Small extension of an irrigation system?

The irrigation system I have dates back to the late 80s or so. I have one section that's always been a little undersupplied: a bed along the foundation, at the top of a 4' high, steep grass slope. The bed's variously planted with shrubs and the like. One end has never been irrigated.

So I want to run a line from the one sprinkler head I have there, over about 20' away. Below is a picture of where I'm planning to tap in.

Clearly it's not the regular white PVC. Would it be polyethylene? Or some other sort of PVC? I thought poly or something similar because it looks like it's being held to the fitting by a clamp and not glue.

I'm going to need to make a sharp left--that is, from the perspective in the picture below, to travel at about 7 o'clock--and run about 15-20'. Any caveats to look out for?

 

That looks to be black poly. You could replace the 90 with a Tee.

The only problem is when you tee into a line like that the flow into the new area can disrupt pressure to the rest of that loop.

Are you adding a single new head or some type of drip or mister ?

 

Look at this before you start cutting. This is a flow chart and explanation of zones.
https://www.lowes.com/pd/NDS-19-in-L...ve-Box/3133533
google this and there are more charts.
sprinkler head flow chart

 

When you say the area is "under supplied" what specifically do you mean? Is is just that the sprinklers are poorly located and you just want to change their position. Or, is there poor flow/pressure and the sprinklers don't have the range or put out the water that they should? This all gets back to what Pugsl mentioned.

You can't just T into the line of an existing zone and add a sprinkler without it affecting the other sprinklers in that zone. They are all being fed by the same pipe so if you add another sprinkler the same water gets spread out between more emitters and they all get lower flow & pressure. Get it too low and pop-up's will not rise and seal properly.

 

There is NO coverage for this area. The two nearest heads can't cover it--one is at the bottom of that slope and can't get enough height as well as distance to get to it, and the other is on the opposite side of several tall, thick bushes. The first one would be able to hit the bed IF the bed were lower, but the spray just can't make it that far up the slope.
The area is small, only about 5x6', so I don't need much output.

 

What you really need to know is how much volume you have vs the GPM for the heads.

Simple evaluation, does this zone have less heads than others?

If yes, go for it!

If no, you may need to install smaller nozzles to reduce the overall water usage to what it was before.

Adding one more head is not going to be an issue beyond the possibility of some adjustments to the other heads.

 

I'm trying to cover the area below.

There was an underground oil tank there which I just had abandoned (top cut open, cleaned out, filled withs sand) so the area is a bit of a mess. I don't quite know what I'm planting there so I wasn't sure what I'll need, watering-wise. I want something do hide the area (foundation wall, downspout) but is OK near a foundation. But if it's large, and the sprinkler is near the foundation, it'll block spray from any plantings in front, along the edge with the grass slope.

The sprinkler I'd be tapping from is about 15-20 feet away, straight off the top of this picture (along the wall). A tee wouldn't work, or at least wouldn't be enough--that line in the first picture runs perpendicular to the foundation wall, so I'd need to take a hard left. I haven't looked hard yet, but optimally I'd need a poly version of a PVC side outlet elbow socket
[ATTACH=CONFIG]80978[/ATTACH]
that, or a tee and and elbow combination.

 

I just did a quick search and did not find same fitting but easy to make with a combo of fittings. You still need to do a flow rate to see it sprinkler will work. Most zones I have installed were close to maxed out.

 

How do I measure flow rate for an existing sprinkler zone without a tap? Do I have to rig up a tap at the valve box and measure into a bucket?

I think I have some leeway here. A year and change back the town did a street drainage project, which involved a private contractor (Three Stooges Contracting) ripping up sidewalks and front yards. In repairing the sprinkler lines they destroyed they removed two heads from the same zone I'm looking at here. THAT is another issue I have (their work left a corner uncovered) but I might have room for at least one more head.

I just planted an arborvitae in the space... I don't recall the variety but it's spec'd to grow to about 30" round. There's another small evergreen in the area, and various bulbs and small flowering plants, so I'll have to account for that in what sort of head I put in.

I was watching a video on installing sprinkler lines, and they specifically didn't use crimp clamps (or anything) when attaching lines to heads, only when coming off the 1" supply lines. Is that normal? Mine has a clamp at the sprinkler.

Is this a 3/4" line? My line looks to be about 1" OD, based on my thumb being an inch wide, and according to this, that means a 3/4" ID.

 

You are just getting an idea of how much flow the lines are providing based on the gmp of the heads.

For example, if you have 4 heads and each is 3 gpm (12 gpm total) and that is working if you add a 5th you may need to back them all down to 2.5 gpm (12.5 gpm total) but I would install first and see.

The pipe looks like 3/4 but just measure the OD and compare that to similar pipe at store, it is also printed on the outside.

Use sprinkler fittings, with the barbs, and hose clamps at all slip on connections.

 

I haven't had the chance to move on this (a dozen other projects had my attention) but while poking about I came across this page.

It contains the following statement:
"Building Foundations and Walls: Keep sprinklers at least 18″ away from foundations and building walls. No water should spray onto a building wall. For this reason any sprinkler that sprays water should be at least 36″ away. Bubblers or “flat” spray sprinklers may be closer if unavoidable and soils are suitable. The water must not spray onto the wall or foundation and the soil must not be expansive."

I don't know if my soil is expansive, but did the installer (many years ago) screw up by installing this head less than a foot from the foundation?