How To Repair Guttering

It is tempting to put off replacing old, decaying gutters and downpipes; but delay can lead to damaged fascias and damp walls. And renewing a guttering system is not as daunting a task as you may think.


Any sort of work on house guttering requires safe and easy access to roof level; that way you’ll be able to move up and down freely with necessary tools or equipment and feel confident aloft. You can use stepladders for a low roof, and extending ladders for a higher one but for convenience on the highest you’ll need a scaffold tower. You can hire any of these.

How to repair gutters

Erect a ladder by first butting its feet against the bottom of the wall. Then lift the top and walk towards the wall. Gradually raising the ladder rung by rung until it’s vertical. Then pull the bottom towards you and lean the top in to the wall.

The ladder’s feet should sit at a distance corresponding to a quarter of its height away from the wall. Always erect an extension ladder unextended and push up the top section once it’s stable.

Make sure the ground is level and firm. If not, slide a board under the ladder’s feet and wedge it with a batten.

Secure the bottom of the ladder by driving a couple of wooden pegs into the ground at each side of the feet and tie it to them with strong rope. If you have a willing helper, ask him or her to steady the ladder from below as you climb.

Set the top of the ladder against the masonry or the fascia board: never rest it against the guttering. Secure it by lashing it to a screw-eye bolt fixed securely in the fascia or masonry. Wrap some rags around the top of the ladder to avoid damaging the paintwork.

A scaffold tower, which you can hire, will prove more convenient whatever height you’re working at, freeing both your hands. Make sure you have enough room around the house to erect the tower, if space is limited you may be able to hire a special narrow tower.

Towers are straightforward to assemble, and usually consist of slot-together sections. Some come with ladders for access. Guard rails and a working platform.

Make sure that the feet of the tower rest on solid ground: lay down planks if necessary. It’s best to get a tower with adjust- able feet: that way you’ll find it easier to ensure it’s level. If you exceed the supplier’s height recommendations, don’t worry: provided you use the outriggers — supporting struts — made for the purpose the tower will still prove perfectly stable.

Make sure you use the ladder sections to give you safe access to the top and, remember. Always lock the castors, if your tower’s fitted with them. Never move a tower with anyone on it.

Safety aloft

When working aloft there are a number of points to bear in mind.

Never lean out too far from the side of a ladder — you might overbalance or cause the top to slide.

Never work from the very top of a ladder — you’ll have nothing to hold on to.

Never weaken an extension ladder by over-extending it to get extra height: at least a quarter of the upper section must always overlap the lower.

When working from a scaffold tower always use toe boards round the platform edges: if you miss your footing you won’t be in danger of falling, and you won’t be able to knock off any equipment accidentally.

Never drop tools or materials to the ground: they could easily hit someone and cause a serious injury. You should pass tools and equipment down to a helper or carry them down yourself. Heavier items. Such as lengths of old gutter. Should be lowered on rope for safety.

If your existing cast-iron gutter-ing has badly rusted or it leaks, sags or continually overflows, it’s best to replace it completely.

Before you start work, brush away all loose dirt and rust. Cast- iron guttering tends to become brittle. As well as rusty. So wear tough gloves just in case you break a section.

Start work on the guttering closest to the outlet to the down- pipe. Undo the bolts linking the sections using an adjustable spanner. If they’re too rusty or heavily over-painted don’t worry: just cut through them with a hacksaw.

You should then be able to prise away the gutter from the downpipe section. Use an old chisel to lever apart each mastic joint to make removal easier.

Cast-iron guttering will either be screwed directly to the fascia boards or supported by brackets fixed to the fascias or the house rafters. Undo the screws and remove each section in turn.

Fix guttering fixed directly to the fascia can prove hard to unscrew. If this is the case, put the blade of an old screwdriver into the screw slot and knock sharply with a mallet: this should loosen it.

If you ‘can’t undo the screws you’ll have to lift each section out from the brackets. Remem-ber. Cast-iron guttering is heavy. So be prepared to take the weight. It’s probably best to have assistance at this stage.

On no account should the guttering be allowed to drop to the ground — it will shatter and could prove dangerous. Either pass down each section to your assistant or lower it on rope.

Never attempt to carry it down a ladder on your own: you could easily overbalance and drop it.

Once you’ve removed all the guttering, deal with the brackets.

With some cast-iron systems, brackets were fitted either to the side or to the top of the rafters.

If your new system requires top rafter brackets, you might have to lift the roofing above each rafter to remove the old brackets and fit the new ones.

On some modern PVC systems the rafter brackets are fitted to the ends of the rafters and don’t require disturbance of the roof.

Don’t bother about trying to preserve the old rafter brackets — just saw through them as close to the rafters as possible.

Next you’ll have to get rid of the old downpipes. Do this section-by-section, working up.

First unscrew the bracket fixing the lowest section of pipe to the house wall. You might have to lever away, but try not to damage the masonry.

On cast-iron systems the joints between each section were often left dry, so you’ll probably find it quite easy to separate each section of pipe. Finally, you’ll be left with just the gutter outlet and offset section to be removed.

Take extra care if you’re deal-ing with an old asbestos roof drainage system. A face mask and thick gloves are essential.

Make sure that the pipes and guttering don’t break when being lowered to the ground, and never just break up the sections so you can dispose of them more easily.

First soak them thoroughly with water, then cut them as neatly as possible using a hacksaw to avoid dust.


Calculating your root’s guttering requirements is complicated. The best answer is to measure your old guttering before taking it down, and buy an equivalent-sized new system: 100mm will be suitable for most homes: 75mm is fine for sheds: 150mm should only be used on homes

with very large roof areas. However, assess your existing system thoroughly before you go out to buy the new guttering.

First check the position that the new downpipe will take.

