Most waste pipes installed today are made of plastic, which is cheap, lightweight and easy to work with. A little practice and careful measuring will enable you to replace all parts of your system.

Waste systems draining baths, basins and sinks used to be made of lead, heavy galvanised steel with screwed joints, or copper. Soil pipes from WCs were traditionally cast iron, as was all the outside pipework for both waste and soil disposal. Nowadays waste and soil pipes are made of one or other of a variety of plastic materials, which may be used for repairs, extension work or complete replacement of an existing system. These plastic pipes are lightweight and easily cut, handled and joined.

They are made of materials usually known by the initials of their chemical names – UPVC (unplasticised polyvinyl chloride), MPVC (modified polyvinyl chloride), ABS (acrylonitrile butadiene styrene) and PP (polypropylene). CPVC (chlorinated polyvinyl chloride) is usually used for hot and cold water supply pipes. Pipes and fittings are available in white, grey or a copper colour, depending on type and manufacture. All these materials are satisfactory for domestic waste systems and – with one exception – can all be joined in the same way: either by push-fit (ring-seal) jointing or by solvent welding.

The exception is PP pipe. This was first developed because of its good resistance to very hot water and chemical wastes, and was therefore extensively used in industry. Nowadays, however, it is frequently used in the home for waste or rainwater drainage. The big difference between PP and other plastic pipes used in waste drainage is that it cannot be solvent-welded. All joints must be push-fit. In most situations this is no great disadvantage but it does make it important to be able to distinguish PP from other plastics. It has a slightly greasy feel and, when cut with a fine toothed saw, leaves fine strands of fibrous material round the cut edges.

Sizes of the waste pipes

When buying plastic pipe and components it is wise to stick to one brand only. Pipes and fittings from different makers, though of the same size, are not necessarily interchangeable. Most suppliers stock the systems of only one manufacturer, although the same manufacturer may make both PP and either PVC or ABS systems. It is worth asking the supplier if there is an instruction leaflet supplied by the maker. There are slight variations in the methods of using each particular make of pipe and fitting.

The manufacturer’s instructions, if available, should be followed to the letter. Buying new pipe Existing waste pipe is likely to be imperial in size – 11/2in internal diameter for a sink or bath and 11/4in internal diameter for a wash basin. Metric sized plastic pipes are normally described – like thin-walled copper tubes – by their external diameter, though at least one well-known manufacturer adds to the confusion by using the internal diameter. Both internal and external diameters may vary slightly – usually by less than one millimetre between makes. This is yet another reason for sticking to one make of pipe for any single project. The outside diameter of a plastic tube that is the equivalent of an imperial sized metal tube is likely to be 36mm and the inside diameter 32mm. The outside diameter of the equivalent of a 11/2in pipe is likely to be 43mm and the inside diameter 39mm.

If in doubt, it is usually sufficient to ask the supplier for waste pipe fittings for a basin waste or – as the case may be – a bath or sink waste. Plain-ended plastic pipe is usually supplied in 3m (10ft) lengths, though a supplier will probably cut you off a shorter piece. Joining solvent-weld types Solvent-weld fittings are neater and less obtrusive than push-fit ones and they offer the facility of pre-fabrication before installation. However, making them does demand a little more skill and care and – unlike push-fit joints – they cannot accommodate the expansion (thermal movement) that takes place as hot wastes run through the pipe.

A 4m length of PVC pipe will expand by about 13mm (just over Vfein) when its temperature is raised above 20°C (70°F). For this reason, where a straight length of waste pipe exceeds 1.8m (6ft) in length, expansion couplings must be introduced at 1.8m intervals if other joints are to be solventwelded. This rarely occurs in domestic design, however, and use of push-fit or solvent-weld is a matter of personal preference. Although the instructions given by the different manufacturers vary slightly, the steps to making solvent-weld joints follow very similar lines. Of course, the first rule is to measure up all your pipe lengths carefully. Remember to allow for the end of the pipe overlapping the joint. When you’ve worked out pipe lengths cutting can start.

