New patio is falling towards house..

OP looking at your picture is looks a decent job and I wonder if the overall patio slopes away from the house and a small section near the patio doors had to be like that to keep the levels right?

In which case there needs to be a strip drain along the front edge of the door.

Edit> I don't see any major risk of flooding because as soon as that pool reaches a certain size it will drain away down the patio away from the house.

Its not right but I don't think its as bad as you imagine but a right pain to put any drain in at this stage.

The fall should be fairly obvious because the old rule of thumb was 1/4 inch for every foot which just shy of a 1 in 50 (1inch drop every 48 inches) sorry thats in old money.

Yup.. In my old house I was worried about water pooling by the patio door , so I had that type of drain put infront of the door , and connecting into the drain that the gutters drain into -

Turned out I didn't have any water pooling, because I laid the paving on pea gravel and then grouted just with sand ... So it drys out in minutes .

It looks like slabs were placed on top of the footpath but then the rest of the patio slopes away from the house. A quick cheap job it looks like. He will probably tell you he couldn’t slope the part beside the door because of the footpath, but he should have discussed this properly with you before starting the job.

Or a proper drain put in against the wall of the house ...

How much was paid in advance ? Did you provide the slabs ? Is there a chance that if you insist he start from scratch ,and the slabs aren't easy to lift cleanly that the builder decides to just feic off, cut his losses and leave you with the problem ?

I'd rip it all out.

It's quite dangerous anyway to be raising external ground level up close to internal floor level but to have the water pooling against the house is a disaster.

It should be sloping away plus have the drainage channel along the house.

Just be careful and make sure he is capable of installing a neat effective drain. Looking at this job I wouldn’t just assume he has the ability.

I agree strongly with this. Aco drains are fine in theory, but in practice they are rarely a success. They are a maintenance burden an they inevitably block up if not kept after. A lip often develops between the channel edge and the paving, as often the paving subsides a tiny bit because I have yet to see a contractor who does proper compaction in layers. The result in ponding.

Aco drains are often not very durable either. How many places have you seen aco drains with missing or bent gratings - nearly always. But a lot of the time that is down to incorrect specification and getting the cheapest. For example, in a petrol station forecourt it should be heavy duty D400 channels, but most builders buy the light duty A75 and hope no-one will pull them up on it.

Long story short, footpaths and paved areas should always slope away from the building, unless there is a very good reason why they cannot.

A lazy contractor is not a good enough reason.

You need to bring him back and fúck him out of it to high heaven, then not pay him.

That's a bit extreme at this stage. The guy that made a balls of the job is due back with the OP today so let's hope some arrangement can be met.

Local conditions should be assessed to see if drainage channels are required at runoff perimeter. Above a certain area this is advised.

pavingexpert.com is a great resource

Sure how is the water supposed to get into the 110 flexi pipe? Through the joints? That might work for a while and in light rain but the joints will clog up after a while and you'll just get ponding. Also, that flexi pipe is notoriously diffcult to lay at proper falls. How do you know that he laid the pipe to a proper fall and gave it a proper permeable surround? And where does it outfall to?

Should be something like a couple of gullies or an aco drainage channel, discharging into a storm drain or to a soakaway.

Also, if he laid some of the paving over the footpath on a thin bedding, and the rest of it on hardcore off the footpath, then, unless he compacted the hardcore really thoroughly (which I doubt, because the never do because it requires time and effort) then it is only a matter of time before you see a step forming along the old kerb line because the off-path paving is settling down more than the paving on the footpath.

To be honest, this job sounds like an absolute dogs dinner by a total chancer that'll all have to be taken up and started from scratch.