Past Projects: Dover’s Grand Shaft

The Dover’s Grand Shaft and the greater Western Heights of Dover are considered as some of the most remarkable fortifications in Britain. This earthwork encompasses a series of strong points, forts as well as ditches made to secure the country from attack. They were made to improve the standing defences and secure the major port of Dover from landward and seaward attack. Dover Grand Shaft is now a Local Nature Reserve.

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Photo courtesy of Heritage Open Days

The History
The Dover’s Grand Shaft was made by General Twiss, a military engineer. It was constructed in the 1st decade of the nineteenth century. This structure takes the system of a tripe helix staircase, offering 3 sets of steps in similar shaft with a principal light well. It has a 140-feet deep shaft that caters pedestrian access to the fortress, especially the Grand Shaft Barracks, from the street of Snargate at the end of the cliffs. There is a tunnel that leads from the base of the shaft to a security room. The 3 sets of stairs confined in the shaft, according to research, are committed for Offices and their wives or ladies, soldiers and their girls and Sargent’s and their partners, but the main reason is to deploy lots of troops in time of an invasion. The barracks were demolished in year 1960 and the channel fell into a tumble-down state. In year 1990, the channel was restored, with new guard spaces built at the base.

Drop Redoubt
This is one of the two fortresses on Dover Grand Shaft and is associated with the Citadel by a sequence of lines or dry moats. Arguably, it is the most striking and immediately evident feature of this structure.
The weaponry at this fort faced generally inland. This is because it was planned to bout an invading force trying to invade Dover at the back. The creation of this fort was in 2 periods – from year 1804 to tear 1808 and from year 1859 to 1864.

Armaments
Initially, the fort of Redoubt was to be armed with twelve smooth bore twenty-four pounder firearms and 2 carronades. On the other hand, it is not likely that a lot were setup since the Napoleonic war was virtually done by the time the construction was finished. In year 1851, just 3 of 24 pounders were setup, 8’ mortar and 12-pounde saluting firearms.
Following the 2nd period, 11 Armstrong 64-pounders rifled were setup on crossing carriages.

Redec Conservation Works
Redec was employed to undertake full repairs to the interior of the shaft and stairs, including: installing a full birdcage scaffold that had 8 platforms along he shaft, rewiring the consumer unit and installing an updated lighting system, lime repairs and limewash decoration throughout.

Today
At this point in time, the place is open for everyone. The barracks are demolished and the Citadel is now turned into Dover Immigration Removal Centre.
The Grand Shaft curved staircase is under the control of the council and is opened yearly by the WHPS or Western Heights Preservation Society.

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Photo courtesy of derelictplaces.co.uk

Even though it is preserved by Dover Council, the Dover Grand Shaft remains under the supervision of WPHS, which opens it to the public during specially organised heritage days. On the other hand, the barracks are open every day and you can visit the site anytime you want (these are operated by English Heritage).

A blog by marketing assistant Jen

Past Projects: South Foreland Lighthouse, Dover

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Photo courtesy of The National Trust

Located on the South Foreland in St. Margaret’s Bay, Dover, the South Foreland Lighthouse stands serene talking of the great Victorian Age that has lived by. It was used for warning ships that approached the Goodwin Sands nearby and earlier managed by the Knott family. Currently the lighthouse is under the care of National Trust after it went out of service in the year 1988.

In 1859, South Foreland Lighthouse became the first lighthouse to be run with the help of electricity. With advancement in technology by the year 1875, the lighthouse was able to use lamps made of carbon arc. It is a famous site in England for it has seen several scientific breakthroughs including the famous Guglielmo Marconi wireless experiments.

The lighthouse received the first ship to shore transmission through radio which was sent as a test message from the East Goodwin lightship and the first ship to shore signal of distress. South Foreland Lighthouse was also the first to receive an international radio transmission and it occurred when a signal arrived from Wimereux, in France in the year 1899.

There was another lighthouse originally further down the edge of the cliff to provide bearing on the leading lights. Both the lighthouses were built in the 1840s but the bearing became inaccurate since the Sands shifted as time passed. The lower light had to be taken out of service in the year 1910. Though the lighthouse remains as a part of the private garden, it is under constant threat from cliff erosion.

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Photo Courtesy of Wiki

It is not certain as to why both the lighthouses were constructed. It is argued the leading lights theory is not convincing as it would not lead a ship to safe passage by turning to port upon lining up the two lights unless the navigator accurately knows how far the ship was from land. Another argument which is considerably stronger says that the ships approaching from the north may line up the lights to know when it was safe to turn in for the Dover Harbor. Still, all the arguments including many others remain uncertain.