Use this table as a guide to choosing new pipework – the first material mentioned is the best or most usual choice. Existing pipe copper lead iron stainless steel polythene UPVC New pipework copper, stainless steel, polythene iron, stainless steel, polythene stainless steel, copper, polythene polythene, copper, stainless steel copper, stainless steel, polythene

CONNECTING OLD TO NEW

Fitting metric to imperial pipework can be complicated by the slight differences in pipe diameters. The problem connections are: copper to copper (compression fittings)
• some metric fittings can be used directly with imperial-sized pipes (eg, 15mm fittings with 1/2in pipe and 28mm fittings with 1 in pipe)
• with other sizes you need to buy special adaptors or larger olives to replace those inside the fittings, so to connect a 15mm branch into existing 3/4in pipe you’ll need a tee 22 x 22 x 15mm with special olives for the 22mm ends of the tee. copper to copper (capillary fittings)
• metric capillary fittings with integral solder rings are not compatible with imperial pipes, but straight adaptors are available to connect the two sizes of pipe
• use these to join in short lengths of metric pipe, the other ends of which are connected to opposite ends of the metric tee
• with end-feed type fittings, extra solder can be added to make a good joint with imperial-sized pipe. copper to stainless steel – as for copper to copper connections, but usually compression fittings only. stainless steel to copper – copper to stainless steel. as above for stainless steel to stainless steel – copper to copper.

Improvements or additions to a domestic plumbing system inevitably involve joining new pipework into old. How you do this depends largely on whether the existing pipework is made of lead, iron or more modern materials – copper, polythene or even unplasticised PVC.

The principle of joining into existing pipework is quite straightforward. You decide where you will need your new water supply – at a bedroom basin or an outside tap. for example – and then pick a convenient point on the plumbing system to connect up your branch line’. At this point you have to cut out a small section of the old pipe and nsert a tee junction into which the branch pipe will be fitted. That’s all there is to it: laying the branch pipe will simply involve routine cutting bending and joining of new pipe, and final connection to the new tap or appliance at the other end. Before you can begin the job, however, you have to do some reconnaissance work to identify what sort of existing pipework you have.

You might be tempted to relate the plumbing to the age of the house, thinking that an old house will have an old system with lead or iron pipework. But this isn’t a reliable guide Many old properties have been modernised and so may actually have a more up-to-date system than a house built relatively recently.

Until the 1950s the only types of pipe used in domestic plumbing were lead and iron, but then these were superseded by thin walled copper piping Today there are’other alternatives too: stainless steel is sometimes used as an alternative to copper, and polythene and UPVC (unplasticised polyvinyl chloride) pipes can be installed for cold water supplies only for the type of pipe you can use. While copper is the most common one for new work, it must never be joined to galvanised iron because of the severe risk of electrolytic corrosion of the iron if the galvanising is not in perfect condition.

First things first

Before cutting into a pipe run you’ll first have to turn off the water supply to the pipe and then drain it by opening any taps or drain cocks connected to it. But this need not be too inconvenient if you make up the complete branch line before you turn the water off so you are without water only while you make the final branch connection.

Connecting into copper pipe

When taking a branch from a copper pipe it’s probably easier to use a compression tee fitting rather than a capillary fitting. A compression fitting can be made even if there is some water in the pipe run – capillary joints need the pipe to be dry – and you won’t have to worry about using a blow-torch and possibly damaging other capillary joints nearby (if they are heated up, their solder will soften and the joint will leak)

• It’s quite easy to work out how much pipe to cut out of the main run in order to insert a tee junction (of either compression or capillary fittings). Push a pencil or stick into the tee until it butts up against the pipe stop. Mark this length with your thumbs, then place the stick on top of the fitting so you can mark the outside to give a guide line. Next you have to cut the pipe at the place where the branch has to be made and prepare one of the cut ends . Now connect to the pipe the end of the tee that doesn’t have the guide line marked on the casing and rest the tee back against the pipe. You will now be able to see where the pipe stop comes to and you can then mark the pipe to give you the second cutting point.

Remove the section of pipe with a hacksaw and prepare the pipe end. With a compression fitting put on the other cap-nut and olive. If you gently push the pipe and tee sideways to the pipe run this will give you more room to position the body before you allow the pipe end to spring into place. When this is done the cap-nut can be pushed up to the fitting and can be tightened with your fingers. Both sides of the tee can then be tightened using your wrenches to give the cap-nuts about one-and-a-quarter turns. Remember that you must use a second wrench to grip the body of the fitting so it stays still as the cap-nut is tightened. If it should turn, other parts of the joint which have already been assembled will be loosened or forced out of position, and leaks will result.

