It is very common that properties suffer with damp walls and ceilings. Many homeowners accept living with damp or use modern products to try and mask areas without investigating the source of the issue. Unfortunately a damp proof course installation is rarely the answer as this doesn’t prevent water causing the issue, only acting as a temporary barrier.
Damp issues can cause significant problems to the building fabric if not resolved. Damp can also lead to an unhealthy living environment, particularly exacerbating symptoms to people with health issues.
Some of the obvious signs of damp are:
- Walls look unsightly with blotchy black mould
- A musty smell exists
- Rooms can feel cold from the trapped moisture
- Bubbling or peeling paint
Casestudy Example
In our example of a Grade II Listed Hall, a first-floor window was showing clear signs of damp;
- The stone was blackened and starting to crumble.
- The room was cold and had a musty smell. The owner did not want to use it anymore.
- The plaster was cracking with paint bubbling and peeling.
- Water streaks showed upon the glazing.
Our investigation found that;
- The lead capping to the roof section required replacement as was allowing water to ingress
- The window had been pointed both internally and externally with cement mortar. This prevented the moisture transmitting via the mortar, becoming trapped within the stone
- Plaster and paint were also modern which did not create a breathable wall
We re-leaded the roof section to prevent water ingress and repointed the window surround internally and externally. We lime plastered the reveal and finish painted with a breathable lime based paint. This limework created a porous route through the entire wall for the trapped moisture to dissipate without further affecting the masonry. The masonry appeared lighter following water evaporation.
Modern Living
Modern building materials were initially introduced to lessen the requirement of skilled labour and save application time. Unfortunately, it became apparent that these are non-permeable (AKA not breathable). This caused moisture to become trapped in the masonry so the stone or brick could fail, and therefore a risk to the structural integrity of buildings.
Typically, modern building materials include; cement for pointing and/or render, modern plaster, paints. To complicate matters, some modern products claim to be breathable! Although insulation and double glazing can also be beneficial if used correctly.
Our traditional housing stock were built using natural materials that allow the walls to ‘breathe’. This means that the internal heat generated (an open fire for example) would transmit through the wall, driving any moisture outside.
In modern living we expect warm dry properties that seal us into our homes and prevent any natural air flow. Therefore, steam from cooking or hot showers becomes condensation.
We must adapt to living in heritage buildings that were built for a different time period; wear warmer clothes in winter and increase ventilation by opening windows or doors. In other words, we live with an old building and not just in it.
Summary
Buildings are designed to shed water away from the property, so anything that prevents this should be addressed such as:
- Keeping a flat roof, gutters and downpipes clear from debris is a maintenance task that should be performed at least on an annual basis. Any blockages could result in cracks appearing and overflowing of water into the wall.
- Over time, cement hardens and cracks which allows water to penetrate. Mortar is considered to be a weathering course which binds the masonry; it is therefore possible that traditional lime mortar may be worn away from years of exposure to the British weather!
- Whilst Damp meters are available for purchase if you did wish to test suspected damp issues yourself, a professional could assist and assess the cause of the damp. We typically look to the exterior shell of the property for non-breathable products – such as cement – and ways that water can ingress.
- Avoid damp proof courses where possible as these do not prevent water from causing issues.
- Open your windows to allow air to circulate when possible, and wear warm clothing when temperatures are low.
