ISSUE 08/08

BUILDING REGULATIONSIf you are altering your existing drainage, or installing a new drainage system you mustalways inform the Building Control Department at your local council offices. You mustpresent plans of the work that you are undertaking and have your work inspected toensure that it complies with The Building Regulations. However, if you are simply replacing damaged sections, they do not need to becontacted.

DRAINAGE SYSTEMSThere are two types of drainage water: (1) Foul water (2) Surface water. Foul water consists of anything that comes from bathrooms, kitchens, utility rooms, carwashing areas etc. This must always go to your foul water drain system.Surface Water is rainwater only. In older properties, the existing rainwater pipes are often discharged to the foul drain.This system is known as combined drainage. In a combined system, the rainwaterpipes are discharged via gully traps, to stop foul air escaping from the drains. Modern systems keep the foul water and the surface water apart in separate drains.This is known as a separate drainage system. With this method, the rainwater isdischarged either to a soakaway, watercourse or surface water sewer. Drainingrainwater to these points does not create foul air. It is extremely important to ensurethat you do not connect foul water to a surface water drainage system. NOTE: if you are unsure about the drainage system around your house get advicefrom the Building Control Department before starting any work.

LUBRICATIONWhere a pipe or fitting needs to be lubricated, always use Wickes Silicone Lubricant432-013 to ease the connection. Never use washing-up liquid / oil or grease, as this will damage the seal causing it toleak.

DRAINAGE FITTINGSWickes 110mm diameter drain pipes and fittings are made in PVCu to BSEN1401 andBS4660 and are compatible with all plastic drain pipe systems. Underground drainpipes must be a golden brown colour to distinguish them from otherburied services.

UNDERGROUND DRAINAGEWickes stock a wide rangeof drainage products,whether it’s to replace olddrainage systems in theevent of collapse, or installnew during homeimprovements.

The purpose of this leaflet isto provide you with basicdetails on what you may findunderground. How to dealwith different types ofmaterials that have beenused over recent years i.e.clay, ductile iron, cast ironand PVCu, showing you howto join new to old.

Providing you with a basicunderstanding of theregulations governing andtesting, of undergrounddrainage. Whilst trying tohelp you avoid some of thepitfalls.

74

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• Check that your Good IdeaLeaflets are kept up to date.Leaflets are regularly changedto reflect product changes sokeep an eye on issue dates.

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Never use black soil pipe underground,the Building Control Officer will tell you toreplace this, using the correct drainagepipe and fittings.

The pipes are jointed by push fit sockets.FIG.1 shows the jointing procedure forunderground drainage.Generally, soil and waste pipes from thehouse are joined to the underground foulwater drainage by the following twomethods:• REST BEND 432-008. This is a largeradius bend, used to connect soil stacksand ground floor sanitary appliances tothe drains. The Rest Bend allows drainrods and the soil from the toilet pan topass easily to the drains. In singledwellings of up to three storeys, thebottom of the bend should never be lessthan 450mm below the lowest groundfloor connection into the soil stack, as canbe seen in FIG.2. FIG.3 shows that whena ground floor WC discharges direct to adrain, the distance between the pan outletand the bottom of the Rest Bend must beless than 1.5 metres.

