It’s been a little while since I posted here, but thought I'd nip back on for a brew and some advice.
I'm planning on doing a self-install of a resin bound (Trowelled) driveway. It’s going to be a fresh construction of a concrete slab during this winter (temperature dependent), and I will probably wait till the weather / temp improves next spring before I apply the resin bound surface.
The driveway in its current form is shown in the attached picture. It has an old concrete drive that has been down for 40 years or so and as you can see has had its day (I’m yet to determine what’s under it, but I would imagine the soil is now well compacted and stable)
I will then we extending the driver on to a previously grassed area, which has been grassed again for 40+ years. The ground also feels stable in this area, but I will re-examine once I’ve dug down to the required depth.
My plan is to lay a 150mm thick concrete slab, which Im thinking of uses two layers of steel mesh reinforcement (as per - Paving Expert - Concrete Hard Standing)
For the small extra cost I’m also wondering if I should have fibres added as well......overkill I know, but it’s not a great deal extra in cost.
I guess my first question is, does 150mm reinforced seem adequate?
Also, would I need to do a MOT1 sub-base for this, or is laying directly on to Damp Proofed ground ok (appreciate this is ground stability dependant)
Most new installations now use a bitmac base/binder course at approx. 65mm instead of concrete.
Something like a ac14 open texture, on type 3 MOT. All permeable then and complies with SUDS.
Do you need your drive to be permeable to comply with SUDS, or can you achieve this another way?
I would personally always install a sub base and not lay directly on earth.
My plan is to use a row of 3 or 4 cobble bricks along the front of the drive (that meet the road side path). Then I was thinking of adding a mono slot drain that I would angle back to a soak away create or gravel pit under the bedding plants I plan on the right side.
Hopefully, this would meet SUDS
Im also thinking concrete is alot more stable than bitmac, but I not an expert so will stand correct if wrong
Excavate the existing driveway and the widened section to a depth of 240mm below finished surface height. In-fill with a minimum of 150mm of Dpt Type 1 Sub-Base and compact in 2 layers of 75mm - ideally using a vibrating roller.
Install edging kerbs or edging blocks - whichever you choose on concrete and haunch.
Install a 65-75mm deep layer of 20mm Base Course tarmac.
You will need to install some underground drainage at the lowest point of the driveway. The resin bound system is fully permeable and the water will drain through the resin surface and then follow the level of tarmac to the lowest point. You can install some Linear Drains and connect into a soakaway. The drains will have to have small slots cut into the sides to allow for water to get into the channel
Then install your resin bound aggregate on top of the tarmac to a minimum depth of 16mm if its a straight drive on, drive off driveway or to a depth of 18mm if its a turning driveway.
This is the construction that I use on all my SureSet Resin Bound installations and I supply an 18 year Guarantee with every job that I do
If you do use concrete for the base, you will have to install movement joints in both the concrete and the resin bound. You will also have to prime the concrete before applying the resin bound
My only issue with the tarmac route is I have never worked with Tarmac before, and I know there is a finite skill in the raking to get things right.
My thinking with the concrete, at 150mm thickness was to also use steel mesh and fibre fill, that way with a 7m x 6m slab I might get away with out the jointing gaps?
If you use mesh and fibres on a slab of 7m x6m you should just about get away with out having a construction joint probably a good idea to go for a252 or bigger to make sure.
In regards to the edges course, do you lay this in concrete and hunch directly on the sub grade (soil) then fill in with MOT1 sub base. Or should I install the MOT1 up to the soil boundary then lay the edging in concrete on top of the MOT1?
Likewise, at the front of the drive where it interfaces with the public footpath, I will install a 3 course row of granite cobbles, the same question applies, if the later is the best way then it becomes difficult as I will be using slot drains that will site between this cobble row and the resin gravel, and then channel the water through underground pipe back towards the front of the house where there is a guttering drainage system. so I can put the sub base in till I fit the slot drains, which I cant fit till the cobbles are in place!
You can lay the edgings either way if you have a sound sub grade, preferably on a sub base.
Lay your pipe then 150 dtp1, insert your slot drain and conbbes on concrete as a finished job then lay your concrete/ tarmac for your resin bond drive.
I know I posted this some time ago, but only recently started the work. I now have 150mm of MOT 1 laid over a stabilising geofrabric. Sub Grade was good stable clay soil. I am now ready to lay the 150mm concrete slab, but was wondering if I need 1 layer or 2 layers of reinforcement mesh for the 7m x 6m slab?
