I'm about to embark on my first trip down dig your old one up and try to relay it in the time span allowed by your missus IE is it possible to do it by last week !
I have an old Patio which consists of 600 x 600 concrete slabs on a grit / cement mix with the subbase being earth which after at least 16 years of having been under the old patio should be well compacted, and having now moved my greenhouse an area of concrete which also has 2 drain covers within that area.
The existing level is about 1 and a bit bricks below DPC.
The area to be relaid is about 29 Sq m
The missus has chosen an 'Eastern natural Limestone' from our local merchant which hopeflly will look good with a nice variation of slab colour.
So.
If i have taken on board the guidance and advice from this site have i got the following right.
With the old taken up i will try and get the level to 150mm below DPC, but an element of digging out may be needed to get the slope right, also the drains will probably require adjusting - reducing in height slightly. they are old lids and frames - i dont know what lies beneath though.
Having got ythe ground work done i intend to lay a bedding of 10:1 dry mix - or is semi dry mix the correct term. about 40mm on the existing soil and individually lay the flags.
I'm not sure of what other pitfalls i'm likely to come across but i suppose the questions i have at the moment are'
1. is 40m sufficient
2. Is the existing subbase adequate im assuming due to the use of the area that a more harder subbase isn't required
3.for the edging slabs can a stiffer mix eg 6:1 be used or should it be a wetter mix.
4. If digging out more of the sub base and weakening the top layer im assuming that if it is rolled or compressed down then it should be OK
5. Any advice on cutting the stone would be appreciated as well as the drain coveres / chambers.
6. any views on the Limestone as well before its ordered ?
Thanks
I have found this site invaluble, its clear and easy to understand.
2 - the earth is a subGRADE not a sub-base, but if itls been there all this time and not moved, it should be fine.
3 - Making the bedding concrete the same as you;d use for flag laying, ie, semi-dry (no added water), but "wet-up" the haunching to make it easier to compact and to adhere to the back of the edging kerbs.
4 - yes: if you loosen the SUBGRADE at all, it should be re-compacted before placing the laying course material.
6 - Keep it as clean as poss while working. You CANNOT use acid-based cleaners to rectify any mortar spillages/staining. Once it's been down 3-4 months, consider getting it sealed with summat decent such as Lithofin MN StainStop.
I have now removed the previous flags, bedding material and concrete ( where flags hadn't been laid ).I now have two holes ! There were 2 metal posts laid into concrete, one of which i have removed the other i have left in situ. The one that i removed looked like an old washing line post which had been cut off at the top of its concrete base but also continued down another 2 + feet the other side ofteh base !. The other post i have left in place it almost looks the same with a lot of old brick and tile etc filling the void down below. I am a bit concerned about digging it all out as the hole will be quite large. It is firm and had supported the previous flags for 16 + y,ears but there is now a small crater that will need filling as will the other hole.
Firstly.
I am wondering with what to fill the 2 holes with as they are right in the middle of where the main area of the patio will be, would it be OK to pack the holes with scalpings and whack them down or would i need a layer of something more substantial ?
I would say that:
No 1 hole ( post pulled out ) is about 2 feet across and not quite as deep in the middle part ( where the post came up that has artly back filled witha lager hole about 1 foot deep.
No 2 hole ( with post in ) is about 2 feet across and again about 1 foot deep I would intend to cut the remaining post down with an angle grinder so that the post is well below the level of of any bedding and sub base if required.
I would add a couple of pictures to make it clearer but im not sure how to.
