Choose the job (renew, replace or new path), the kind of line, its diameter, run length, depth and connections, the condition and material of any existing pipe, and the ground. The finder checks every method in that family against published size, length, accuracy and ground ranges, then marks each one shortlist, possible or unlikely and gives the reasons, the access it needs and the standard to ask about.
- The job you pick decides which family of methods is screened: renewal, replacement on the old path, or a new path.
- Every method starts on the shortlist; each rule can only move it down, and each move is explained in the result.
- Sizes, lengths and accuracy limits come from ASTM standard scopes and the Iowa SUDAS design manual, Chapter 14.
- For a new gravity line, the finder compares a ±1% bore tolerance with the total fall of your run.
- It is a screen, not a design: capacity, structure, permits, utilities and price are for the engineer and contractor.
Trenchless Method Finder
01 /What does the Trenchless Method Finder do?
It narrows a long list of trenchless methods down to the few worth asking about for one run of pipe. Trenchless covers at least a dozen distinct techniques, and a contractor will usually propose the one their crew owns. The finder puts every method in the relevant family on the table, applies the limits published for it, and shows which ones survive and why. That lets you walk into a conversation knowing whether the method on the quote is a natural fit, a stretch, or out of its usual range.
Nothing in the result is a price, an eligibility decision or an engineering design. The finder does not know your capacity needs, the structural condition the camera will reveal, where other utilities run, or what your municipality allows. It only knows the numbers you give it and the published ranges below, and it says so in every result.
02 /What are the ten inputs, and why does each matter?
| Input | Choices or range | What it changes |
|---|---|---|
| 1. The job | Renew in place / replace on the same path / new path or crossing | Which family is screened |
| 2. Kind of line | Gravity sewer or storm drain / pressure line / casing or culvert | Grade rules, coatings, pressure liners |
| 3. Inside diameter | 10 to 4,000 mm | Each method's size range |
| 4. Length between access points | 1 to 2,000 m | Typical and maximum run lengths |
| 5. Depth to the pipe | 0.3 to 30 m | Cover rule, heave, trench protection note |
| 6. Service connections | 0 to 40 | Digs for bursting and slip lining; reinstatement for lining |
| 7. Condition | Unknown, sound, broken, collapsed, sag, too small, corroded | Renewal and replacement gates |
| 8. Material | Clay or concrete, cast iron, plastic, ductile iron or steel, fibre, unknown | Bursting vs splitting, reaming, coatings |
| 9. Ground | Clay, silt or sand; gravel and cobbles; rock; high groundwater; unknown | Boring, ramming, moling and bursting limits |
| 10. Available slope | Percent, for a new gravity line | The grade check for new-path methods |
Condition and material only matter for renewal and replacement, and slope only matters for a new gravity line; the finder ignores them otherwise. If you pick renew or replace and leave condition as "not known yet", the result is labelled provisional, because a recorded camera run is what actually decides whether a pipe can be lined or burst.
03 /How does the finder rate each method?
Every method in the chosen family starts at Shortlist. Each rule that applies can lower it to Possible or Unlikely, never raise it, and each rule adds a sentence to that method's row. Methods are then listed from shortlist to unlikely. The large heading shows the shortlisted methods, or the possible ones if nothing survives at shortlist level.
Two calculations appear in several rules. The tolerance check takes one percent of the run length as the likely error of a bore that is steered to about ±1% of its length, and compares it with the total fall of the run (slope times length). The cover rule is the SUDAS rule of thumb of roughly one foot of cover per inch of bore diameter, used to flag shallow bores that may heave or crack pavement.
| Method | Moves to Unlikely when | Moves to Possible when |
|---|---|---|
| CIPP lining | Diameter outside 50–2,743 mm (ASTM F1216's 2–108 in); collapse; sag | Broken; too small; pressure line; casing or culvert; run over 200 m |
| Slip lining | Collapse; sag; too small | Under 150 mm; broken; three or more connections |
| Close-fit liner | Collapse; sag | Always, noting declining use in northern climates; also broken or too small |
| Epoxy or spray coating | Pressure: pipe that is neither metal nor marked corroded, outside 13–914 mm (ASTM F2831), or broken, collapsed or sagging. Gravity: any condition except sound or unknown. Fibre pipe. Casings. | Gravity pipe that is sound or not yet inspected |
| Method | Moves to Unlikely when | Moves to Possible when |
|---|---|---|
| Pipe bursting or splitting | Sag; rock | Outside 50–914 mm; plastic, ductile iron or steel (splitting); fibre; collapse; cobbles; under 1 m deep; over 120 m |
| Pipe reaming | Cast iron, ductile iron or steel host; sag | Material unknown; collapse; under 100 mm |
| Pipe eating or ejection | Under 254 mm | Always otherwise (specialised); under 30 m |
| Method | Moves to Unlikely when | Moves to Possible when |
|---|---|---|
| Directional drilling | Over 1,524 mm; gravity line with slope under 1%, or with ±1% of length at or above the total fall | Other gravity lines; over 254 mm on a run under 60 m; cobbles or rock; cover rule not met |
| Auger boring | Rock | Under 203 mm or over 914 mm; over 69 m; gravity line where ±1% meets the fall; cobbles; high groundwater |
| Pipe ramming | Over 91 m; rock | Outside 51–1,397 mm; over 46 m; any gravity line |
| Microtunnelling or pipe jacking | Under 254 mm | Over 3,048 mm; under 30 m |
| Impact moling | Over 152 mm; over 18 m; any gravity line; rock | Cover rule not met; cobbles |
04 /Where do the numbers come from?
