Squared circle in small garden - Sub base or not

[KevB]

Hi. Last posted back in 2007 when layed patio from the excellent guidance provided by site and given by other members.

I've been asked to lay a squared circle patio of 2700 x 2700 centrally into a lawn of an area of 6m x 3m.
It will be light use for an OAP.

The house is about 4 years old and the quality of the ground beneath the existing lawn is unknown.

I would like some advise from those of you with experience in this type of installation as to whether or not a sub base is required the main site suggests that it is not essential.

Thanks in anticipation

Kevin B

[GB_Groundworks]

which bit suggests a sub base is not needed? as it is an essential part of the patio.

where you planning on just laying on top of the turf??????

[KevB]

1. Look at FAQ's sub bases - is a sub base really needed.
2. No im not going to lay on turf.
3. My point was, given the relatively small area and the use, was a sub base necessary below the bedding layer.
4. It was my intention to dig out for sub base etc but just thought i'd canvass more experienced opinion.

Thanks

[Tony McC]

If the ground is firm, stable, and free of organic matter, then a sub-base is not always essential beneath a patio.

[Rich H]

A good example is when chalk is the sub-grade. Once you've taken up the turf and topsoil the chalk and flints will be at least as solid as a new sub-base if not more so.

On the other hand if you have roots, clay, loam, etc., then you will deffo need a sub-base.

[KevB]

Thanks Tony and Rich.
In summary then when the turf is dug up and the ground beneath is for example a clay loam / soil then its best to lay a sub base, if there is a more substantial layer ie. more stony then i'd probably get away with just the bedding layer

[lutonlagerlout]

you just need to identify the subgrade
we have a lot of chalk round these parts and that is solid and unyielding,great subbbase
then in other areas it is really heavy clay
personally i like putting 100mm of stone done as you can wack that nice and flat and therefore use less bedding than if you are bedding on ground
LLL

[KevB]

Thanks.
couple more questions:
Will a semi dry mix be ok.
The flags are obviously of different sizes ( but will be of the same depth) with the smallest obviously in the centre, with a regular joint width all round.
would it be ok to use a jointing compound such as romex easy in this situation, or would it be more appropriate to use a more conventional mortar and buttered joints
I used it 2 years ago and its done fine so far.

[Tony McC]

Normally, I'd recommend a semi-dry or moist mix, but following our experiences with the small pieces that form the centre of the Celtic Knot Circle laid in my garden last week, I'd now suggest a wet mix for any fiddly bits.

Warning: that's a BIG page!

[Rich H]

Superb work Tony, a really useful page. Although I like to used a semi-dry mix for all paving, I switched to a wet mix for circle kits a couple of years ago. Although I like to do all the pointing at the end of the job, circles should be pointed immediately as they seem to be magnets to customers who inexplicably want to trample all over them regardless of the warnings given!

[KevB]

Thanks Tony

As Rich H say's an excellent and a 'really usefull page' which has answered all my questions.

Kevin

[lutonlagerlout]

is that ken from kgc paving?
top quality work there like the basalt romex
as per your comments would be worried about any damage to the small elements
LLL

[Tony McC]

Had an email from Mr Stonemarket this morning saying that they will be making replacement elements available, just in case of breakages.

And yes: Ken from KGC Paving is the underwear model.

[ken]

the underwear was a right bugger to drive home in! and made a right mess of the washing machine!