Browse Forums Landscape & Garden Design 1 Nov 07, 2016 9:39 am I'm re-landscaping my front yard and will have someone do the irrigation for me. To save costs I agreed to dig the trench for the main line. I chose to do it along the fence line as there was a massive root left from a photinia i got stumped that i couldnt remove on the other side. (I've gone 150-200mm deep for the trench - twice as deep for the valve box). However, now that I've started to plant my Viburnum Tinus hedging I'm concerned that they will be too close to the mainline + wiring once they are in the trench. Here's a snap for a visual - http://imgur.com/a/FgTmU. I mentioned it to the irrigation installer and he said they could run it above ground as close to the fence line as possible but under mulch etc to avoid exposure) and then bring it underground to the valve box & garden tap. I'm new to the caper but googling around I couldn't find any examples of main line irrigation being above ground - and common sense would suggest you want it underground to avoid weather exposure or accidental damage. So 2 questions - 1. Is above ground an option for irrigation main line + wiring? 2. How do people go about avoiding root damage when needing to run the main line or any subsurface irrigation near trees or where trees/plants will be growing? It's possible i just need to dig the trench deeper. Re: Irrigation main line above ground? 2Nov 07, 2016 5:26 pm I assume that you are using LDPE. No problems at all running it under mulch, that's how I would do it. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Irrigation main line above ground? 3Nov 07, 2016 7:13 pm SaveH2O I assume that you are using LDPE. No problems at all running it under mulch, that's how I would do it. That's good to know - will save me more digging. Interestingly the irrigation installer said "mainline is High Density poly & wiring conduit Medium Density, but over time they may get strangled by roots". Is that cause for concern given you specifically mentioned LDPE? Re: Irrigation main line above ground? 4Nov 08, 2016 6:56 pm HDPE is high density polyethylene whereas LDPE is low density. Poly is an inert plastic that doesn't attract roots and the HDPE is very strong anyway. The only concern with HDPE would be damage to the plant's root system if you ever needed to pull it up but that would also apply to LDPE anyway. LDPE has a lower pressure rating of 300 kPa but irrigation systems usually use a 100 kPa pressure reducer and sometimes a filter at the tap and so LDPE is commonly used also. There actually isn't a lot of difference cost wise between the two pipes but HDPE fittings are more expensive. I can't really comment on the pipes being used because I don't know the design or what fittings are being used plus the irrigation guy will know a lot more than me anyway. The big advantage of running the pipe under mulch is ease of access should you ever need to change or add to the system at some later time. EDIT 23/02/2017 Holman LDPE has a higher pressure rating of 400 kPa. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Hi everyone, Looking for some advise. We are about to build an above ground pool in our backyard. There is a private sewer line running under the pool at 1.6m… 0 11812 Hi all I am looking to run a water line under my concrete footpath which is directly next to my home, was seeing if this is possible without cutting the entire section… 0 20229 4 10852 |