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How to Select a Rainwater System: Plastic, Aluminium, Cast Iron...

Cast Iron Gutter System, Six Heritage Colours

In terms of value for money, how do cast-iron, 'solid' aluminium (eg Marley/Alumasc), formed-on-site aluminium, glass fibre and plastic gutters compare?
With regards to 'value for money' you must first of all balance the final appearance of the system against the overall costs of installation to determine the best choice. An example of this would be if you were renovating a Victorian cottage, would 'formed-on-site' aluminium provide you with the original appearance of cast iron? If not, then you must decide if cost is even worth considering or if value-for-money is your ultimate aim. Whichever system or material you use, appearance should be an important consideration, otherwise the words ‘tar and ha'pence’ spring to mind.

After refining your choice on appearance, material costs must be determined and any relevant merchant will quote you prices, which can then be easily compared.

Once material prices have been determined, it's then down to the labour cost, effort and time of installation. Dependant on the installation and, of course, safety implications, scaffolding may need to be costed in with heavier metal materials, whereas lighter plastic or glass fibre systems may only require a ladder. Also, heavier materials may require additional labour.

Although cast iron systems are available ready painted, you must remember to allow for primer, undercoat and topcoat paint for when lengths of gutter and pipe are cut to size, to prevent corrosion at the unprotected cut ends. If you choose a non-painted 'primed' cast iron system, you must allow for paint, painting and drying time and ensuring the correct amount of paint is applied to ensure any guarantee remains valid.

These considerations should enable you to determine a real value-for-money choice for your particular project.

How permanent is a black finish on each of the above?

All of the systems mentioned above will be available with excellent weathering properties and a minimum of ten years would apply to any quality manufacturer’s products.

Fall on gutters - can I use zero fall if I go for a section with a lot more capacity than I need?

Some systems must be fitted level, due to the design and appearance of the gutter profile and these rely on capillary action to drain the water. Level installation needs to be very precise to ensure that no slight backfalls are present, resulting in standing water in the system. Correctly sized and installed, a level system will enhance the final appearance and prevent additional costs of an oversized capacity.

A slight fall towards the gutter outlet (1:600) may be preferable to speed the flow, improve the self-cleansing properties and help keep the system free from debris, especially if trees are in close proximity to the installation. In such circumstances, foam or plastic grid inserts are available to prevent debris entering the system and provide excellent protection against blockages.

For further information on the Cascade range visit Cascade Cast Iron Style Systems.