MDPE pipe query

[robgraham]

I'm looking at putting a polytunnel in the garden at the 'back' of our 60 ft long stone cottage (originally 2 farm cottages). There is no water supply at all there and I'm trying to find the best way to arrange that - the gable end of the house is on public road so a very long hose system is not realistic.

My latest thought is to take an extension off the feed to the cold water tank in the attic over the wall head and drop it down the 3m wall. The underground path to the polytunnel will be in MDPE.

My question is - if I use MDPE for the drop and enclose it in a wooden case (or something similar) for it's exposed vertical section, will that be OK? I would envisage putting a drain facility at ground level

- should I think about trying to get that below ground level ?

Thanks Rob

[meow2222]

It'll freeze, so no. Some people collect the runoff from the polytunnel.

NT

[Tim Lamb]

There are 4 standpipes fed in blue MDPE here which freeze and unfreeze regularly.

The only one to give problems has a short length of 15mm copper connecting the tap.

The issue you may have with an undrained *top fed* supply is that freezing will occur from the top-down and trap the water between the ice and the shut off valve at the polytunnel.

Others may know how MDPE responds to occasional expansion.

You are unlikely to be using much polytunnel water in severe cold spells so I guess attention to frost forecasts and not taking long holidays in February will overcome any issues:-)

[robgraham]

I could rain water harvest off the tunnel, but then what do you do with all the water collected during the winter months ? I've already looked at going down that road to avoid putting in a new soakaway for the 60 ft rone on that side of the cottage, and realised that I would have to put the soakaway in anyway for the winter months (and clearly now the months from April to October!!).

Re. freezing - my intention was to drain down the 'top fed' pipe from about now onwards, so that freezing within it would not occur. The last question in my original post was whether I could get away with the drain c*ck being at ground level, or whether I would need to try and get it below ground. On the basis that there is only 1 litre of fluid in 3m of 20mm pipe, draining that off will not be a problem.

Rob

[Tim Lamb]

Apart from saving the planet issues, collecting and storing water above ground is that you have a warm, chlorine free source for watering your plants.

My experience of *down pipe* diverters is that they quickly clog up with crap from your roof and then trickle the water into your wall and foundations. I think a down pipe should be directly connected to your store and then a decent size overflow to your soak.

You are digging a trench to the polytunnel. Put your drain c*ck at that level and use a short length of 6" plastic pipe for access. I know you can get a screw on cap for 110mm, perhaps there is one for 6"?

[Tim+]

+1

They seem like a good idea but the first largish leaf to go down gets jammed and from then on, every bit of crap seems to lodge there. If you can arrange the plumbing so that you can clean it out regularly then perhaps not too bad an idea.

Tim

[The Natural Philosopher]

+1 again.

[Andrew Gabriel]

I've had one running for 12 years now, and that hasn't been a problem, but there are no trees overhanging the roof or close by. I do clean the inlet filter in water butt a couple of times a year, and flush out the coupling pipe which gets some sand in it from the roof tiles, but if either block, the water simply runs past into the soakaway. Never needed to clean the downpipe diverter.

1/4" of rain will refill the water butt from almost empty (depends on your roof area, of course - this one collects from half the house's roof).

One other tip - the plastic water butt stands can't take the weight of a full water butt. (Mine did last 10 years before bending and splitting, but a neighbour's more recent one only lasted about 3 months.) Build a brick stand with a flat top, which is what I have now, although I haven't actually got around to mortaring it yet - the bricks are just piled up;-).

[robgraham]

The rain water recycling does appeal as the other problem that exists on that side of the 60 ft long cottage is that the rones soakaway needs replacing.

So I have the potential of a lot of water - I am working on planning for a 1 m^3 intercept soakaway. My difficulty is seeing how the storage and watering in the tunnel would work and also how to get rid of the excess water during the winter (and summers in Scotland!).

The mains pipe is easy engineering and gives me pressure to distribute water round the tunnel, but putting in some sort of storage, over and above having to put in the soakaway (necessary for the winter), and presumably an electricity supply for a pump, seems a degree of overkill.

Rob

[Huge]

I pushed a tube made of wire mesh into the top of the downspout, so the crap collects there instead of inside the diverter. It does help that the gutters on that side of the house are only about 8 feet up, so it's easy to clear when it fills with crap.

[Huge]

What he said. we have two water butts, both of whose stands failed, now one is standing on a pile of bricks with a paving slab on top, and the other on a ~24" section of oak tree I "nicked" off the local tree surgeon, whose yard is nearby.