Recurring dampness on chimney breasts above damp proof course level is not uncommon even after they have been treated and re-plastered. This is probably due to a number of factors including:
– Penetration from falling damp down the flue.
– Penetration from debris/infill present within the chimney breast which remains damp because it is sitting on a damp sub-site and effectively bridges the damp proof course.
– High levels of ammonium or other sulphate salt contamination .
We always advise our clients of the potential problems that may occur and make recommendations that will be effective in controlling the dampness. (ie. just the same as any other defect that “may allow moisture to enter the building fabric”).
For more information on solutions for persistent penetrating dampness, please contact us on 0800 030 4701 or email us.