The connection into the main pipe run is now complete and you can connect up the branch pipe. If you are using a capillary tee fitting there are a number of points to bear in mind. It’s easiest to use one with integral rings of solder (this saves the bother of using solder wire) and after the pipe ends and the inside rims have been prepared and smeared with flux the fitting can be ‘sprung’ into place. The branch pipe should also be inserted at this stage so all the joints can be made at the same time. When using the blow-torch, it is important to protect the surrounding area from the effects of the flame with a piece of glass fibre matting or the back of a ceramic tile. It’s also worthwhile wrapping damp cloths round any nearby capillary joints to protect them from accidental overheating and thus ‘sweating’.

Inserting a tee junction into lead pipe involves joining the run of the tee into two ‘wiped’ soldered joints. Join short lengths of new copper pipe into opposite ends of a compression tee. Measure the length of this assembly, and cut out 25mm (1 in) less of lead pipe. Join the’ assembly in with wiped soldered joints – a job that takes a lot of practice, and one you may prefer to leave to a professional plumber until you have acquired the skill. You then connect the branch pipe to the third leg of the tee.

Connecting into iron

Existing iron pipework will be at least 25 years old, and likely to be showing signs of corrosion. Extending such a system is not advisable – you would have difficulty connecting into it, and any extension would have to be in stainless steel. The best course is to replace the piping completely with new copper piping.

Connecting into polythene pipe

If you have to fit a branch into a polythene pipe it’s not a difficult job, especially if you use the same material. Polythene pipes are joined by compression fittings similar to those used for copper. Polythene hasn’t yet been metricated in the UK and each nominal pipe size has a larger outside diameter than its copper equivalent. So you’ll have to use either special gunmetal fittings for polythene pipe (still made to imperial sizes) or else an ordinary metric brass fitting a size larger than the pipe – 22mm for 1/2in polythene. You also need to slip a special metal liner inside the end of the pipe before assembling each joint to prevent the pipe from collapsing as the cap-nuts are tightened. In addition, polythene rings are used instead of metal olives in brass fittings. Apart from these points, however, inserting a tee in a length of polythene pipework follows the same sequence as inserting one into copper.

Connecting into UPVC pipe

As with polythene it’s an easy job to cut in a solvent weld tee – a simple collar fitting over the ends of the pipe and the branch. After you’ve cut the pipe run with a hacksaw you have to roughen the outsides of the cut ends and the insides of the tee sockets with abrasive paper and then clean the surfaces with a spirit cleaner and degreaser. Solvent weld cement is smeared on the pipe ends and the insides of the sockets, and the pipe ends are then ‘sprung’ into the sockets. You have to work quickly as the solvent begins the welding action as soon as the pipes meet.

Wipe surplus cement off immediately, and hold the joint securely for 15 seconds. After this you fit your branch pipe to the outlet of the tee.

One of the advantages of domestic copper pipe is that it’s easy to cut and bend. Few tools are required and even if you’ve only a few bends to make in a pipe run, it makes sense to know how it’s done. Making accurate bends may need some practice, but it’s cheaper than buying specially-shaped fittings.

In all plumbing water has to be carried from a source to a fixture and often then to some type of exit where it can disperse as waste. Basic to all of this is that water must run smoothly with nothing causing resistance to the flow — an important factor when the pressure is low. Generally the best plumbing practice is to make pipe runs as straight and direct as possible. But sometimes bends are unavoidable (like, for example, when pipe has to go around a room or to turn down into an area below) and if available fittings are neither right for the angle nor attractive to look at, then you’ll have to bend the pipe to suit.

Copper piping, because it is both light and resistant to corrosion, is a popular choice for home plumbing work. It can be joined with either capillary or compression fittings and when bends are needed you can create the angles in several ways. The first essential is to accurately work out the pipe lengths you require. Once you’ve made the measurement double check it — it’s quite easy to forget to allow for the pipe that will fit into the socket ends of the joints. You can make the actual marks on the pipe with pencil as this is clearly visible on copper and is a good guide when you come to cutting.

