Everything You Need to Know About Updating Your Guttering
Tell-tale maintenance checks and timely repairs are key to keeping your home free of damp and water ingress
Professional advice from: Lior Brosh of Brosh Architects; John Petersen of JPL Design and Construct; Peter Currie of Peter Currie Architects
“Gutters and downpipes were introduced to Britain by the Romans,” Lior Brosh explains. “Up until the Georgian era, they were mainly made from lead, then cast iron was used throughout the Georgian, Victorian and Edwardian periods.”
From the 1970s and 1980s, uPVC downpipes were introduced and became popular because of their low cost and speedy installation. “For some, uPVC is not aesthetically pleasing,” Lior says, “and in recent years we’ve seen more guttering in zinc, aluminium and copper.”
“Cast-metal systems are jointed with gaskets, whereas seamless systems are usually riveted together with a gasket material in the joint to provide a good seal,” he continues. Like cast metal, plastic gutters have gasket joints.
While gutters fixed to fascia boards and the like are sealed, downpipes are not. “Downpipes are loose-fitted, with a spigot above [which joins it to the gutter] and sockets joining the sections below,” Peter says. “This allows the downpipes to be dismantled for removing blockages, such as leaves.”
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“I’ve even witnessed downpipes made from asbestos,” Lior says. “Never attempt to remove these by yourself – if you’re considering replacing them, make sure you contact a specialist.”
The point of guttering and downpipes is to stop the walls of a house from getting wet, and to ensure the ground under the edge of the roof doesn’t become saturated.
“This means gutters have to be set correctly with respect to the edge and angle of the roof slopes,” Peter says. “They need to be able to allow even the heaviest rain to flow easily to the outlets [downpipes]. The outlets need to be frequent enough, in the right position, and of the correct size to allow these flows to be discharged easily.
“Poorly designed systems may splash and overflow at the corners,” he says. “Downpipes with ‘swan necks’ or other changes of direction or angle can give rise to blockages.”
Metal rainwater gear can corrode and this is a particular problem with aluminium, according to Peter. “Inappropriate fixings or the proximity of other metals can give rise to ‘galvanic action’, which can accelerate this process, leading to physical damage and leaks.”
uPVC systems can be affected by hot weather. “Sunlight causes changes in the polymer and the plastic becomes brittle and leaks,” Peter says. “Long runs of gutter, particularly those facing south, will bend and bow if the spacing of the supports is inadequate. This will encourage the build-up of debris and cause overflowing, and will also stress the compression joint, which can then fail and leak.”
Blockages in parapet and valley gutters [ie gutters that are built into the fabric of a building rather than being attached to the outside] can be particularly problematic. “They can cause large amounts of water to enter the building after storms,” Peter explains, “and because small leaks in the lining of these gutters are difficult to identify, they can allow areas of the building to become saturated over time.”
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“If you see a wet patch on the wall coming from the ceiling downwards, in most cases the reason is a blocked or damaged gutter or a faulty roof,” Lior says.
“When you have rising damp, ie wet patches with mould coming from the floor upwards, it’s likely that the ground water is penetrating into the house due to a broken or cracked damp course,” he says. “However, if the bottom of the rainwater pipe is broken, or not directed properly into the drain hole, the water will be constantly splashing onto the brick, which sucks up the water,” so this could be the cause.
“Damage from leaking gutters and downpipes is evident externally and internally by the appearance of damp patches, mould, corrosion and moss growth from prolonged dampness,” John agrees. “In some cases, efflorescence, or white powdery deposits [from salts evaporating on surfaces] on brickwork, blockwork and plaster is the result of untreated surfaces and leaks. The fascia boards or eaves to which the gutters and downpipes are fixed may also be rotten due to prolonged exposure to dampness. This is evident by the timber breaking up.”
More: How to Deal With Penetrating and Rising Damp
On the exterior of a building, leaking or overflowing gutters and defective downpipes usually exhibit one or more of the following:
- Visible dripping when rain has ceased.
- Staining of brickwork underneath showing up as a comparatively dark patch where the brickwork is wet.
- Appearance of efflorescence on the surface of the brickwork.
- Local rot in window joinery close to, or directly under, the leak.
- Plastered finishes that are damp to the touch.
- Localised areas of water damage to ceilings.
- Development of mould growth and mildew on limited areas of walls.
Where damp patches are found on external or internal walls directly underneath gutters or adjacent to downpipes, investigate the cause as quickly as possible, John advises.