The lighthouse marks the advancement of technology during the Victorian era and also serves as a milestone to mark the breakthrough of many scientific discoveries.  Visitors can reach the lighthouse by walking through a footpath for one mile from St. Margaret’s village. It also has an optional path which is an approximately fifty minute walk from the White Cliffs Visitor Center. Many take the latter option as it takes you along the crest of the popular White Cliffs of Dover. Upon arrival, there is the main shaft to explore with views of France (on a good day!), a holiday cottage, a tea shop and gift shop.

Redec was employed by the Trust to undertake a full conservation refurbishment and redecoration, this included: fully designed scaffolding, brickworks, lime render repairs, chimney pot repairs, removal of decayed paints, window repairs, general making good, new lightening protection, roof members, glazing, fencing and joinery repairs.

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A blog by marketing assistant Jen.

Insulating a local landmark…

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A beautiful example of vernacular Kentish architecture as influenced by the popular Dutch style originating from the 19th Century

Our small works team recently undertook the refurbishment of a Dutch-gabled Victorian gatehouse which is within the curtilage of a large country house near Ashford.  The property was in a state of dilapidation that had been expedited from historic condensation and previous poor workmanship.

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The main country house and grounds upon which the gatehouse is located within, photo: Kent Guides (c).

 

The aim of the project was to refurbish the building to a habitable state and to finally sort out the condensation issue once and for all.  The process proposed was to use an insulating wood fibre system but to install this via the internal faces of the building rather than the typical external faces method.  The internal face of the walls were lined with (the SPAB approved) ‘Warmshell Interior’ system of wood fibre by Lime Green.  After fixing, the boards were finished with a lime plaster to suit. ‘Warmshell Interior’ is a practical solution when fitting insulation to the outside of property cannot be achieved.  In this case, the building is apart of a country house’s estate and is therefore apart of the listing and also within a conservation area.  Due to this status we cannot alter or adapt the outside of the property, it wouldn’t be practical or in keeping with the architectural style of the building – therefore an internal system would have to be employed.

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The insulation panels are installed

Both internal and external insulation methods have their challenges, and this was no exception.  Inside we had to move all sockets, switches, pipes, radiators, partitions and door frames plus building supports for the new insulation panels, along with all the necessary making good and conservation to the existing structural timbers.  It became a large undertaking but the final result was well worth it.

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Redec Plasterer Mark gives the walls a final skim of lime plaster

Once all wall fixings and furnishings are moved or temporary disconnected, the Warmshell insulation boards are secured to the internal wall faces.  The insulation boards are cut to size and fixed into position (cables for sockets and light switches may need to be extended through the insulation, though this isn’t always necessary).  The wall insulation is plastered with lime and then decorated with a suitable breathable paint such as clay based or a limewash.  This whole system of insulation uses natural lime plasters, paints and wood fibre boards which allow the walls to breathe – which should overtime cure any condensation issues and work in tandem with the original historic fabric of the house.

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Redec Mason Len works to conserve the porch

The works also included installation of a new kitchen and bathroom, conservation repairs to windows and structural timbers, lime repointing and brickwork repairs throughout, sheep wool insulation to the loft, a full re-wire, installation of a complete new bay window, roof repairs, glazing replacements, redecoration and renewal of all floor coverings.  The works were supervised by Conker Conservation and approved by Ashford Borough Council’s Conservation Officer.

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A newly penny-pointed lime mortar wall – can’t see the difference between the new and the old pointing?  That’s the Redec quality difference right there!

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The finished project

You need to have the knack when you knap a gallet…

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A small section in progress

 

Our stone masonry section within Redec maybe one of the smallest departments but it is definitely one of the busiest. Running all over the South East of England working on Castles, Stately Homes and Grand Estates, undertaking larger projects such as our recent successful refurbishment to Walmer Castle to small sites where only a small amount of consolidation or repair may be required, they are true #heritageheroes.
One such project this summer included a huge amount of lime repointing to a galleted rubble-core stone wall. The process of galleting required gallets (or prepared flint flakes) to be placed within the mortar beds to act as spacers/protectors throughout the stonework, they are often dressed into the mortar in decorative patterns with their quality and sizing being very important to the beds they are installed in. It is always important to retain and conserve the original gallets as much as possible, however when further gallets are required the flints must be prepared onsite by means of knapping to match the missing or damaged gallets within the walling that you need to repair.

