Common Defects

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Asbestos was widely used as a construction material from the 1930s until the late 1990s when it was finally banned in construction. 

It is a material that was cheap to produce and had excellent resistance to fire and did not deteriorate due to oxidation or ultraviolet light damage. During the immediate post war period in the 1950s, this material was used in a number of different forms and was cheaply mass produced into many common building materials with different asbestos content. 

It was discovered in the late 1950s that asbestos fibres (a natural mineral) are jagged and when the human respiratory system is exposed to these fibres, permanent and irreversible damage is caused to the plural cavity. This leads to lesions and plaques and significant and irreversible damage can be caused to the lungs and in some extreme cases, the early symptoms lead to cancers. 

For this reason, asbestos has to be considered one of the greatest hidden risks to be encountered in a home environment and when discovered, clear advice on removal, regulation, and disposal or management is necessary. 

Asbestos can be present in many forms. 

For example:- 

· Textured wall and ceiling coatings 

· Water tanks and cisterns 

· Pipe lagging and insulation 

· Floro tiles 

· Wall boards and fire stopping 

· Older boiler systems and water heaters 

· Older electrical consumer unit fuse guards

· Gutters, soffit boards, fascia boards, window panels 

· Corrugated sheet roofing 

· Gas fires and gas fires with back boiler installations

Removal and management of asbestos is regulated by the government and asbestos surveyors and removal contractors are required to be licenced.  Disposal of asbestos waste is also licenced, and both the removal and testing can be expensive.  

Often these are the highest and most exposed external elements of a domestic property and will be subject to extremes of temperature, wind, and rain and as most are no longer working chimneys, will bear the legacy of decades of internal exposure to combustion gases and heat from open solid fuel fires. This latter aspect affects the chemistry of the materials used to construct the chimney and there are often reactions between chemicals in the smoke, ash and mortar bricks that lead to defects that are not always visible externally to the untrained eye. 

Chimneys are often also not easily or safely accessible for routine maintenance and are often therefore neglected especially at the intersection of roof and chimney weathering details. 

The orientation and position of flues are safety critical in terms of carbon monoxide poisoning and fire prevention. Changes to regulations have not always been complied with especially in properties where there has been a long-time occupant that is now moving on. 

Cracks and movement to property is fairly common, and has a variety of causes, these can include subsidence, heave, thermal movement, lateral movement and overloading of the structure. 

Subsidence 

Foundations to walls and columns can be affected by localised subsidence of the soil. This leads to the foundation moving downwards and in some cases outwards. The causes of the movement can be as a result of: 

· soil instability

· shrinkage in clay

· washing away of granular materials 

· former mining activities

· water main leaks and other issues. 

The pattern of cracking in such cases is not always consistent and often it is necessary to engage with a structural engineer and soil specialist to dig some trial pits to examine the condition and plasticity of the soils, to determine the cause. 

Heave can also be caused by sudden re-hydration of a shrinkable soil by removal of trees for example. The patterns of cracking as above are not the whole picture, and it is difficult to determine without an engineering approach how the damage is being caused. 

Thermal movement 

Most domestic properties are affected by solar and other temperature loadings. Different materials have different coefficients of thermal expansion. This means that over a range of temperatures, these materials expand and contract at different linear rates. If you place a steel element such as a lintel within a wall, the materials may be heated by solar action and will expand and contract at different rates, hence the materials need an expansion joint to make sure that they don’t interfere with each other. In such cases where poor design and execution has occurred, this can lead to cracking. This is also the case with many wall and ceiling boarded finishes that are poorly detailed or installed and often do not consider the thermal movement of different elements. 

Lateral movement 

The vertical sections of an outside wall can bulge outwards, and this can be an indicator of tie failure in a cavity wall. A cavity wall is made of two skins, usually of brick and block masonry, tied together with a steel tie or in a solid wall where there is no tie to the superstructure of the house internally. 

In terms of a cavity wall, the ties used up to the 1980s were routinely not galvanised or stainless steel and are prone to corrosion and failure. Replacement is an expensive and necessary action in such cases. 

In terms of lateral movement in an older solid wall building, the slenderness ratio of the walls (its ratio of height to thickness) was not widely understood by designers up until around 1900 and some walls will bulge outwards over time, especially if affected by other issues or pathology. In such cases, tie rods are bolted to the timber frame inside the house, and painted metal crosses midway up a wall or a disc, restrains the wall and ties it back to the superstructure. 

Overloading

Often seen on parapet walls where an inappropriate roof covering has been used, it loads the wall outwards and pushes it out of alignment with the vertical plane. 

 Dampness is a common defect found in properties and has a number of causes. 

Rising dampness is something that can happen where a property has no damp proofing design and is often found in much older properties, constructed before this defect was commonly understood, most of these have been retro fitted with a system to reduce the effects of moisture rising from the subsoil and up the brickwork, but these chemically based systems do fail over time due to changes in the chemical properties, deterioration, localised damage or bridging. 

