FAQ

If you have a listed property and are looking for advice on the best way to restore or maintain the structure, we would recommend visiting www.spab.org.uk.  The Society for the Protection of Ancient Buildings (SPAB) believes old buildings have a future. From cottages to castles and from churches to cathedrals we are here to help buildings and the people who care for them. Through our unique training schemes, courses, advice and research they help people put our expertise into practice.

Founded by William Morris in 1877, the SPAB was established in response to the work of Victorian architects whose enthusiasm for harmful restoration caused irreparable damage. Today the SPAB encourages excellence in new design to enrich and complement the built historic environment. They train new generations of architectural professionals and building craftspeople to shape this landscape with sensitivity and skill, and we play a statutory role as adviser to local planning authorities.

What are the consequences of poor rainwater disposal be?

Frequently, those first noticed are internal. Concentrated and prolonged wetting is likely to cause damp patches and plaster mould on walls and ceilings, and the decay of timber skirting boards, panelling etc. Investigation will often reveal rot in concealed timbers, such as roof truss bearings beneath parapet gutters.

Externally, masonry can suffer from algae growth and eroded mortar joints. Render may fail locally, particularly inappropriate cement-based coverings that draw in mortar through hairline cracks. External joinery can be attacked by wet rot where there are leaks above doors and windows. Blocked gullies may lead to a build-up of water and damage to foundations.

Why might my rainwater fittings be causing problems?

Commonly because of poor maintenance. Gutters, downpipes and gullies can become blocked if leaves, moss and debris (for example, broken tiles) are allowed to accumulate. In addition, components may corrode through lack of decoration. Gutters can fracture where bolt fixings rust, and downpipes frequently leak at joints where blockages hasten corrosion.

Poor detailing is a further factor. Over-sized and over-fixed lead linings may suffer fatigue, for instance. Eaves gutters supported by too few brackets can sag. Where maintenance is neglected, bad detailing – such as excessive swan-neck arrangements – may accelerate deterioration.

Rainwater fittings can be broken or distorted by mechanical damage. Lead downpipes are also vulnerable to knocks from passers-by at low level and ladders higher up.

What maintenance should I be undertaking with my rainwater fittings?

Good maintenance involves regularly clearing out rainwater fittings, particularly after the autumn leaf fall, and checking the system for defects. Periodic redecoration of ironwork is required to inhibit corrosion.

It can be advantageous to fit plastic leaf guards to gutters or wire balloons above downpipes. Leaf guards still admit pine needles and are sometimes easily dislodged, and material left to gather around wire balloons may cause blockages. Where visually acceptable, overflow pipes can be introduced above hopper heads.

Snow should be cleared from parapet and valley gutters with wooden or plastic shovels to prevent moisture seeping through joints. Alternatively, duckboards or electric heating tapes can be provided to keep gutters clear of snow.

Fittings are best checked for leaks in heavy rain. Proprietary adhesive tape is available for temporary repairs. Where poor access hinders maintenance, additional hatches or fixed ladders might be considered.

How should I go about redecorating rainwater fittings?

Paint selection will depend, among other considerations, on site exposure and the historic interest of the building or surviving early finishes. Cast iron rainwater fittings at the SPAB’s Grade II–listed headquarters have been redecorated with a solvent-based system. An epoxy phosphate primer and acrylic urethane gloss finish were specified.

Surface preparation is important, and unsound old paint and rust should be removed. Any defective gutter joints should also be resealed. Care should be taken to ensure the backs of downpipes are redecorated, particularly if of the rectangular type. It may be beneficial to fit spacers or holderbats if access is limited.

Is the repair of old rainwater fittings preferable to their replacement?

Absolutely, where feasible, to retain the maximum historic fabric. Lead, wrought iron and sometimes cast iron can be repaired with various welding techniques. Soldered dots or patches may be used for copper. Remember fire safety, though, when undertaking work of this kind.

