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Posted: Wed Apr 08, 2020 4:33 pm
by LockdownDIY
Hello
Photos below
I have a patio circle half way down the garden which has been neglected and was installed by the previous home owner.
The garden slopes away and the edge of the patio sits higher than the lawn. This edge is gradually crumbling away, looks like it has been patched up using various methods over the years.
The vast majority of slabs don't seem to have movement but all the pointing has also crumbled, gaps average between 30mm and 50mm.
I'm hoping I can salvage the patio as a diy job and eventually have a nice plegola over the top for a lounge area. Could you advise the best way to increase the strength of the raised edge close to the lawn and how to move forward.
I am thinking of digging away the base around the edge and using concrete blocks around the edge.
Lift all slabs
Set down a new bed
Lay slabs closer together 15mm??
Photos
https://ibb.co/VxkCkNB
https://ibb.co/74LhSCc
https://ibb.co/LYzpJRc
https://ibb.co/FwKZbW9
Posted: Thu Apr 09, 2020 9:57 am
by Tony McC
The outermost ring, at a minimum, needs to be re-laid, and the bext way to achieve that is to break out the old bedding and start again.
However, because that lawn edge is elevated, you need some form of retainer, You could use bricks, or kerfed lengths of plywood strips, or you could just allow the new bedding to spill out 50-100mm or so beyond the outermost edge and then trim it down after, say 24 hours while it's firm but still green, and then polish up the exposed edge.
Because that edge is exposed, I go for a slightly stronger bedding mix, and becaus eof the depth, I'd look to use a concrete rather than a mortar. A C20/ST4 grade concerete is what I'd recommend - https://www.pavingexpert.com/mortars#mixing-on-site - mixed to a moist slump (S2) - https://www.pavingexpert.com/conc_slump#site-terms
It would do no harm, either, to use a bond bridge slurry priimer to give that extra adhesion and security at the open edge - https://www.pavingexpert.com/bond_bridge_01
Plenty reading there to keep you occupied for a while! 
Posted: Sat Apr 11, 2020 6:08 pm
by LockdownDIY
Thanks Tony, some very useful info
new photos below
After a tad more investigation work today, I have lifted all slabs from the raised outer ring. The majority of the base is solid as a rock. Some areas had movement which I have removed.
I am hoping I can repair these sections rather than the full ourter ring.
I have some edging stones in the garden, as you can see on one of the photos, which I could use around the outside edge. I only have enough to lay them landcape on the raised section.
I am hoping to fill the small trench I have made with concrete, lift all patio, lay a new bed, relay all patio, then finish off with the edging stones around the exposed edge.
Any advice is be very grateful
Thank you
Photos
https://ibb.co/pLztN3f
https://ibb.co/2NygVvb
Posted: Sat Apr 11, 2020 8:33 pm
by lutonlagerlout
those " edging stones " are not big enough,at least 1/2 needs to be underground
IMHO it was the pointing that caused the issues
its going to be tough now as realistically the lot will need redoing
LLL
Posted: Sun Apr 12, 2020 9:12 am
by LockdownDIY
Not the news I was hoping for LLL! but thanks for the reply.
Posted: Sun Apr 12, 2020 11:07 am
by Tony McC
If they were laid the narrow way, so greater height than width, there's a chance they'd be OK, but I can't really see to be sure.
However, the planned sequence of operations is nonsensical: you need something to retain the edge *before* you re-lay the outer ring of paving, and that should be your edgings or whatever you end-up using.
So, my sequence would be:
1 - break out old bed and anything else that needs binning.
2 - set edgings or alternative retiner on concrete bed with suitable haunching front and back.
3 - when edgings/retainer solid, backfill with concrete to form base for re-laid paving
4 - re-lay paving on mortar bed over concrete backfill
5 - point as required.
The edging/retainer needs to have its base at least 50mm lower than the ground - see: https://www.pavingexpert.com/edging3
You need something like this....
Posted: Sun Apr 12, 2020 3:09 pm
by LockdownDIY
Thanks Tony
I've uploaded a better photo of the stones. As you can see with the stones upright, at 50mm below ground level they come up to the previous bed height.
https://ibb.co/FsjLyZD
From your diagram I think I need something a bit longer so that they sit proud by 50mm of the old bed?
I was hoping there would be a way I could get these to work!
Back to the drawing board. Thanks for the sequence, I understand what you mean now.
Posted: Mon Apr 13, 2020 10:38 am
by lutonlagerlout
Lockdown to be frank I question why the whole thing is so high out of the ground?
I would hook the lot out ,maybe save the type 1 (if there is any) and redo it from scratch so that the bottom edge is slightly high to your grass
this raised patio detail looks odd and is not userfriendly
if the ground is on a slope you can build a low retainer at the back side
I hope this makes sense
cheers LLL