• GULLIES. A gully holds water like atrap, to stop foul air escaping from thedrains. One of its purposes is to acceptwastewater from ground floor bathrooms,kitchens and utility rooms. Wickes supplythe Roddable Bottle Gully 432-002 andthe Multi Gully Trap 432-053. TheRoddable Bottle Gully has a removablegrating and a quarter turn rodding accesscap. This enables the gully to be cleanedout and the drains to be rodded if ablockage should occur. It has one 110mmoutlet and three closed inlets for eitherwaste pipe or 110mm connections. A 110mm pipe can be glued directly intothe side inlets after the centre has beenremoved. Should you wish to dischargeyour waste pipes to this gully, adapt thesmaller closed inlets by drilling them outwith a 48mm hole cutter and inserting theappropriate rubber reducer (431-950 and431-951) to accept the 32mm and 40mmwaste pipe. These items will be found inthe soil and waste range of products.Where a Roddable Gully is not required,the Multi Gully Trap may be used. A square hopper and grating act as theinlet into the gully trap. Hoppers are joinedto gully traps with a short piece of 110mmdiameter drain pipe. Glue the hopper tothe pipe and push the chamfered andlubricated end into the socket of the gullytrap. The waste pipe should pass throughthe grating and stop above the water line.A 45° or 90° drain bend is fitted to thegully to achieve the required angle of theoutlet, as seen in FIG.4.

FIG.5&6 show that as well as wastewaterfrom domestic appliances, the Bottle Gullymay be used to receive rainwater frompaved areas and roofs.The RainwaterGully 158-828 is designed to be the

1. Cut pipe square, using a fine tooth saw. Wrappaper around pipe as guide line.

2. Chamfer end of pipe, using medium file orrasp. Standard lengths of pipe are already chamfered.

3. Remove swarf, dust and filings from end ofpipe.

4. Lubricate end of pipe.

5. Check that ring seal is in position in housing. 6. Push pipe fully home mark lightly with pencil.

7. Spigot fittings will have mark already shown. 8. Withdraw pipe (10mm). This will allow forexpansion. All fittings must be supported by abracket when installed vertically.

JOINTING PROCEDURE FOR UNDERGROUND DRAINAGE

FIG.1

10mm

FIG.2 FIG.3

450mmMIN.

CROWN OF TRAP

INVERT OF DRAIN

1.5m MAX.

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connecting point between a rainwaterdownpipe and a soakaway drain.68mm downpipes are simply connected tothe top inlet. The outlet is 110mm pipespigot sized.The cover can be lifted to allow theremoval of debris such as leaves. Thegully can be rodded should the drainbecome blocked.The 68mm Rainwater Reducer (432-009)is used to connect the 68mm circularrainwater pipe directly to the drain. It isfitted over a section of chamfereddrainpipe, lubricated and pushed into theMulti Gully Trap. Use the square-to-roundadaptor (432-040) with the reducer toenable 65mm square rainwater pipes tobe connected to the drain.The Roddable Bottle Gully and the MultiGully Trap should be supported by eithera lean mix of concrete (no richer than1:18) or a ready made concrete slabbefore surrounding them with granularbackfill. To ensure a gully is easilyaccessible for cleaning out, the baseshould be within easy reach from groundlevel. Refer to FIG.4.Due to the tightness of the trap bend, theMulti Gully Trap is not roddable, it shouldtherefore be connected to the nearestmanhole. If possible the Roddable Gullyshould be connected to a manhole also,but as it is roddable it may be positionedup to 22 metres away from one. It can beconnected straight into a drainpipesection with a 45° junction. (432-005)However, the Gully must be less than 12

metres from the drain and a set of drainrods must be able to pass right through tothe junction. If the drain is made of clay,convert it to plastic by using two suitabledrain connectors. Full details are givenlater in this leaflet.

PIPE LAYINGWhen a PVCu pipe passes through a wallof a building, a lintel should be built inabove the opening which has beenformed to give at least 50mm clearanceall round the pipe. The hole should becovered with a rigid sheet to prevent theentry of soil or vermin. See FIG.8. Otheralternatives can be discussed with theBuilding Control Officer.

TRENCH PREPARATIONA drain trench should not impair thestability of a building. When drains are laidparallel to the foundations, care should betaken that the foundations are notundermined. See FIG.9. When installing anew drainage system do not dig thetrench too long before laying the pipe.Then backfill as soon as possible afterhaving the system inspected and tested.For maximum safety it should be open forthe minimum time and the trench wallsshould be adequately supported.The trench should be as narrow aspossible for at least 300mm above the topof the pipe. To permit room to work in thetrench allow the width of the pipe plus150mm on each side.

