Same yard, same square footage, same paver on the page. The gap between the high number and the low one is real, and it is almost entirely below grade — where you will never see it again once the job is finished.
On a paver patio the surface is the cheap end of the job. Most of the days on site, most of the machine time and most of the material tonnage go into things buried before you ever walk on it.
That is why the cheapest bid is usually cheaper. Not because somebody found a better price on pavers — everybody buys from the same handful of yards at similar numbers. It is cheaper because something got left out, and the only people who will know are the crew who left it out and whoever comes back in year five.
Below is where bids diverge. For each item: what the cheap version looks like the day the crew drives away, and what it looks like three years later. None of it is a trade secret. It is published installation guidance, and any honest contractor will walk you through it.
A patio wants 7 to 10 inches out of the ground — base, bedding sand and paver together. Digging 4 or 5 inches is faster and leaves room for almost none of it.
Day oneIdentical. You cannot see excavation depth through a finished patio.
Year threeToo little material between the pavers and clay that moves every season. The field telegraphs every wet spring.
4 to 6 inches of compacted dense-graded aggregate. ICPI sets 4 inches as the patio minimum over well-drained soils, and calls for bases 2 to 4 inches thicker in colder climates over wet or weak soils. Johnson County clay is that.
Day oneFlat and tight either way.
Year threeTwo inches of stone cannot spread load over soft clay. Low spots hold water after rain.
ICPI calls for compacting the base in 4 to 6 inch lifts with a 7,000 lbf reversible plate — thinner with lighter machines — to at least 98% of standard Proctor density. Dumping the full depth and running a rental plate over the top compacts the top two inches.
Day oneFlat, because the top of the base was compacted.
Year threeThe uncompacted bottom half consolidates under use and the field drops unevenly.
ICPI's rule of thumb: the base extends beyond the restraint by at least the thickness of the base. A 6 inch base runs at least 6 inches past the spikes. It costs stone and a wider hole.
Day oneInvisible. It sits under the mulch line.
Year threeThe perimeter has nothing under it. The outside row drops and the edge walks outward.
Geotextile between soil and stone. ICPI recommends it over clay and moist silty subgrades and where there is freeze and thaw — essentially every yard here. It stops soil migrating up into the base.
Day oneNothing to see. A couple hundred dollars of material nobody looks at.
Year threeClay has pumped up into the voids in the stone. The base loses bearing and the patio dishes.
1 inch of screeded concrete sand, uncompacted. ICPI is blunt: bedding sand must not be used to compensate for an uneven base, because the unevenness reflects through to the surface over time. Mason sand and limestone screenings are not acceptable.
Day oneTwo or three inches of sand can true up a sloppy base and look perfect.
Year threeDeep sand migrates and ruts under the traffic path.
The most skipped item on a cheap bid. It gets spiked into the compacted base with at least 1 inch of vertical surface against the side of the paver. ICPI states plainly that soil backfill is never a suitable edge restraint, that it is never set on top of the bedding sand, and that garden bed edging is not acceptable.
Day oneA shovelful of soil packed against the outside row looks like a finished edge.
Year threeThe field spreads, joints open across the patio, and the cut pieces at the perimeter rock underfoot.
Plain sand fills the joint and stays loose. Polymeric binds when it is wetted. It costs more and takes more care. It is not a cure for a bad base — it is the difference between a joint that stays full and one that does not.
Day oneBoth look like full joints, especially if nobody vibrated the sand in properly.
Year threePlain sand has washed out at the perimeter and under the downspout. Weeds in the open joints, units rocking.
A 400 square foot patio dug 8 inches deep is roughly ten cubic yards of dirt in the ground, and it swells maybe a quarter once loose. Real trucking, real dump fees. Spreading it in the back of the yard costs nothing.
Day oneA mound behind the shed, or a thin layer raked into the lawn.
Year threeA dead patch you are paying somebody else to remove — and if it went toward the house, the grade water runs on has changed.
ICPI puts the minimum slope at 1.5%, about 3/16 inch per foot. Most of us shoot 2%, a quarter inch per foot, checked with a level rather than by eye. Downspouts discharging at or under the patio have to be piped away.
Day oneLooks level — which is what most people want it to look like.
Year threeWater standing along the house, ice in January, and a saturated base at the exact point where the base is thinnest.
Units made to ASTM C936 average 8,000 psi, absorb no more than 5%, and take at least 50 freeze-thaw cycles with under 1% loss. Pavers should be pulled from three or four bundles at once so colour variation blends across the field.
Day oneLaying pallet by pallet leaves visible colour banding — this one you see immediately.
Year threeA discontinued colour lot means you cannot buy six matching units to repair a corner.
Saw cuts rather than split ones, gaps over 3/8 inch filled with a cut paver, and no slivers at the perimeter. Cutting well is slow, dusty, and takes a wet saw.
Day oneChipped edges and thin slivers read as rustic on handover day.
Year threeThe slivers have cracked out and popped loose, and the perimeter looks ragged.
All four are decided at bid time, and all four are invisible on handover day. That is the entire reason the gap between bids exists.
Ask these of everyone, including me. Write the answers down. A contractor who builds it properly answers all twelve without hesitating, because they are describing a normal day.
The last one catches more money than the other eleven put together.
If one proposal specifies six inches of compacted base, fabric and haul-off, and another says "install paver patio, 400 sq ft," you are not comparing two prices. You are comparing two different products that share a name.
The fix costs nothing. Take the answers to those twelve questions, write them onto one page, and hand that page to all three bidders. Or take whichever proposal you have that is most specific, strip the price off it, and ask the others to quote that scope.
One of two things happens. The numbers converge, and you know who is cheapest. Or one comes back well above their first number, which tells you what that number was missing. It cuts both ways: a contractor who bid a proper build and lost to somebody who did not will not start cutting corners to match. A written scope is how the good bid gets a fair hearing.
Sources. Base thickness and lift compaction, Proctor density, bedding sand depth, base extension past the restraint, edge restraint contact and fastening, minimum slope and cut sizing are from ICPI Tech Spec 2 and Tech Spec 3. Paver unit requirements are from ASTM C936. Johnson County soil descriptions are from USDA NRCS soil survey data. Excavation volumes and the practical notes are mine.
Also worth reading: paver patio vs concrete patio in Kansas City →
Excavation depth, base thickness, lifts, fabric, sand, restraint, joint sand, spoil, drainage, paver and cuts — written down, with a fixed price. Use it to price me against anybody, including people you like better.