Chimney Defects in Older Homes: What Buyers Should Know
Chimneys are an important architectural feature of many older homes, but their exposed position means they are particularly vulnerable to deterioration.
A chimney stack can look perfectly sound from ground level while defects are developing around the brickwork, mortar joints, flashing or chimney pots. Left unaddressed, these problems can contribute to water penetration, dampness and deterioration of the surrounding roof structure.
For anyone buying an older property, the condition of the chimney should therefore form an important part of the building survey.
At Delamere Nicolet LLP, our surveyors regularly inspect period and older properties. As part of our Full Building Surveys, we use extendable pole cameras where appropriate to obtain closer views of chimney stacks, roof coverings and other high-level areas that can be difficult to assess from ground level.
Here are some of the chimney defects buyers should be aware of.
Why Are Chimneys Particularly Vulnerable?
Chimney stacks occupy one of the most exposed positions on a building. They are subjected to rain, wind, frost and changes in temperature throughout the year. Unlike much of the external walling, a chimney may also be exposed on several sides at once.
Over time, these conditions can affect brickwork, mortar, flashing and chimney pots. Older chimneys may also have undergone numerous repairs or alterations during the life of the property. Even if the fireplace below is no longer used, the chimney itself remains part of the building and still needs to be maintained.
1. Deteriorated Mortar Joints
One of the most common defects affecting older chimney stacks is deterioration of the mortar between the bricks.
Years of exposure can cause mortar joints to weather and erode. Once joints become significantly deteriorated, they can allow additional moisture into the masonry and may eventually affect the stability of individual bricks.
Repointing may be required, although the appropriate materials and methods should be considered carefully, particularly with historic or traditionally constructed buildings.
Previous inappropriate repairs can sometimes create problems of their own, so the presence of newer pointing does not necessarily mean that no further attention is required.
2. Damaged or Weathered Brickwork
The bricks themselves can also deteriorate.
Moisture entering masonry can contribute to damage, particularly when combined with repeated freezing and thawing. The face of a brick may begin to break away or deteriorate, a process often referred to as spalling.
A small amount of localised deterioration may require relatively straightforward repair. More extensive damage can indicate that the chimney has been exposed to moisture for a prolonged period and may require more substantial work.
3. Defective Chimney Flashing
The junction between a chimney stack and the roof is particularly vulnerable to water penetration.
Flashing is installed around the base of the chimney to form a weather-resistant junction with the roof covering. If it becomes damaged, displaced, poorly installed or deteriorated, rainwater may enter the building.
Internally, this can sometimes appear as staining or dampness around the chimney breast, ceilings or roof timbers.
It is important not to assume that damp around a chimney breast automatically means the flashing has failed. There are several potential causes of chimney-related dampness, and the surrounding construction needs to be considered as a whole.
4. Cracked or Damaged Chimney Pots
Chimney pots are also highly exposed to the elements.
Surveyors may identify cracked, damaged, loose or deteriorating pots. The mortar or flaunching around their bases can also deteriorate.
Because these elements are positioned at the very top of the stack, defects can be extremely difficult for a buyer to see during a normal property viewing.
A loose or unstable chimney pot should be taken seriously because of the potential safety implications if materials become detached.
5. Deteriorated Flaunching
Flaunching is the mortar or similar material around the bases of chimney pots at the top of the chimney stack.
Its purpose includes helping secure the pots and encouraging rainwater to shed away from the chimney.
Over time, flaunching can crack, deteriorate or become loose. Once this happens, water may penetrate into the top of the stack and contribute to further deterioration.
This is another defect that can be almost impossible to assess properly from pavement level.
6. Leaning or Unstable Chimney Stacks
A chimney that appears to be leaning can understandably cause concern.
Some older chimney stacks may have historic movement that has remained unchanged for many years, while others may require further investigation.
A surveyor will consider the visible condition of the chimney alongside factors such as cracking, deterioration and the surrounding building.
Where there are concerns regarding stability or structural movement, further specialist investigation may be recommended.
7. Damp Around Chimney Breasts
Damp staining around a chimney breast is relatively common in older properties, but determining the cause is not always straightforward.
Potential sources can include defective flashing, deteriorated masonry, rain entering through an exposed chimney, condensation or moisture associated with the way a redundant flue has been altered or ventilated.
There can also be staining associated with deposits within an older chimney.
Simply redecorating the affected area may therefore not resolve the underlying issue. The likely source of the moisture needs to be understood first.
8. Redundant and Poorly Ventilated Chimneys
Many older homes retain chimney breasts and stacks even though the original fireplaces are no longer used.
Problems can arise when redundant fireplaces or flues have been sealed without adequate consideration of ventilation and moisture.
A disused chimney does not necessarily need to be removed, but alterations should be appropriate for the construction of the building.
Where fireplaces have been blocked, a surveyor may look for associated signs of dampness, condensation or inadequate ventilation.
9. Removed Chimney Breasts and Structural Alterations
Sometimes a chimney breast has been removed internally while part of the chimney structure remains above.
