Moulded gutters are made of cast iron, like half-round gutters, but sit on a stone corbel. Sometimes also called ornamental gutters (OG), referring to the profiled edge of a cast iron gutter or rhone pipe.


Leaks at gutter joints may be the cause of staining on the stone under the gutter. Bad stains suggest that the water is soaking the wallhead, potentially leading to rot in timbers below.

Moulded gutter seen from below. Note the staining, suggesting leaks from a gutter joint.

Older cast iron gutters will eventually rust and leak.

Lack of an undercloak under the gutter can lead to water soaking the wallhead when the gutter overflows.

Plant growth, leaves and debris from the roof can block gutters, so regular checks and clearing out are required to prevent gutter overflows. Fitting a leaf guard over the gutter can prevent some of these problems.

Leaf guard. A leaf guard will prevent leaves from getting into the gutter and will allow rain to flow underneath.

Points to note in repairing and replacing

Moulded gutters can be replaced with cast iron, cast aluminium, or heavy gauge-pressed aluminium. Glass fibre is a possible replacement material. Pressed aluminium is the cheapest solution, but you may need lots of welded joints around curved bay windows.

Glass fibre gutters may also be used on straight lengths, but require plenty of storm clips to prevent the sides being bent by snow. Glass fibre gutters have a shorter lifespan than aluminium or cast iron.

Cast iron gutters are long lasting and robust, but they should be painted inside and out before installation.

If the gutter is being part replaced, it may be difficult to make watertight joints between different sizes or shapes of gutter.

It is worth getting a lead undercloak fitted as a safety measure. This should be taken up under the roofing felt to catch overflows from the back of the gutter, which may otherwise soak the wallplate.

Exposed roofing felt by gutters should be UV protected.

Make sure the gutters are flow tested before the scaffold is taken down.

Professional help recommended?

Although the work may appear straightforward, ensure your builder or tradespeople have the skills for the job. If in any doubt, get professional help to specify and organise the repair.

Further information

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