Skibo castle
DESALINATION TRIAL WITH WESTOX COCOON ON SANDSTONE
Kevin Bannerman | 2018-08
www.westox-nordic.se
A brief history of Skibo castle.
Skibo Castle (Scottish Gaelic: Caisteal Sgìobail) is located to the west of Dornoch in the Highland county of Sutherland, Scotland overlooking the Dornoch Firth. Although largely of the 19th century, and early 20th century, when it was the home of industrialist Andrew Carnegie, its origins go back much earlier.
The first record of Skibo Castle is a charter from 1211. From its early history, the castle was a residence of the Bishops of Caithness. Skibo Castle remained the residence of subsequent bishops until 1545, when the estate was, as a tactical measure by the church, given to John Gray in order to reinforce its alliance with a powerful family as the threat of a Protestant uprising spread towards the north.
It is currently operating as The Carnegie Club, a members-only residential club offering members and their guest’s accommodation in the castle or estate lodges, a private links golf course and a range of activities including clay pigeon shooting, tennis and horse riding.
Skibo castle was built on a foundation of sandstone. Over the centuries the castles sand stone foundation has been exposed to the elements with wetting & drying cycles from lateral & rising moisture, resulting in exfoliation of the sandstone. The caretaker of the castle Mr. Gary Gruber has been in contact with several heritage organizations for example BGS (British Geological Survey) SLCT (Scottish Lime Centre Trust) and HES (Historic Environment Scotland – formerly Historic Scotland) to solve the problem before he got in touch with Westox and Mr. Kevin Bannerman.
After a short survey on the site it was felt that the problem was caused by harmful soluble salts, which was soon confirmed after an analysis of samples taken from the stone, a trial was then arranged to verify if the harmful salts could be removed with a poultice treatment on one of the sandstone blocks.
The product to be used named Westox cocoon originated in Sydney Australia, an invention by Barrie Cooper, the managing director of Westox building products.
Three samples were taken at three different depths to be sent to a laboratory to be analyzed by Ion chromatography. On the following pages the results before and after desalination can be seen.
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E S T O
B U I L D I N G P R O D U C T S W X
ABN.17 001 446 037 16 Frost Road, Campbelltown NSW 2560 Sydney Australia
Tel. +612 4628 5010 Fax +612 4628 5020
Certificate and report of salt analysis
Laboratory Report 7112 7113 7114 Report Date 8/8/2018 Number
The following report contains the percentage weight of cat ions and an ions Analysis shown to the weight of the sample.
Apparatus 761 Compact IC Metrohm
WESTLEGATE PTY LTD - Campbelltown, NSW 2560 Australia Certification Ray Wu chemist B. App. Sc, B. Sc, QA: ISO 9001:2000 LIC6553
Site or project Skibo Castle
Submitted by Kevin Bannerman
RESULTS OF THE ANALYSIS
Sample Sample number Na K Mg Ca Cl NO3 SO4 Total % 0-10mm #1
File of IC net 0.013 0.015 0.014 0.162 - - - 0.204 Total salts 1808081043 present in sample File of IC net - - - - 0.088 0.299 0.309 0.696 1808081419
Total percentage of soluble salts (nd = below detectable limit) 0.900
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Sample Sample number Na K Mg Ca Cl NO3 SO4 Total % 10-20mm #2
File of IC net 0.010 0.012 0.017 0.127 - - - 0.166 Total salts 1808081125 present in sample File of IC net - - - - 0.066 0.138 0.056 0.260 1808081419
Total percentage of soluble salts (nd = below detectable limit) 0.426
Ray Wu. Chemist. B.App Sc. B.Sc.
Sample Sample number Na K Mg Ca Cl NO3 SO4 Total % 20-40mm #3
File of IC net 0.007 0.014 0.011 0.114 - - - 0.146 Total salts 1808081209 present in sample File of IC net - - - - 0.040 0.061 0.033 0.134 1808081653
Total percentage of soluble salts (nd = below detectable limit) 0.280
www.westox-nordic.se The analysis results show high readings of Nitrates and Sulphates a bit over the preferred 0.2 % “safe level” required to prevent further deterioration. The type of salts found is explained later in this report.
The trial commenced with Mr. Bannerman applying the Westox cocoon on the selected area immediately over the area where the initial sampling was carried out.