“It may simply be the case that the gutters are blocked by leaves, moss or other debris. They need to be cleaned out on an annual basis, especially those in close proximity to trees,” he says. “If gutters and downpipes are clear of blockages, it’s more than likely the joints are loose or the seals are missing or loose.”
“In the UK, leaves start falling in late August and can still be causing problems as late as November,” Peter says. “We usually suggest a check in late October and another in January.
“If leaks, rather than blockages, are noticed, they need to be addressed,” he continues. “Leaking compression joints may only need opening, cleaning, possibly greasing or lubricating, and then reforming, but leaks due to physical damage, corrosion or ageing will need replacement parts installing.”
“However, because the definition of a facsimile repair is elastic, it’s always wise to obtain advice from the local conservation officer before proceeding,” he suggests.
“Any repair work and/or replacements to gutters on listed buildings will require Listed Building Consent,” Lior says. “If you’re unsure of how to deal with it, Historic England has a very helpful website with a guide for owners of listed buildings, which includes links for professional help.
“Alternatively, contact your local council and speak to the duty planner – and make sure you get their answer in writing,” he says.
“Contact an expert if you don’t see any visible gutter or rainwater pipe problem, but notice wet patches,” Lior says.
If your house is a listed building and/or located in a conservation area, always ask for professional advice before you take any action, he says. Contact one of the following:
- An architect, who will not only be aesthetically aware about buildings, but have knowledge of planning guidelines and would be able to suggest a tested contractor or specialist.
- A planning consultant or conservation professional.
- A building surveyor, who will have some similarities to an architect, but without the design qualifications.
- A builder, who can give advice. You must, however, do your research: you need to make sure the builder knows what he or she is doing and, if possible, comes highly recommended.
“If a leak is resolved simply – by remaking a weeping compression joint, for example – and there’s no internal damage, it may well be an over-reaction to seek professional advice,” Peter says. “If, however, the leak is merely a part of the problem and there are other issues that also need addressing, then it would be sensible to consult an architect or surveyor.”
Who you call in to do the repair will depend on the damage. “Most roofers will be competent to repair or replace uPVC guttering and the like,” Peter says. “However, a plumber will be needed to deal with lead gutters and flashings. Specialist companies are best used for repairs and alterations to cast-metal rainwater gear, and repairs to asphalt gutters will need asphalters.”
“In exceptional cases, where there’s evidence of extensive damp externally, internally or both, it’s advisable to seek advice from a building surveyor,” John says, “as the remedial work may extend beyond the renewal or repairing of the leak on the gutters and/or downpipes.”
“If uPVC gutters and downpipes are cracked, they – or the damaged section – need immediate replacement,” John says.
“If cast-iron gutters and downpipes are cracked, split or badly corroded, then immediate replacement should also be actioned,” he says.
Extruded aluminium, galvanised or coloured steel gutters and downpipes rarely develop material issues and usually simply need seals replacing,” he adds.
If the leak is easily fixed and there are no, or very few, related issues, then a repair is the obvious way to proceed, Peter says. “However, if the cause of the leak is old age or corrosion, or because the original installation was poorly designed, or if the leak has resulted in damage that means the gutters need to be removed and then reinstated, then replacement may be the only sensible option,” he explains.
“Every case should be looked at individually,” Lior says. “Personally, I think removing an old or original feature would be the absolute last resort, for example if it was damaged beyond repair or if not replacing it would harm the building. If you do choose to replace an original downpipe feature, and receive Planning Permission to do so, then I would suggest replacing it ‘like for like’.”
The choice will depend on the age, style and location of your property – as well as your budget and personal preference, say our experts.
“Some rainwater systems, such as uPVC, are easily fitted, have low maintenance costs, and need no decoration,” Peter says, “but they aren’t very robust and have a particular appearance and limited life.
“Other options are more expensive, have a significantly longer life expectancy, are more durable, and exhibit a more appropriate appearance,” he says. “In conservation areas and with listed buildings, the choice of system may already be prescribed.”
“When it comes to a period or listed building, the first priority would be to go with what is suitable for the building,” Lior says. “Do the research and replace like for like – or exactly how it used to be.”
“Extruded aluminium or galvanised/coloured steel gutters and downpipes tend to be substantial, eco-friendly and low maintenance,” John says.
Was this advice useful for your own guttering and pipework? Share your thoughts in the Comments.