100 x 75mm (4"x3") Cast Iron Downpipes

Purchase 100 x 75mm (4x3) Cast Iron Downpipes

When replacing the existing 4" x 3" cast iron downpipe, you should first check whether you need a new pipe or just a replacement section. In fact, old buildings often have perfect pipework, but some damaged socket, shoe or offset needs repair.

Our Alumasc Apex Heritage P43 range features 100 x 75mm rectangular cast iron downpipes in various lengths, finishes and fixing types, along with the corresponding accessories for assembly.

1.83m or 0.9m Cast Iron Downpipe Lengths?

Two lengths are standard: 1.83m (6ft) and about 0.9m (3ft).

Longer runs are best assembled with the 1.83m sections because they require fewer joints. Sometimes the 0.9m lengths may be required near offsets, lower sections or limited spaces. One point to keep in mind is that these are nominal pipe lengths. The actual height after installation will depend on the socket joint and connection fittings.

It would be good to measure the entire run before ordering, including the swan necks and changes of direction.

Cast Iron Downpipes With Ears or Without Ears?

As you see, our 4x3 square cast iron downpipes come both with ears and without them.

Eared pipes feature traditional fixing lugs cast in their sockets, enabling them to be fixed to the building with suitable fixings. They are especially useful for replacing the old pipework with visible ears.

Uneared pipes have plain sockets and use special supports, such as holderbats. None of these options is better by default. The choice depends on your existing installation and desired fixation method.

Selecting Your 100 x 75mm Cast Iron Fittings

First of all, you should check the entire pipe run from top to bottom. There are matching 100 x 75mm cast iron downpipe shoes, bends, swan necks, plinth offsets, access pipes and sockets in this range.

Swan necks help to direct the pipe around projecting eaves, while plinth offsets are used to guide the pipe around the raised stonework or brickwork at lower levels.

Special attention should be paid to the direction and projection of the bends. Rectangular fittings cannot be rotated in the same way as round pipe fittings, so precise measurements are important.

Will New 4x3 Cast Iron Pipes Fit My Existing System?

They may not fit. Even if the old pipe has approximately 100 x 75mm diameter, the size of its socket may be different from the modern Alumasc Apex casting.

In case of replacement of one section, it would be good to measure separately the pipe body and socket. An image of the pipe end and fixing method is especially useful.

To see other sizes, please visit our Rectangular Cast Iron Downpipes collection.

Need Assistance in Selecting the Proper Parts?

Are you unsure which 100 x 75mm cast iron downpipe fittings you need? Just send a few photos and some measurements to Cast Iron Warehouse: info@castironguttering.co.uk.

We can help you to choose proper Alumasc Apex products whether you need to replace a damaged pipe or assemble a whole heritage rainwater system.