BACKFILLINGThe material dug from the trench may besuitable to surround the pipe but it willneed to be examined to ensure that itmeets the required standard.Always reject any material that has sharpedges such as broken bricks. Themaximum particle size should generallynot exceed 20mm but occasional particlesup to 40mm may be acceptable as longas they are only a small fraction of thetotal quantity.

When the dug material is not suitable asbackfill a nominal 10mm sized aggregatecomplying with BS882: Part 2 must bespread evenly on the trimmed trench bottom before the pipes are installed.

The trench should be excavated to allowfor a 100mm thickness of the granularbedding under the pipe.NOTE: Bricks and / or other hardmaterials will damage the pipe, this mustnever be used as temporary orpermanent support. The bedding should be properlycompacted with shallow hollows made toaccommodate the pipe sockets. Thisprovides continuous and uniform supportfor the pipe.After inspection and testing of thedrainage the granular material should beevenly backfilled and compacted to adepth of at least 100mm above the pipe.Above this, the original dug material isused to further backfill the trench. Itshould be compacted in 300mm layers.Do not use heavy compactors until thereis at least 300mm of cover but lightvibratory tampers may be used sensiblyto aid compaction. FIG.10 shows a typicaltrench cross section.

NOTE: When drains are located underroads / pavements seek specialist advice in relation to backfill.

GRADIENTS110mm diameter main foul water drainsthat carry the discharge from multiple soilstacks and buildings may be laid at a fallof not less than 1:80 (12.5mm fall permetre). However, branch drains fromindividual gullies, sanitary fittings or soilstacks should be laid at a steepergradient of 1:40 (25mm fall per metre).110mm diameter main surface waterdrains that carry the discharge frommultiple rainwater pipes may be laid at afall of not less than 1:100 (10mm fall permetre), while branch drains fromindividual rainwater pipes should be laidat a steeper gradient of 1:50 (20mm fallper metre).

PROTECTIONAny part of the drain system that is lessthan 600mm below a garden should beprotected from damage by garden tools. Apreformed concrete slab should be buried100mm above the top of the drain if thesystem is not protected by paving orconcrete at ground level.

FIG.4 FIG.6

FIG.5

WASTE PIPE

GROUND LEVEL

PROTECTIVE LAYER(E.G. BELOW PAVING SLAB)

MAX DEPTH 305mm BELOWGROUND LEVEL

GRANULAR FILL

RAINWATER PIPE

FOOTPATH

BOTTLE GULLY

110mm PIPETO DRAIN

BOTTLE GULLY

RUN-OFF SURFACE WATER

CONCRETE BED

110mm PIPE

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NOTE: Where flexible pipes are in a road andwhere adequate cover cannot beprovided, the pipes should be protectedby concrete encasement not less than100mm thick and having movement jointsformed with compressible board at eachsocket or sleeve joint face.

CLEARING BLOCKAGESYour drainage system must be designedso that all parts of the pipework areaccessible to a set of drain rods. Thismeans that a drain route should be asstraight as possible between two points.Nevertheless bends are allowed in thesystem but should not be less than 45°and should be positioned near to anaccess point within the system.

ACCESS TO DRAINAGE SYSTEMCOMPONENTS

W.C. Pans, whether on wood or concretefloors, should always be screwed to thefloor. The joints between the pan and floorand the pan and drainpipe should neverbe made with a cement mortar mix. Thisensures that the pan can be easilydisconnected if it is necessary to removea difficult blockage in the pipe.

