lime

Insulating a local landmark…
IMG_7834

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.

goddinton_house_ashford

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.

IMG_9186

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.

IMG_9179

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.

IMG_6115

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.

IMG_6208.JPG

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!

IMG_7832

The finished project

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…

walmer 3

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.

walmer 4

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.

walmer castle

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.

walmer

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.

walmer castle

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.