Again refer to your old system, as this is likely to be determined by the position of the gully into

which the pipe delivers the rain-water. Then start at the opposite end of the guttering.

Using 25mm rustproof screws fix a bracket high up on the fascia board and about 75mm from the end of the timber. The guttering will have to be installed on a slight fall from this point to the outlet. This will increase the flow in the gutter and avoids standing water.

Aim for a fall of approximately 5mm every metre of guttering. At no point should the distance between the roof drip and guttering exceed 50mm.

1. Attach a weighted stringline to the first bracket and run it to a nail fixed in the fascia close to the projected outlet. Check with a spirit level that the string is horizontal then lower the nail by the amount necessary for the correct fall from end to end of the guttering run. Remove the nail, fix a bracket in its place and replace the stringline. You can then use this as a guide for fitting the rest of the brackets.

Where you fix the brackets exactly is determined by the system you’re using and the jointing methods it employs. There are two common methods — one where each joint is supported by a bracket with further brackets at about lm intervals, and another where a bracket is fixed about 150mm each side of each joint and then at about 900mm intervals.

2. With all the brackets in position you can start fixing up the guttering, working towards the outlet. Slide in the rear edge first so that it butts up tightly to the back of the bracket. Then simply press down the front edge so that the gutter snaps under the clip on the top front edge.

If you are going to join onto your neighbour’s guttering, you may have to obtain a special adaptor. Joining onto an old cast-iron system with a new plastic one isn’t difficult; fit the adaptor to the fascia and line the part carrying the old cast-iron gutter-ing with a thick bed of mastic.

But. If you’re trying to link up with another plastic system it might prove difficult if it is made by a different company. The best thing is to check what make your neighbour has before buying.

The jointing method varies between systems but there are two common types in use. With one. Each gutter section has a built-in seal at one end and a spigot end at the other. The spigot is laid in to the seal of the next length and held firmly.

To assembly a joint. Place the spigot end into the seal end of the next section and hold it firmly in place with a clip.

With the other method, both sections are laid into a third —called a union clip — which in-corporates a rubber seal. As each section of guttering is pre-notched. It can be held in place by special nibs on the union.

Here you turn the notched end of each length into the clip so that the notch closest to the fascia is held by the retaining clip.

Then press down the front edge of the gutter until it snaps under the front retaining clip. 3. To take your guttering round an internal or external corner. Hold the angle piece in place before dealing with the straight sections. Then mark the line of the guttering and where it will join onto fascia.

Jointing will be by the same method as before but you’ll have to fix brackets on each side of the joints. You might also have to cut lengths of guttering to size.

Measure at roof level and use a hacksaw to cut the section as squarely as possible. If neces-sary, clean -up any roughness with a file. The chances are that you’ll have to renotch the end of the section. Do this using a wood file to the dimensions given or obtain a special notch cutter.

Check that the system works by pouring water onto the roof: once you’ve installed the new downpipe it should run smoothly into the guttering. Then pour water into the gutter at the point furthest from the outlet. Inspect each joint for leaks: check for standing water.

Downpipes linking the guttering to the underground drain may have to be replaced indepen-dently of fitting new guttering. Make sure that the pipes suit the guttering already installed.

1. As it’s unlikely that the guttering will sit flush with the walls, enabling you to connect the downpipes directly to the outlet. you’ll have to construct an ‘offset’ or ‘swan neck’ section incorporating an offset socket, an offset spigot and a length of suitable pipe. This will pass from the outlet, under the soffit and engage the downpipe.

Cut the pipe to the correct length. Making sure that you file away all rough edges. Wipe both the sockets and the pipe ends and assemble the offset.

Make pencil lines along the pipe and fittings to ensure correct alignment. Then remove the pipe from the fittings and apply solvent cement round the spigots and inside the sockets.

Line up the pieces with the pencil marks and reassemble. Pressing them firmly together. I,eave the solvent to set before fitting the offset into position.

2. There are two types of clips that can be used with down-pipes.

One of these is one-piece while the other consists of a clip and backplate. Prepare the first length of downpipe by fixing a clip round the socket. Hold the offset in position after slipping its socket over the gutter outlet. Then place the downpipe in position so the offset spigot is held in its socket.

Use a spirit level to check the pipe is vertical and make sure of the position of the clip on the wall. If this falls in a poor spot for drilling, simply shorten the downpipe slightly to allow the clip to be re-positioned a little higher up.

Mark its position on the mortar and drill a hole with a 13mm masonry bit. Plug the hole and then fit the baseplate or clip and pipe in position.

Vertical joints in the down-pipe don’t have to be sealed with solvent: simply slot the offset end socket over the gutter outlet and the first downpipe socket over the offset end spigot. Then fix them into position. Clips should be fitted round every socket: again, just screw into mortar joints as the pipes are quite light.’ Intermediate pipe clips should be fitted at lm intervals on any downpipes exceeding 2m in length.

You must allow an expansion gap of 10mm between the spigot end and the bottom of the socket at each joint. Fit the pipe right into the socket and make a pencil mark on the outside to indicate its position. Lift the pipe 10mm and make another mark above the first. Use the lower of the two marks as a guide when fitting the pipe into position.

3. How your downpipe discharges its water will depend on the system of underground drainage. If you already have a trapped or open gully all you have to do is fit a ‘shoe’ section on the end of the downpipe.

Cut and fit the last length of pipe so that the shoe will sit about 50mm above the gully. You’ll have to use solvent cement again, as the joint isn’t vertical, and fit a clip. If you want to connect the pipe to the back inlet of a gully trap to take it direct to a drain then you’ll have to fit a special adaptor.

4.To check that the system works, pour water into the guttering and ensure that the shoe is positioned correctly.

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