Any Old Iron ? Resale houses over 20 years old

Any old iron?


When buying a resale house over 20 years old, it is important to know which type of plumbing has been used.


Prior to the standard use of copper pipe work (and more recently plastic), most properties in Spain were plumbed in galvanised iron with cast iron joints, (lead in very early cases). Decay in this type of pipe work tends to start from day one (the zinc coating is ‘sacrificial’ and corrodes at a very slow rate, later breaking down (e.g. after 5 years), such that more rapid corrosion of the underlying iron then occurs. The life of the pipe work depends on it’s thickness and whether or not it is set in the ground (in which case corrosion will normally occur from both sides, while above ground internal  pipe runs will normally only be affected from the inner side).


In addition, the composition of the cast joints is different to the main pipe runs, such that an electrolytic cathodic reaction occurs, making the joint ‘sacrificial’ i.e. it takes the brunt of the corrosion process, which is further aggravated under higher temperatures, hence it is normal for the joints on the hot run of pipe work to start leaking around 25 years after installation. The process is usually gradual, but will eventually lead to damage to decoration and later the building structure, along with the risk of possible flooding, (a joint can suddenly fail completely) or even electrocution if water from a leak tracks to live cables or a socket.


How to check for leaks:-


Some leaks are more obvious, e.g. a saturated lower wall or floor area, which remains damp in dry weather periods or dries out after a few days when the mains supply is switched off. However many leaks are more difficult to find. The following signs may indicate a leak:-


A warm patch of tiled flooring in a pipe run area (a pipe detector will confirm existence of a pipe run below) The area may not necessarily be damp, as the leaking water obviously flows downwards, but the heat in the area will rise upwards.


Pipe noise. When all taps and appliances are definitely off (stop cock on), try  pressing the metal end of a large screwdriver against a tap or exposed area of pipe work (this can sometimes  even work on tiles or render above a leak), then press the handle to your ear. If you hear a faint hissing, you may well have  a leak, the location of which is normally closest to the tap or area, with the loudest hiss. This can be further investigated with a listening device, which some plumbers may have, or can be hired from some locations.


Blown render, tiles or areas of rust staining in pipe run areas, especially close to ground level (caused by expanding pipes as they corrode)


Rusted appliances , metal fittings in the property. Black mould on ceilings (a result of condensation from the constant humidity caused by the leak).


Boiler makes more noise that usual when on standby, sometimes fires up slightly on it’s own, or takes longer to extinguish when tap is turned off.


Low water pressure, even when the boiler has been recently cleaned.


Higher than normal meter readings (check with other owners with similar daily usage but newer pipes e.g. copper, as to what they normally pay). Meter moves, even when all taps/outlets are switched off.


Use of a listening device or damp meter can help in both damp diagnosis and location.


Most  joints eventually become very brittle and friable which means that replacement of a localised joint will often result in new leaks from other joints elsewhere, so you are normally buying very little time, if you don’t opt for complete replacement.


Pools and irrigation


Older swimming pool and irrigation pipe runs will often also use wider bore galvanized pipe work, which suffer the same corrosion problems, especially where they run in walls, sub ground and under terraces. Some pool leaks are not due to failure of the pool itself, but simply due to pipe corrosion.


What does this mean for property buyers and existing owners?


In short, many buyers allow for adding a new bathroom and kitchen when buying an older property, but assume that the supply pipes are OK. In the worst cases the new installations are made, only to find later that they have to come back out as the hidden pipe work is riddled with leaks.


Existing owners may suffer health risks from living in a damp property along with risks such as electrocution, but will also have much higher water and gas bills for as long as the leak continues (extreme cases can result in water bills over €1000 euros! compared to say €30, and even a low level leak may treble a normal bill). In long term cases, the structure can be damaged to the point of failure, e.g. where foundation or floor substrate erodes away (or heaves), or the steel reinforcement of structural floor beams decays as a result of constant or regular saturation.


It is important to assess the age of a house and how it is plumbed, such that you can allow for total re-plumbing if necessary, which may run to thousands of euros depending on the size of the property, and just because you see the odd run of exposed copper or plastic pipe work in a property, does not mean that hidden pipe work is of the same material! Also be careful when buying properties that have been ‘totally’ refurbished. If the work has been carried out for the owner to live in, they may well have re-plumbed, but if funds are limited or the property has been done up just to sell on, expensive items such as re-plumbing hidden pipe work may have been ignored.


If you have a building structure related question you can e-mail Mark for free initial advice :–   This email address is being protected from spambots. You need JavaScript enabled to view it. A free 16 page buyer’s guide is also available on request.


NB:- Information for advice purposes only. Proper legal and safety procedures should be followed for all property purchases and building works.


Information provided by Mark Paddon BSc Hons Building Surveying. ICIOB. Property purchase advisor in the Valencia region. 


T: 962807247  M: 653733066



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