Breaches of a damp proofing system are another common defect caused by poor design or execution of external alterations. 

Leaking gutters and drainpipes are another common defect and allow water to penetrate over time into the external wall surfaces above the protective damp proof course. 

Gutters, downpipes and gulleys need to be regularly inspected and cleared to prevent overflow and leakage. If left without repair, they become ineffective and cause a number of serious issues. 

Underground drainage can connect to a mains sewer or private sewage arrangement. There are new stringent regulations in relation to private sewage provision and cess pits, and should your property have this sort of arrangement, we shall report upon the requirements and compliance as appropriate. 

Underground pipes and chambers need to flow to a fall or invert level and should be free flowing. Displacement of damage to underground pipes is common and some low-cost housing can have pitch fibre pipework from chamber to chamber that is susceptible to failure and blocking. 

  Visible damage can often be seen to brick faced walls and takes many forms such as frost damage, poor mortar details, cracking and bulging, cavity wall-tie failure, render defects, poor detailing of expansion joints, poor detailing of damp proofing systems or non-existent damp proofing, historical construction methods, and non-standard construction systems. 

In the post war period, there was a rush to build new homes using lower cost techniques and prefabricated elements. There was widespread use of such materials in many public housing schemes, that have been bought under a tenants’ right to buy and some of these can be challenging in terms of the long-term performance of the materials used, such as: 

· reinforced concrete (RC) panelling 

· no fines concrete, cross wall construction

· early forms of timber framed prefabrication

· cavity wall-tie failure

· reinforcement failures and the thermal performance of such construction methods. 

Some of these post war properties can be difficult to raise a mortgage against and if offered, lenders can apply higher rates of interests and require larger deposits.  

All gutters should be cleared out regularly and any leaks repaired where necessary to help prevent dampness and damp penetration occurring, which can lead to other problems within the building, such as deterioration of masonry.

Our surveyors detect defects on all  plastic and  metal rainwater fittings which are leaking to some degree and in a lot of cases are corroded, meaning they often require replacement. As mentioned above, leaks can cause significant damage. Replacing fittings with PVC can however detract from the aesthetics of the property, particularly with regard to period property.

Movement in buildings can be caused by downpipes that do not allow water to drain away properly. A high concentration of water in a localised area can cause the soil beneath foundations to erode away leaving the structure of the wall unstable. This is quite common where water butts are used, often for conservatories and they are left to overflow. A conservatory normally has quite shallow foundations that can be easily influenced by movement beneath.

  Masonry paint is often used on older buildings that have been rendered, such as Victorian and Edwardian properties. If it is used on masonry that is likely to remain dry, then this isn’t an issue but any dampness within the building can cause the paint to blister as well as the masonry to perish. It is not always possible to identify the type of paint that has been used, but mineral paint can also be acceptable as this allows the masonry to breathe. However, impervious masonry paint (including that described as ‘microporous’) can cause these issues to occur. If the wrong type of paint has been used, it can sometimes be necessary to remove all the paint, before repainting using mineral paint.

Masonry paint can also be used on stucco or stone dressings and is sometimes directly applied to brickwork and in these places, it can also be an issue. Our reports may recommend further investigation or that advice is obtained from a specialist in either external rendering or external decoration so that it is possible to quantify the cost of any necessary remedial work.

The render itself can also be an issue depending on the type of material that has been used and if problems exist, it may become necessary to remove the render so that the appropriate finish can be applied.

    An earth retaining wall is a structure that holds back earth to a terrace or levelled area. These are supposed to be designed with a factor of safety and are often overlooked in terms of their construction. These can be overloaded, as the design criteria, as set by engineering and building regulations standards, has changed a number of times over the past sixty years. 

Often the only way to stabilise these once failed is to insert sheet pile sections to provide reinforcement. 

Inspection of roof coverings requires an understanding of how the roof has been constructed and the original layout and alteration to the roof are factors that will affect the performance of the coverings over time. 

Not all roof coverings are appropriate, and, in many cases, unsuitable tile coverings can be selected during a refurbishment on the basis of cost that place additional load on a roof framework that was never designed to support the additional load. 

Ridges, hips, valleys, and flashings can be damaged by high winds, poor construction execution and by the failure of materials or by impact with debris. Frost and moss can cause degeneration of the tiles themselves. Nail fixings and damage to battens and underfelt can allow the roof to degenerate more quickly, and careful consideration needs to be given to such cases to ensure that any repair programme is effective and appropriate for the subject property. 

Flat roofing systems can have a limited lifespan, the relative benefits of newer construction materials on such roof formats have changed the profile of maintenance requirements. However, there are all too often, mistakes made in using these newer systems that require careful inspection and appraisal.