the achievement of making a structurally sound and water-tight shell, it was possible to make progress inside making the shell a home. The plan was always to salvage and reuse as much of the original fabric as possible, whilst utilising sustainable and traditional materials in a modern way that would enhance the environmental performance of the building. Cut care would be needed to ensure the intrinsic qualities and value of the building were not lost. Great care was therefore taken to ensure that everything that was salvageable was indeed salvaged and saved from the skip! Following treatment of the entire timber fabric, floorboards and doors were kept, and the sound parts of rotten floor and ceiling joists were set aside for reuse and repurposing. De-nailing was a big and dirty task.
This has been a long awaited moment, the installation of the glazed panels and pivot door within the modern porch annex. The minimal, slim-profile frames, level threshold and unsupported open corner are key elements in our vision for the entrance drama to the cottage.
The installation is packed with very elegant design details and the end result, once the paving inside and out is complete, will look stunning.
Thankfully, everything fitted like a glove! No last minute dramas or teeth gnashing.The glass is in and one can now get a feel for the finished look. The interior flag stones are in place and these will flow on the same level to outside the porch into the upper courtyard – currently a builders’ yard!Looking from what will be the front-door threshold through the open porch to the courtyard and the estuary beyond.
Having completed the timber form-work for the porch, fixed it to the steel structure and creating the up-stands for the roof light, the small area of flat roof and canopy gutter could be covered in glass fibre with flashing up to and behind the larch cladding of the cottage. This will provide a nice long-term watertight weather seal for the roof. The insulated warm-deck roof is now ready to receive the glass prior to being clad in Corten Steel https://en.wikipedia.org/wiki/Weathering_steel
Ventilation is a big issue these days. We need good clean air to live. As you may have noted from elsewhere in this project blog, the need to manage humidity and condensation in a timber framed building is of great significance. This, above most other things, has been a guiding principle impacting most design decisions on the refurbishment project. The installation of an efficient mechanical ventilation and heat recovery (MVHR) system was anticipated at day one and carefully integrating such a system into the cottage was always going to require forethought and care.
Such systems are common place now in modern new-builds. Less so in refurbishments where retro-fitting is more complex. We opted to make use of the highly efficient Vent-Axia MVHR system supplied by BPC Ventilation https://www.bpcventilation.com/vent-axia-kinetic-advance-s
The system is simple. Fresh air is drawn in from outside and passed to the internal living rooms of the cottage, but only after it is pre-heated by exchanging heat from warm moist air drawn from the bathrooms, WCs and kitchen spaces. The extracted waste air is then exhausted to the atmosphere. The system is said to be over 90% efficient.
Our system was supplied as a ready to install kit. However, given the constraints imposed by the building’s listed structure, we needed to find ways of installing the MVHR unit, plenums and the ducting without compromising the historic fabric. The MVHR unit is sited in the small loft space above the bathrooms. This makes for easy access to the eves for the supply and extract air ducts. The MVHR unit air filters can also be accessed ready for regular cleaning and maintenance.
The MVHR unit (above top left) sits snugly up in the loft space (above), providing ready access to the soffit ventilation points (supply and exhaust) one on either side of the cottage (eg: top right of top right-hand photo above).
The supply and extract ducts radiate from a pair of stainless steel manifolds, the number of supply and extract ducts matching as far as possible to enable a “balanced” system. Whist this would be especially important in the case of a fully sealed “passive house”, it is good practice in this case notwithstanding the inevitably “leaky” nature of this historic building refurbishment. The real benefit will be minimising the potential for humidity and condensation build-up without the sacrifice of heat loss, particularly during the winter months.
water supply and ventilation ducts running vertically through the back of the walk-in wardrobe
Extract plenum in the en-suite within the ceiling void
All services are installed without the need to damage original structure
Ducts are temporarily sealed to avoid construction dirt
The loft deck with supply ducts and water plumbing
The air supply manifold
A redundant chimney flue provides the best way to get fresh air down to the ground floor and snug
The main supply and exhaust ducts are individually insulated to maximise efficiency
The challenge of threading up to 15m of ducting to the various extremities of the cottage was overcome by making use of one of the four chimney flues that extend through the full height of the building. Three ducts were dropped down the flue through a small aperture in the loft side of the stack. The flue used to serve the lower ground floor fireplace at the bottom of the building, so it provides a ready and direct route for supply air to the most distant parts of the building.
One day soon we’ll be switching the system on for the first time, so hopefully it works as I intended!
The metal structure with its cantilever roof has now been measured by the glass fabricators in anticipation of the glazing being installed. This was to have been in around twelve weeks time. Not now I’m afraid. Like everyone else, we’ve been struck by the global Covid-19 virus pandemic and this has hit our supply chain.