Replacement, where unavoidable, should normally be on a like-for-like basis. Inappropriate substitute materials can erode the character of a building (for example, using PVCu instead of cast iron) or lead to premature failure (as with certain combinations of dissimilar metals).

Some changes may be justified. Substituting cast iron with painted cast aluminium might be acceptable where access for redecoration is exceptionally awkward. Such work may require listed building consent.

Should gutters and downpipes be provided where none exist?

This depends upon the circumstances. Where maintenance is likely to be neglected, existing rainwater disposal arrangements are satisfactory or new gutters and downpipes would be hard to install unobtrusively, it may be better not to provide a new system.

Where a rainwater system is added, it should be uncomplicated. Downpipes should be sited away from wall paintings. Again, such work may require Listed Building Consent.

Further reading:

English Heritage (2014) Building Environment, Practical Building Conservation, Farnham: Ashgate Publishing Ltd

Society for the Protection of Ancient Buildings (2017) Control of Dampness, SPAB Technical Guide, 5^th edition, London: SPAB

The most common type of cast iron rainwater pipe failure is a split in the back and the main reason for this is because a large number of rainwater pipes either touch the wall or the gap is very small, making it virtually impossible to maintain without removing it.

If there are blockages and water is trapped in the pipe this can freeze in winter months leading to the pipe splitting.  When the warmer weather returns water can escape from the pipe potentially damaging your wall.  It is therefore a good idea to undertake some type of maintenance in the autumn to clear away and leaves from your gutters and prevent them from falling into the pipes.

If your pipes remain structurally sound and no water is escaping from the rear then a simple annual inspection and clean should be sufficient.  If there is any paint damage then this should be addressed by applying a metal primer prior to a top coat.  If you can access the rear of your pipes with a paint brush then you have a much better chance of extending their life.

When a pipe is leaking it should be removed at the earliest opportunity to reduce the risk of structural damage to the property.  It is occasionally possible to have cast iron rainwater pipe repaired and in the case of special or unique castings, this should be actively encouraged.  For more common round profiles it is likely to be as cost effective to replace the defect piece with a new one.

Properly installed and maintained cast iron rainwater pipes can be expected to last in excess of 100 years so provided that you are able and willing to undertake the work the replacing of your cast iron rainwater pipe should at worst be a once in a lifetime experience.

Unlike cast iron soil pipe which is jointed to keep any smell inside the pipe, the joints on cast iron rainwater pipe are often left open.  It varies from job to job and some installers will always insist on sealing joints using a variety of materials including gaskin or caulk rope or lead wedges which are then covered with a sealant.

Others prefer to leave the joints open as this can make locating blockages easier.

Each project is different and there are pros and cons for each option.  Whatever you prefer it is advisable to discuss this with your contractor prior to undertaking the work to ensure that you get the finish you want.

We offer our cast iron rainwater pipe in 4 standard diameters which are:

65mm (2.5”)
75mm (3)
100mm (4”)
150mm (6”)

These sizes relate to the internal diameter of the pipe body (not the socket).  If you are measuring the outside of your cast iron pipe then add 5mm to those measurements for the first three sizes of pipe and 9mm for the biggest 6” profile.

There are also a number of other measurements to consider such as the length of pipe that you need.  If you are joining our cast iron rainwater pipes to your existing ones then the internal socket diameter is important to make sure that they can be connected.

A rainwater pipe consists of a tube of cast iron with a socket at the top.  The socket sections can be plain or have ears which aid the fixing of the pipe to the wall.

It is important that pipes are straight and have a consistent wall thickness.  Cast iron rainwater and soil pipes are not necessarily smooth like plastic, as the manufacturing process but they should be even and without obvious defects such as cracks or an uneven wall thickness.  It is also important that the inside of the pipe is free from any obstructions as this is likely to restrict the flow.