The cocoon was left on the trial area covered with a temporary shelter to prevent washing off by rain, once dry the temporary covers can be removed. Each application was left for a dwell time of 3 weeks with samples being taken before removal of the first application and again following removal of the second application. All samples were taken within a 50mm radius of the initial drill site. The samples taken were clearly labeled in small plastic bags and sent to the laboratory for analysis.
The results of the second application are displayed on the following pages along with a report explaining the findings based on past experience. The last page is a comment from Mr. Gary Gruber the caretaker of the Skibo castle.
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Applied cocoon on trial area.
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E S T O
W B U I L D I N G P R O D U C T S X
ABN.17 001 446 037 16 Frost Road, Campbelltown NSW 2560 Sydney Australia Tel. +612 4628 5010 Fax +612 4628 5020 Certificate and report of salt analysis
Laboratory Report 7203 7204 7205 7206 Report Date 25/9/2018 Number 7207 7208 7209 7211
The following report contains the percentage weight of cat ions and an ions Analysis shown to the weight of the sample.
Apparatus 761 Compact IC Metrohm
WESTLEGATE PTY LTD - Campbelltown, NSW 2560 Australia Certification Ray Wu chemist B. App. Sc, B. Sc, QA: ISO 9001:2000 LIC6553
Site or project Skibo Castle
Submitted by Kevin Bannerman
RESULTS OF THE ANALYSIS
Sample Sample 10mm Na K Mg Ca Cl NO3 SO4 Total % number Hole 2
File of IC net 0.006 0.006 0.008 0.087 - - - 0.108 Total salts 1809241252 present in File of IC net sample - - - - 0.029 0.072 0.203 0.304 1809241413
Total percentage of soluble salts (nd = below detectable limit) 0.412
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Sample Sample 20mm Na K Mg Ca Cl NO3 SO4 Total % number Hole 2
File of IC net 0.005 0.006 0.009 0.067 - - - 0.087 Total salts 1809240123 present in File of IC net sample - - - - 0.019 0.048 0.064 0.131 1809241618
Total percentage of soluble salts (nd = below detectable limit) 0.218
Sample Sample 40mm Na K Mg Ca Cl NO3 SO4 Total % number Hole 2
File of IC net 0.004 0.007 0.005 0.106 - - - 0.121 Total salts 1809240154 present in File of IC net sample - - - - 0.026 0.072 0.012 0.110 1809241135
Total percentage of soluble salts (nd = below detectable limit) 0.231
Sample Sample 10mm Na K Mg Ca Cl NO3 SO4 Total % number Hole 3
File of IC net 0.004 0.006 0.008 0.102 - - - 0.119 Total salts 1809240225 present in File of IC net sample - - - - 0.029 0.092 0.204 0.325 1809241136
Total percentage of soluble salts (nd = below detectable limit) 0.444
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Sample Sample 20mm Na K Mg Ca Cl NO3 SO4 Total % number Hole 3
File of IC net 0.004 0.007 0.007 0118 - - - 0.136 Total salts 1809240314 present in File of IC net sample - - - - 0.021 0.061 0.066 0.148 1809241137
Total percentage of soluble salts (nd = below detectable limit) 0.284
Sample Sample 40mm Na K Mg Ca Cl NO3 SO4 Total % number Hole 3
File of IC net 0.004 0.007 0.008 0.167 - - - 0.186 Total salts 1809240345 present in File of IC net sample - - - - 0.039 0.074 0.023 0.136 1809241136
Total percentage of soluble salts (nd = below detectable limit) 0.322
Sample Sample Cocoon Na K Mg Ca Cl NO3 SO4 Total % number #1
File of IC net 0.018 0.006 0.007 0.065 - - - 0.096 Total salts 1809240415 present in File of IC net sample - - - - 0.070 0.156 0.381 0.607 1809241133
Total percentage of soluble salts (nd = below detectable limit) 0.703
www.westox-nordic.se Sample Sample Cocoon Na K Mg Ca Cl NO3 SO4 Total % number # 2
File of IC net 0.032 0.006 0.013 0.045 - - - 0.095 Total salts 1809251033 present in File of IC net sample - - - - 0.218 0.474 0.193 0.885 1809241649
Total percentage of soluble salts (nd = below detectable limit) 0.980
Ray Wu. Chemist. B.App Sc. B.Sc.
