Clear that blocked drain yourself. You know what’s down there.


How I got into drains

It wasn’t out of choice believe me, just sheer necessity. It all started when we decided to convert a dining room into a kitchen quite a few years ago. All there was left to do was connect the outlet from the new sink to a big old iron downpipe that was conveniently situated just the other side of the wall. I got a plumber in and he tried to drill a rosette of holes in the pipe to attach a plastic collar for the new outlet. After breaking his fifth drill bit, he managed to hook it all up. I turned on the taps and the sink wouldn’t drain. The plumber slunk off defeated and suggested I get a drain guy out. The van arrived like Ghostbusters and the proud operator, armed with his high pressure hose, assured me that the pressure from this baby could ‘cut through steel.’ I said ‘well what’s that going to do to these clay drainpipes?’ and he didn’t have an answer for that. Anyway, he tried shifting the blockage from a nearby manhole cover but it still wouldn’t budge. I now had a gleaming new kitchen but no waste outlet. In despair I went to a Ma and Pa hardware store and got lucky. Pa behind the counter was brilliant. He gave me all the bits to do the job and told me exactly how to do it. It entailed cutting out a section of the iron pipe with an angle grinder and putting in a new plastic section with a ‘slip’ joint. When you’ve slipped it in you heat the ends of the joints with a blow torch, which causes them to nip in and make a tight, permanent  seal. After cutting out a section of the pipe, I found out what the blockage was-over 4lbs of finely milled ferrous oxide-rust that had accumulated at the bottom of the pipe because the outlet hadn’t been used for years.

In period properties, another possibility is that your clay drain pipes have cracked and plant roots have found their way in to block it. In this case, you need specialist help. It is possible to reline a run of old pipe without digging up your back garden and turning it into a scale model of the Somme.

Collapsed drains don’t happen overnight though, it takes quite a few years. This is what happens;

A (clay) pipe cracks because of frost or some mechanical disturbance  and begins to leak. This leak eventually washes away the earth underneath, This means the pipe is no longer supported by compacted soil. Eventually it will collapse. At the same time, plant roots will tap into this new supply of moisture and form a dense mat inside the pipe. Until it gets completely filled by a root ball, you probably won’t notice what’s going on down there. Drains are one of those things that you may never need to think about in your lifetime. But when they do go wrong, they go wrong in a big way.

How do you know it’s blocked?

When you empty a large amount of water from a sink or an appliance it will be sluggish in draining. You may notice ‘off’ smells in the kitchen. Trust your nose, something is wrong. Course this might just mean that the pipe from the kitchen to the drain is blocked. If possible, empty a full bath or as large amount of water as you can in one go. If a wet patch suddenly appears around the edges of an outside drain cover then the main drain is the problem. This blockage can go on for months without you realizing it because the drain acts like a sort of septic tank. You probably won’t notice the wet patch either. Fluids will eventually drain away but the solids and semi-solids will continue to build up. In autumn and winter it may not be particularly smelly but when summer comes, the problem usually becomes impossible to ignore.

Won’t the council or my water supplier fix it?

If you own your own home, you are responsible for the maintenance of all the pipes until the point where they cross your property boundary line and they enter the main drain which normally serves the entire street. Oh the joy of being a home owner.

So where’s the drain cover?

You may have several depending on the size of your gaff. Both front and back or just front. What you’re looking for is a big square metal plate a few metres outside the walls of your building. In hot weather, just follow the flies.

It’s not unknown for people to pave over drain covers on driveways at the front or conservatories at the back so you’ll have to use your skill and judgment.

Look for a squat ‘periscope’ about the size of a brick sticking up somewhere at the front of your house nearest to the main road and work backwards from there to find the blockage. This air vent  joins the main sewer and is designed to counteract a possible build up of highly explosive methane gas unwittingly pumped into the main street sewer by homeowners who tile or tarmac over man-hole covers for cosmetic purposes or even worse, saw off and fill in these ugly-looking air vents. Anyway, enough about unexplained gas explosions. Your first or only drain cover should be about a metre from this squat little sticky up vent .  If it isn’t then it’s been covered over. The options are: get a specialist drain firm to try and clear the blockage from a more remote location or excavate your drain cover.

