Typical profiles
Footpath, driveway and car park build-ups laid out with slab thickness, base depth and storage, ready to adjust to your site.
For engineers and specifiers
Pervious concrete, written into a specification
No fines. That's the whole trick of pervious concrete: leave them out and water goes straight through instead of running off. Permcon is our take on it. What follows is what the spec needs to say.
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Pervious concrete, and where Permcon sits
Three words for one thing. An engineer draws up "pervious concrete", while a homeowner searching online is more likely to type "porous paving" or "permeable driveway".
Permcon is what we pour. The admixture is proprietary, and it goes down through our own crews as one unbroken slab: no control joints, no pavers to lift. A spec that reads "pervious concrete" and stops there hands the real decision to whoever wins the tender. What should follow is the figures, the base build-up, the modelling inputs and a clause naming what's actually being poured.
Numbers beat adjectives on a tender
- Strength: 25+ MPa. One mix, whether it's a footpath or a car park.
- Voids: 20 to 25 per cent, connected from the surface down to the base.
- Surface infiltration: 8,000 to 10,000 mm/hr.
- Thickness: 125 mm as standard. Go deeper for heavier vehicles: the axle load chart covers slabs from 100 mm to 300 mm and shows the working.
- Aggregate: 7 mm in Victoria, 10 mm everywhere else.
- Slip: P4 slip rating.
We don't promote the strongest mix. The lever worth talking about is thickness, and how much more weight it lets you put on the slab. There's a colour decision too: plain grey, charcoal, soapstone or sandstone. Send the draft spec with a site plan and we'll go through it before it's issued.
Ponding after rain means the base failed
A pervious slab over the wrong base behaves like a sealed pavement. Ours sits on clean screenings, sized to 85 per cent design capacity: every 100 mm of depth stores 28 litres per square metre, which is the number that feeds the detention calculation on the engineer's model.
If the subgrade will take water, the base drains straight down into it. Heavy clay, or a site where soakage isn't allowed, changes the answer: the base holds the water and an under-drain bleeds it away slowly, at whatever rate the drainage engineer sets. Build-ups for a footpath, a driveway and a car park are laid out on the technical page. Surface, base and outlet get designed together, and Permcon carries MUSIC certification, so send through the project and we'll get parameters to your modeller.
Leave the spec at "pervious concrete" and a no-fines mix, built for a different job and a lower load, can be poured instead and still pass on the day. Name Permcon and its figures, or write those figures in as the floor. The difference between the two is worth reading before you sign off.
What we send with a specification
The loading chart
Axle load estimates against slab thickness, with the working shown, so you can size a pavement before the drawings are locked.
Maintenance schedule
What to check monthly, what to sweep annually, and the warning signs between the two, laid out for budgeting.
10-year warranty
If it fails structurally inside ten years, we come back, assess it, and pour the slab again.
Pervious concrete questions from specifiers
Is pervious concrete the same as permeable concrete?+
Same idea, different mouths. Engineers write "pervious" on a drawing; most owners type "permeable" or "porous" into a search bar. What actually varies between suppliers is strength, void content and how carefully the slab gets compacted. Put those figures in the spec rather than trusting a name.
What thickness should I specify?+
125 mm covers the majority of jobs we pour, as above. Start from the estimated loading chart, then check that number against your subgrade and the traffic it'll actually see.
Can a general concreter place it?+
No. Whether the voids stay open comes down to how it's compacted, and that's not a skill we hand to someone else's crew. It's our own crews who place it, so what's in the ground matches what's in the spec.
Send us the spec and the site
Get us the drawings, the loading and a soil report if one's been done. We'll walk the ground ourselves, then put slab thickness, base depth and the storage it buys you down on paper.
Check the site before you specify
Check if permeable concrete suits your site
A few quick questions about your site. You get a straight answer about whether permeable concrete is the right call, including when it isn't, before anyone asks for your details.
Site check · 1 of 5
What are you surfacing?
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Tell us about your project
Tell us where the site is and what you're planning. An estimator from your state team will call you back, look at the site with you and give you a real figure, from a single driveway to a council car park.
📞Call us1300 010 499✉️Email us[email protected]
📍Head officeFactory 7, 25-39 Cook Road, Mitcham VIC 3132
Permcon, poured