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Before and after to a lintel section

Knapping can be carried out in a variety of methods depending on the purpose of the final flakes. For stone tools and flintlock strikers, chert is worked using a fabricator such as a hammerstone to remove linear flakes from the core of the fint. The process is a little haphazard, so it has to be undertaken over and over to produce enough gallets to undertake the works at hand. Flakes can then be further refined using wood, bone, and slicer tools to perform pressure flaking to create the finer gallets. Once the process is completed (often by the junior member of staff), the gallets are handed to the senior mason who works out a plan based on the quality and sizing to install the best gallets into the prepared walling.

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A bucket of gallets, next to a bucket of prepared NH lime mortar

The knapping process can be very painstaking but great attention to detail must be taken to avoid accidents, as such full PPE should always be provided. Selecting an open space, away from human or vehicular traffic is always best and despite being out in the open air, full dust masks should be provided that has been fully face-fitted (which is now a HSE requirement).
Proceeding on this basis will ensure your stone walling is conserved to a high standard.

Redec Partners with Kent County Council

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County Hall Maidstone where the Framework contract was signed this week

We are delighted to announce that Redec has been appointed onto the prestigious new KCC Principal Contractors Framework. Securing a place under Lot 1 for projects from £1 to £750,000 with a projected contractual spend of £90m on either a design and build or construct only basis. The ethos of the new Contractors Framework will be to provide the highest degree of professionalism in the way that Kent County Council projects are delivered and to create a dependable list of local contractors to drive the county’s big plans forward from 2016 onwards.

 

The framework will last for 5 years and will include increased apprenticeships and training, community benefits such as local purchasing, the use of BIM, increased engagement of local SMEs and reduction in construction waste being sent to landfill.  KCC being the largest property owning body in the South will engage the select contractors from this new framework for all works to schools, colleges, offices, pupil referral units, care homes, waste disposal sites and transportation within the county with other buying authorities able to join the list from next year.

 

Redec Director Chris said, “This is a fantastic opportunity for both the County and our Company.  It is something that I personally have been working on for over 2 years now, and I cannot wait for it to commence.  Working closely alongside 19 other organisations in a spirit of collaboration will ensure the property portfolio of Kent will be in safe hands for years to come.”

Colouring a Castle…

Walmer Castle & Gardens

Walmer Castle & Gardens

This week our Supervising Decoration Conservator Roger talks about how he and his team worked with English Heritage to match the colours of Walmer Castle during our recent contract as main contractor to conserve and refurbish this beloved castle…

Colour is very important at Walmer Castle. The castle has a vast array of colours throughout the property, which have been sympathetically updated from each custodian to the next. Though colours and finishes have altered through the years the main stalwart of the castle is the use of “Walmer Blue”. The colour, which is unique to Walmer was exceedingly difficult to colour match.

Various samples sent off for analysis

Various samples sent off for analysis

It was only in the middle of the last century that paints became industrialised for use. Popping down to your local hardware shop to purchase a tin of paint was not an option, so most people would engage an experienced decorator who mix the paint onsite (or at their yard) for the specific site they were working on.
It is also true that some large estates have interesting stories when it comes to the origin of ‘their’ colour; one such nearby example is Knole House in Sevenoaks (a National Trust property which Redec has also worked on), where the “Knole Blue” was a mixture of many leftover paints to form a ‘bluey-black’ colour that is seen throughout not only the house and grounds but also along Sevenoaks High Street. The likely origin of the Walmer Blue is likely a composite of colours used to satisfy the requirements of the then insitu Lord Warden and their family.

A decoration conservator's tool box

A decoration conservator’s tool box

The walls and panelling have been redecorated several times over the centuries with each coloration being slightly different from the last. Past redecorations were likely undertaken by the The Ministry of Works (1943 – 1970) and the Property Services Agency (1970-1996) whom would have likely used experienced decorators to match up the distinctive colour by eye; evidence of historic touching-up to the woodwork was evident in the corridor and rotunda.
For the 2015 refurbishment we decided to undertake a mix of modern and traditional techniques to discover the true makeup of the Walmer Blue. Initially it was within the project to match up the colours using Redec’s paint conservator and only touch-in the worst affected areas of damage to the corridor only. It was quickly decided that for the budget of undertaking this, we could match-up the colour and then redecorate the whole corridor rather than selecting just a few isolated areas.

