Why it costs more to build
The pavers are comparable in price to good conventional pavers. The cost sits underneath:
- A deeper excavation. The base has to store water, so it is thicker than a conventional driveway base.
- Washed open-graded stone instead of ordinary granular. It costs more per tonne, and you need more of it.
- More disposal. Deeper dig, more spoil, and disposal is charged by volume.
- Joint aggregate rather than polymeric sand.
- Geotextile and, on clay, sometimes an underdrain.
- Care at the edges, so infiltrating water goes where it should and not against your foundation.
Indicative numbers
| Conventional interlock | Permeable interlock | |
|---|---|---|
| Installed rate | $18–30 / sq ft | A premium above that range |
| 300 sq ft, built | $5,400–9,000 | Higher |
| Rain Ready rebate | $0 | Up to −$5,000 |
| Net, if eligible and approved | $5,400–9,000 | Frequently the lower of the two |
We have deliberately not printed a permeable rate. The premium varies a great deal with soil, depth required and whether an underdrain is needed, and a made-up per-foot figure would mislead you. Get it measured.
The rebate is not retroactive and funding is first-come, first-served. Until you have written approval from the City, price the project as though you are paying the full amount, and treat the rebate as upside.
When permeable is the wrong answer
If your address is not in a Priority Stormwater Retrofit Area, and you do not have a drainage problem to solve, conventional interlock is very likely the better buy. Permeable is a good product, not a moral obligation. We will tell you which one we would put on our own house.
Get both options priced side by side
We'll quote conventional and permeable on the same measure so you can compare the finished numbers rather than the rates.