Concrete floor producing puddle by drain when rains

[wiffers2003]

Hi all,
I have recently moved and in the garage (right next to the house) the rain water goes into a sealed drain (sealed by mastic). All has been ok until it rained really heavy the other day and i walked into the garage to see a puddle lying on the ground right next to the drain. I checked all the sourrounding pipe work which was all dry and there are no water marks down the side of house next to the drain (inside the garage).
I can only therefore conclude that the water has come up through the floor, which to me sounds like very bad news !!
I have another very small rain water drain (small hole) out the front of the house which appears to be in line with the drain in the garage, but there is no manhole cover on the property that i can lift to check if it is blocked. I think its under the extension!
I was wondering if you experts have any ideas of what i could do to check if its blocked, or how to remove the mastic from the floor so that i can try to rod it somehow.
Many thanks in advance, Carl

 

[mattysupra]

When you say mastic do you mean silicon or no-more nails or something? Try cutting through with a stanley knife.

 

[wiffers2003]

All i can is its black looks like it has been painted onto the floor and seals the pipes to the floor, also its slightly soft ie you can put your finger nail into it.

 

[mattysupra]

sounds like a sort of putty or bitumen based sealant or something. They may or did use this to seal the drain shut. I would cut it up to get to the drain. If you don't it may lead to other problems if already flooding into concrete base.

 

[Space cat]

Mattysupra is right. Your drain is almost certainly blocked and the sooner you get to the bottom of it - literally in this case - the better. A blocked drain can only get worse.

No other manhole cover? Where does your soil stack go? Do you know whether you have one pipe or two pipe drainage? Your local council should be able to tell you this but be sure to frame the question in general terms. You don't want them coming round and finding that a previous owner has built on top of manholes!

You'll have a real problem on your hands if there's another one blocked further downstream. Rodding a drain through a hidden manhole and on into the next pipe can be difficult - and damn near impossible if it's got an intercept trap! You'd need more than a set of drain rods to sort that out.

After you've got the cover up, the next thing you'll need to know is which way the drain runs. There's no point rodding upstream from a blockage! Other houses in the same street may provide a clue. Do they have manholes in their drives, or maybe in their back gardens. Alternatively, try to get a look at the original building plans.

Best of luck. You'll need it!

 

[wiffers2003]

I think we have a manhole cover under the tongue and groove floor in the kitchen. This would then line up with the one in the neighbours back garden. It wouldn't be easy to lift it though as the floor goes under all the kitchen units.

When we had the survey done, it said that we had right of way of the neighbours drains (or something like that), have you come across this before and what does it mean exactly !!???

I'll check out the neighbours to see if they have a manhole at the front as well as the rear, and looks like i'll have to start cutting at the black sealant to try and get to the drain...........urgh !

thanks again, Carl

 

[Space cat]

When we had the survey done, it said that we had right of way of the neighbours drains (or something like that), have you come across this before and what does it mean exactly !!???

I'm guessing here but it sounds like you don't have a direct connection from your final manhole to the main sewer. Your drain goes into somebody else's manhole and so your waste has right of way through their drains. It's an arrangement that's not entirely satisfactory because a blockage in their drain will affect you too.

This raises two interesting possibilities:

1) That blockage might be further downstream in somebody else's garden.

2) You might not be the last house in the line. A blockage in your manhole - the one you can't get to - could affect somebody upstream.

These shared drainage systems can be problematic. I saw a documentary once that revolved around a blocked, shared drain. The programme was about neighbours rather than drains so the cameras were following the dispute about whose responsibility it was and who would pay for the plumber. Much of the argument, which had gone on for several days , took place around a small lake that had formed in the street! Towards the end, two figures were seen in the background carrying a drain rod. The presenter told us that the whole business had now been sorted out by two residents who had the gumption to stop talking and get rodding!

You first job is to get into the manhole you can see and confirm that it's blocked. The usual next step would be to work your way downstream to establish exactly where the blockage is but that's not so easy in your case. You could have a careful prod around in the hope of breaking up a blockage. It might work but you'll have to hope that it doesn't end up wedged in somebody else's drain. What you mustn't do is get your rod into the pipe and give it a good shove. If the next manhole - the one under your floor - is flooded, not only will you not clear the blockage; you might force its lid off!