Excessive moisture is the single largest cause of deterioration to buildings. At best it can be a nuisance and make a room feel cold, unwelcoming and unhealthy. At worst it can indicate structural issues with the property and new studies warn that it is detrimental to health. Damp is caused by an excess of moisture and it is essential that excessive moisture is prevented or eliminated from areas intended to be dry.
Damp is often referred to as ‘rising damp’ or ‘penetrating damp’ but there are many causes of damp in a property that your surveyor will be looking for.
Some of these are listed below but these are by no means exhaustive:
- Poor construction
- Broken or blocked gutters
- Cavity wall insulation, particularly when retro-fitted (injected)
- Damaged bricks
- Damaged damp proof course (DPC) or lack of damp proof course
- Cracks in walls
- Cracks around windows and door frames
- Leaking pipes
- Lack of sealant around bathroom fittings
- Missing, cracked and broken roof tiles
As well as identifying areas in the property affected by damp, using an electronic moisture meter, the surveyor will also look to identify the cause of any damp in the property you are buying. By identifying the cause we can recommend the necessary action to take to deal with the damp and prevent it reoccurring.
It can be worrying when you see cracks in a property, but a crack doesn’t always mean there is a structural problem. Some cracks naturally occur and over time most properties are likely to develop them.
For example, hairline cracks of less than about 0.1 mm are classed as negligible and fine cracks up to 1mm can be repaired easily with normal decoration.
However, larger cracks need to be investigated as not only can they impair the weather tightness of the building, they can also be a sign of something much more sinister requiring major repair works.
So what causes cracking?
Your surveyor will inspect any cracks found in the property and will try to identify the cause, what they mean and what type of repair may be necessary. If at the time of the inspection it is not possible to identify the extent or cause of the crack, further investigation may be recommended with a Structural Engineers report.
The list of possible causes below is by no means an exhaustive, but only outlines a few common issues that can cause serious structural movement.
Subsidence can cause serious structural damage to a property.
It is a very specific issue that occurs when the ground under your house collapses, or sinks lower, taking some of the building’s foundations with it. This puts a strain on your home’s structure as one side sinks, causing cracks to appear
Associated with the settling, or initial bedding in of the foundations of the structure, often the result of soil shrinkage or poor foundations.
In contrast to subsidence or settlement, heave occurs where excess water becomes present in the soils beneath a property, causing it to lift, or ‘heave’.
Drains running near or directly beneath a structure can be a problem if they suffer damage.
Depending on the soil type, water leaking out of a broken drain can cause the supporting ground to be washed away.
This cracking is commonly caused by the expansion and contraction of construction materials. Limited movement of this nature is normal but should be monitored to ensure it does not become progressive.
Trees growing close to a property can cause movement through disturbances caused by root growth.
Where cracking is evident at a property your surveyor will try to identify its cause during the inspection and determine whether it is historic, so not likely to change, or current meaning the problem could become worse.
However, if the surveyor is unable to identify the cause or nature of the crack, they may decide that further specialist advice is required and will recommend that a structural engineer is employed. A structural engineer would proceed to recommend remedial works where necessary.
Condensation occurs when warm, moist air, comes into contact with a colder surface or colder air. This condensation can form water droplets that can become extremely harmful to your home causing:
- Structural damage of the timbers due to wood rot or wood boring insect infestation [wood worm].
- Degradation of insulation through damp penetration.
- Mould growth on ceilings and walls that can damage the internal decoration, plaster and paintwork, and potentially be damaging to health.
Condensation is often caused by a lack of ventilation or by ‘thermal bridging’. A thermal bridge (sometimes referred to as thermal bridging, a cold bridge or thermal bypass) is where there is a direct connection between the inside and outside of the property through
As a result, there will be wasteful heat transfer across this element, its internal surface temperature will be different from other, better insulated internal surfaces and there may be condensation where warm, moist internal air comes into contact with the, potentially cold, surface. This condensation can result in mould growth.
Thermal bridges are common in older buildings, which may be poorly constructed, poorly insulated, with single skin construction and single glazing.
In modern buildings, thermal bridging can occur because of poor design, or poor workmanship. This is common where elements of the building penetrate through its insulated fabric, for example around glazing, or where the structure penetrates the building envelope, such as at balconies.
Wood rot is defined as either ‘Wet Rot’ or ‘Dry Rot’. Both are a type of fungus and are caused by excess moisture in building timbers. They are commonly found in roof spaces and sub-floor spaces.
Wet rot attacks timber and is a common cause of structural defects particularly when allowed to go unchecked. Any timber exposed to excess moisture can provide the ideal breeding ground for wet rot spores, meaning wet rot can occur for a number of reasons. It could be from a leaky roof, burst pipes, damp or even a lack of sealant around a bath… The possibilities are endless. Whatever the reason, if timber has been exposed to damp for a sustainable period of time, the outcome is generally a form of wet rot
Dry rot is the most severe form of wood rot, but it is also the least common. Dry rot usually occurs where timbers are adjacent to a source of slight dampness combined with a poorly ventilated “warm” environment. Concealed timbers are at the greatest risk and also the hardest to detect.
It is impossible to give a total assurance that dry rot is not present as the superficially visible evidence is usually only present once the outbreak is well established. Many older buildings offer the correct conditions for the development of dry rot (or the reactivation of a concealed “dormant” infestation) but the incidence is rare, where it does occur it is often devastating and very expensive to eliminate. Small changes in the status quo of a building (e.g. by alterations to the pattern of heating and ventilation) can be sufficient to create the conditions where dry rot quickly develops.
