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Stone size for piped land drains

  • 21-05-2013 11:37pm
    #1
    Registered Users, Registered Users 2 Posts: 5,422 ✭✭✭


    What size clean stone do you use for piped land drains?

    Talked to friend today who works in one of the local quarries and they provide various grades. A lot of farmers go for 4" or 2-4" from what he says. If I recall correctly, the journal a while back was recommending 12-20mm which is a lot smaller and expensive! I'll be talking to the boss man tomorrow about cost of various grades so that will dictate.


Comments

  • Closed Accounts Posts: 1,363 ✭✭✭Juniorhurler


    Put in about 4km of them over the last two years with 2" down.


  • Registered Users, Registered Users 2 Posts: 5,422 ✭✭✭just do it


    Put in about 4km of them over the last two years with 2" down.

    How many loads will 500m take?


  • Registered Users, Registered Users 2 Posts: 943 ✭✭✭trabpc


    just do it wrote: »
    How many loads will 500m take?

    I put a 200 m drain in last year. I filled to about 400mm of 2" stone high. Took two and a half loads or 50 tonne. Cost stone €500. So your 500 m section should cost about €1250 for the stone.

    Load 20t stone cost €200.

    You should have enough in 7 loads @ 20t e.a. €1400. Should see you out well.

    But depends on depth of drain and amount of stone you want to use. My drain was deep in parts 7 ft. But kept stone depth to 400mm over pipe.


  • Registered Users, Registered Users 2 Posts: 2,274 ✭✭✭Figerty


    20mm Pea gravel is recommended. I had a long chat with at ground specialist last week.

    Anything over 20mm and the pores between the gravel will allow clay or organic matter to travel and block the pipes.

    20mm down would mean the largest particle would be through a 20mm screen which means that it will have smaller particles that will move through the gravel over time and seal the drain.

    The same applies to 2inch clean stone. Eventually the gaps or pores fill but will depend on the conditions. A good flood of rain would do it over night if it brings silt with it. The journal are right on this one, but of course it depends on the soil conditions.

    Do you sums carefully. If you claim back the vat and then offset the cost of the more expensive gravel against the cheaper gravel against tax as a loss then how much of a difference is there? not as much as you would think

    I have put in ten 18 tonne loads of pea gravel in the last two months in boggy ground. I am only doing this once and want to make sure it works!

    Anything over 20mm that was used in the past has clogged and is useless. I can send you photos of blocked 30mm stone and clean 20mm after 10 years.


  • Registered Users, Registered Users 2 Posts: 943 ✭✭✭trabpc


    Never understand why we dont use some kind of terram over these shores. All motorways and construction sites use them on drainage channels to stop the silt entering the stone. About 30 years ago I remember breaking up small square bales of straw to place over top of stones in a drain. Same idea as terram. No-one seems to bother today. But with any kind of terram it would not matter what size stone u use. I agree that 2" is a bit big. But in good free draining soil its cheaper and certainly if covered with a terram/ straw before backfilling soil should be fine.


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  • Closed Accounts Posts: 1,242 ✭✭✭iverjohnston


    trabpc wrote: »
    Never understand why we dont use some kind of terram over these shores. All motorways and construction sites use them on drainage channels to stop the silt entering the stone. About 30 years ago I remember breaking up small square bales of straw to place over top of stones in a drain. Same idea as terram. No-one seems to bother today. But with any kind of terram it would not matter what size stone u use. I agree that 2" is a bit big. But in good free draining soil its cheaper and certainly if covered with a terram/ straw before backfilling soil should be fine.

    If you ever have a need to dig up drains dug by hand, you sometimes find that the people digging them had carefully cut the sod and then used it (upside down) on top of the stones, to prevent silting up. Amazingly, giving that these drains were probably dug in the 20's and 30's, the sod will still be intact.

    Had to dig up a stone shore last week, as it had blocked and was destroying the field. Its almost 2 foot to the top of the shore!
    When you consider that the stone was probably also broke with a sledge it is humbling indeed.


  • Registered Users, Registered Users 2 Posts: 364 ✭✭PN14


    You don't want to put any material with down in the description into landdrains i.e. 2" down etc and this means stone is crushed & screened in quarry to allow all material from crusher from 2" down to dust to past through the screener. Dust in draiange stone will act the same as silt and will block shores. Ideallly you want a single sized stone say 20-30mm or thereabouts.
    Good point about terram. The NRA detail for land drains has either the connaught agri type pipe wrapped in terram or more usually terram lined down both sides of trench and wrapped across top. Terram is not that expensive to buy around 150e for 150 x 5m wide roll = 750m2. Say trench 800mm deep you need 800 one side + 300 bottom + 800 other side + 300mm on top = 2.2m2/m say 3m2 top allow laps so cost would be around 60cents / m of trench. There is a good bit of extra labour required for this method.
    On stone costs it depends on depth of trench & depth of stone backfill. If you have relatively free draining soils you only need stone surround around the pipe with cover over the pipe of 200mm. If you have heavy clay ground in particular the success of the drain will depend on the amount of stone in the trench. Last few areas we drained I have filled trench to underside of topsoil with stone as the fields are adjacent to a river and are really heavy clay which is almost impermeable to water. These drains work really well but are expensive as a lot of stone required and also material dug out of the drains has to be hauled away.
    Example of stone cost say 20mm drainage stone at 10e per tn delivered. Drain 800mm deep allow 100mm bed 100mm for pipe surround & 200mm cover over pipe total depth of stone 400mm. Say trench 400mm wide on average (dig with 1ft bucket plus allow for overdig). Total M3 stone per m of trench at stone depth of 400mm = 0.16m3/m conversion for drainage stone from m3 to tns say 2tn/m3 therefore 0.32tns of stone per m of trench. Allow for some wastage say 0.35tns/m @ 10e /tn = 3.50euro /m for stone costs.