MANHOLES AND CHAMBERSFIG. 7 shows Wickes InspectionChambers allow easy access to thedrainage system for maintenance,inspection and the removal of debris. Traditional manholes can be built aroundchannel pipe and fittings, while preformedplastic inspection chambers are a simplepush-fit assembly.Manholes and inspection chambers

should be provided in the followingsituations:1. At all changes in direction (exceptwhere the change is not too great forrodding).2. At all changes in gradient (exceptwhere the change is not too great forrodding).3. At all drain junctions that areinaccessible to a set of drain rods.4. Where a junction between two drainsdoes not have a manhole. Access shouldbe sited on the branch drain within 12metres of the junction.5. At the head of each run of drain.6. At changes in pipe diameter.

INSPECTION CHAMBERS 250 & 450mmWickes Inspection Chambers have beendesigned to offer easier and moreeconomical alternatives to traditionalconstruction methods. They are made of atough polypropylene material, are impactresistant, simple and straightforward toinstall.The chamber raising pieces are designedfor simple dry jointing, providing aninstant watertight joint. They havestrengthening ribs and webbing. Theraising pieces can be simply built-up tothe required overall height between thechamberbase and cover.Both Wickes 250 & 450mm pre-formedunits comply with all current regulations.They are designed with a built-in fall forgood flow performance.Wickes 250mm diameter, three waste portinspection chambers allow easy access todrains within close proximity to any building.

*NOTE: Whilst the 45° rule is a good guide, thetrench should be open for the minimumtime and the trench walls must beadequately supported. Even greater caremust be taken when trenching in sandy,gravel, loose or saturated soils. If in anydoubt, seek professional advice.

The chamber base accepts up to threeconnections and comes complete with tworemovable blanking plugs to seal anyunused inlets. Two 45° swept side inletsand one rear entry inlet allows for anefficient flow into the main 110mm channel. The full assembly comprises a base(432-028); two raising pieces (432-029)and a round aluminium cover (432-004).CHART A SHOWS THE DEPTH OF THECUT RISER

FIG.8

NEVER EXCAVATE FOR DRAINAGE IN THIS ZONE AS IT MAY UNDERMINE FOUNDATIONS

DRAIN TRENCHGROUND LEVEL

*45º

FIG.9

‘A’ LESS150mm

CONCRETE

DRAIN

WHEN ‘A’ IS MORETHAN 1 METRE ANDTRENCH BOTTOM ISLOWER THANFOUNDATIONSINFILL TRENCHWITH CONCRETE ASSHOWN

DRAIN TRENCHGROUND LEVEL

‘A’

PIPEPENETRATING

WALLS

LINTELLED OPENINGTO GIVE 50mm CLEARANCE ALLROUND THE PIPE

50mm

50mm

COVER BOTH SIDESOF OPENING WITH

RIGID SHEET MATERIAL TO

PREVENT ENTRYOF SOIL ORRODENTS

PIPE

A. 432-001 Underground Pipe 3mB. 432-008 87.5˚ Rest BendC. 432-004 Chamber Aluminium CoverD. 432-029 Chamber Raising PieceE. 432-028 Shallow Access Chamberbase

FIG.7

CHART AASSEMBLY DEPTHincluding cover in mmBase 155mmBase + 1 Riser 355mmBase + 2 Risers 565mm

*

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A square top system is also available,making for easy installation of patio &driveway paving blocks and slabs.NOTE: To allow easy removal of debrisfrom the 250mm-chamber assembly, itmust never be deeper than an armslength (600mm).The 450mm chamberbase unit comprise four swept inlets at 90° and 45° andcomes complete with three removableblanking plugs to seal any unused inlets.The assembly comprises a base (435-228); raising pieces (435-229) and plasticcover (435-230).Pre-formed 450mm diameter chamberbases and risers with 450mm diametercovers can be used up to 1200mm indepth. Up to this depth, they will officiallybe known as shallow inspectionchambers.

