First Flush Concrete Co. · Pervious flatwork & stormwater · Mizzleford, the Dallow Levels · Since 2011
THE LOT THAT DRINKS ITS OWN RAIN.
Pervious concrete is 4,000-psi pavement with fifteen to twenty percent deliberate void — rain passes straight through the slab into a stone reservoir underneath and away at the water table, the way it did before anyone paved anything. No ponding at the door. No retention basin eating your buildable land. No compliance letter from the Levels authority.
Vacuum-swept twice a year by us, not you · 118 lots on the Levels with zero retention basins · the stormwater credit filed with every permit
The Dallow Levels, 2025 — 2026
Watch it take a storm
Six pervious pours from last season — photographed during rain or straight after it, because a pervious lot in sunshine is just a handsome lot. A pervious lot in a downpour is the whole argument, with standing water nowhere in frame.
The pervious card
Pervious lot or drive$13.60 / sq ft
6 in open-graded stone reservoir, 6 in pervious 4,000-psi, roller-screeded
Pervious walkways & aprons$11.90 / sq ft
Same reservoir section, 5 in slab — foot traffic and cars, not lorries
Edge restraint & curbing$18 / linear ft
Pinned concrete beam or unit curb — pervious wants an edge like any slab
Engineered stormwater fileincluded
Percolation test, reservoir calculation, the credit letter for your permit
The twice-yearly vacuum sweep$0.22 / sq ft
April and October, booked by us — the only maintenance pervious asks
Regenerative-air restoration$0.85 / sq ft
For lots neglected by previous owners — restores infiltration, tested
The pervious card
Priced like pavement, because it is
The card reads like any concrete card on purpose: this is a structural pavement that happens to drain, not a landscape feature. What is NOT on the card is the basin you do not build, the pipe runs you do not trench, and the land the calculator hands back — on a typical eight-thousand-foot lot, that cheque is bigger than the pour.
I have signed off retention basins for nineteen years, and I will tell you what nobody does: they silt up, they get mowed around, and they fail quietly. First Flush’s market lot passed a two-inch-hour storm straight into the ground while I stood on it in full rain gear. I recommend pervious in every pre-application meeting I chair now.
How it goes
Test, reservoir, pour, sweep
A pervious slab is a soil project wearing a lid — the sequence respects that, and the soil is the one thing we test before we quote.
Day 0
The percolation test
A hole, a head of water, a stopwatch. If your ground drinks slower than the reservoir can hold, you hear it before you love the number — clay gets a designed outlet and an honest revised card.
Week 1
Excavate & reservoir
Six inches of open-graded stone placed in lifts over geotextile, level-checked against the water table. The stone IS the drainage; the slab is only its roof.
Week 2
The pour
Low-slump pervious mix, roller-screeded in single passes — never power-trowelled, which closes the voids and kills the entire point. Edges hand-struck, curing blanket down the same day.
Day 28
Test & file
Infiltration checked with a ring infiltrometer against the design rate, the stormwater credit letter signed for your permit file, and the first sweep booked before we leave.
Twice a year
The vacuum sweeps
April and October, from our calendar. Pervious does not clog from below — it clogs from above, and a vacuum pass twice a year keeps the voids open for decades.
Before you call
Straight answers about the holes
The five every first-time pervious buyer asks, usually while squinting at the surface. The shop line below runs seven to five; the estimator grew up on the Levels and can tell your soil by the colour of your ditch.
Will it clog?
It clogs from the top down — sediment and fines settling into the voids — which is why the twice-yearly vacuum sweep rides our calendar, not yours. The 2013 lot in the gallery still infiltrates at design rate after thirteen years of it. What actually kills pervious is a landscaping crew blowing mulch and silt across it all autumn; we will tell you exactly where the clippings should not go.
How strong is it, really?
It is 4,000-psi structural pavement — cars, delivery lorries and fire apparatus are all fine on the six-inch section. What it honestly is not is a heavy-industrial yard: steady HGV traffic concentrated on small areas will ravel the surface years early, and we say that at quote time rather than sell you the wrong pavement and blame the mix.
What about freeze-thaw?
The voids ARE the freeze protection. Water does not stand on the surface, does not sit in the slab, and is through both into the reservoir within minutes of landing — the Levels authority’s own test lot has taken eleven winters without a spall. The failure you have seen in ordinary paving is water with nowhere to go; pervious is the nowhere-to-go, removed.
Can I use it on clay soil?
With a designed outlet, yes: the reservoir stores the storm and a calibrated slow drain bleeds it to a ditch or field tile across twenty-four hours — which still beats a basin and still earns most of the credit. What we will not do is pour full-retention pervious over clay and call it a drinking lot; the percolation test exists to keep us honest.
What changes in winter?
No sand, ever — sand is manufactured clog. De-icing salt works at reduced rate and pervious needs far less of it, because the ice has nowhere to stand in the first place. The plow runs on shoes set by us, in writing, for your contractor every November.
The garden centre needed forty more parking bays and the authority wanted a basin that would have eaten eleven of them. Pervious got us all forty bays, no basin, and the stormwater letter in the permit file. During the March gale the aisles were dry underfoot while the road outside was a river.
Twelve townhomes, one shared drive and a drainage covenant nobody could agree on. The lot settled it — every drop stays on site, and the sweep crew turns up on a schedule none of us thinks about. The driver waves to the kids now; that is the entire relationship, and it is perfect.
We inherited a pervious lot nobody had swept for six years and assumed it had gone decorative. One regenerative-air restoration, an infiltration test run in front of me, and the thing drinks like it is 2013 again. They could have sold us a re-pour; they sold us a Thursday.
Living with pervious
The rhythm, once it’s down
Pervious asks less of an owner than any pavement you have owned: no basin to mow, no drain grates to clear, no ice sheet to salt. The two things it cannot take are sand and sealed-coat — both close the voids, and neither is reversible — and the sweep contract covers everything else. When the lot turns fifteen and you want it tested against its design rate, the infiltrometer comes out and the number goes in writing, same as day 28.
Pouring season April to November · percolation mornings year-round · stormwater files reach the Levels authority inside a week · (555) 312-5087 · rain@firstflushconcrete.example
Get the number, and the basin you won’t build
Square feet and what the ground does in rain are enough to start — the percolation morning settles the rest and the card-rate quote follows inside two days. Or call and describe your ditch; the estimator will know the soil. rain@firstflushconcrete.example