The analysis shows that the chloride and nitrate contents have been lowered to well below the “safe level” of 0.2% of total an-ion salt by weight, The Sulphates however have only reduced by approximately 30%. It is probable that the sulphates are an integral part of the stone or from the cement joints and as Calcium Sulphate (Gypsum) is only sparingly soluble in water the solubility increases with temperature up to 40 degrees C and then decreases again. Although there has been unusally high temperatures in Scotland during the year it is possible the temperatures did not reach 36 to 40 degrees C which would assist in the removal of sulphates. There has however been a significant transfer of sulphates into the cocoon so the surface of the wall temperatures must have been close to the ideal. It appears there is a slight increase in the samples from test hole 3 compared to test hole 2, although this is not unusual if rain has occured during the test period, we would expect the results from 2 and 3 to be the other way round in stable weather. The total salts in both test holes 2 and 3 are now considered safe, the only depth where the 0.2% of total an-ions in exceeded is at 0 to 10mm, as the content is predomonately sulphate we would expect the deterioration of the stone surface to cease which should be monitored over the next few months to confirm our expectation.
Barrie Cooper. 2nd October 2018.
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Sent: Thu, 6 Dec 2018 at 6:56 Subject: Cocoon.
Kevin,
Thanks so much for you time and workmanship in introducing us to Cocoon and the undoubted benefits it brings.
I have included a quote below for your use, and a picture of the Castle.
“We knew we had high levels of salts within some foundation stones of the castle but we hadn’t been able to quantify this until we engaged Kevin Bannerman and the analysis team. The team undertook detailed analysis of the stone and were able to prescribe a treatment process using Cocoon. We have been hugely impressed with the reduction in salt levels which are now within an acceptable range, limiting further stone deterioration.”
We have been very pleased with the results and while unable to undertake a more expansive programme at this time, I would hope to revisit this in mid-2019 and discuss the possibilities of prioritising areas and implementing a management programme utilising Cocoon.
Once again, many thanks.
Kind regards.
Gary
Estate Director The Carnegie Club Skibo Castle Clashmore Dornoch IV25 3RQ
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WESTOX Cocoon
Manufactured from pharmaceutical grade filter paper. Features a very high internal surface area with high porosity and purity.
USES
A poulticing medium designed specifically to remove salts associated with rising and lateral damp from masonry walls, works especially well on sandstone.
FEATURES
Clean application
Applied by spray or trowel
Easy removal with salts
Cost effective
Low maintenance
No detrimental effect to the masonry
Premixed, no onsite mixing
Made from non-toxic materials
Fast removal of salts
TECHNICAL DATA pH 8+/-.5
S.G 1.1
Flash Point Non flammable
LIMITATIONS
Cocoon should not be applied to external walls if inclement weather is forecast before the material dries, this normally takes approximately four days @ 25°c and two days @ 30°c. If the material is wetted after initial drying, some shrinkage can occur, in this case the loose material should be removed and new Cocoon applied. Do not apply to surfaces that have free or running water present.
PREPARATION
www.westox-nordic.se Sweep the surface of the masonry to remove any loose sand or salts to provide a reasonably sound surface. Dispose of material removed from the surface to an appropriate land fill area.
APPLICATION
Mask and cover areas if spraying. After preparation, apply one coat of Cocoon by trowel or spray at the rate of 6 to 7kg of mixed material per square meter. This will provide a wet film thickness of approximately 10mm. It is preferable that the surface is left with the textured finish to provide a greater surface area. However, troweling the surface flat to provide a more even finish can be done without effecting the poulticing too much. Leave each application for a minimum of 14 days before removal unless directed otherwise by the manufacturer.
REMOVAL
To remove the Cocoon (normally after two to six weeks) simply peel from the substrate and dispose of removed material to an appropriate land fill area.
CLEAN UP
If allowed to dry, the Cocoon will peel off and any residue can be removed with a stiff nylon bristled brush. Flush machinery thoroughly with clean water after spraying.
Click the attached link if you like to see some films and read more about the product.. http://westox-nordic.se/cocoon-en/
Kind regards
For contact:
Jonni Ekdahl Sweden [email protected]
Kevin Bannerman Scotland [email protected]
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