Cutting pipe accurately

For smaller pipe sizes, a sharp-bladed hacksaw is the best tool to use to make the cut. You’ll need to hold the pipe firmly, but if you use a vice be careful not to over-tighten the jaws and crush the bore of the pipe. It’s important to cut the pipe square so that it butts up exactly to the pipe stop in the joint. This will ensure the pipe is seated squarely in the fitting which is essential for making a watertight seal. It will also help to make that seal. It’s surprising how near to square you can get the end just cutting by eye. But the best way to make a really accurate cut is to use a saw guide. This can be made very easily by placing a small rectangle of paper round the pipe with one long edge against the cut mark. By bringing the two short edges of the paper together and aligning them you effectively make a template that’s square to the pipe.

All you then have to do is hold the paper in place and keep the saw blade against it as you cut. Any burr that’s left on the cut edges can be removed with a file. If you intend to carry out a lot of plumbing, or are working mainly in the larger pipe sizes, it may be worthwhile buying (or hiring) a wheel tube cutter. Of course using one of these is never absolutely essential, but it does save time if you’ve more than, say, half a dozen cuts to make. And once you have one you’ll use it for even the smallest jobs. It’s quick to use and will ensure a square cut without trouble every time. You simply place the pipe in the cutter and tighten the control knob to hold it in place. The cutter is then rotated round the pipe and as it revolves it cuts cleanly into the copper. This circular action automatically removes burr from the outside of the pipe, but burr on the inside can be taken away with the reamer (a scraping edge) which is usually incorporated in the tool.

Bending copper pipe

If a lot of changes of direction are necessary in a pipe run it’s cheaper and quicker to bend the pipe rather than use fittings. This also makes the neatest finish particularly if the pipework is going to be exposed. Under a pedestal wash-basin, for example, the hot and cold supply pipes rise parallel to each other in the pedestal before bending outwards and upwards to connect to the two tap tails.

Using fittings in this situation would be more costly as well as possibly being unsightly, while the cheaper alternative, making bends, means the pipework is less conspicuous. The pipe can also be bent to the exact angle required so this method of changing direction is not limited by the angles of the fittings. And with fewer fittings in a pipe system there are fewer places where leaks can occur.

The smaller sizes of copper pipe, those most commonly used in domestic plumbing (15mm, 22mm and 28mm), can be bent quite easily by hand. The technique of annealing — heating the pipe to red heat in the vicinity of the bend to reduce its temper (strength) and so make bending easier — is unnecessary when working in these pipe sizes. But you will need to support the pipe wall, either internally or externally, as the bend is made. If you don’t you’ll flatten the profile of the pipe. Using it in this condition would reduce the flow of water at the outlet point. For small jobs a bending spring is the ideal tool, supporting the pipe internally.

It is a long hardened steel coil which you push into the pipe to the point where the bend will be made. It’s best used for bends near the end of the pipe, since the spring can be easily pulled out after the bend is made. However, it can be used further down the pipe if it is attached to a length of stout wire (which helps to push it into place, and is vital for retrieving it afterwards).

Bending techniques

You actually bend the pipe over your knee, overbending slightly and bringing back to the required angle. The spring will now be fixed tightly in the pipe and you won’t be able simply to pull it out. However, its removal is quite easy. All you have to do is to insert a bar — a screwdriver will do — through the ring at the end of the spring and twist it. This reduces the spring’s diameter and will enable you to withdraw it. It’s a good idea to grease the spring before you insert it as this will make pulling it out that much easier.

Slight wrinkles may be found on the inside of the bend, but these can be tapped out by gentle hammering. It’s wise not to attempt this before taking out the spring. If you do you’ll never be able to remove it. Bending springs are suitable for 15mm and 22mm diameter pipe. But although it is possible to bend 28mm pipe as well, it’s advisable to use a bending machine instead. This is also preferable if you have a lot of bends to make. And if you don’t want to go to the expense of buying one, you can probably hire a machine from a tool hire shop.

A bending machine consists of a semicircular former that supports the pipe externally during the bending operation and a roller that forces the pipe round the curve when the levers of the machine are brought together. The degree of bend depends on how far you move the handles.

Flexible pipe

This is a kind of corrugated copper pipe which can be bent easily by hand without any tools. You can buy it with two plain ends for connection to compression joints or with one end plain and one with a swivel tap connector for connection to a tap or ball-valve. As it’s the most expensive way of making a bend, it’s not cost effective to use it when you have to make a number of changes of direction in a pipe run. It’s not particularly attractive to look at so it is best used in places where it won’t be seen. As such it’s most commonly used for connecting the water supply pipes to the bath taps in the very confined space at the head of the bath. And it can make the job of fitting kitchen sink taps easier, particularly when the base unit has a back which restricts access to the supply pipes.

