Castle Drogo Restoration
Granite blocks needed to be removed from a National Trust castle without damage or any marks.
Castle Drogo on the edge of Dartmoor in Devon, was the last castle to be built in England. However, of all the hundreds of castles ever built in Britain, this is one that has never had to endure an attack or a siege as it was only completed in 1930.
Castle Drogo, despite its youth, now faces a far more deadly enemy, “the weather”. Its vast roof is leaking, as well as its 900 windows and the pointing between the enormous slabs of granite are letting in water. The National Trust, has launched a campaign to raise the estimated £11 million needed to make the castle watertight. The work is expected to take around 5 years to complete.
In various areas some of the granite ashlars blocks had to be removed so that repairs could be made to make it water tight. The building is protected by a conservation order so none of the visual elements of the stonework can be altered or damaged. Failure to comply with this is classed as an offence!
The contractor commented:- 'When asked to cut out large individual granite ashlars on Castle Drogo at the start of a £6M contract; we decided to carry out some trials. As the Castle is a Grade 1 listed building, we needed to take special care not to touch or mark the stone. The first job was to remove the pointing to a depth of 20mm with hand tools. This exposed the arises and the size of the joints.
The mortar joints were approximately 10 to 12mm wide and between 250 and 400mm deep. A cut was made through the centre of the joint with a 9" angle grinder, taking care not to come into contact with the stone. Next a hammer drills drill was used with masonry bits to stitch drill out the mortar. This process took between 12 & 19 hrs to free the ashlars. It also used approximately 24 drill bits per stone and took a large toll out of both the drill, and the mason.
The next method tried was a diamond chain saw with blades to suit the depth of cut required. EC Hopkins Ltd, the UK master distributors of ICS based in Birmingham, attended site to carry out the trial cut using the ICS 880 Hydraulic Chainsaw, powered by an EC Hopkins 3 phase power pack. The first ashlar was removed in under 30 minutes. The cut was clean, easy to control and fast making it a major improvement over any other method.
As you can see from the photos a cut was made in the mortar joint all around a block (taking care to avoid contact with the block face and the surrounding blocks) it was then finally eased out with a crow bar. The actual cutting time was 25 minutes, compared to the time and method described in the above quote. the contractor, adopted this improved method and the advice and training that EC Hopkins provided, and continued its journey on helping make Castle Drogo water tight again.
ICS 890F4 Hydraulic Diamond Chainsaw
ICS 890F4 diamond chainsaw is the largest saw in the range with the ability to cut upto 63cm deep in concrete, including reinforced concrete, natural stone and thick masonry walls.
The ICS 890F4 diamond chainsaw is the ideal choice for professional concrete cutters, specialist builders and the utility industry. The 890 saw has a quiet, smooth and service free hydraulic motor with a rugged body plus an easy to change drive sprocket, making it engineered to stand up to the toughest of jobs.
Available with different length guidebar and chains to give 25cm, 38cm, 50cm and even upto 63cm depth of cut using the superior Force4 diamond chains or the Crosslink diamond chains with one suitable for every application. Whether it is for modifying lift shafts, altering buildings or cutting concrete sewer culverts the ICS890 and the ICS diamond chains are the best solution for the construction and utility industry.
Give us a call on +44 (0)121 506 6095 or drop us an email to firstname.lastname@example.org
Alternatively you can request a callback below, fill out the form and we'll be in touch as soon as possible.