This is an important issue for buyers because remaining masonry needs appropriate structural support.
During a survey, visible evidence of chimney removal or alteration may therefore warrant closer consideration. Where necessary, further investigation may be recommended.
Buyers should also ask their legal adviser to investigate relevant approvals and documentation relating to significant structural alterations.
10. Vegetation Growing From Chimneys
Plants growing from a chimney stack may look relatively harmless, but vegetation can indicate that maintenance has been neglected.
Roots can establish themselves within deteriorated mortar joints and may contribute to further damage as they grow.
Vegetation can also be an indication that moisture and debris have accumulated in areas where they should not.
Removal may therefore need to be accompanied by repairs to the underlying masonry rather than simply cutting the plant away.
11. Previous Chimney Repairs
Older chimney stacks often show evidence of previous repairs.
This is not necessarily a concern. Regular maintenance is part of owning an older property, and appropriate repairs can extend the life of the structure.
However, repeated patch repairs, mismatched bricks, deteriorating pointing or poorly executed flashing can indicate that previous work has not fully addressed the underlying problem.
A surveyor will consider repairs in the context of the chimney’s overall condition.
Why Chimney Defects Can Be Expensive
One of the difficulties with chimney repairs is access.
A relatively small area of defective pointing might sound like a minor job, but contractors may require scaffolding or specialist access equipment to carry out the work safely.
This means the cost of accessing the chimney can sometimes represent a significant proportion of the overall repair bill.
If several roof-level defects need attention, it may be practical to coordinate repairs to the chimney, roof coverings, gutters and flashing while appropriate access is in place.
For a prospective buyer, identifying these issues before purchasing can help provide a more realistic understanding of future maintenance requirements.
Getting a Closer Look at Chimneys With Pole Cameras
The height and position of chimney stacks can make them particularly difficult to inspect from ground level.
A pair of binoculars can provide useful information, but some defects require a closer view.
As part of our Full Building Surveys, Delamere Nicolet LLP uses extendable pole cameras where appropriate. This allows our surveyors to obtain closer images of high-level elements while remaining at ground level.
Depending on the configuration and accessibility of the property, a pole camera can help provide clearer views of:
- chimney pots and flaunching;
- brickwork and mortar joints;
- lead or other flashing around the chimney;
- areas of visible cracking or deterioration;
- vegetation and debris;
- adjoining roof coverings; and
- evidence of previous repairs.
This additional perspective can be particularly useful when surveying older properties with tall or complex chimney stacks.
Why We Don’t Always Rely on Drones
Drones can be useful surveying tools, particularly for certain large, complex or inaccessible buildings. However, they are not necessarily the most practical option for every residential survey.
Weather can restrict drone use, particularly in unsuitable wind or rain. Residential surroundings can also present additional considerations because of neighbouring buildings, gardens, trees and other obstacles.
There is also the potential for noise and unnecessary disruption to neighbours. A camera-equipped drone operating above or close to neighbouring homes can attract attention and may raise understandable privacy concerns.
Drone operations also have to be carried out in accordance with the relevant rules and restrictions.
For many residential properties, an extendable pole camera provides a quieter, less intrusive and highly practical method of obtaining closer views of a chimney stack. It allows the surveyor to concentrate the camera on specific areas of concern without an aircraft operating above the property and surrounding gardens.
There will always be situations where a drone or another inspection method is more appropriate. The important point is to select an inspection method that suits the particular building and circumstances.
A Chimney Is More Than What You Can See From the Street
When viewing a property, buyers often see little more than the outline of the chimney above the roof. A building survey considers much more.
The external condition of the stack can be assessed alongside visible evidence within the roof space and property. Damp staining, alterations to chimney breasts, ventilation arrangements and evidence of previous leaks can all contribute to a better understanding of the chimney’s condition.
Technology such as our extendable pole cameras supports this process, but photographs alone do not replace professional judgement. The findings need to be interpreted in the context of the building’s age, construction and overall condition.
Buying an Older Property? Speak to Delamere Nicolet LLP
Chimneys are an important part of many older and period homes, but their exposed location means defects can develop without being obvious to a prospective buyer.
From deteriorated pointing and damaged flashing to dampness, unstable chimney pots and previous structural alterations, identifying potential problems before purchasing can help you understand the maintenance and repair liabilities you may be taking on.
At Delamere Nicolet LLP, our surveyors have experience inspecting older properties and identifying defects that may require attention or further investigation.
As part of our Full Building Surveys, we use extendable pole cameras where appropriate to obtain closer views of chimney stacks, roofs and other difficult-to-view high-level areas, helping us provide buyers with a more informed assessment of the property they are considering.
If you are buying an older or period property, contact Delamere Nicolet LLP to discuss our Full Building Survey service.
This article is intended for general information only. Chimney construction, condition and accessibility vary between properties. Inspection methods are subject to access, weather, site conditions and safety considerations, and further specialist investigation may be recommended where appropriate.