Health check
Knowing how to fix problems with guttering and drainpipes is a must for any homeowner, so find out how to identify and remedy common issues
Expert Roger Hunt advises on caring for rainwater goods
Collectively known as rainwater goods, gutters, hopper heads and downpipes form the system designed to channel rainwater safely away from a building and prevent damage to its fabric and structure. The most common problems are caused by blockages, and defects due to inadequate maintenance.
These issues are sometimes made worse because of changes to the building, particularly the roof, that over time have resulted in awkward reconfigurations of the rainwater system. The problems are compounded by today’s more extreme weather events associated with climate change, which cause older systems to be compromised, as they have insufficient capacity to deal with the larger volumes of rainwater.
Always put safety first when working on rainwater systems at height and ensure that contractors have relevant and adequate access, equipment and insurance.
Maintenance checklist
● Clear debris from gutters
● Ensure downpipes are free from any blockages
● Identify the reason for plant growth or discolouration around guttering
● Repair loose, broken or cracked sections of rainwater goods
● Check water is draining clear of the base of downpipes
● Repaint cast-iron rainwater goods
Questions and answers
Matthew Wellesley-smith, specialist surveyor and environmental scientist at Hutton+rostron Environmental Investigations, answers some common questions about the maintenance and repair of rainwater goods.
QHow often should rainwater goods be checked?
At least three times a year. Nothing beats physical ground and high-level inspection during rainfall to ensure the system is functioning as intended, but this isn’t always practical. Pole cameras and drones have their place where the use of ladders is unsafe. In the right hands, telescopic gutter cleaning poles are useful, but a heavy-handed approach can cause damage.
QWhat are the main causes of problems with the system?
Evidence of water overflowing or leaking from gutters and downpipes is often the first indication of trouble; algae growth and eventual plant growth indicates saturation of the structure behind. Lack of maintenance leads to rainwater goods becoming blocked or partially blocked by debris
and/or plant growth. Blockages also occur to gulleys and drains at the base of rainwater downpipes. Poorly levelled gutters will result in water overflowing rather than discharging via downpipes. Cracked, leaking, broken or missing sections of pipes or gutters and corrosion at joints are other common issues.
QWhat happens if rainwater goods are defective?
Damage to finishes such as paint, wallpaper and plaster is common. It can quickly escalate to the growth of timber decay fungi and mould in affected structures. Corrosion to iron and steel elements will result in rust staining and eventual structural damage; there may also be corrosion and short-circuiting of electrical fixtures and fittings. Efflorescence and spalling to pointing, brickwork and masonry may occur externally. A musty smell from floor voids is another indicator of leaks, especially where internal downpipes are present.
QWhat is the best method for removing leaves and debris?
Most important is safe and convenient access. Generally, this means that it is a two-person job, requiring a ladder and, for large properties, the use of an access tower or hydraulic platform. A bucket or sack, a small trowel and protective gloves are generally required. Downpipes may need rodding equipment, although sometimes a hosepipe may be used to provide a water jet.
QHow can debris be kept out of gutters and downpipes?
The most ‘failsafe’ way of keeping debris out of gutters and rainwater downpipes is to use high-capacity rainwater goods detailed so that they ‘self-clean’, in conjunction with regular inspection and maintenance. Many systems and products have been developed in attempts to prevent blockage with debris, including perforated lead grilles, copper or galvanised steel mesh, grilles and balloons, plastic grids and brushes. Unfortunately, these are not universally effective and, although they may be useful in certain circumstances, none of them eliminates the requirement for routine maintenance and cleaning.
QWhat should be considered when choosing new gutters and downpipes for an older property?
Maintainability is the first concern.
The largest capacity rainwater goods should be chosen that are practically and aesthetically acceptable. Generally, square section and other fancy profile rainwater goods should be avoided as these are more prone to blockage and overflowing. Where possible, incorporate failsafes, such as overflows, weirs and chutes and flashing details. These should discharge water clear of the structures beneath if the main rainwater system becomes blocked. Whether steel, cast iron, aluminium, plastic, lead or other materials are used is a decision based on aesthetics, planning requirements, service life and cost.
QAre there special considerations when working with lead?
Lead rainwater goods are vulnerable to physical damage and thermal movement. Long-term ‘creep’ (deformation under their own weight) of lead hoppers and downpipes can result in constrictions, partial blockage, sagging and splits. This is often exacerbated by the failure of the ferrous fixings used to secure heavy lead hoppers, excessive loading on underlying downpipes and resultant splitting. Underside lead corrosion is a possibility for lead parapet and valley gutters where the lead sheet is weakened by a corrosion process that occurs as a result of condensation.
QWhen refitting rainwater goods, what are the most important considerations to be aware of?
Hoppers and downpipes should be refitted with an air gap between rainwater goods and the masonry behind to minimise the risk of any leaking or overflowing water draining back into the structure. Similarly, gutters should be relaid so that any overflowing water will drain clear of the structures beneath.