Prior to the pandemic hitting we did manage to get the porch’s timber structure and insulated warm-deck roof formed, ready for cladding and finishing when conditions allow. The roof-light aperture and the extent of glazing is now apparent and the roof structure appears to magically float, completely unsupported adjacent to the cottage – it’s going to look fabulous!
Some additional fixings were required!
The aim is to keep the roof structure as slim as possible.
Well the roof supports the boss’s weight!
The porch roof ready for glass-fibre finishing and Cor-ten cladding.
The porch structure appears to float next to the cottage, and its possible to now get a good idea of the upper / ground floor level morning garden space.
Work is still progressing slowly on the interior. Steve and Healey are continuing to work for the sake of their own livelihoods, at least until such time as authority dictates otherwise. Strict social distancing measures, however, require that I cannot be on site, which is an enormous frustration. In the circumstances I’m going to use this time of enforced isolation from the cottage to try and bring this blog up to date and provide further details of what was happening prior to the pandemic hitting.
The team from Argles Medal Design have now installed the steel structure to form the porch extension. The huge cantilever is amazing, structures always fascinate me and this is no exception! The clear unsupported open corner that will be possible when the glazing is opened up will really make this space. The social spaces within the ground floor to the cottage will hopefully spill seamlessly into the courtyard/garden outside. It should be a fabulous space for its small size.
Setting the columns and brace that will support the roof above.
The prefabricated roof structure was hoisted as one piece over onto the preset columns. All we need now is some glass and cor-ten steel cladding! That’ll be a few weeks away.
The entrance to the cottage will be through a starkly contrasting contemporary glass and steel “porch”. The foundations for the structure were put in place a year ago before the scaffolding was erected, but now the scaffolding is gone, we can get the extension fabricated.
This is the most expensive single element of the project involving use of “weathering” or COR-TEN® steel: https://twopointseven.co.uk/blog/f/what-is-cortenweathering-steel . Weathering steel, best-known under the trademark COR-TEN® steel, is a group of steel alloys which were developed to remove the need for painting and form a stable rust-like appearance when exposed to the weather for several years. Consistent with my aim for a truly sustainable restoration of the cottage, weathering steel is not only made from recycled steel, it is also 100% recyclable itself.Â
The choice of steel as a material was also deliberate, it relates back to the building’s original use associated with the old forge of Frederick James Joscelyne that was sited immediately to the north on Leigh Hill. See more on the history page of this site: https://28leighhill.files.wordpress.com/2018/11/heritage-record-statement-final.pdf
The structural steels in fabrication at Paul’s workshops at Unit 2, Windsor Gardens, Rectory Road, Hawkwell, Essex. The design involves the creation of a long cantilevered, unsupported steel span to form the opening for the floor-to-ceiling glass that will provide visitors with their first experience of and introduction to the refurbished cottage. The structure is necessarily completely independent to that of the rest of the cottage, it being self-supporting and rigid in a way the timber structure of the cottage never can be.
The details on the external facades matter – from an aesthetic and functional point of view.
The soffit boards neatly incorporate the ventilation to the rear of the timber cladding below, whilst also discretely accommodating the ventilation terminals for the MVHR system (Mechanical Ventilation and Heat Recovery), more about that in a later post. The cast metal rainwater goods are robustly supported upon individual timber plates.
A big part of this project has been the joy of working with real craftsmen. The old wooden hoods above the original windows had zinc panels affording a measure of protection; they were broken, brittle and in a generally rotten state. Originally they’d have been fashioned in lead. The new hoods have been traditionally and simply clad in lead, flashed-up behind the larch cladding, seams welded and screws covered with melted lead. The workmanship is lovely and its such a shame craft skills like this are getting harder to find. These will keep the water out!
Almost a year to the day, the scaffolding around the cottage has been gradually removed to reveal the refurbished exterior with its beautiful natural slate roof, repaired chimney stack and the crisp white larch cladding. The rainwater down-pipes still need to be completed, but these must wait for the drains to be connected. The windows also need installing and these are going to wait until the interior work is complete as they can be fitted from within. Everyone involved is chuffed to bits!
The confined nature of the site at 28 Leigh Hill has meant we’ve had to find space to store salvaged wood, materials awaiting use, and a place to do preparatory painting. A pair of vacant shops nearby have proved invaluable for this purpose and without them, we’d have been falling over ourselves at Leigh Hill. Once the the interior wood wool insulation arrived, we virtually filled a shop with the insulation batts.
Leigh Hill Progress 