Re using / adding to existing sub bases

[deegan1979]

Hi guys.
I am lifting my patio this weekend, it is sound and has been so for 18 years so im wondering can i lift the slabs and bed, compress the existing sub base down and add 50mm crushed type one then compress again?
Would be helpful time wise if this is acceptable to save digging out further. The sub base appears to be compacted dirt/broken roof tiles and rubble.
Thanks luke

[seanandruby]

Have you got enough depth without compromising the 150 below dpc ? It is compacting not compresssing.

[deegan1979]

Hi. Yes adding 50mm brings the slab to exactly 150mm below the dpc plus makes the step down from the back door a bit more manageable for my little ones

[deegan1979]

I'm planning to have my patio level flush with astro turf.
Would I be right in thinking I can level the entire area with compacted type 1, lay my patio, then add compacted sharps sand up to the required level for the astro turf to sit on. Or does the patio sub base need to be a seperate structure to the astro turf base?
Many thanks

[seanandruby]

The astro astro turf will be just sand and your patio will be cbm and haunched slightly to stop movement of the flags and sand migration. So yes 2 seperate structures.

[deegan1979]

Thanks again for you're help with this Sean and ruby.
I am going to seperate the patio and turf with a edging brick,
Sorry to fire loads of questions at u but here goes,
Can the edging brick be bedded onto the compacted type 1 with concrete and haunches slightly or will it need a footing?
I have the existing type 1 sub base plus I am adding about 75 mm more to level the garden.
Also not really paving talk but the patio slopes away from the house with no real drainage ( has been fine for 18 years) do u know if it would be ok for it to drain onto the astroturf?
The base for the turf is 150mm crushed type 1 and 50mm sharp sand?
Many thanks again for your time?

[local patios and driveway]

look up bridging bond, much better way to complete an edge and stronger than haunching. ive not haunched a thing for 10 years.

[seanandruby]

Haunching, or bond bridge the choice is yours, which is more viable for a small installation? If you lay your turf in compliance with the manufacturers recommendations drainage shouldn't be a problem.

[local patios and driveway]

haunching is a) not very efficient and prone to failure. b) quicker. and c) wastes less material. its defo the way forward

[seanandruby]

Dan your last 2 replies seem to contradict each other, unless i'm reading it wrong ???

[deegan1979]

If by bond bridge u mean applying a sbr/cement slurry to the back of the slab then.im already doing this to all slabs. And of this means the edge will be stuck well enough and won't need hunching or an edge brick then I'm a happy man, is it the case?
Many thanks both of u

[deegan1979]

haunching is a) not very efficient and prone to failure. b) quicker. and c) wastes less material. its defo the way forward

Hi mate, can u take a look at my reply above
Cheers

[deegan1979]

Can anyone conform what has been said above? Using a bridging bond to finish a free edge removes the need for haunching or using an edge brick

[seanandruby]

Sorry Deegan. Yes, as long as it's laid on a good cbm not just sand.

[deegan1979]

Sorry Deegan. Yes, as long as it's laid on a good cbm not just sand.

Thanks buddy appreciate you're help

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