Loose slabs and crumbling concrete base

If the concrete base was laid by same company that laid the sandstone then really it falls down to them to work with you to resolve the issue, also we wouldn’t recommend laying sandstone on a concrete base as you find the water has no where to drain, and will sit beneath the slabs and in cold temperatures freezes and in turn will cause slabs to come loose and concrete to crack, all our sandstone is laid on a mortar bed and slabs are primered as they are laid

How big is the concrete slab ?
The slab should be minimum of 100 mil thick and a sub ade of 50 mil stone , it should of been troweled finish or brush Finnish
Did they put mesh in ?
Did the use a poker on the concrete?

I would be going back to the contractor and
Asking for it to be re-done or fixed

First off I would get them back to fix any problem you have unless your going to be paying some else to fix problems

Any loose slabs may indicate a failure in the sub-base and/or mortar underside of slab. Any sub-base should have an adequate make up of aggregates in correct proportions and quantities to avoid subsidence. A good practice is to paint underside of slabs with a primer to help slab and mortar cohesion. I would investigate and check if these were carried out, as legally there may be an argument to rectify work.

Any reputable tradesmen should redo any work that has failed. As far as the Indian sand stone, SBR slurry should have been applied to help adhere the motor to the slab. They are made very thin nowadays and will pop easily in freezing temperatures

I am not a legal expert, but I can offer some general advice. If you're experiencing issues with the Indian stone and concrete base laid by a contractor, your legal standing may depend on the terms of your contract and local consumer protection laws.

Here are a few steps you might consider:

1. Check the terms and conditions outlined in your contract with the contractor. It may specify the quality of work, materials used, and potential guarantees.

2. Take clear photographs and document the problems with both the Indian stone and the concrete base. This evidence can be useful in discussions or any potential legal proceedings.

3. Send a written communication to the contractor detailing the issues, expressing your concerns, and requesting a resolution. Keep a copy of this correspondence for your records.

4. If the contractor is unresponsive, you may want to seek legal advice to understand your options and rights under local consumer protection laws.

5. In some cases, mediation can be a less formal and more cost-effective way to resolve disputes. Check if there are local mediation services available.

Remember, legal options can vary based on your location and the specifics of your situation. It's advisable to consult with a legal professional who can provide guidance to your circumstances.

They should relay the slabs and Propley

The issue would be that the concrete and or mortar does not have enough cement added and that the slabs were not primed before being laid.
You mentioned this was done over 12 months ago however your guarantee should have restarted at the point of the last repair done by the contractor.
Should the guarantee be amiss you should contact there trade body if they are registered with one and report the fault, they maybe able to help.
Further to this get a quote from a reputable contractor and a fault report and take it through the small claims court to recover the repair funds

My advice to you is firstly to find out if your job is guaranteed. If it is then I would recommend taking the company to a small claims court.

you might want to document the issues with photos and reach out to the contractors, expressing your concerns. It could be beneficial to review your contract with them and check for any warranties or guarantees. If communication doesn't resolve the issue, consulting with a legal professional might be a next step to understand your options.

They obviously haven't used a primer slurry on underside of slabs to aid adhesion.
As for the concrete slab...if its beginning to crumble then whoever poured it needs to fix it.

If you got an invoice take them to small claims court. Same with messages.

Regarding the indianstone sounds to me like they didn’t use slurry on back of your indianstone as this wouldn’t happen if they did. A lot of company’s do this just because they can’t be bothered to do it. #cowboys

Always make sure they use slurry on back of any porcelain, indianstone.

the mixture was not made strong enough for the strength required or was not laid thick enough, or maybe the ground needed to be reinforced to hold and stop the movement on unsustainable ground. Depending on what you specified on the spec before the work was undertaken then they would be obliged to repair or relay the patio depending on the concretes position

maybe the slabs is loose because they evier never put enough cement in the mix and more sand but
The way my team layes the slabs is with a full bag of cement and we mix it with water and it’s slurry we brushes it on the back of the slabs and the concrete base same thing they never put enough cement in or it’s not thick enough it’s hard two say because I haven’t seen it

Sounds like the concrete mix they made was not right, and same for the indian sand stone

They have done a poor job, but as it was over a year, they probably won't be liable

The tradesman should have given you a guarantee of ATLEAST 5 years for the patio a 5 to 1 sharp sand and cement mix should have been used

A C20 concrete mix with a metal mesh should have been used this helps bond and strengthen the concrete

All work should come with a guarantee if the work hasn't been finished to a professional standard the liability stands with the trades person

Preparation works to Indian stone/flagging is critical in ensuring slabs are not loose/re-lifting. Crumbling concrete base should not occur a year on from initial works being carried out. Weather forecast can impact the strength of concrete, so may be a factor in the poor finish. If the concrete base is unlevel, this can create pooling (wet patches). All work should be guaranteed and remedial works undertaken to ensure customer is happy with the finished product. Legal advice or a case filed via small claims court is always an option, should the contractor/tradesperson that carried out this work continues to avoid rectifying their works.

Sounds like your Indian stone has been layed with a dot 'n' dab concrete mix bed, which should realistically be layed with a full coverage of concrete mix bed to ensure the resistance and endurance of day to day activities. The concrete base sounds like it doesn't have any steel mesh, and with it holding water in places doesn't sound level. Obviously this is just what I reckon/suggest may have happened, its may also not be the case.