Specifier Review
Round-Rainwater-Pipe-In-Cast-Iron - Guttering System

A guide to buying rainwater systems

At Metal & Glass we know how important it is for you to get the rainwater system right on your property. They are an essential part of your roofing system and not only make a huge impact on the aesthetics of your property, but also prevent problems such as water ingress, damp and condensation. They channel rainwater away from roofs, windows and doors, transporting it to drains and keeping your house dry.

There is a vast array of different guttering systems on the market making it difficult to know which one is right for your project. This guide will give you an overview of the different guttering types available, how to maintain them and how to fit them yourself, so you can choose the right option for your property.

Which type of gutter do you need?

The type of gutter profile you’ll require for your build will largely depend on the style and age of your property. A popular choice in the industry, half-round gutters are a good fit for both contemporary and traditional buildings. They’re instantly recognisable, featuring a half cylinder, which is open at the top to collect rainwater.

Properties constructed in the Victorian era often benefit from ogee gutters, as these add an air of tradition and authenticity to buildings. If you’re working on a refurbishment project, it’s a good idea to consider a deep gutter that will hold more water. This is strongly advised in areas affected by high levels of rainfall. For a more modern structure, box gutters provide a great finish. They have a larger capacity compared to other types of guttering, and their rectangular shape is popular for stylish builds.

There’s an abundance of choice when it comes to guttering materials too. There are pros and cons to using aluminium, plastic, stainless steel, copper and cast iron, but the main factors to consider are the type of building you’re working on and the look you want to achieve. Of course, at Metal & Glass we only sell cast iron rainwater products so for the purpose of this article we will focus on this kind.

Understanding the parts of a guttering system

Alongside the main gutter channels that we’re used to seeing on building fascias, guttering systems are made up of a variety of specialist parts. From running outlets to gutter clips and shoes, there are many important pieces to navigate when installing a guttering system.


One of the most recognisable parts of a guttering system, gutters collect rainwater and channel it away from a building via a downpipe. Gutters are available in different profiles, including half-round, ogee, deep and box.

Gutter angles

Gutter angles support the gutters around the corners of a property.

Gutter union

A gutter union is used to connect separate lengths of gutter. Unions are fixed to the fascia board and provide additional support to the joint.

Stop ends

Stop ends are used to cap off the gutter to prevent water from escaping. You’ll find both internal and external options available on the market.

Support brackets

Support brackets are also known as gutter clips. They’re screwed into the fascia to keep the gutter in place and can also be used to secure the downpipe to the wall.

Running outlet

Running outlets are installed to create a channel to connect the gutter to the downpipe.

Offset bend

Offset bends are angular pipes which enable guttering to travel from the fascia to join the downpipe. The angle of the offset bend allows a flush fit with the exterior wall.


A downpipe carries rainwater from the roof to ground level drainage.

Downpipe connector

A downpipe connector is simply used to connect two lengths of downpipe together.

Downpipe branch

Similar to a downpipe connector, a downpipe branch also connects two pieces of downpipe together, but a branch connects them at an angle.

Downpipe shoe

A downpipe shoe is fixed to the bottom of a downpipe to direct water into a drainage system. They’re commonly used when the downpipe doesn’t flow directly into a drain and are not necessary for every guttering system.

How to choose the right gutter sizes

Before choosing and installing a rainwater system you need to know it can cope with the water fall from your roof. A gutter that is too small will block easily and spill water out, while a system that’s too big will look bulky and unattractive.

Begin by measuring the area of your roof. You can generally calculate the square footage by using a tape measure. If you have a gable-end roof then you only need to know the measurements of each slope. A more complex roofing structure will take longer to measure as you’ll need to find out the surface area of each individual surface.

You must factor in the pitch of your roof too – the steeper the roof, the more rainwater the guttering will need to catch. A spirit level and tape measure can be used to determine the roof pitch factor, which will allow you to choose a guttering system that’s a perfect fit to your property.

If you’re unsure about this measurement it is worth contacting a professional.

Understanding gutter fall and flow

While its primary task is to catch rainfall from the roof, gutters also need to drain water away relatively quickly. The flow rate of a gutter system varies from profile to profile, but it’s also affected by installation and position. Gutters should be installed with a fall, (the amount by which the gutter drops to allow water to drain away). This is usually at a ratio of 1:500 meaning that for every 5m of guttering, the gutter falls 20mm. This is to ensure water does drain into the downpipe and does not stagnate.

How much does it cost to install new guttering?

The cost of guttering very much depends on the size of the property or the lengths of guttering and downpipe required. In addition, a variety of factors to consider when budgeting for a new rainwater system should include the condition of the existing fascias, roofline access and the type of property you’re working.

Installing a new rainwater system often requires the erection of access equipment, the removal of the existing system, and the supply and fit of the new guttering. This means the estimated cost will vary depending on roof design and access problems.

Gutter maintenance advice

At Metal & Glass we only supply cast iron rainwater systems as we believe they offer not only the best aesthetics, but will also last a long time. Despite the longevity offered by cast iron, it is advisable to inspect your guttering at least twice a year – more if it’s close to trees or in a coastal area.

When checking over the guttering, inspect the downpipe thoroughly as a blocked downpipe can cause issues with drainage. It’s common for leaves and general debris to accumulate here, so it’s worth checking that it remains clear. You’ll also need to check that the joints haven’t weakened over time and that there’s no corrosion hidden under rust or gutter debris.

When inspecting your gutters you should also check the outlet capacity. Older systems may need updating in order to cope with the amount and intensity of rainfall we see in the UK. If this is the case, you’ll notice the guttering system is failing to drain efficiently or over-spilling due to the volume of water.

How to clean your gutters

To ensure the maximum lifespan of your gutters, one of the easiest things to do is ensure they are regularly cleaned. This will keep them performing well, save you money on repairs and keep the exterior of your home clean and tidy.

Conducting an inspection of your gutters provides a good opportunity to clean them too. A stable ladder, protective gloves and a layer of tarpaulin are required for this job, and once you’re set up you can remove debris from the roof and gutters.

How to fix a leaky gutter

If one of your inspections does uncover a problem, it doesn’t necessarily mean you have to call in the professionals. Gutters can leak for a variety of reasons including blockages, joint issues and incorrect installation.

Gutter guards

If you find you are getting a regular build-up of debris or are experiencing problems with insect infestation, you should consider investing in a gutter guard. Guards are placed above or into the gutter, and prevent leaves and big items of debris from entering the guttering system. They’re not visible from the ground so won’t compromise the look of your property. They are relatively inexpensive and can be a big help in reducing debris that can build up in gutters.

Even if you install gutter guards it is important to continue to clean and inspect your guttering regularly.

If you need any further assistance in choosing your rainwater system or would like to discuss replacing your old system, then get in touch with one of the friendly, knowledgeable Metal & Glass team.

Tel: 01794 745445.