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Posted: Fri Jun 15, 2012 5:11 pm
by graniteman
Good afternoon, I am away to lay a new gravel garden path and am looking for some advice. So here goes;
The problem - My driveway requires to be widened to improve access down the side of my car for wife and two small children. The block driveway is not in great condition overall but funds dictate it will have to remain as is (therefore I shan't discuss it further).
https://picasaweb.google.com/1093316....ectlink
My Chosen Solution - Excavate a circa 1m wide trench down the length of the existing driveway to a depth of 100mm. 75mm of compacted DTp1 sub layer, 25mm of gravel. Retain granite cassie (sett) edging of drive and mirror this with new cassies on new path edge.
Dimensions - The section of path is 11m long. There are 50 cassies required to edge it. The cassies are 20mm x 15 x 10 roughly.
Things I need advice on
i) Existing drive edging - This has not been finished correctly in the past. The blocks had no concrete bed/haunching. I intend on re-using these and installing on a decent bed of concrete with haunch behind. Does this seem a reasonable approach? Do you compact in the sub layer first and then dig out to accommodate the required concrete depth?
ii) Depth to dig for path - The expert advice from the site is a depth of 100mm. I have dug a test hole and it is 350mm down to solid ground. Is it acceptable to only dig 100mm in this case when there is still soft soil, and do you just have to go over well with a Wacker?
iii) Membrane - any thoughts? I was not going to bother
Feel free to add any other advice you have. Thanks in advance
Based in Aberdeen if anyone close by wants a couple of hours consultancy fee!
Posted: Sat Jun 16, 2012 8:16 am
by mickavalon
Hi Mate. If your just making the path to walk on, then just excavate as you propose, re-set your drive edgings and hauch, fit your new edgings and haunch, then put your DTp1 in compact it, for the sake of 25mm I'd put in 100mm of sub-base, on top of membrane if you wish.
When you say you dug 350mm down to solid ground, what do you mean? From what I can see on your picture, the lawn looks pretty dried out to me, so I'd guess the ground is pretty firm. As long as your not sinking into the earth it should be stable enough for a path at 100/150mm depth.
Posted: Sat Jun 16, 2012 9:57 am
by graniteman
Hi, thanks for reply;
What I was getting at with the ground is that it used to be a flower bed down that side and it is a loose-ish soil and I wasn't sure if a path had to be dug down like a foundation until you reached harder ground, or whether 100mm was sufficient if you compacted the soil underneath.
The grass is a red herring, it is mostly moss and surprisingly for Aberdeen looks yellow due to some recent hot weather. It is not due to the underlying soil being compacted in any way.
Will heed the advice and go for a 100mm sub-base.
Cheers
Posted: Sat Jun 16, 2012 10:00 am
by lutonlagerlout
Dimensions - The section of path is 11m long. There are 50 cassies required to edge it. The cassies are 20mm x 15 x 10 roughly.
what are these cassies that are 20 by 15 by 10 mm?
i take it you mean 15 cm by 10 cm by 20mm thick?
very odd size
as mick has said if its just for walking on dig 150 mm lay new row of cassies put weed membrane inside and lay gravel on that
The existing looks ropey,i wouldnt touch it as it could be a can of worms
used to drink in the bobbin when visiting my cousins but sadly you are too far for a site visit
cheers LLL
Posted: Sat Jun 16, 2012 10:01 am
by graniteman
20cm x 15cm x 10cm! Sorry
Posted: Sat Jun 16, 2012 10:10 am
by graniteman
Bought the house off an old biddie and I have a funny feeling there may have been an Irish influence to the work but I will never know... Having lifted the odd block there is not much underneath. A tidy up job will have to suffice for now. Got a quote from Roy Cowie (Gardener to the Queen at her Deeside Estate) who does things properly and nearly feinted. Things are not cheap up here.
The Bobbin is still going strong on King Street for the students, AFC are moving to a new stadium potentially so it will miss out on the matchday crowd.
Thanks again for all the advice
Posted: Sat Jun 16, 2012 2:40 pm
by graniteman
Out of interest is there an acceptable concrete mix that could be used for both the bedding and the haunch of the cassies? Or should I be doing both an ST1 and ST4?
Posted: Sat Jun 16, 2012 4:48 pm
by lutonlagerlout
most on here would do half a bag of cement in a mixer full
just wet it up a bit for the haunching,dry mix for the bedding
LLL
Posted: Sat Jun 16, 2012 5:15 pm
by graniteman
Sorry LLL you lost me a bit there...could you expand for a novice please
Posted: Sat Jun 16, 2012 6:07 pm
by seanandruby
LLLis saying: throw half a bag of cement in a mixer full of your ballast. I would lay them on a semi dry mix. You use the same mix for haunching ( sloping the sides up to hold them in place ) but will need to wet it up more so you can rub it up, smoothish. Hope this helps.
Posted: Sat Jun 16, 2012 9:15 pm
by graniteman
S&R; I was going to use grit sand as ballast so will do as suggested and use half bag cement with full mixer. What thickness of bedding is required for the cassies? I will lay all the cassies with the semi dry mix and then mix up a wetter batch and go back and haunch all of them. Will the bedding and haunch merge OK being different mixes? Also what should I use for the joints between the cassies? Thanks
Posted: Sun Jun 17, 2012 9:19 pm
by graniteman
....also I can't get my head around something else. If you only dig out say 150mm depth for hardcore and gravel, but the edging cassie is 150mm deep and needs to sit on a bed of say 50mm semi dry mix, how does that work as you would need to excavate deeper than 150mm for the edge course. Is my thinking flawed, as I can't think how you would excavate a narrow channel a little deeper just for the edge course. Apologies if this is basic!
Posted: Sun Jun 17, 2012 9:54 pm
by seanandruby
graniteman wrote:....also I can't get my head around something else. If you only dig out say 150mm depth for hardcore and gravel, but the edging cassie is 150mm deep and needs to sit on a bed of say 50mm semi dry mix, how does that work as you would need to excavate deeper than 150mm for the edge course. Is my thinking flawed, as I can't think how you would excavate a narrow channel a little deeper just for the edge course. Apologies if this is basic!
Dig it deep and throw it well back :;): :laugh:
Posted: Mon Jun 18, 2012 1:37 pm
by graniteman
??? can anyone help with the last two questions please. Not sure how to deal with the depth of the edge course without excavating more than is necessary for the rest of the path.
Posted: Mon Jun 18, 2012 6:45 pm
by lutonlagerlout
just put a string line between 2 pegs and excavate 100 deeper than the depth of your thickest edging
so if your edgings are 150mm deep you need to dig out 250mm beneath them
sorry but this is bread and butter to us I am sure we would struggle in your particular field
maybe this will help
LLL