Why’s it blocked?

You use products containing synthetic fibres like disposable wipes or you flush the packaging from hygiene products.  A lot of hygiene products are actually dirty. Essentially, anything that’s not compostable can eventually block a drain and will have to be resurrected at some point.

Where’s it blocked?

Usually where the pipe takes a sharp turn and the water slows down. The back of the house is a common problem area because the pipe has to go through a 90 degree bend to join up with the main public drain in the front road

How do I unblock it?

You will need a set of drain rods and possibly a nosegay of some description. Drain rods used to be made of bamboo but are now usually made of bendy fiberglass and come in lengths of about a metre and a half in length and they also double as a chimney sweeping tool. They are cheap, simple and available from all good, family-run independent hardware stores that haven’t yet caved in to the multiples.

You will have to work out how many sections you need to reach the problem area. At each end the rods have a coarse threaded brass screw. You will also need a screw-on tip for the business end. The one that looks like a bit like a corkscrew is the one to get for drains. (The one that looks like a spiky brush is used for chimney sweeping.)

First, find the drain pit where it’s blocked (wet patch) then find the next one down that’s nearer to the main road and try unblocking it from there.

This one will be downstream of the blockage and will have the pressure of the trapped water behind and should be easier to pull clear. It also means you don’t have to go poking down a full cess pit to try to push the stuff away.

Lifting the drain cover

Old cast iron covers are held down by sheer weight of metal, you will need a strong thin blade to prise then up. The edge of an axe, a spade, or ideally a wide masonry chisel should start to budge it. Have a bit of wood ready, thicker than human fingers, to keep the lid wedged open once you manage to lever it up with the blade. These lids are very heavy, so mind your pinkies.

Newer, galvanized covers usually have four big stubby screws at the corners that you can undo with the edge of a coin. Though if it’s that new, chances are you don’t have a problem.

If you have a drain cover covered in block paving to match your drive, you will need a couple of ‘lifting keys’ and probably an assistant.

Assemble the drain rod. As you push section after section up the drain there’s only one thing to remember: Every time you push or pull the rod turn it clockwise to keep the sections screwed ever tighter together. Push and twist clockwise or pull and twist, clockwise every time. If that thing becomes uncoupled and there’s a section of drain rod stranded up your pipe then you really do have a problem.  Simple enough,  just don’t forget to push and twist in your eagerness to dislodge THE BLOCKAGE.

Have a sheet of plastic ready for what you will find at the end of your drainrod. Find dignity in what you are doing and try to front it out with your neighbours. A tangled mess of blackened and torn hygienic wipes fluttering in the breeze from your drainrods? Classic Kurosawa image.

Be prepared for when the blockage starts to come loose. When you hear bloops and burps like Jabba the Hut with dyspepsia, stand back. The inspection pit could fill up very fast and overflow depending on how much stuff is backed up in the pipes. Now just flush everything through with a hosepipe, replace the covers and have a nice shower.

Clearing drains is actually quite therapeutic. Like colonic irrigation but on a much bigger scale.

1 Comment

Filed under DIY, maintenance, plumbing

One response to “Clear that blocked drain yourself. You know what’s down there.

  1. Thanks for the tip, though the vibrating snake seems to me like a clever piece of professional kit designed to create a ‘shockwave’ in the slurry, whereas I’m trying to give simple low cost and preferably no cost answers to household problems that most people can do for themselves. Course in some case you may well need a heavy duty solution, for instance, if the problem was root intrusion, I’d get professional help. Though on the two occasions when my drain has been blocked, I’ve been fortunate enough to be able to shift it with just the simple drain rods.

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