New patio - Slab base

[x1/9Dave]

I am laying a new patio 6m X 7m the soil is very compacted with lots of old building and demolition bricks and concrete in it, the patio will only have people on it no traffic of any kind except maybe my grandson in his electric car, what i need help with is the slab I am looking at laying a slab of ready mix on the compacted soil with a DPC will 50mm deep be okay if so what strength should i get, and will I need any form of expantion joint
Thanks

[cookiewales]

I am laying a new patio 6m X 7m the soil is very compacted with lots of old building and demolition bricks and concrete in it, the patio will only have people on it no traffic of any kind except maybe my grandson in his electric car, what i need help with is the slab I am looking at laying a slab of ready mix on the compacted soil with a DPC will 50mm deep be okay if so what strength should i get, and will I need any form of expantion joint
Thanks

100mm minimum soil is not a good base use wet concrete with some steel mesh then no need to have expansion joints expect up against building put your fall in the base will make job easier :;):

[dig dug dan]

Woa! are you laying the concrete as the final surface, or is it to then lay the slabs on?

[x1/9Dave]

Woa! are you laying the concrete as the final surface, or is it to then lay the slabs on?

My idea was to lay the concrete let is set and then lay slabs on top with a morter bond between any better ideas will be very welcome

[dig dug dan]

My idea was to lay the concrete let is set and then lay slabs on top with a morter bond between any better ideas will be very welcome

thats what i was afraid of.
This method is way over the top, and a costly option.

All you need to do is lay crushed concrete or type one,compact it, then slab on top of that. It will be fine for a patio.

Unless you plan to park a car on it, i wouldn't be too concerned.

[dig dug dan]

no need to have expansion joints

not so. You will need expansion joints when you go over a certain size slab. the slab will still crack otherwise.

Drive round the southern section of the M25, and all the concrete has expansion joints!

[cookiewales]

My idea was to lay the concrete let is set and then lay slabs on top with a morter bond between any better ideas will be very welcome

thats what i was afraid of.
This method is way over the top, and a costly option.

All you need to do is lay crushed concrete or type one,compact it, then slab on top of that. It will be fine for a patio.

Unless you plan to park a car on it, i wouldn't be too concerned.

concrete slab is way over the top but not if your puting it on top of crap ground and a 42m2 slab with mesh will not crack on a patio i would dig out and put in proper base you need to weigh up the cost and time saving or get the pro guys in 4.5 cubes plus mesh 650 pounds approx good luck :;):materials only



Edited By cookiewales on 1273002593

[x1/9Dave]

My idea was to lay the concrete let is set and then lay slabs on top with a morter bond between any better ideas will be very welcome

thats what i was afraid of.
This method is way over the top, and a costly option.

All you need to do is lay crushed concrete or type one,compact it, then slab on top of that. It will be fine for a patio.

Unless you plan to park a car on it, i wouldn't be too concerned.

concrete slab is way over the top but not if your puting it on top of crap ground and a 42m2 slab with mesh will not crack on a patio i would dig out and put in proper base you need to weigh up the cost and time saving or get the pro guys in 4.5 cubes plus mesh 650 pounds approx good luck :;):materials only

cookiewales thanks for your answer mate sorry to be a numpty, done lots of site work sparky though not used to patio laying but how would you lay a proper base
Thanks again
Dave

[cookiewales]

hi dave look under heading for base for patios all the info is there and correct . you need to go down to sub soil to start and take into account damp course 150mm min below then upto 200mm below that then base sand cement then paving all this is in the main index and am sure you will do a good job concrete base is good for bad ground or very wet clay then lean mix is good often use this in the winter or when raining as we travel so much down time costs money so extra for concrete is okay.a example we pointed a driveway 4x4 sets 110m2 with instermac flow point nine pound fifty per bag 64 bags used pointed and cleaned of six hours 3men slurry pointing would be 12 hours plus over 2 or three days so to me there is no saving useing slurry when you can be earning elsewhere.big plus open to foottrafic 2 hours cars next day.good luck with the patio :;):