How do I get a slight grade on pvc pipe?

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Smpl Mnmlst
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#1908044 26-Nov-2017 18:01

You might be able to get the correct size flexi from Hirepool or Kennards.

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Rickles

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#1908061 26-Nov-2017 18:30

Can the downhill side of the drain pit/sump be angled as required?

JayADee

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#1908236 27-Nov-2017 08:14

Rickles:
Can the downhill side of the drain pit/sump be angled as required?

You mean by simply tilting the whole thing? Yes. :) That's one possibility and certainly the cheapest. I could even add a surround of partially buried brick to make it look level and provide a nice border/mow strip.

If you mean tilt the fitting on the pit, no. It's manufactured to install a certain way and I've already screwed and siliconed it on.

That would work for the pipe I've brought up here. What I haven't mentioned in this thread (to avoid confusion) is I have another more complex case where that wouldn't work. For that one in particular I'm liking the flexible coupler if I can get one that fits so I might as well get two and have the first pit sit flush with the ground.

Putting an elbow out to the side (and rotating to get any angle) would be pretty sweet too if it weren't for the fact that I have to have the pit exactly where it is and the best outlet location happens to be 8 m directly in front of that! (I could still use the side elbow idea but it would mean cutting the pipe in a few more places and adding elbows to get it back to the termination point whereas the flex joint means it as a single fitting and only one cut at the end of my pipe where the outlet grate goes) So my second favourite option in the thread so far is heat bending.

debo

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#1908241 27-Nov-2017 08:36

What type of pipe are you using? If it is waste water, then the walls are thin. There will be enough flex in the pipe to get the drop you need. It may take a couple of meters to do so but so what? If you are using pressure pipe, then the walls are thicker and it will need a little more distance to flex the desired amount. If you are using down piping, then the walls are ultra thin, and there will be no issue. Can you pick up the pipe and see how much it flexes under gravity?

JayADee

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#1908264 27-Nov-2017 09:19

debo:
What type of pipe are you using? If it is waste water, then the walls are thin. There will be enough flex in the pipe to get the drop you need. It may take a couple of meters to do so but so what? If you are using pressure pipe, then the walls are thicker and it will need a little more distance to flex the desired amount. If you are using down piping, then the walls are ultra thin, and there will be no issue. Can you pick up the pipe and see how much it flexes under gravity?

90 mm storm water, the thin stuff.
Really? So my 8 m pipe would work as is. Great! I haven't got the 8 m pipe yet, I'm grabbing it this morning.
I'll try it out.

My other one it won't work for (too short where I need it) but the rubber coupling will.
And good news, Bunnings has the 90 mm ones https://www.bunnings.co.nz/aqualine-jenco-joiner-storm-water-pvc-pvc-90mm-black_p00138586 for $22.10

nickb800

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#1908268 27-Nov-2017 09:28

JayADee:
debo:

What type of pipe are you using? If it is waste water, then the walls are thin. There will be enough flex in the pipe to get the drop you need. It may take a couple of meters to do so but so what? If you are using pressure pipe, then the walls are thicker and it will need a little more distance to flex the desired amount. If you are using down piping, then the walls are ultra thin, and there will be no issue. Can you pick up the pipe and see how much it flexes under gravity?

90 mm storm water, the thin stuff.
Really? So my 8 m pipe would work as is. Great! I haven't got the 8 m pipe yet, I'm grabbing it this morning.
I'll try it out.

My other one it won't work for (too short where I need it) but the rubber coupling will.
And good news, Bunnings has the 90 mm ones https://www.bunnings.co.nz/aqualine-jenco-joiner-storm-water-pvc-pvc-90mm-black_p00138586 for $22.10

And furthermore, you'll need two lengths to make up 8m, so you can gain a few more degrees in the socket joint between the two lengths.

My comment about fall was assuming that you were worried about achieving the correct fall, rather than just getting the pipe outwards and downwards away from the gully

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BTR

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#1908271 27-Nov-2017 09:34

If you can't work it out get a drain layer in, most pipe I have seen allows a certain amount of flex unless you are trying to use metal or concrete pipe which I doubt. Long lengths of PVC pipe should have enough flex to do what you want.

Rickles

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#1908380 27-Nov-2017 12:00

What about cutting the pipe at an angle, viz. the angle of drop desired?

The 'width' diameter stays the same as original pipe, but you may need to cut a bit of the top (vertical dimension/diameter will have increased) ... and should jam up against the outlet anyway sufficient to glue or pack into place?

JayADee

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#1908385 27-Nov-2017 12:10

Pipe is arriving either today or tomorrow (2 lengths of 6m). When it gets here I'll check the flex in it.

My pipe supplier stocks none of the larger sized flexible rubber couplings, only smaller ones. Luckily my husband has an x-ray ( if you call needing an x-ray lucky I guess) tomorrow so we have to drive to town anyway. I'll hit up Bunnings for the coupling.

JayADee

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#1908398 27-Nov-2017 12:40

nickb800:
JayADee:
debo:

What type of pipe are you using? If it is waste water, then the walls are thin. There will be enough flex in the pipe to get the drop you need. It may take a couple of meters to do so but so what? If you are using pressure pipe, then the walls are thicker and it will need a little more distance to flex the desired amount. If you are using down piping, then the walls are ultra thin, and there will be no issue. Can you pick up the pipe and see how much it flexes under gravity?

