We have a profesional masonary team working on various stonework projects.
Key areas of work include,
Pointing repairs - Many houses have stone on which previous builders have used cement to repair pointing on the walls. This is actually the incorrect repair and only leeds to further damage to the existing stone. Stone walls require lime based mortar pointing to allow release of moisture and as such the existing cement pointing needs cut out and replaced with lime based mortar. Please find below additional details on lime based mortar pointing to help explain further the process and additionally the importance for repairing walls which have had cement based mortar added in previous repairs.
Stone repairs – Replacement of damaged stone and repair of damaged stone using Lithomex. Lithomex is a specially formulated lime based stone repair mortar designed for use on natural stone and period brickwork. It is pre coloured and from a sample can be matched specifically to match the host stonework. Once applied it can be dressed or carved to match the existing stone finish.
Lime Pointing Repairs Information
Traditional mass-masonry wall construction (which includes most walls built before 1919) works on the basis that moisture entering a wall is able to escape as water and water vapour as easily as possible. Lime mortars can readily handle the transmission of water and water vapour between the inside and outside of a masonry wall, owing to the complex interconnected pore structure of masonry.
The use of cement mortars is widely recognised as being detrimental to such buildings and structures as they can drastically alter the way in which a wall handles water and water vapour. Cement mortars tend to have a consistent and 'closed' pore structure that traps water rather than allowing the building to breathe (not necessarily a problem in modern cavity wall construction). Any trapped moisture will expand if subjected to freezing conditions, and mortars may ultimately fail, often causing damage to the surrounding masonry in the process.
Masonry walls need to be maintained and repaired, just as roofs and rainwater goods do. Where walls are solid, without a cavity, keeping them in good repair is necessary for the interior to remain functional and dry. Pointing is the most common repair, and often one of the most poorly executed.
The two main reasons for lime-pointing repairs are:
The masonry has been re-pointed with a cement-based (or other inappropriate) mortar at an earlier date, which is causing problems to the building and/or the adjacent masonry and must be replaced with a more appropriate mortar.
The original lime pointing has decayed over time and needs to be replaced. This may be the result of gradual decay through weathering, or failure as a result of poor maintenance. Blocked gutters or overflow pipes, for example, lead to damp masonry and can result in frost damage.
As stone is a natural material it has a grain similar to wood and if it has been built with this grain running incorrectly it is more susceptible to the elements and can cause an accelerated deterioration. Previous repairs to actual stone that have been cement based will have the same effect as the cement based pointing. And where areas have been cracked, chipped or scratched are all good candidates for lithomex stone repair.
Please note any stone left with cement repairs will only deteriorate and result in further damage and additional costs to repair if left unattended.