Size ranges for lining and coatings are the scopes of the ASTM practices: F1216 covers inverted resin-impregnated tubes in pipes of 2 to 108 inches, F1743 pulled-in-place tubes of 2 to 96 inches, F2019 UV-cured glass-reinforced tubes of 4 to 72 inches, and F2831 non-structural epoxy barrier coatings in metallic pressure piping from ½ to 36 inches. The finder uses the widest CIPP range, since the three practices overlap.
Everything else comes from Chapter 14 of the Iowa SUDAS design manual, a public engineering manual that sets out each trenchless method with sizes, lengths and tolerances. It reports common auger-boring sizes of 8 to 36 inches with typical bores of 175 to 225 feet; pipe ramming from 2 to 55 inches, usually under 150 feet and up to about 300; mini-directional drilling to 10 inches under 600 feet and larger rigs from 12 to 60 inches; microtunnelling from 10 to 120 inches; compaction methods such as impact moling to about 6 inches over 40 to 60 feet; and bursting of pipes from 2 to 36 inches over the 300 to 400 feet between manholes. Metric conversions are rounded.
| Method | Typical line and grade accuracy |
|---|---|
| Auger boring, unsteered | About ±1% of bore length |
| Auger boring, steered | About ±0.1% vertically, ±1% horizontally |
| Pipe ramming | Non-steerable; usually better than ±1% of length |
| Directional drilling | About ±1% of bore length; 6 to 12 inches for mini rigs |
| Microtunnelling and pipe jacking | Within about 1 inch (25 mm) of line and grade |
| Compaction and moling | No control once started; not used for sanitary sewers |
05 /Worked examples
A cracked 100 mm clay lateral, 20 m, one connection, renew in place. CIPP stays on the shortlist and the result notes the connection is reopened from inside. Slip lining drops to possible because a smaller pipe inside a 100 mm lateral costs a lot of bore, and one connection needs a dig. Close-fit is possible with the cold-climate note, and a coating is possible only because the pipe is round and sound.
The same lateral, too small, replace on the same path. Pipe bursting is shortlisted with a note that it can go up a size, and the result counts three excavations: launch, receiving and the connection. Reaming is shortlisted because clay is non-metallic. Pipe eating is unlikely because microtunnelling machines start at about 254 mm.
A new 150 mm gravity line, 40 m at 2%, new path. Directional drilling is possible only: 2% over 40 m is 0.8 m of fall, and a ±1% bore could be off by ±0.4 m. Auger boring is possible because 150 mm is below its common range. Microtunnelling is unlikely at this size and the result suggests asking about guided pilot-tube boring. Moling is unlikely on both length and grade.
A 600 mm casing under a road, 45 m, cobbles. Pipe ramming and microtunnelling are shortlisted. Auger boring is possible because boulders larger than a third of the casing cannot pass its flights. Directional drilling is possible, flagged for a big rig on a short bore, stony ground, and 3 m of cover against the roughly 7 m the cover rule would ask for a 600 mm bore.
06 /What the finder cannot tell you
- Capacity. Renewal methods shrink the bore; whether the smaller pipe carries your flow is a hydraulic check.
- Structural design. Liner thickness, pipe dimension ratio and casing wall come from the product standard and site loads.
- Other utilities. Bursting pushes soil outward and bores can strike services; only locates and exposure tell you what is there. In Alberta, Utility Safety Partners notes that customer-owned water and sewer service lines are not registered with it, so a private locate may be needed.
- Rules and permits. Some owners prohibit particular methods or set their own tolerances. Confirm with your municipality or the owner of the pipe.
- Price. For residential planning ranges see the trenchless sewer cost guide; for mains and crossings, price comes from a tender.
To see what a shortlisted method would dig up on your lot, try the Dig vs Trenchless Disruption Calculator. To understand the methods themselves, start with every method compared. When you are ready, request quotes and include the finder's result with your camera footage.
FAQQuestions people ask
Why does the finder start every method on the shortlist?
So that every downgrade has a stated reason. A method only drops when one of the published rules applies to your answers, and the sentence explaining it appears in that method's row.
Why is directional drilling rarely shortlisted for a gravity sewer?
Because a bore held to about one percent of its length can be off by as much as the whole fall of a flat sewer. The finder compares the two numbers and only allows HDD as possible when the fall is clearly larger.
What does "Provisional — no camera run yet" mean?
You chose renew or replace without a known condition. The levels assume the pipe is passable; a collapse or sag found on camera would rule several methods out.
Can the finder say a method is approved in my city?
No. It knows published technical ranges, not municipal approvals. Ask the pipe owner or your permit office which methods and specifications they accept.
Why are no prices shown?
Method choice comes before price, and many of these methods are priced only by quote or tender. Residential planning ranges are on the cost page.
NETWORKGo deeper across the HAUSE Sewer network
Is trenchless sewer repair worth it? Lifespan, cost and when it fails
Is trenchless sewer repair worth it? How long lining and bursting last, when trenchless beats digging on cost, and the pipe conditions where it fails.
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Auger Cable Sizer: choose the line, the distance to the clog and the clog type to get drum or sectional cable, length, head, machine class and a pro flag.
PipeCleaning.caPipe Method Matcher: which cleaning methods suit your pipe
Pipe Method Matcher: enter your house era, pipe material and symptom to see which pipe cleaning methods are recommended, safe with conditions, or avoid.
SOURCESSources and further reading
- Iowa SUDAS Design Manual, Chapter 14: Trenchless Construction
- ASTM F1216 — Rehabilitation by inversion and curing of a resin-impregnated tube
- ASTM F2831 — Internal non-structural epoxy barrier coating, metallic pressurized piping
- CCOHS — Trenching and Excavation
- Utility Safety Partners — Click Before You Dig, homeowner overview