The cast iron pipes offered by Metal & Glass are cast centrifugally and with the socket cast on as an integral part of the pipe.  This means that the pipes are a single piece of cast iron which is the best way to manufacture round pipes.  This method of production offers a number of advantages over pipes which are not produced in this way:

• Centrifugal casting is the only method of producing straight pipes with a consistent metal thickness and an even surface finish over the length of the pipe.
• Cast the socket on as part of the manufacturing process, as opposed to attaching a separate socket later, ensure the integrity of the pipe and also ensure that the internal flow is efficient. By using a separate socket which is fitted inside of the cast iron pipe, it significantly reduces the internal diameter.

Centrifugal casting is only possible for round and half round products, all other cast iron products such as fittings, square and rectangular pipes and other gutter profiles are cast using traditional methods.

To view our range of cast iron round pipes and fittings, click here.

Yes, our team are on hand via phone, email or our contact form to answer your questions. Our experienced team are happy to guide you through the products, the way they join together and the installation requirements of a cast iron rainwater or soil system. For those looking to specify cast iron rainwater or soil systems, we can provide a drawing take-off service, provide drainage calculations or even provide a site survey. We have a number of technical data sheets and installation guides which can be downloaded from our website

Yes. Unique castings can be created by a skilled team of craftsmen to bespoke designs for special requirements. Made to order castings can include radius gutters or ornamental rainwater hopper heads. All standard products can also be altered to meet your requirements. These include, extended pipe offsets, unusual angles and bespoke bracketry.

Metal & Glass are based at Unit 5, Pinnacle Business Park, Tinners Way, Callington, PL17 7FF. Whilst this is our physical address we have customers from all over Great Britain, Ireland and further afield. We can dispatch our products direct to your door usually within 2-3 days of order so whilst we may not be located in your area, we can certainly get there.

It is a common misconception that plastic is fine to replace cast iron and works out cheaper. No other material looks or performs like a cast iron rainwater system. The benefits of cast iron far outnumber those of plastic whether it is strength, durability, life span, low noise levels, environmental benefits or maintaining original features. Suppliers of plastic gutter alternatives to cast iron regularly point to two areas which they see as a benefit of plastic; 1, it is light and 2, it is cheap. Having a very light material is definitely a benefit if you are looking to launch it into space but when it comes to building materials, being heavier usually equates to additional strength, robustness and being able to better withstand elements such as strong winds and snow. As for cost, there is no doubt that plastic guttering has a lower upfront cost than cast iron rainwater goods but you might be surprised to know that if you look at the whole life cost of cast iron gutters and pipes, then it works out to be around a third of plastic. Our blog section has a number of articles and informative pieces to help you make the choice for your rainwater systems.

Our cast iron half round profiles can be jointed using our gutter jointing kits. These kits come with rubber gaskets, nuts, bolts and washers and each pack will cover 10 joints. Deeper half round and Ogee cast iron profiles would use a low modulas silicone combined with the nut, bolt and washer. All of these products are available in our Gutter & Pipe Accessories section.

Whether your existing cast iron rainwater system can be repaired will depend on a number of factors. Firstly it is reasonably important that the bulk of the piece is still structurally sound. If you have something which has badly corroded, full of holes or is brittle then it is unlikely to survive the repairing process. In most cases, people will take their old iron rainwater system to a local company to be shot blasted before a new primer and top coat is applied. It is essential that the company undertaking the blasting are careful because using the wrong shot can result in the complete destruction of the product.

Metal & Glass do not undertake repairs to gutters and pipes and quite often the cost of replacement can be less than repairing the original. That said for pieces of significant historical interest or those which are unique to a building, we would always like to see the originals restored. Where that is not possible, our bespoke pattern service can match original cast iron gutters, pipes and hopper heads to provide a match which will last for the next 100 years.

It is possible to cut cast iron gutters and pipes and it is usually best to do this with a disc cutter and a sharp blade. You can use a hacksaw but this is a much more labour intensive process. Whichever way you cut your cast iron guttering or pipes, it is important that all cuts are primed and then painted to ensure a long life.