The asphalt crew is booked for Thursday. Base rock is down, the curbs are poured, and someone finally asks where the irrigation sleeves are for the parking lot islands. Nobody put them in. Now you are choosing between saw cutting fresh concrete, boring under compacted base, or running pipe the long way around every island. All three cost time and money you did not plan for.
The fix is not complicated. Irrigation sleeves are empty pipes laid under future concrete and asphalt so water lines and valve wire can cross later. They need to be on the drawings, in the schedule ahead of base course, sized with room to spare, capped and marked at both ends, and checked before anything goes over them. Here is how to keep them from slipping through.
Why irrigation sleeves get missed
Most of the time it is a gap between scopes, not carelessness.
- The irrigation design shows up late, or it is design build, so the civil set shows curbs and islands with no crossings drawn.
- The site utility sub sees sleeves as landscape work. The landscape sub is not mobilized until the end of the job. Each assumes the other has it.
- The spec says "sleeves by others" and nobody is ever named as the others.
- The sleeves went in but were never marked, and grading or curb work buried or crushed the ends.
That last one hurts the most, because you paid for the sleeves and still end up cutting.
Know every place a line has to cross
Before you can schedule sleeves you need a list of crossings. Lay the civil, landscape and irrigation sheets side by side and mark every spot where a planted area is cut off from its water source by concrete or asphalt. The usual ones:
- Parking lot islands and end caps
- Medians in drive aisles and entries
- Planter strips between sidewalk and curb
- Beds on both sides of a walk to a building entry
- Landscape areas on the far side of a fire lane or loading area
- The run from the meter or backflow assembly to the first valve
Each crossing may need more than one line. An island might need mainline coming in, a lateral heading out to the next island, and control wire to a valve. Drip and spray zones sharing a bed may need separate supply.
If the irrigation design is not finished, that is the first thing to push. You cannot place sleeves for a system nobody has drawn. Getting the planting irrigation scope laid out early, even roughly, gives you crossing locations while the site is still open dirt.
Size and material
Follow the project spec where there is one. Where it is silent, a few field habits save trouble.
Go bigger than the pipe
A sleeve that barely fits the pipe stops being usable the moment there is a fitting, a slight bend or a little mud inside. Many specs call for a sleeve roughly twice the diameter of the pipe it carries. Pulling pipe through a tight sleeve under a wide drive aisle is miserable work, and sometimes it simply will not go.
Give wire its own sleeve
Valve wire pulled through the same sleeve as pressurized pipe is easy to nick and hard to replace. A separate, smaller wire sleeve turns a future wire repair into a pull job instead of a dig.
Add spares
An extra sleeve at each major crossing costs very little while the trench is open. Plan changes, added zones and future repairs all end up using spare sleeves. Without them, any change means cutting.
Use pipe that holds up
Thin wall pipe can crush under compaction equipment and traffic. Use the wall thickness the spec calls for, bed it properly, and keep it deep enough to sit below the base course with real cover.
Mark both ends so they can be found
A sleeve nobody can find is the same as no sleeve.
- Run each sleeve well past the back of curb or edge of walk so the ends land inside the planting area, not under the curb.
- Cap or tape both ends. In western Washington this matters more than people expect. A site that sits through a wet winter between rough grade and landscape install will fill open sleeve ends with silt and standing water, and a sleeve packed with mud has to be jetted out or abandoned.
- Leave a pull string inside, tied off at both ends.
- Mark each end above grade with painted lath, and paint a mark on the curb face at each crossing so the location survives after the stakes get knocked over.
- Record locations on the as-builts with measurements from fixed points like curb corners or building lines. A photo with a tape in the frame helps.
When the landscape crew shows up months later, those marks are the difference between pulling pipe in an hour and probing an entire island with a bar.
Put sleeves in the schedule as a hold point
The drawings are not enough. Sleeves need to be a task with an owner and a date.
- Name who installs them in the contract. The site utility sub already has trenching equipment on site. The landscape sub knows what the system needs. Either can work if it is written down.
- Set sleeve install after rough grade and curb layout, before base course.
- Make a sleeve walk a hold point before base rock goes down, the same way you hold for underground inspections.
Our weather makes this tighter. Asphalt work in King County and Pierce County tends to bunch into dry windows, and when a window opens, crews move fast. If the sleeves are not in and verified before that window, the pressure will be to place the asphalt now and sort it out later. Getting the sleeve walk done early means you never have to make that call.
Verify before anything gets placed
Run a short check before base course and again right before the pour or the asphalt:
- Count the sleeves at each crossing against the plan.
- Find both ends of every sleeve.
- Confirm caps are on and pull strings are inside.
- Confirm the ends extend into the planting area past the curb or walk.
- Check that curb paint marks and as-built notes match what is in the ground.
Get the landscape or irrigation sub on that walk if you can. They are the ones who will use the sleeves, and they will catch a missing wire sleeve or an end that lands right where a tree is going.
When the sleeves are already missing
Sometimes you find out too late. The options, roughly in order of how much finished work they disturb:
- Bore under. A small boring setup or a pneumatic piercing tool can push a sleeve under a walk or curb from one bed to the other without touching the surface. Results depend on distance, soil and what else is buried there. Rocky glacial fill can deflect a piercing tool, so expect it to take more than one try on some sites.
- Reroute. Feed the island from an end where it meets another bed, or run the line around the end of a walk. It works, but longer runs, extra fittings and odd routing make future repairs harder.
- Saw cut and patch. Reliable, but visible, and a patch in brand new concrete or asphalt is the kind of thing owners point at during the walkthrough.
Whichever you choose, decide before final grading in the beds so you are not trenching through finished soil preparation and fresh plantings. Then document the reroute. Whoever maintains the site later needs to know where the line actually runs. A crossing that does not match the plan turns the first broken lateral into a hunt, and a simple irrigation repair becomes a long day of digging. Small misses like this also have a way of piling up at landscape closeout.
The short version
- Draw every crossing while the site is still dirt.
- Size sleeves larger than the pipe, give wire its own, and add spares.
- Cap, string and mark both ends, and put them on the as-builts.
- Make the sleeve walk a hold point before base rock.
If you have a project with a landscape and irrigation scope coming up, feel free to send the plans over through our general contractor landscape services page or request a quote.
