The Stones of Coupar Angus
Scotland has a long tradition of building with stone and lime stretching back to Roman times. Most of Scotland’s buildings built before 1920 used lime mortars in both construction and finishing. Ordinary Portland cement was only invented in the early 19th century and its use did not become common in Perthshire until the mid 20th century. Unfortunately, it has now become the norm both for new construction and for repairing traditional buildings that were originally built with lime mortar.
Fine Masonry
Beautifully constructed masonry walls can still be seen around Coupar Angus. The picture below shows a section of the YWCA building, a former secession church built in 1826 and Listed as Category B. In the picture you can see some of the original masonry. Notice the fine mortar joints, small pinning stones between the larger masonry blocks and the distinctive pale lime mortar. The grey mortar at the top of the picture is made with cement, not lime, and has been put on as part of more recent maintenance work. Observe how it is already falling off the wall while the lime mortar is still sound. You can also see how the later cement mortar has changed the appearance of the building, covering much of the fine masonry work.
Decay
You may have noticed many walls around Coupar Angus where the stone has eroded leaving mortar joints proud of the surface. A particularly severe example is shown in the picture of a boundary wall in George Street below. See where the stone has eroded up to 50mm back from the surface since the cement mortar was applied.
This decay has happened because the cement is so much stronger and more impermeable than the stone. Decay like this does not occur with lime mortar. Cement pointing and renders can also trap moisture within old walls making buildings cold and damp. Although using cement is often seen as a cheap and easy option, it can cause long term damage that is very expensive to repair.
Grants
The use of lime mortar is a skill that is no longer known by most builders, but both the materials and training courses are available. All stonework repaired with a grant from Coupar Angus Townscape Heritage Initiative must use lime mortar.
Training courses
There is still over £450,000 worth of grant eligible work to be carried out within the THI scheme before 2012. If you are a local builder who wishes to be invited to tender for these projects, you will be required to demonstrate proven experience in using lime or to attend an approved course. The THI have small grants available to local builders to cover some of the costs of attending an approved lime course.
Examples of short courses where you can learn a variety of traditional masonry and plastering skills can be seen on http://www.scotlime.org Our grants are also applicable to other traditional craft skills such as lead work, joinery, slating and many more.
If you would like more information relating to the maintenance of your stone property in Coupar Angus, please contact the Scottish Stone Liaison Group on 01383 872006 or visit their website at www.sslg.co.uk.
An application form to apply for a training grant from the THI can be downloaded here. Otherwise, to apply for a training grant from the THI or for more information on the use of lime, please speak to the THI Project Officer on 01738 475373 or email scarruthers@pkc.co.uk