Conservatory guttering - drain pipe onto patio, not into drain?

[David Robinson]

This isn't DIY, but I'm sure some people here might have thoughts on this. (!!!)

We've had a conservatory built. It was supposed to stop about 10cm before the kitchen window. The drain pipe from the conservatory gutter was supposed to go down the side of the kitchen window (i.e. between conservatory and window), and run across underneath the kitchen window to a drain the other side. Not pretty, but easiest thing without adding another drain.

I'm sure you can see where this is going: The conservatory has been built slightly closer to the kitchen window. Putting the drain pipe where it was supposed to go will block the kitchen window - meaning it can't be opened!

I've suggested using a narrower drain pipe to fit in the gap, but I've been told they don't exist, or won't carry all the water away, or won't fit into the standard fittings.

The conservatory company have suggested it makes more sense to put the drain pipe elsewhere, where there isn't anything in the way(!) and, importantly, where there isn't a drain either! They suggest just letting the water from the drain pipe flow onto the patio. "It'll find its way into the drain in the end."

Is this sensible?

Any other suggestions?!

Cheers, David.

[mark]

They suggest just

How good are your ice skating abilities?

mark

[MrFerrous]

Depending on the surface area of the conservatory roof, I would be worried about future subsidence problems if the rainwater is not disposed of properly. Have you considered miniature guttering systems eg.

you could buy one of these miniature downpipes, lay it on its side, put some weights on it, and then heat it with a hot-air gun until it is oval in the middle?

[The Natural Philosopher]

half sensible.

You get splashing that way, which compromises the DPC.

if at all possible. dig a french drain or piped drain around the patio, to either a mini soakaway or the existing drain, and put in a proper gridded water collector thingie - forget the proper name - to stop leaves etc blocking the pipe or French drain.

[David Robinson]

all the water through. I'm not sure this makes sense. It does rain a lot up here, but there's 1 standard 65mm square pipe for whole back half of the house roof, whereas the conservatory roof is only 3m*3m! Would that really push a 50mm pipe over capacity? I realise that's less than half the cross-sectional area of the 65mm square pipe, but still, it's about half the roof area too.

That's not a bad idea! I think 50mm might _just_ fit, if an angle joint was used to pull it as close to the conservatory as possible.

Cheers, David.

[David Robinson]

We might choose to dig up the patio eventually (which would solve the problem I think - we could probably put a drain to the other corner of the conservatory then), but in the mean time, even the French drain idea would involve some serious concrete digging.

Cheers, David.

[Tabby]

Small bore downpipe plus gutter leaf guards sounds like an option. Better would be to run the downpipe in the interior of the conservatory.

NT

[The Medway Handyman]

> I'd seen them, but the conservatory company claimed they wouldn't let

Sounds like cobblers to me :-)

50mm downpipe is used on sheds & greenhouses. A 10 x 8 shed isn't far off that in roof area.

[David Robinson]

Inside? How would that work? The roof is on already btw.

I think small bore sounds like the best bet. With 50mm pipe and a bend in the right place, I think it should be fine.

Until we dig up the patio and put a drain in to the opposite corner - that would be ideal - but that's hassle and expense - don't need that right now!

Cheers, David.

[Tabby]

Not an ideal time to retrofit such a thing, but doable.

Yes, as long as its filtered.

[Dave Liquorice]

It's not being built to the specification, get them to rebuild in the correct place at their cost.

Letting the water flow across the pation is not an option I would accept. They built the thing in the wrong place they have to find a way of getting the down pipe to the drain and still allow the window to open.

The smaller diameter downpipe (eg Marley Miniline) rather than the standard 68mm might work. Put two in to get the capacity. The problem will be joining this small down pipe to standard guttering half round or deepflow and possibly bracketry to fix them. Below the window they could empty into a standard hopper and then take 68mm under the window to the drain. Still a bit messy though.

[Dave Liquorice]

Have a dig about on the Marley site and see if you can find the what they reckon the miniline stuff can cope with. Look in the "specifier" section?

[David Robinson]

Yes, I can see them doing that. This would be the conservatory company that didn't give a final specification, didn't give a final quote, and the builder that walked off the job half way through, and then came back again.

I think you're spot on there Dave - I also think a DIY-er would use some initiative, googling, etc to find parts and make it work as best as possible - whereas I suspect these guys will just say "can't be done" / "can't get the parts". The fact they suggested letting the water stream across the patio makes me uncomfortable.

Cheers, David.

[David Robinson]

Excellent. Found this:

limit is 15m^2 for flat guttering, 19m^2 for 1:600 fall.

By my rough calcs, including half the vertical house wall "above" the conservatory due to wind driven rain hitting that wall (according to that doc), it takes it beyond the "flat" limit, but just within the

1:600 fall limit. Not ideal, but I think it'll do.

Otherwise, if they're very clever, I reckon they could _just_ fit some

65mm square pipe in with 2mm to spare. I doubt that'll happen, but if it was me doing it, I'd try!

Cheers, David.

[Roberts]

I had a similar problem and the nearest drain is connected into the sewage sysytem and as I don't like the garden being flooded with crap, I would not use it. I extended the bottom elbow of the rainwater piping by about 3feet and dug a pit 2feet deep for the water to go into. I planted a hydrangea on the edge. This plant is now very large and drinks all the water it can get and the pit is covered by the hydrangea so no one can fall in. Yes it is a bodge up but it works and is better than toilet paper and the rest floating about in the garden Alan >