For cutting pipe:
• hire a wheel tube cutter (which ensures perfectly square pipe ends) or use a hack saw
• use a metal file for removing ragged burrs of metal and for squaring ends of pipe that have been cut with a hacksaw. A half-round ‘second-cut’ type is ideal.

For compression joints:
• use two adjustable spanners or pipe wrenches (one to hold the fitting, the other to tighten the cap-nut)
• steel wool to clean the surface of pipes before assembling a joint.

For capillary joints:
• a blow-torch to melt the solder
• steel-wool for cleaning pipe surfaces
• flux to ensure a good bond between the solder and copper
• solder because even if you’re using integral ring fittings (which already have solder in them) you may need a bit extra
• glass fibre mat (or a ceramic tile) to deflect the torch flame from nearby surfaces.

TIP: CUTTING PIPE SQUARELY
For a perfect fit, pipe ends must be cut square. If you’re using a hacksaw, hold a strip of paper round the pipe so its edges align and saw parallel to the paper edge. Use the same trick if you have to file an inaccurately-cut end.

TIP: PROTECT NEARBY JOINTS
With capillary fittings, the heat you apply could melt the solder in nearby fittings. To help prevent this, wrap them in wet cloths.

Types of capillary joint

The most common type of capillary joint has a ring of solder pre-loaded into the sleeve. It is known as an integral ring or ‘Yorkshire’ fitting -the name of a leading brand. The end feed’ type of capillary joint is virtually the same as an integral ring fitting, but you have to add the solder in a separate operation. The sleeve is slightly larger than the pipe and liquid solder is drawn into the space between by capillary action.

Flux and solder

Essential in the soldering operation, flux is a chemical paste or liquid which cleans the metal surfaces and then protects them from the oxides produced when the blowtorch heats the copper so a good metal solder bond is formed. Mild non-corrosive flux is easy to use as it can be smeared onto the pipe and fitting with a clean brush or even a finger. Although it is best to remove any residue this will not corrode the metal. There is an acid-corrosive flux which dissolves oxides quickly, but this is mostly used with stainless steel. The corrosive residue must be scrubbed off with soapy water. Solder is an alloy (mixture) of tin and lead and is bought as a reel of wire. Its advantage in making capillary joints is that it melts at relatively low temperatures and quickly hardens when the heat source (blow-torch) is removed.

Blow-torches

A blow-torch is an essential piece of equipment when making capillary joints. It is easy, clean and safe to use providing you handle it with care. Most modern torches operate off a gas canister which can be unscrewed and inexpensively replaced (larger cans are relatively cheaper than small). Sometimes a range of nozzles can be fitted to give different types of flames, but the standard nozzle is perfectly acceptable for capillary joint work.

Using a blow-torch

When using a blow-torch it’s most convenient to work at a bench, but you’ll find most jointing work has to be carried out where the pipes are to run. Pipework is usually concealed so this may mean working in an awkward place, such as a roof space, or stretching under floorboards. However, always make sure you are in a comfortable position and there’s no danger of you dropping a lighted blow-torch.

When working near to joists and floorboards, glass, paintwork and other pipework with capillary joints it is important to shield these areas with glass fibre matting.

Applying the heat

When making a capillary joint gradually build up the temperature of the copper by playing the flame up and down and round the pipe and then to the fitting. When the metal is hot enough the solder will melt and you can then take away the flame. The joint is complete when a bright ring of solder appears all round the mouth of the fitting. Stand the torch on a firm level surface and turn it off as soon as you have finished. Where two or more capillary joints are to be made with one fitting, for example the three ends of a tee, they should all be made at t he same time. If this is not possible wrap a damp rag round any joints already made.

Repairing a compression joint

If a compression joint is leaking and tightening of the cap-nut doesn’t produce a watertight seal you’ll have to disconnect the fitting and look inside – after turning off the water supply. If a cap-nut is impossible to move, run a few drops of penetrating oil onto the thread. If that doesn’t do the trick, you’ll have to cut it out and replace the fitting and some piping. Once you have unscrewed one of the cap-nuts there will be enough flexibility in the pipe run to pull the pipe from the casing. Usually the olive will be compressed against the pipe. First check that it is the right way round and if it isn’t replace it with a new one making sure that it is correctly set. Sometimes the olive is impossible to remove and needs to be cut off with a hacksaw – make the cut diagonally. Reassemble the joint following the procedure on page 182 and repeat the operation for the other end of the pipe. Turn on the water supply to check that the repair is watertight.

