This property in Bournemouth was suffering from penetrating damp caused by multiple external defects, including failed sealant, damaged mortar joints and a faulty downpipe allowing water to enter the property during periods of heavy rain.
Because this side of the property is south facing, it receives significant exposure to driving rain throughout the year, making any weaknesses in the external protection far more noticeable.
After carrying out a full damp investigation, our team identified the moisture entry points and completed remedial works internally and externally to stop the issue long term.
Investigating the Cause of the Damp
Once the affected wall was opened up internally, moisture damage could clearly be seen around the masonry and surrounding areas.
We discovered:
• Failed and loose external sealant around the window area
• Deteriorated mortar joints allowing water ingress
• A leaking downpipe connection
• Moisture penetration through exposed masonry
• Damp affected plaster internally
These combined issues allowed rainwater to track into the wall structure over time.
Internal Damp Proofing & Membrane Installation
To protect the internal wall from further moisture ingress, we installed a cavity drain membrane system before boarding and preparing the wall for plastering.
Works included:
• Removing damaged plaster and materials
• Installing damp proof membrane protection
• Boarding affected wall sections
• Preparing surfaces for replastering
• Allowing the wall to dry correctly
This system helps manage residual moisture while creating a dry internal finish ready for decoration.
External Repairs to Stop Water Ingress
External repairs were also completed to prevent further penetrating damp issues.
This included:
• Resealing around window areas
• Repairing mortar defects
• Addressing failed sealant gaps
• Repairing the faulty downpipe connection
• Improving weather protection around exposed areas
These repairs help stop driving rain entering the property during poor weather conditions.
What Causes Penetrating Damp?
Penetrating damp is commonly caused by external defects that allow water to enter the building fabric.
Common causes include:
• Failed pointing or mortar
• Cracked render
• Loose sealant around windows and doors
• Faulty guttering and downpipes
• Damaged brickwork
• Poor drainage around the property
If left untreated, penetrating damp can lead to mould growth, damaged plaster, cold walls and ongoing moisture issues internally.
