Cost effective permeable sub-base for resin bound gravel

[bmj1]

Hi all,

 

So my plan was:

(1) 150mm MOT type 3

(2) 80mm Open textured Asphalt or pervious concrete

(3) 20mm Resin Bound Gravel

 

I've got ~100m2 to cover in total, and I've been shocked how the costs have ramped up (e.g. tarmac was meant to be cheap!)

 

At this stage I've just mucked away to create this 200mm buildup, any suggestions or ideas?

 

E.g. Specific suppliers ? Types of product ? How should I best proceed from here ?

[Thorfun]

Have a look at crushed concrete with zero fines as a cheaper alternative to type 3. Might fit the bill for you. 
 

we were originally planning resin bound driveway but the build costs with the world the way it is means we have no money left for it so we’re looking at gravel instead. 

[nod]

Tarmac around where we are tends to be 50m2 and that with all the prep work done fore them Sun base drains etc 

 

We are using block pavers again 550m2 Ouch plus a 100m2 in front of the garage in gravel

Which I’m regretting already Horrible to drive on and worse to walk on 

A ready reckoner for anyone buying gravel I bought 20 ton for a 100 m2 

12 ton would have been enough 

The other 8 had to be dumped in the field 

[SBMS]

  On 22/03/2025 at 07:17, nod said:

Tarmac around where we are tends to be 50m2 and that with all the prep work done fore them Sun base drains etc 

 

We are using block pavers again 550m2 Ouch plus a 100m2 in front of the garage in gravel

Which I’m regretting already Horrible to drive on and worse to walk on 

A ready reckoner for anyone buying gravel I bought 20 ton for a 100 m2 

12 ton would have been enough 

The other 8 had to be dumped in the field 

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We are still debating what drive surface to use. We’ve got a lot to cover as well - resin far too expensive. What’s up with gravel? Did you put crates down?

[nod]

  On 22/03/2025 at 08:39, SBMS said:

We are still debating what drive surface to use. We’ve got a lot to cover as well - resin far too expensive. What’s up with gravel? Did you put crates down?

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No 

We probably should have put crates down But that brings it up to the price of Tobermore paving 

As I stated Gravel is bad to walk and drive on Better with crates 

Tobermore is costing 16m2 plus sand 

[SBMS]

  On 22/03/2025 at 09:20, nod said:

No 

We probably should have put crates down But that brings it up to the price of Tobermore paving 

As I stated Gravel is bad to walk and drive on Better with crates 

Tobermore is costing 16m2 plus sand 

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Looks nice. You laying it yourself? Where did you get the tobermore from?

Edited March 22 by SBMS

[nod]

  On 22/03/2025 at 09:20, nod said:

No 

We probably should have put crates down But that brings it up to the price of Tobermore paving 

As I stated Gravel is bad to walk and drive on Better with crates 

Tobermore is costing 16m2 plus sand 

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yes laying ourselves 

As I type 😂

CW Berry 

But Buildbase {Hews Grew)) where about the same 

[bmj1]

  On 21/03/2025 at 19:18, Thorfun said:

Have a look at crushed concrete with zero fines as a cheaper alternative to type 3. Might fit the bill for you. 
 

we were originally planning resin bound driveway but the build costs with the world the way it is means we have no money left for it so we’re looking at gravel instead. 

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You just saved me a few hundred. Thank you..

 

Follow up: I was planning 80mm pervious concrete on top. Do I need to go so thick with this layer or could I make thinner and do more of the layer below ?

[BadgerBodger]

  On 22/03/2025 at 20:17, bmj1 said:

You just saved me a few hundred. Thank you..

 

Follow up: I was planning 80mm pervious concrete on top. Do I need to go so thick with this layer or could I make thinner and do more of the layer below ?

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For vehicle traffic or pedestrian? I’d say 100mm overall thickness is the least I’d go without reinforcement. Not sure how reinforcement works with permeable concrete. I did a job with it a long time ago (16 years) on a military base and the only thing I recall was the first hi-ab that went on it left impressions in it. 
 

I think you’d be better using permeable macadam which is somewhat flexible. 
 

A lot of it depends on the quality of your substrate i.e what’s below the stone…

[bmj1]

  On 22/03/2025 at 20:31, BadgerBodger said:

For vehicle traffic or pedestrian? I’d say 100mm overall thickness is the least I’d go without reinforcement. Not sure how reinforcement works with permeable concrete. I did a job with it a long time ago (16 years) on a military base and the only thing I recall was the first hi-ab that went on it left impressions in it. 
 

I think you’d be better using permeable macadam which is somewhat flexible. 
 

A lot of it depends on the quality of your substrate i.e what’s below the stone…

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It's for a domestic driveway.

 

I figured if 80mm of tarmac was fine (typical build up for resin bound gravel), then surely pervious concrete would be? False assumption?

[BadgerBodger]

They have significantly different properties which are prone to different defects. Tarmac is considered a flexible wearing course which is much more forgiving for movement without breaking down. Whilst concrete will likely have increased compressive strength compared to tarmac it is much more rigid and prone to cracking which is why we have rebar in concrete. Concrete cracks for all kinds of reasons even just in the process of curing (without load)

in some cases. 

 

If I were doing it I’d use porous tarmac over porous concrete for the reasons above. Adding to this with porous concrete being far less common than porous concrete (in my experience) it’s more likely to be done wrong. 

[bmj1]

  On 22/03/2025 at 22:08, BadgerBodger said:

They have significantly different properties which are prone to different defects. Tarmac is considered a flexible wearing course which is much more forgiving for movement without breaking down. Whilst concrete will likely have increased compressive strength compared to tarmac it is much more rigid and prone to cracking which is why we have rebar in concrete. Concrete cracks for all kinds of reasons even just in the process of curing (without load)

in some cases. 

 

If I were doing it I’d use porous tarmac over porous concrete for the reasons above. Adding to this with porous concrete being far less common than porous concrete (in my experience) it’s more likely to be done wrong. 

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And what's the most cost effective way to get the porous tarmac done ? Any pointers ?

[BadgerBodger]

I’ve never had it done domestically. I’ve used it and seen it used commercially as part of SUDS and MUGAs so that would always be by a local tarmaccer. I’d be surprised if your resin drive people couldn’t organise it. If not reach out to some local driveway companies who offer tarmac options? See if they do it. Get some quotes. 

[bmj1]

Just posting this here for anyone reading later on - I've brought the digger back and I'm taking out another 50mm, that takes my planned buildup to:

• 200mm - MOT Type 3
• 80mm - AC10 tarmac
• 20mm - Resin Bound Gravel

Having spoken to some of the well reviewed local driveway companies, it became clear I was skating on the edge of typical specifications, and that seemed like a silly corner to cut.

[Alan Ambrose]

Thanks for the update.

[bmj1]

  On 25/03/2025 at 13:39, bmj1 said:

Just posting this here for anyone reading later on - I've brought the digger back and I'm taking out another 50mm, that takes my planned buildup to:

• 200mm - MOT Type 3
• 80mm - AC10 tarmac
• 20mm - Resin Bound Gravel

Having spoken to some of the well reviewed local driveway companies, it became clear I was skating on the edge of typical specifications, and that seemed like a silly corner to cut.

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To add this is London clay we are building on.