Repairing a capillary joint

Poor initial soldering is usually the reason why a capillary fitting leaks. You can try and rectify this by ‘sweating’ in some more solder but if this doesn’t work you’ll have to remake the joint. Play the flame of the blow-torch over the fitting and pipe until the solder begins to run from the joint. At this stage you can pull t he pipe ends out of the sockets with gloved hands. You can now reuse the fitting as an end feed joint or replace it with a new integral ring capillary connection. If you reuse the fitting clean the interior surface and the pipe ends with abrasive paper or steel wool and smear them with flux. Then follow the procedure for making an end feed capillary joint.

Capillary fittings are
• cheap to buy
• unobtrusive when fitted
• useful in confined spaces
• very quick to install – and to unmake during alterations, BUT
• using them requires a blow-torch to melt the solder
• if the joint leaks you have to completely remake it.

SAFETY TIPS
When using a blow-torch always
• wear thick heat-resistant gloves
• put down a lighted blow-torch on a firm flat surface with the flame pointing into space
• clear any flammable material from the area where you are working

Compression fittings are
• easy to assemble – you’ll only need two wrenches or adjustable spanners – BUT
• they’re much more expensive than capillary fittings
• they are much bulkier and obtrusive on exposed pipe runs
• in awkward places you may not be able to get wrenches in to tighten up the joint. Leaks can sometimes be cured by further tightening.

Joining copper pipe is one of the basic plumbing skills. Compression and capillary joints are easy to make and once you’ve mastered the techniques, you’ll be prepared for a whole range of plumbing projects.

Connecting pipes effectively is the basis of all good plumbing as most leaks result from poorly constructed joints. For virtually ail domestic plumbing purposes you will only have to use compression or capillary joints. Compression joints are easy to use but expensive, while capillary joints are cheap but need some care in fitting. If you are making a join into an existing pipe system remember to make sure the water supply has been turned off at the relevant stop-valve either on that section or below the cold water storage cistern, and the pipe has been completely drained.

Preparing the pipes

Before joining pipes together, check that the ends are circular and have not been distorted. If they have been dented, cut back to an undamaged section of the pipe using a hacksaw with a sharp blade or a wheel tube cutter. The ends should also be square. Use a file to make any correction and remove ragged burrs of metal. If you’re using a capillary joint clean up the sides of the pipe with abrasive paper or steel wool.

Compression joints (friction joints)

A compression joint, as its name implies, is made by compressing two brass or copper rings (known as olives or thimbles) round the ends of the pipes to be joined, so forming a watertight seal. There are two main types of compression joint – the non-manipulative fitting and the manipulative fitting. Although not the cheapest means of joining a pipe, a non-manipulative joint is the easiest to use and requires only the minimum of tools. It comprises a central body made of brass or gunmetal with a cap-nut at each end which, when rotated, squeezes the olive tightly between the pipe end and the casing. This is the most commonly used type of compression joint suitable for most internal domestic plumbing purposes.

A manipulative joint is now rarely used in indoor domestic water systems. Because it cannot be pulled apart it is sometimes used for underground pipework, but capillary joints will do equally well in these situations. The joint usually comprises a male and a female union nut. These are slipped over the pipe ends which are then flared (‘manipulated’) using a special steel tool called a drift. Jointing compound is smeared on the inside of the flares and a copper cone is inserted between them. The nuts are then screwed together to complete the seal.

How a compression joint works

The olive (thimble) is the key part of a non-manipulative compression joint. When the cap-nut is rotated clockwise the olive is forced between the casing and the pipe and is considerably deformed in the process.

A watertight seal is dependent upon the pipe ends having been well prepared so they butt up exactly to the pipe stop in the casing. This forms a primary seal and ensures that the pipe is parallel to the movement of the rotating cap-nut. An even pressure is then applied to the olive so that it does not buckle under the strain of tightening.

What size of pipework and fittings?

