Blocked downpipe turns out to end 5" below ground not connected to anything. What should I do?

[DownpipeToNowhere]

I have unblocked a cast iron downpipe that had weeds growing out of a gap between its socket and the spigot of the next higher up section. Excavating around the pipe on the ground, I was shocked to find it was not connected to anything. I removed a load of soil and rocks and am wondering what to do now. It does not seem right to just put back the rocks and soil even though I have unblocked to downpipe.

A nearby cellar gets small puddles in it after very heavy rain. The downpipe system is cast iron and dates from WW1. Was this the normal design to send rainwater straight down into the earth next to the foundations? I at least expected to find a bottleneck or P trap gully or even an elbow to take the water away from the foundations, but the down pipe just terminated. It doesn't seem rocket science to add an elbow and drill a gently sloping horizontal tunnel underneath a nearby foot path and take the water 5 ft away and let it drop down a terrace wall on to some steps, but would that damage the foundations of the terrace wall? Should I get a surveyor in to specify a better drainage system? Please see photo of the situation. Any help appreciated.

 

[^woody^]

It's only been like it for 100 years. Put the soil back and leave it for the next 100 years.

 

[DownpipeToNowhere]

Thanks, but the cellar has been damp for a 100 years, and I would like to eliminate all the possible causes of its dampness. There are up to 3 other downpipes around the cellar that may have the same design, none of which I have got round to investigating yet. Also the house is on a slope, and glass tell-tales have been installed to monitor for possible subsidence. Concern about subsidence at some point led to having the house underpinned just in case. It just seems so stupid to have such a naff rainwater drainage system if all the downpipes have the same design.

 

[bobasd]

OP, you have solid concerns given the conditions you describe and the house history - good question and photo.

go round an check all the RWP's and see where they drain to (if anywhere) and how they drain?
clean out and water test any gulley traps that you might find - all RWP's leading to manholes should have trapped gulleys.
untrapped gulleys or bends are for surface water only to, hopefully, disperse in sumps.

the pic shows the CI pipe fixings pulled away from the wall - a pic of the full pipe would maybe show if it was safe?

your options are 1. to trap and lead the water to a manhole or 2. use a rest bend to lead water to a sump thats downhill and away from the house.

 

[^woody^]

Also the house is on a slope, and glass tell-tales have been installed to monitor for possible

That sounds like tell tales have just been fitted on the off chance. Is there movement or not? Tell tales would/ should only be fitted along with other checks of the ground ...... and drains.

A damp, untanked cellar under a place of that age is going to be damp for one of several other reasons, not because of one pipe.

You should not be thinking of diverting water over steps, for obvious reasons. If you are going to resolve it properly, you need to install a drain and soakaway.

 

[Leofric]

all RWP's leading to manholes should have trapped gulleys.

Only if it is a combined foul and surface water drainage system
- as you say

untrapped gulleys or bends are for surface water only

 

[Leofric]

If you are going to resolve it properly, you need to install a drain and soakaway.

Yes agree , but subject to percolation tests to see if the ground conditions are suitable.

 

[bobasd]

i'm not sure what point your trying to make? but i'll reply.

not so - beggars cant be choosers and BCO's and Utility inspectors recognise that needs not Regs. must rule in such circumstances as the OP describes.

the odds are that in a 19thC house then the rainwater is already being combined at some place(s).

all pipes discharging into manholes must be trapped.

 

[^woody^]

Yes agree , but subject to percolation tests to see if the ground conditions are suitable.

It's had a 100 year long ongoing test!

 

[DownpipeToNowhere]

Many thanks for all your replies. One poster elsewhere backs up Woody by asking about the roof area that is being drained (if the amount of water collected isn't significant, put the stones and soil back and leave it alone? i.e Woody's advice). It is only about 42 sq. ft. so one pipe probably isn't causing all the damp in the cellar. However, the other side of the roof of exactly the same area dimensions had extra rainwater collection duties imposed on it from a new gutter design of a higher up jerkin roof dropping water via a downpipe on to it and all this being channelled into a single downpipe on the other side of the house, together with extra water from a shed roof. I am sure that if the downpipe on the other side of the house is the same design as the one in the photo then that may be the cause of the damp in the cellar: the 1915 builder would not have anticipated another builder would come along in 1980 and treble or quadruple the rainwater throughput through his 1915 rainwater collection design, and the 1980 builder would maybe not have queried whether the 1915 design could handle the extra water, I wonder?

Bobasd, the downpipe in the photo may look insecure but it isn't: one of the wooden dowel spacers is missing, exposing a part of the metal coach screw. The unevenness of the stonework means there have to be spacer dowels (the downpipe can't be flush against such uneven stonework), as well as different diameter dowels actually in the stone wall acting as plugs for the coach screws. The dowels in the actual stonework and the coach screws simply won't budge, so the entire downpipe (5 or 6 metres of it) is very secure indeed. I did think of dismantling it all to unblock the bottom section of downpipe, but am glad I used a vacuum pump and pressure washer to get the soil out of the bottom section.

I agree it is not right to divert water on to stone steps (moss will grow and make them slippery). Anyway I feel I am getting closer to solving what is causing the damp in the cellar. Thanks for all your help.

 

[Leofric]

It's had a 100 year long ongoing test!

Yes but a test of the rainwater going where

 

[Leofric]

i'm not sure what point your trying to make? but i'll reply.

not so - beggars cant be choosers and BCO's and Utility inspectors recognise that needs not Regs. must rule in such circumstances as the OP describes.

the odds are that in a 19thC house then the rainwater is already being combined at some place(s).

all pipes discharging into manholes must be trapped.

I was simply saying that rainwater pipes only need trapped gullies if they are connected to a combined drainage system , not just because they are discharging to manholes. A separate surface water drainage system can have rwp's discharging to manholes without having trapped gullies, but yes, if the surface water is combined at some point rwp's should have trapped gullies.

 

[^woody^]

all pipes discharging into manholes must be trapped.

Soil and vent pipes included?

 

[DownpipeToNowhere]

To be fair, the cellar has always been damp (I remember it in 1960), but getting actual puddles in it is probably a more recent thing (the last 30 years or so) so I do think as none of the downpipes, at least where they enter the ground, has had any maintenance done on them in my life time that the problem is due to gradual silting up of downpipes and one of the downpipes being expected to carry more water than was originally intended. I can post photos as I get around to investigating all of the downpipes over the coming weeks. I may even have to try out coloured dyes to work out what the problem is.

 

[bobasd]

yes, SVP's will typically be trapped at fixture