90 mm storm water, the thin stuff.
Really? So my 8 m pipe would work as is. Great! I haven't got the 8 m pipe yet, I'm grabbing it this morning.
I'll try it out.

My other one it won't work for (too short where I need it) but the rubber coupling will.
And good news, Bunnings has the 90 mm ones https://www.bunnings.co.nz/aqualine-jenco-joiner-storm-water-pvc-pvc-90mm-black_p00138586 for $22.10

And furthermore, you'll need two lengths to make up 8m, so you can gain a few more degrees in the socket joint between the two lengths.

My comment about fall was assuming that you were worried about achieving the correct fall, rather than just getting the pipe outwards and downwards away from the gully

Well I'm worried about both. :)
For this one there's plenty enough slope away from the house to carry water, how to get any angle on the pipe from the pit was my main concern. I only have a metre of the pipe at home so I didn't realise it flexed.

Now the other pipe I am doing is a whole other thing. There's next to 0 slope where it is going, it's a short run (under 5 metres) and there's a 45 degree turn. Plus I'm putting on a pop up emitter (relief valve) at the end because I am just running it out from the side of the house to a location on the grass where the water can run off naturally as a slight slope begins there.

This pit is located at the junction of the side of a flight of deck stairs and house wall so to get enough pressure for the emitter I am putting this pit above ground and relocating some rocks and plants to put around it to make it look nice.

I am running the first bit of pipe in at a steep angle using an elbow (probably 45 degrees or possibly 22) then the bottom of that section will get the rubber elbow for a bit of slope I have dug into the trench, the next a 45 elbow and then a T, a very short section of pipe leading to daylight from the T with my pop top emitter lid at the top. I tried it out with some flexi and it works well pressure wise. Water wells out like it's supposed to.

JayADee

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#1909030 28-Nov-2017 15:10

debo:
What type of pipe are you using? If it is waste water, then the walls are thin. There will be enough flex in the pipe to get the drop you need. It may take a couple of meters to do so but so what? If you are using pressure pipe, then the walls are thicker and it will need a little more distance to flex the desired amount. If you are using down piping, then the walls are ultra thin, and there will be no issue. Can you pick up the pipe and see how much it flexes under gravity?

Got my pipe this morning, got most of my trench dug last night after tea.
You were right, there is enough flex in the 6m pipe even before I join the other two metres. Works out fine. I have the slightly thicker 90mm recycled grey stormwater pvc from my local drainlayers which is just a touch thicker than the Bunnings I think.

On the other pipe project I've decided to see if I can get away without the rubber joint by leaving a short section of no-slope pipe. Easy enough to pick one up if I need it.

Thanks for the help everybody!

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JayADee

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#1909031 28-Nov-2017 15:11

BTR:
If you can't work it out get a drain layer in, most pipe I have seen allows a certain amount of flex unless you are trying to use metal or concrete pipe which I doubt. Long lengths of PVC pipe should have enough flex to do what you want.

You're right, it does!

Rickles

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#1909036 28-Nov-2017 15:24

When are we all invited round to 'toast' the drain?

frankv

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#1909061 28-Nov-2017 16:04

I thought this was standard knowledge amongst plumbers and so on, and therefore amongst DIYers and other plumber wannabees...

Get a hosepipe a bit longer than the distance from one end of your piping run to the other. Fix one end so that the end is exactly at the right height. Go to the other end and fill the hose with water. Once the water starts running out the other end, lower your end a bit and pour a bit more water in. Do this fairly slowly, so you don't get the water sloshing to and from through the hose. Repeat until you can't lower your end without water coming out, and can't pour any more in. At this point, both ends of the hose are exactly level. Mark the wall at this point, and measure relative to that.

If you want to avoid all the lowering and filling, join a bit of clear pipe to the end of your hosepipe and add some food colouring to the water. Fill the hose with colored water, and you'll be able to see the level of the water (which is the level of the far end of the hose if it's full) through the section of clear pipe.

Ob Geek disclaimer: Gravity waves will distort your results.

Ob DIY point: The OGD above is useful when your measurements aren't quite right and water pools in your pipe rather than flowing down it.

Yogi02

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#1909285 29-Nov-2017 05:25

I was just about to reply with the hose levelling solution as well ;)

frankv:

I thought this was standard knowledge amongst plumbers and so on, and therefore amongst DIYers and other plumber wannabees...

Get a hosepipe a bit longer than the distance from one end of your piping run to the other. Fix one end so that the end is exactly at the right height. Go to the other end and fill the hose with water. Once the water starts running out the other end, lower your end a bit and pour a bit more water in. Do this fairly slowly, so you don't get the water sloshing to and from through the hose. Repeat until you can't lower your end without water coming out, and can't pour any more in. At this point, both ends of the hose are exactly level. Mark the wall at this point, and measure relative to that.

If you want to avoid all the lowering and filling, join a bit of clear pipe to the end of your hosepipe and add some food colouring to the water. Fill the hose with colored water, and you'll be able to see the level of the water (which is the level of the far end of the hose if it's full) through the section of clear pipe.

Ob Geek disclaimer: Gravity waves will distort your results.

Ob DIY point: The OGD above is useful when your measurements aren't quite right and water pools in your pipe rather than flowing down it.

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