Pipework is now sold in metric dimensions, but plumbing in your home may be in imperial sizes. The metric sizes are not exactly the same as their imperial equivalents. These differences can cause problems. With capillary joints you have to use adaptors when converting pipe from one system to another. Adaptors are also needed for some compression joints although the 12mm, 15mm, 28mm and 54mm sizes are compatible with their imperial equivalents. This means if you already have imperial compression joints you can connect in new metric pipework, without replacing the joints. Adaptors are made with different combinations of metric and imperial outlets to fit most requirements. A plumbing supplier or a plumber will advise on what replacements to use.

Capillary joints

A capillary joint is simply a copper sleeve with socket outlets into which the pipe ends are soldered. It is neater and smaller than a compression joint and forms a robust connection that will not readily pull apart. Because it is considerably cheaper than a compression joint it is frequently used when a number of joints have to be made and is particularly useful in awkward positions where it is impossible to use wrenches. Some people are put off using capillary fittings because of the need to use a blow-torch. But modern gas-canister torches have put paid to the fears associated with paraffin lamps and are not dangerous.

How a capillary joint works

If two pipes to be joined together were just soldered end to end the join would be very weak because the contact area between solder and copper would be small. A capillary fitting makes a secure join because the sleeve increases this contact area and also acts as a brace to strengthen the connection. Molten solder is sucked into the space between the pipe and fitting by capillary action, and combines with a thin layer of copper at the contact surface thus bonding the pipe to the fitting. To help the solder to take’ the copper needs to be clean and shining, flux is applied to prevent oxides forming which would impair the solder-copper bond.

EQUIPMENT CHECKLIST

For replacing existing taps, you will need the following tools and equipment:

• new taps of the right type and size
• an adjustable spanner
• a basin wrench (‘crowsfoot’)
• an adjustable wrench
• penetrating oil
• plastic washers
• plumber’s putty
• PTFE tape You may also need tap tail adaptors (if the new taps have shorter tails than the old ones) and new tap connectors (if your new taps have metric tails instead of imperial ones).

WHAT ABOUT WASHERS?

With ceramic basins, use a plastic washer above and below the basin surface so you don’t crack the basin as you tighten the back-nut.
You can use plumber’s putty instead of the upper washer. On thin basins, use a special top-hat washer between basin and back-nut.

TIPS TO SAVE TROUBLE

• to undo stubborn back-nuts, add extra leverage to the crowsfoot by hooking a wrench handle into its other end
• if this fails, squirt penetrating oil around the back-nuts. Leave for a while and try again
• in really stubborn cases, remove the basin completely, and turn it upside down on the floor so you have more room to work
• grip the tap body with an adjustable spanner to stop it turning as you use the crowsfoot; otherwise the tap lugs could crack the basin

Changing the old taps on your basin is a bright and practical way of making your bathroom more attractive. It may also be a good idea if they are old and inefficient.

There may be a number of reasons why you wish to replace the taps supplying your sink, basin or bath. They may continually drip or leak, where new taps would give efficient, trouble-free service. Perhaps you want the advantages that mixers have over individual taps or perhaps it is simply that the chromium plating has worn off leaving the taps looking incurably shabby. It is more likely, however, that appearance, rather than malfunction, will be your reason for changing. There are fashions in plumbing fittings as in clothing and furniture. Taps of the 1950s or 60s are instantly recognisable as out-of-date in a bathroom or kitchen of the 1980s. Fortunately, fashions in sinks, basins and baths have changed rather less dramatically over the past three decades. There is probably no more cost-effective way of improving bathroom and kitchen appearance than by the provision of sparkling new taps or mixers.

Choosing taps

When you come to select your new taps you may feel that you are faced with a bewildering choice. Tap size, appearance, the material of which the tap is made, whether to choose individual taps or mixers and – for the bath – whether to provide for an over-bath shower by fitting a bath/shower mixer: all these things need to be considered. Size is easily enough dealt with. Old taps and mixers might be in imperial sizes.

There are, however, most suppliers designate taps by the metric size, not of the taps themselves, but of the copper supply pipes to which they will probably be connected. Such a supplier might refer to bath taps as 22mm and sink and basin taps as 15mm. Most taps are made of chromium-plated brass, though there are also ranges of enamelled and even gold-plated taps and mixers. Although taps and mixers are still manufactured with conventional crutch or capstan handles, most people nowadays prefer to choose taps with ‘shrouded’ heads made of acrylic or other plastic. In effect, these combine the functions of handle and easy-clean cover, completely concealing the tap’s headgear. A still popular alternative is the functional .

