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The Repair and Care of
Heritage Stone Walls

This page has been produced as a bilingual leaflet which you can download by clicking on the image.

The Town walls of Pembroke provide security, shelter and privacy.  Nevertheless, proper repair and care is vital to ensure the historical evidence they contain is not lost or inadvertently destroyed.

These walls are bound together using a mortar mix made of a binding agent of lime with an aggregate. Crucially this is softer and more porous than the masonry to allow any moisture absorbed into the wall to be released out.  This prolongs the life of the masonry as the mortar fails first and can be more easily repaired and repointed.


Observe your walls:

Regularly check and photograph the wall looking out for:

  • Condition of mortar joints, stone and failing capping stones.

  • Crumbling faces or mortar failure

  • Cracking or bulging.


If concerns are raised, then seek advice from


What should I do if my wall is missing cappings, masonry is failing, or the pointing is missing or crumbling?

Seek advice on undertaking repairs, only where necessary, by a qualified person.  SPAB make it very clear that unsatisfactory repointing cannot only be visually disturbing, but harmful to the actual fabric it is intended to protect.


What should I do if my wall is bulging or leaning?

Talk to the Pembroke Town Wall Trust.  A structure may need to be monitored by a structural engineer experienced in conservation to finally establish whether or not it is moving.


Should a wall be cleaned?

Surface cleaning can cause considerable damage, accelerated decay and the loss of historical evidence such as graffiti or the remnants of a previous structure built against the wall. Surface cleaning is typically only considered suitable if the integrity of the wall is threatened by surface growth.


Should ivy be cleared?

The removal of ivy from historic structures is a hotly debated subject.  As with most conservation challenges there is no simple yes or no answer.  A recent English Heritage study provided the following clear management recommendations – Ivy can perform a bio-protective role so:

  • Don’t just remove ivy ‘because it’s there’ – take a close look at any ivy covered structure to see if the ivy is actually doing any damage. Clear a trial section if necessary.

  • Be sure that any removal for structural or presentational reasons is justified.

  • Ensure removal is not going to make things worse by exposing fragile fabric to the elements.

  • If the ivy is actually rooted into the wall, rather than the ground at the bottom, removal is always the best option.  Ivy is not a tree, but be under no illusion, its stems can reach the proportions of a small tree.”


If ivy removal is deemed necessary:

  • Only remove an Ivy canopy out of the bird nesting season – nesting is from  March to end of August.

  • Remove a trial section to find the best method and to see if any damage to the wall is likely.

  • Bear in mind that the youngest stems (usually near the top) are the most difficult to remove, older stems are often only very lightly attached.

  • If money is not available for the whole job, start at the top and work down – cutting back in this way will cause the ivy to re-grow at the cut level, but does not encourage rooting into the wall.

  • If stability of sections of wall are of concern, cutting back the arboreal growth to near the main stem will greatly reduce the ‘windsail’ effect.

  • Never cut at the bottom and leave to die. This is likely to cause the ivy to try to root into a wall.  


A word of caution:

Please note that Listed Building Consent is required for all works of demolition, alteration or extension to a listed building that affect its character as a building of special architectural or historic interest. This may include works to attached and curtilage structures. If there is any doubt over whether the works require LBC, please contact the local conservation officer first and ensure that a written response is received and retained.

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