A Redec Decoration Conservator applies the final touches

A Redec Decoration Conservator applies the final touches

Upon receiving this crucial decision, a call was made to leading UK colour expert Patrick Baty of London’s Papers & Paints Ltd. Patrick was briefed about the colour and requested samples of the paint work in various different locations were sent to his London office for analysis. In keeping with the past redecorations, the specification called for an oil-based eggshell to be used, which added time to the diagnosis of the colour due to the fact that oil-eggshell takes far longer to dry than a modern water-based paints. Initially the samples were placed under a microscope to see the composition of the paint. The samples’ stratigraphy (layers) and composition were all detailed and surveyed, these showed that the corridor area had received over 8 redecorations in the lifetime of the panels within the corridor, which were believed to date back to the 18th Century.
After which, using a variety of dark bases in this finish P&P crafted various samples daily to match the colour using the colour spectrum of the Munsell colour range, which is one of the widest colour ranges in the world. Daily updates were provided to English Heritage by onsite visits by our project manager (Chris) until finally the colour was identical to the samples received.
The big day came when on 16th December my team and I (as Supervising Decoration Conservator) received the paint matched to Patrick’s exacting formula from English Heritage’s preferred paint supplier ‘The Little Green Paint Company’. Quickly it became apparent that the colour had been matched absolutely perfectly. So well in fact that once areas had dried in the upper corridor, it was hard to tell where the new paint started and the old paint continued, other than the fact that the old paint was more worn from people traffic – on colouration alone they were identical!

The works have returned the drama to the central rotunda of the main corridor.  Photo copyright (c) English Heritage

The works have returned the drama to the central rotunda of the main corridor. Photo copyright (c) English Heritage

Though colouration of Walmer Castle’s interiors were only a small part of our works onsite, it goes to show that the devil is always in the detail and nowhere is this more important than when you are tasked with conserving such an important building like this.

Walmer Castle is now open following our works with English Heritage to conserve and refurbish the main building, please see their website for opening times and prices: http://www.english-heritage.org.uk/visit/places/walmer-castle-and-gardens/

Walmer Castle Stone Works

This week we hear from our Stonemason Foreman Paul, who recently worked for REDEC’s busy Refurbishment department on Walmer Castle near Deal in Kent…

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Scaffolding carefully going up to the problem areas.

During the works a number of leaks were found, these were traced back to two different windows. It was found that a combination of issues had caused the leaks; a box gutter that was getting overwhelmed during heavy rain and historic stone repairs that had been undertaken by the former keeper of the castle, the Ministry of Works.

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The Architect first inspecting the in situ mortar quality

As you can see in the photo a number of stones had been repointed in a cementitious mortar. This form of mortar would have been relatively new to the market during the early to mid-20th Century and the dangers of using such mortar was not known at the time. The mortar dries far harder than lime mortar (which should be used), it prevents nature moisture from leaving the stones, which leads to frost damage and cracking and its removal can also damage the in situ stones.
The other main issue with the cementitious mortar at Walmer is that it is not decoratively consistent. The original pointing was ‘galleted’, which calls for locally collected flints to be ‘knapped’ (cut into shards) and placed decoratively into the mortar beds. The ‘gallets’ are then stacked and cut to match the size of each respective stone in a decorative fashion. Part of our project here was to remove the faulty cementitious mortar, replace with a lime mortar (colour matched using ash and clay) and then ‘gallet’ throughout to match the mason’s patterns dating back to when the castle was originally built in the Tudor era.

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Various photos showing the process at hand. Our excellent stonemason Rob is working around the lead hopper in the last photo.

The first task in repointing stonework is to accurately (to as far as reasonably possible) test what the makeup of the in situ mortar actually is. Sandberg LLP was appointed to test the mortar; they found that the mix used originally was a 1:1 mix of non-hydraulic lime and local sand. A similar mix was used, along with some fired ash and a hint of clay to colour the mortar to match the patina of the in situ mortar. Our stone masons used sand procured from a local supplier in Dover and added small quantities of the original mix back into the new mixes.

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Our top notch stonemason Gary working hard to carefully remove the cementitious mortar

We then carefully removed the modern cementitious mortar, which luckily had not damaged the stones too much. Once the mortar had been mixed and the colour/finish approved by English Heritage and the Architect, the next task was to ‘knap’ the locally sourced flints to replicate the Tudor gallets. Knapping can take a considerable amount of time and can be very dangerous; fortunately our stonemasons are highly skilled for such tasks.
The finish as you can see below shows how well we matched the existing stonework and helped conserve this important scheduled ancient monument.

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Paul our excellent stonemason had been with REDEC for over 9 years and first undertook his apprenticeship working on Westminster Cathedral some 30 years ago.