‘Supatap’, nowadays provided with plastic rather than metal ‘ears’ for quick and comfortable turning on and off. There is also a very competitively priced range of all-plastic taps. These usually give satisfactory enough service in t he home, but they cannot be regarded as being as sturdy as conventional metal taps, and they can be damaged by very hot water. So far as design is concerned the big difference is between ‘bib taps’ and ‘pillar taps’. Bib taps have a horizontal inlet and are usually wall-mounted while pillar taps have a vertical inlet and are mounted on the bath, basin or sink they serve.

Taking out old basin taps

When replacing old taps with new ones the most difficult part of the job is likely to be – as with so many plumbing operations – removing the old fittings. Let’s first consider wash basin taps. You must, of course, cut off the hot and cold water supplies to the basin. The best way of doing this will usually be to tie up the float arm of the ball valve supplying the cold water storage cistern so as to prevent water flowing in. Then run the bathroom cold taps until water ceases to flow. Only then open up the hot taps. This will conserve most of the expensively heated water in the hot water storage cylinder. If you look under the basin you will find that the tails of the taps are connected to the water supply pipes with small, fairly accessible nuts, and that a larger – often inaccessible – back-nut secures the tap to the basin.

The nuts of the swivel tap connectors joining the pipes to the taps are usually easily undone with a wrench or spanner of the appropriate size. The backnuts can be extremely difficult – even for professional plumbers! There are special wrenches and basin or ‘crows foot’ spanners that may help, but they won’t perform miracles and ceramic basins can be very easily damaged by heavy handedness. The best course of action is to disconnect the swivel tap connectors and to disconnect the trap from the waste outlet. These are secured by nuts and. are easily undone. Then lift the basin off its brackets or hanger and place it upside down on the floor.

Apply some penetrating oil to the tap tails and, after allowing a few minutes for it to soak in, tackle the nuts with your wrench or crowsfoot. spanner. You’ll find they are much more accessible. Hold the tap while you do this to stop it swivelling and damaging the basin. Fitting the new taps When fitting the new taps or mixer, unscrew the back-nuts, press some plumber’s putty round the tail directly below the tap body or fit a plastic washer onto the top tail.

Push the tails through the holes in the basin. Slip flat plastic washers over the tails where they protrude from beneath the basin, screw on the back-nuts and tighten them up. Make sure that the taps or mixer are secure, but don’t overtighten them. To make tightening • easier, (and undoing, if ever necessary) use top-hat washers. All that remains to be done is to connect the swivel tap connectors to the tails of the new taps or mixer. You will see that a tap connector consists of a lining – with a flange – that is inserted into the tap tail and is then secured by the coupling nut.

This nut is provided with a washer to ensure a watertight connection. When renewing taps you may well need to renew this small washer. It is possible that when you come to connect the water supply pipes to the taps you will get an unpleasant surprise. The tails of modern taps are slightly shorter than those of older ones and the tap connectors may not reach. If the water supply pipes are of lead or of copper it is quite likely that they will have enough ‘give’ to enable you to make the connection but, if not, there are extension pieces specially made to bridge the gap.

Bib taps

If you’re replacing existing bib taps with those of a more modern design, it’s a relatively simple matter of disconnecting and unscrewing the old ones and fitting the new taps in their place. However, it’s quite possible that you’ll want to remove the bib taps altogether and fit a new sink with some pillar taps. This will involve a little more plumbing work. To start with, turn off the water supply and remove the taps and old sink. If the pipework comes up from the floor, you’ll need to uncover the run in the wall to below where the new sink will go. You should then be able to ease the pipes away from the wall and cut off the exposed sections.

This will allow you to join short lengths of new pipe, bent slightly if necessary, to link the pipe ends and the tap tails. Alternatively, if the pipes come down the wall you’ll have to extend the run to below the level of the new sink and use elbow fittings to link the pipe to the tap tails. In either case it’s a good idea to fit the taps to the new sink first and to make up the pipework runs slightly overlong, so that when the new sink is offered up to the wall you can measure up accurately and avoid the risk of cutting off too much pipe. Rather than having to make difficult bends you can use lengths of corrugated copper pipe. One end of the pipe is plain so that it can be fitted to the 15mm supply pipes with either a soldered capillary or compression fitting; the other end has a swivel tap connector.

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