  • Registered Users, Registered Users 2 Posts: 1,003 ✭✭✭Zoo4m8


    trabpc wrote: »
    Never understand why we dont use some kind of terram over these shores. All motorways and construction sites use them on drainage channels to stop the silt entering the stone. About 30 years ago I remember breaking up small square bales of straw to place over top of stones in a drain. Same idea as terram. No-one seems to bother today. But with any kind of terram it would not matter what size stone u use. I agree that 2" is a bit big. But in good free draining soil its cheaper and certainly if covered with a terram/ straw before backfilling soil should be fine.

    Put in 2ft culvert with pea gravel wrapped in terram down the drive three years ago.
    Had to put in a manhole to the side a couple of months ago, when the terram was opened it was full of clean water and the gravel looked like it went in yesterday, lovely!
    Definatly recommend it.. :)


  • Registered Users, Registered Users 2 Posts: 936 ✭✭✭st1979


    I have a FREE supply of course sand and marl clay. Was thinking of putting it in over pipes and fill to the top. I think it might work as marl is very stable clay. So dont see it silting up. And i have never seen a boggy beach!!. But maybe it would block the perforations in the pipe. But maybe a strip of terram would sort it. Now i know pea gravel is the job. But it costs


  • Registered Users, Registered Users 2 Posts: 5,422 ✭✭✭just do it


    Ordered pipes today. Went with 4" rigid corripipes in the end.

    Lads around here seem to go with 2", 3", or 4" stone. No one mentioned 20mm stone. The quality of the stone seemed to be the main thing lads were taking about. Didn't get to price it yet though.


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  • Registered Users, Registered Users 2 Posts: 892 ✭✭✭grange mac


    Lads, where ye get yere terram from? Bought a roll last yr and paid €270. Great job but now need another 2 rolls of it. Looking for somewhere that will deliver to west cork.


  • Closed Accounts Posts: 1,363 ✭✭✭Juniorhurler


    Ya my mistake.2" clean was what I should have said. I am buying 2" down at the mo for a yard and had that on my mind.


  • Registered Users, Registered Users 2 Posts: 2,274 ✭✭✭Figerty


    just do it wrote: »
    Ordered pipes today. Went with 4" rigid corripipes in the end.

    Lads around here seem to go with 2", 3", or 4" stone. No one mentioned 20mm stone. The quality of the stone seemed to be the main thing lads were taking about. Didn't get to price it yet though.

    If you have 'Iron water' as we have in west Clare, then limestone will react with it and block the pipes.

    The pea gravel has rounded edges that is less likely to catch dirt on the way down and the tight pore size prevents small particles passing through to block the pipe.


  • Registered Users, Registered Users 2 Posts: 4,881 ✭✭✭mf240


    I done a good bit of shoring with no pipe just 2" round stone. super job.


  • Closed Accounts Posts: 839 ✭✭✭Dampintheattic


    Figerty wrote: »
    If you have 'Iron water' as we have in west Clare, then limestone will react with it and block the pipes.

    The pea gravel has rounded edges that is less likely to catch dirt on the way down and the tight pore size prevents small particles passing through to block the pipe.

    Iron water is bitch in any modern drain. Blocks the holes in the pipes without any help from its reaction with the limestone.

    Seems to me, it is best handled by the old stone drains and no pipe, or no small stones.


  • Registered Users, Registered Users 2 Posts: 14,907 ✭✭✭✭CJhaughey


    grange mac wrote: »
    Lads, where ye get yere terram from? Bought a roll last yr and paid €270. Great job but now need another 2 rolls of it. Looking for somewhere that will deliver to west cork.
    I got a 4.5m x 100m roll from Cork Builders providers in Forge Hill.
    cost 250 or so.


  • Registered Users, Registered Users 2 Posts: 2,274 ✭✭✭Figerty


    Iron water is bitch in any modern drain. Blocks the holes in the pipes without any help from its reaction with the limestone.

    Seems to me, it is best handled by the old stone drains and no pipe, or no small stones.

    This is true, but I have spent the last couple of years replacing those drains that have collapsed under modern machinery and wet weather. They have become reservoirs of water by blocking the drains and back filling.

    It's the vibration as much as the loads that cause the problems.


  • Registered Users, Registered Users 2 Posts: 430 ✭✭Bigbird1


    Thinking of carrying out some drainage work four short drain leading into an existing one,planning on using 2inch clean stone on it's own with no pipe. What an people's opinions on this method?
    Thanks


  • Registered Users, Registered Users 2 Posts: 364 ✭✭PN14


    IMO put in the pipe. Its the cheapest part of the job.


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