DRAIN CONNECTORSTo simplify the modification of yourexisting drainage system Wickes have twotypes of drain connector.If you are connecting to an existing drain,the age of your property may indicate thetype of drains you have. However you willneed to carefully expose the drain todetermine what it is made of i.e. PVCu orclay.All underground drainage pipes are agolden brown (old clay drains tend to be adarker brown); to distinguish them fromother buried services.For recognition, PVCu drain pipework iseasily scored with a pointed object. It’seasily cut with a multi purpose saw and isjointed with push-fit fittings.There are two types of clay drain:

• Vitrified ClayThis is the most modern form of claydrainpipe and is recognised by its smoothmatt finish and black polypropylenecouplings. The pipes are approximately1600mm long.You can dismantle this type of vitrifiedclay pipe at a coupling, or it may besimpler to cut the pipe with an anglegrinder and leave a chamfered pipe end.

NOTE: Vitrified clay pipes are divided intotwo types: thin walled and thick walled. Thin walled vitrified clay pipe has beenmade since about 1984. To adapt to thispipe use the Wickes Flexiseal Connector(430-042). This black rubber flexibleconnector will allow PVCu drain pipe tobe joined to a variety of pipes which havean outside diameter of between 121-136mm, such as the thin walled vitrifiedclay, glazed vitrified clay, ductile iron orcast iron.The Flexiseal Connector is fitted with twostainless steel clamping bands which aretightened around the pipe ends with ascrewdriver or 8mm nut driver.Thick walled vitrified clay pipe was madeprior to 1984. After chamfering andlubricating, both pipe ends, this pipe canbe replaced in PVCu using the push-fitconnector (432-046).

• Glazed Vitrified Clay (Salt Glazed Ware)

This oldest form of clay pipe was stillbeing used around the late 1960s andearly 1970s. It has a glazed surface andis jointed by sockets filled with a cementmortar mix. Simply cut the pipe with anangle grinder to leave a chamfered endon the pipe. Then you can convert toPVCu by using the Flexiseal Connector.(430-042)

TESTINGAll drains must be tested to ensure thatthey do not leak before being coveredover. If your work is subject to BuildingRegulations, your Local Building ControlOfficer will want to witness the testing.NOTE: Make sure your drain will pass therequired test before asking the BuildingControl Officer to visit, this will save youboth a lot of time and effort.Under normal situations the pipe andfittings are fully supported by the weightof the backfill surrounding the pipe.However, as they are unsupported whenbeing tested, the internal pressure maypartially push fittings apart causing themto leak during a test. If you feel that this

may happen take precautions against it. Old drains must never be tested withwater as they cannot withstand theinternal pressure but new drains may betested this way.For further details contact your localreference library which may hold a copyof Approved Document H of the BuildingRegulations.A simpler alternative is to carry out an airtest using a ‘U’ gauge. The equipment canbe hired from a hire shop.

TEST PROCEDUREThis test is in accordance with ApprovedDocument H of the Building Regulations.All gullies should be filled with water andtest plugs or bags put into the ends of thepipework to be tested. One test plugshould be fitted with a tee piece. A branchof the tee goes via a flexible hose to the‘U’ gauge. The other, also via a flexiblehose, to a small hand pump. If there are gullies on the system air ispumped into the pipe until a pressure of50mm is obtained on the gauge. Then themaximum acceptable loss of pressureshown on the gauge is 12.5mm in a fiveminute period.If there are no gullies on the system areading of 100mm is required on thegauge with a 25mm drop being themaximum allowed in a five minute period.If a system does not meet theserequirements, pump in more air whilstsomeone applies soapy water to thejoints. Bubbles will form when a badlyassembled joint is detected. Oncedetected check that the fittings have notbeen partially pushed apart causing themto leak air.If this is not the case, the leaking jointshould be taken apart and the ring sealshould be removed. Thoroughly clean thering seal and the seal housing, to removeany dirt or grit, then reassemble the fittingand re-test, as above.

SHOPPING LISTUnderground drainage products stockedby Wickes are listed on the back page.You should be able to install, replace oradd to almost any drainage system usingsome of these items. (Please note thatstocked items may change dependingupon requirements).Use the ‘I NEED’ column to make up yourown In-Store shopping list.

