Checking and mending your gutter system

The weight of trapped water can bring a gutter crashing down—a real danger if it is a cast-iron one.

Deal with blockages as soon as you see an overflow. Make a gutter scoop by cutting the bottom from a suitably shaped plastic motor-oil container and use the spout as a handle—it will hold much more than a garden trowel. Empty debris into a bucket hung from the ladder.

Bung a rag temporarily into the top of the downpipe to prevent rubbish being swept into it as you scoop.

Read more: Comprehensive guide to fixing leaky gutters

To avoid having to move the ladder frequently, make a gutter rake. Cut a small piece of 9 mm or 12 mm plywood, or solid wood, to match the shape of the gutter. Use a screw to fix this to the end of a length of broom handle, about 1.2 m (4 ft) long, then attach a loop of cord to the other end to secure it to your wrist. Finally, drill some holes in the end piece of the rake for water to escape through.

Keep autumn leaves out of gutters by fitting plastic mesh leafguards if trees overhang the roof, but if you do need to put up a ladder to clean them, make sure it is fitted with a stand-off and do not rest it on the guttering.

Install extra support brackets if a gutter is sagging. They should be fixed about every 600–900 mm (2–3 ft). Scoop out any water lying in the gutter. Then, with the aid of a string line or straightedge, position and fix extra brackets on the fascia making sure that they are in line with the existing ones.

Test the fall by pouring water into the gutter at its highest point. If puddles form, the brackets need adjusting.

Water seeping from a joint on a section of downpipe indicates a blockage in the pipe somewhere between the affected joint and the outlet. Try unblocking the pipe from ground level first. Cover the gully to keep debris out, then push a length of stiff wire or a running garden hose up the pipe to shift the rubbish.

If this doesn’t work, unblock the pipe from the top using drain rods.

A wire mesh excluder Ïtted at the top of the downpipe will stop potential blockages such as leaves, moss and tennis balls from getting into the pipe in the first place.

Putty was traditionally used to seal the joints between sections of cast-iron and aluminium guttering, but a suitable sealant is far better for the job. If you’re renovating either of these gutter types, use an old chisel to remove the putty.

Then make sure the area is dry before you re-make the joint with the sealant. Have a hacksaw handy to dismantle sections; the nuts and bolts securing them are usually rusted and seized. Saw through nuts and punch bolts out from below—but take care, cast iron is brittle.

Replace them with mushroom-head plated gutter bolts and nuts.

Cast-iron gutters and pipes are heavy—don’t try to manhandle them from the top of a ladder. They also shatter if dropped, and corrode to sharp edges, so wear sturdy gloves.

Use a scaffold tower, and knock some 150 mm round wire nails into the fascia as temporary gutter supports, angling the nails so that the gutter cannot slip off them. Get help to remove and replace long lengths of gutter.

If only part of the cast-iron guttering has corroded, you can buy new—for a price—or scour architectural salvage yards for a matching replacement. Alternatively, ask a builders’ merchant if a plastic adaptor is available for joining on some plastic guttering with a similar profile.

Take a look at our guide to fitting a guttering system