Avoidance of wet and dry rot internally is possible by eliminating all moisture. In some historic buildings this may not be desirable (see Dampness above) and some risk may have to be tolerated. If dry rot is suspected it demands urgent attention by an expert. Where dry rot has been treated previously there seems to be a likelihood that it will reoccur.
Flat felt roofs are a cheaper alternative to pitched roofs but have a limited life, typically about 10 - 15 years although some of the newer felts are thought to be capable of lasting longer.
The type of decking (usually concealed) can influence
Asphalt flat roofs typically have a life of up to 30 years, again, dependent on the decking, exposure, etc.
Fibreglass claddings are occasionally used for flat roofs but there are few approved contractors locally. Such claddings are currently viewed with suspicion but should have a life of 10 – 15 years or more.
Repair and replacement of flat roofs
The provision of insulation and ventilation (to avoid condensation problems) should be undertaken when recovering the roof. Sometimes insulation can be provided above the decking to create a “warm deck” roof which will not require ventilating.
As insulation is becoming an increasingly important factor in property, it is important to make sure your home is suitably insulated.
For example, it is recommended that 275mm of standard quilted loft insulation is the roof space.
However, poorly fitted loft insulation can have serious consequences. Roof ventilation is commonly found at the eaves and poorly fitted insulation can disrupt the flow of air resulting in a
Many homes have had cavity wall insulation retro-fitted and there have been some problems with this type of insulation where again it has been poorly (or wrongly) installed. If you are considering having cavity wall
Similarly, some older properties may have had internal or external wall insulation installed. If incorrectly installed this can lead to issues of condensation or damp in the property
Double glazed windows and doors must comply with Building Regulations and are enforced by FENSA and the Building Control Department. When buying properties with windows installed after 4th March 2002 there should be a FENSA certificate issued as proof of compliance. This is something we investigate during a survey as part of our pre-inspection research. If no installation is evident then this will be highlighted as an issue for your legal advisor to investigate.
Consideration also needs to be given to emergency escape routes and providing a satisfactory level of ventilation.
Japanese Knotweed can cause serious damage to property and affect the ability to take out a mortgage on a property where it has been identified. Although there are many different species of Knotweed, Japanese Knotweed is the most feared and has been listed as one of the world’s worst invasive species!
Its thick, hollow stems can reach a height of 3m – 4m in
Awareness of the threat of Japanese Knotweed has risen greatly of late leading to banks and building societies refusing mortgage applications on properties that could be at risk
The RICS guidelines on Japanese Knotweed suggest four risk categories:
Not seen on the property, can be seen on neighbouring land but in excess of 7m from the boundary.
Not seen on the property, can be seen on neighbouring land within 7m of the boundary but in excess of 7m from habitable spaces.
Present within the boundaries of the property but in excess of 7m from habitable spaces. Further investigation required.
Present within the boundaries of the property and within 7m of habitable spaces, and/or, causing serious damage to structures such as outbuildings, boundary walls or drains etc. Further investigation required.
There are various methods for eradication and management which may be advised by
Pitch Fibre Drains
Pitch fibre was commonly used in the construction of underground pipes from the 1950’s to the 1970’s.
It was popular as it was a relatively cheap and easily handled material lending itself to use in the forming of drainage pipework. However inherent problems soon became apparent as the Pitch fibre degrades causing it to collapse resulting in a blockage of the drain.
Pitch fibre drains can affect a property’s insurability, meaning that an insurance policy on normal terms may not cover
Although this is also a form of infestation, it warrants a chapter of its own. There are several species of woodboring insects and they are well known for their destruction of property.
Destruction occurs by the larva burrowing (feeding) for several years within timber of a suitable type and age. Most timbers used in dwellings locally are suitable. The flight holes are the only indication. These are formed at the end of the larva stage when the insect emerges. Insects have a short life during which they lay eggs which produce more larva and so on. Treatment is usually needed to prevent eventual failure. Given early treatment it is rare for insect infestation to cause failure of a timber. Woodworm, etc. will occur in concealed timbers such as floor joists and treatment needs to recognise this.
Insect infestation normally occurs eventually in all houses and is usually fairly easily treated by a specialist contractor. We would recommend that you engage a competent timber treatment specialist to inspect the property, opening up the structure
Infestation can take many forms including vermin, birds, wasps or bees and even bats. It is rather common and typically affects the roof space.
Unfortunately, it can negatively affect the property. As well as a health hazard from droppings, vermin can cause damage to the property by, for example, chewing through electrical cables. Bats are a protected species so a bat infestation could put off a potential buyer.
Asbestos is commonly found in properties built before 2000. It is a generic term used in reference to fibrous forms of mineral silicates which naturally occur in igneous and metamorphic rocks. Asbestos has desirable qualities such as incombustibility and its strength when combined with other materials (such as plastic or cement) lends itself to be an effective reinforcement agent. As a result, asbestos fibres have been exploited commercially and can be found in many building materials. In the UK only two forms are known to have been used significantly:
- Chrysolite (white asbestos).
- Crocidolite (blue asbestos).
It is widely recognised that the inhalation of airborne fibres of asbestos can cause significant health problems, although this was not recognised until 1920. Due to increasing concerns
Asbestos is typically found in
- Artex (or similar textured) ceiling finishes.
- Insulation (pipe lagging and insulation board)
- Soffit boards
- Roof tiles.
- Corrugated roof coverings.
- Pipework (commonly soil and vent pipes).
- Certain composite floor tiles (e.g. thermoplastic).
There are various methods for removal and management which may be advised by
Where it is suspected that building materials containing asbestos fibres are present no works which would disturb these components should be undertaken before consulting an appropriate expert. If asbestos is found to be present the removal or disposal of materials affected will be increased.