FIG.10WHERE THE BACKFILLABOVE THE PIPE CONTAINS STONES LARGER THAN 40mm ORWHERE THE PIPEWORKIS DEEPER THAN 2m INPOOR GROUND, THESELECTED GRANULARMATERIAL SHOULDEXTEND TO AT LEAST100mm ABOVE THE PIPECROWN.

SIDE FILL MINIMUM 150mmWIDE EACH SIDE OF PIPEREGARDLESS OF DIAMETER

FIRST 300mm OFBACKFILL SELECTED

TO BE FREE FROMSTONE EXCEEDING40mm (UNLESS THEGRANULAR MATERI-AL EXTENDS 100mmABOVE PIPE CROWN

- SEE NOTE OPPO-SITE).

GRANULAR SIDE FILL

MINIMUM 100mmGRANULAR BEDDING

7648_GIL_074_07_08.qxd:GIL 074 01 06 27/8/08 16:47 Page 5

Whilst every care has been taken to ensure that the product design, descriptions, specifications and techniques of constructing the products are accurate at the date ofprinting. Wickes products will inevitably change from time to time and the customer is advised to check that the design, descriptions, specifications and techniques of con-

structing any of the products described in this leaflet are still valid at the time of purchase or placing an order.© Wickes Building Supplies Limited 2008

All rights reserved. No part of this publication may be produced or transmitted in any form or by any means electronic, mechanical, photocopying, recording or otherwise orstored in any retrieval system of any nature without the written permission of the copyright holder and the publisher.

Code Drainage Products ‘I NEED’

432-001 3m Underground Pipe 158-830 4m Underground Pipe (selected stores only)432-050 Slip Coupling432-012 Double Coupling Socket432-007 100° Socketed bend432-006 20° Single Socket Bend432-016 45° Single Socket Bend432-008 87.5° Single Rest Bend432-015 45° Double Socket Bend432-018 87.5° Double Socket Bend430-082 110mm Adjustable Twistlock Bend432-005 Equal Socketed Junction432-014 Blanking Off Plug432-002 Bottle Gully Rod Eye432-053 110mm Tick Gully432-026 Square Hopper432-027 150mm Square grating432-009 Downpipe Adaptor to 68mm (Black)430-042 Clay to PVC Adaptor435-194 110mm x 87.5° Drain Branch435-196 Inlet Hopper Grating (Brown & Black)240-631 3" Weatherproofing Tape435-225 110 x 40 / 32mm Drain Adaptor435-226 Drain Rodding Point (selected stores only)158-827 30° Drain Bend Single Socket158-837 87.5° Drain Bend Single Socket (selected stores only)158-831 110mm Single equal Branch (selected stores only)158-828 Rainwater Gully158-834 110mm x 87.5º Triple Socket Branch (selected stores only)

Manhole Chamber Fittings432-028 250mm Shallow Access Chamber Access Base432-029 250mm Shallow Access Chamber Riser432-004 Aluminium Access Cover & Frame (250mm)435-227 Square Top for Shallow Access Chamber (250mm)435-228 450mm Access Chamber Base435-229 450mm Access Chamber Riser435-230 450mm Access Chamber Cover & Frame

Channel Drainage240-733 1m Drive Channel (Polymer)240-734 Drive Channel End Cap (Polymer) END CAP158-821 1m Drive Channel (Polymer)158-825 Drive Channel End cap (Polymer)

Manhole Covers430-007 305 x 305mm Drain Tidy (12 x 12")240-730 5 Ton Steel Manhole Cover 450 x 600mm240-731 Internal Manhole Cover 450 x 600mm 240-732 Block Paving Cover 450 x 600mm240-041 Keys for internal Manhole Cover – Pack of 2432-013 Silicone Lubricant 250ml

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