Why base prep decides everything in Michigan
The part of your patio you will never see is the only part that determines whether it is still flat in ten years.
What freeze-thaw actually does
Water expands by about nine percent when it freezes. That is not a small force - it is the same mechanism that splits boulders and buckles roads.
Now put that under your patio. Water sits in the base material, freezes, and lifts everything above it. Then it thaws and the surface drops - but not evenly, because the water was never distributed evenly. Southeast Michigan runs through that cycle dozens of times between November and March.
A patio built on a properly compacted, properly drained base handles it, because there is very little standing water in the base to freeze and the load is distributed. A patio built on four inches of loose sand does not.
What "properly built" means, layer by layer
- Excavate to depth. Seven to nine inches below finished grade for a patio, ten to twelve for a driveway. Deeper in poor soil.
- Geotextile fabric. Macomb County clay migrates upward into aggregate over years, contaminating the base and destroying its drainage. Fabric between soil and stone stops that. It costs very little and is skipped constantly.
- Aggregate in lifts. Crushed stone placed in layers of three to four inches, each compacted before the next goes down. This is the step that separates real work from fast work. A single thick dump-and-roll compacts the top and leaves the bottom loose - and the bottom is what everything rests on.
- Grade for drainage. Roughly a quarter inch of fall per foot, away from the house. Water that cannot leave will find somewhere to sit, and somewhere to sit is somewhere to freeze.
- Screeded bedding layer. About an inch of coarse sand, screeded flat. Bedding sand levels the pavers - it must never be used to correct a bad base.
- Edge restraint. Pinned properly. Without it, pavers spread sideways a little more every year until the joints open and the field loosens.
- Polymeric sand and final compaction. Locks the joints against weeds and washout.
Why the cheap quote is cheap
Look back at that list and notice that steps one through four - the majority of the labour and material cost - are completely invisible the day the job is finished. Two patios, identical in the photograph, can have four inches of difference underneath.
That is the entire economics of a lowball hardscape bid. It is not usually dishonesty about the visible work; it is depth and compaction, where the customer will never know until Michigan tells them.
How to spot it in year three
- Low spots that hold water after rain
- A wavy surface, most visible when you sight along it at a low angle
- Joints opening up and sand washing out
- Edges spreading, pavers loose at the perimeter
- Pavers sitting at slightly different heights near a downspout or low corner
All of those are base problems presenting as surface problems, and none of them are fixable from the top. The repair is a rebuild.
Ask the question
When you get quotes, ask each contractor how deep they excavate and how many lifts the aggregate goes in. The answers will differ, and the difference is the whole ballgame.
See our cost guide for the real ranges, and how we build a paver patio step by step.