Blocked pipe... at our wits end

sarahTT

So... we have an almost blocked drain in the kitchen, it all happened completely out of the blue and is the first time we ever had one. I tried to get rid of it by heating some water plus baking soda, fully dissolved, and then into the sink. Strangely, this made things a lot worse... pipe was now totally blocked. Hubby has a long drain snake to unblock pipes which we've used for the downpipe from the gutters... pushed that into the pipe and when we saw waste water coming out (after removing the manhole cover in the garden) we thought all was good.

A week later same thing. Hubby grumbles and gets his snake and this time goes in very deep (the thing is more than 7m long and it was almost fully inside the pipe) and turns it vigorously for maybe 10 minutes. We put a lot of water through and some grey stuff comes out in big shards, very hard and if put into vinegar, fizzles: probably built-up scale. But water flows freely and we think all is good.

Two weeks later same thing. Now I've been extremely careful not to put anything, and I mean anything, into the drain and there's nothing else that uses this pipe. We don't understand what could cause these repeated blockages... as I said this happened out of the blue. An animal? A broken pipe (but the drain snake looked clean though it was a bit smelly)?

We're at a loss and have no idea what to try now!?

Vitor

I'd bite the bullet and pay for a proper CCTV inspection of the run. A plumber with a camera will see immediately if the pipe has a belly, a crack, or an obstruction your snake is only tunnelling through. 

Have the run professionally jetted. High-pressure water jetting removes the material right back to the pipe surface. A DIY snake usually leaves most of the mass behind. If the blockage is purely fat and scale, this often solves it.

Slinky

How much baking soda did you put in? I think I made things a lot worse with a blocked bathroom sink by bunging in soda crystals and a kettle of water. I think the soda crystals came up against the blockage and then hardened in the pipe. I tried one of those snake things, it became detatched in the pipe which was buried in the wall, it's still there. 

We were changing the bathroom a few months later, and the sink is in a different position now. The pipework under the floor was a right bodge with some 90 degree turns and very little fall which didn't help at all.

gwynlas

Try the sink unblocker you purchase by the bottle or caustic soda rather than baking soda.

Section62

gwynlas said:

Try the sink unblocker you purchase by the bottle or caustic soda rather than baking soda.

Pouring chemicals into blocked sanitary drainage isn't the best idea... if it doesn't clear the blockage (often the case) then it leaves a horrible cocktail behind for whoever has to disassemble the pipework to find and remove the blockage.

WIAWSNB

Blimey, Sarah, your hubby inserted 7m worth of snake? That must surely have got right outside yer hoosie, and probably to an accessible inspection cover? 

So, what's outside your house on that side? Does the sink waste point into a drain cover/gulley? Is there an inspection cover further along?

Eldi_Dos

@sarahTT

               If you can dismantle the u bend under sink try this cheap and cheerful method before calling in professional's and paying top whack.

Dismantle u bend then attach a cork to a long enough piece of string and float it through pipe to outside manhole, then attach a long piece of blue rope (can buy in hardware stores) and pull that through. Once you have enough through tie knots in middle of rope to slightly smaller size than pipes.

Pull this back and forward a few times to scour out what is lining/ restricting the pipe.
Not the most pleasent of jobs but for the price of a few metres of rope and some time could save you money.

Edit: If drain snake can reach from u bend to manhole just attach blue rope to that then try the scouring method.

sarahTT

Thanks all for your helpful comments!

@Slinky I did fully dissolve the soda, as I wrote in my OP. It was just clear water, no crystals.

@Eldi_Dos We had removed the U bent already as the drain snake is way too big to go through that But an interesting idea, we'll think about it.

We have now studied the actual pipe as it leaves the sink and discovered that it's strangely going UPHILL. It leaves the sink downwards in a vertical bit and then, almost at the concrete floor, does a 90 degree turn right and then goes on for about 2m ending in a bigger pipe coming out of the floor. However, this point is about 7 or 8 inches ABOVE the 90 degree turn which goes almost to the floor. So everything has to go upwards for those 2m and if there's not enough water pressure then stuff will stay put, I think. So we will try again with the snake and put as much water through as we can while we have the snake inside.

Will report.

WIAWSNB

Any chance of some photos?
And, any idea why it first runs along the floor - is it to be underneath the base units?
Do you plan to sort this correctly by rerunning the pipe with a slight fall? 
Can it go behind the base units? If not, it'll likely have to go through them, but no big deal - this should be neatly doable.

bjorn_toby_wilde

sarahTT said:

Thanks all for your helpful comments!

@Slinky I did fully dissolve the soda, as I wrote in my OP. It was just clear water, no crystals.

@Eldi_Dos We had removed the U bent already as the drain snake is way too big to go through that But an interesting idea, we'll think about it.

We have now studied the actual pipe as it leaves the sink and discovered that it's strangely going UPHILL. It leaves the sink downwards in a vertical bit and then, almost at the concrete floor, does a 90 degree turn right and then goes on for about 2m ending in a bigger pipe coming out of the floor. However, this point is about 7 or 8 inches ABOVE the 90 degree turn which goes almost to the floor. So everything has to go upwards for those 2m and if there's not enough water pressure then stuff will stay put, I think. So we will try again with the snake and put as much water through as we can while we have the snake inside.

Will report.

That sounds like the problem.  I regularly have to unblock a basin at my parents’ place because there’s not enough drop on the pipe. About 1/2” drop in two metres is not enough so it clogs up every six months.

7 or 8” uphill in two metres is bonkers. That will definitely clog up, and frequently. Sounds like you need to remove enough of that vertical pipe to get a proper drop on it, always assuming the outlet into the soil pipe is low enough to accommodate.

If not, you may be able to add a new lower boss onto the soil pipe (that’s the bigger pipe coming out of the floor).

sarahTT

It's hard to take a good photo as it's 2m long and only 7/8 inches height difference.

And yes the pipe runs below three units till it reaches that bigger pipe. As to rerunning the pipe... it looks as if that would mean to dismantle almost the whole row of units (but I'm no expert). We live in that house for two decades now and never had that sort of problem before, so I'm hopeful that if it's really cleared fully (one way or another) we'll be fine for another 15 or 20 years... we can always hope