Leaking roof caused by builders not making watertight

Leahd88

I'm currently having a wrap around extension built on my bungalow as well as a porch.  Its started to rain heavy. A leak has occurred at the back of the property in my son's bed room where the join of the flat roof meets the bungalow roof (I have a picture they haven't replaced a load of tiles so there is a massive hole going into my loft!)
This has lead the water to trickle along from my boys room, and down the hall. Rain also coming through lights in his room and the hall.
Secondly where they haven't made the porch watertight at the front of the property, rain has come in around the front door in the hallway and in my bedroom. We've tried to cover it up now best we can however more rain now and over next few days means water is still trying to come in.
The carpets are wet the walls are dripping and the place smells strongly of damp which is unhealthy for me and the young children.
Question is, where do I stand. I can't afford to immediately pay out an air b n b for us to stay in whilst the damp subsides. Can I suggest the builders put us up in one? 
What are they legally obliged to do?
Obviously I'd expect them to say they would replaster/paint everywhere but what are there obligations) and how will I know exactly how much damage has been caused. Do they also have to consider the inconvenience caused? Or is this a legal route I would have to go down?

Hoenir

Goes without saying the weather has been exceptionally bad in the past week. What did your builders say when you contacted them? 

Leahd88

But the water has come through the roof on my original house not the extension. This was Monday. We made it watertight as we could Monday. Said they would be in contact. Contacted them again today and they've said they would come make water tight tomorrow! Bit late when it's already come in

PHK

You need to allow them a chance to put it right. If they don’t then you can get someone else to do it and sue them for the cost. 

As for other costs, you’ll need to minimise these and then have a discussion with them to see what they say. 

You can also contact your house insurer. Even if you don’t claim they need to know or it might affect any future claims. You could also take advantage of their legal helpline. 

user1977

Had you told your insurer that you were having significant building works carried out?

Aylesbury_Duck

Much will depend on the exact set-up.  I've got a few houses undergoing significant works on my estate at the moment, some of which have big scaffolding rigs with canopies over the houses.  It's clear that in this week's exceptional weather, at least two of those houses have had water ingress, despite all reasonable precautions being taken.  We've had squalls alongside the rain and it's led water to places that ordinary rainfall wouldn't reach.

Where you stand is going to depend on a few things, it's not necessarily simply a case of the builder being at fault.  Your best bet at this stage is to speak to your insurer for advice, and hopefully you have told them about the significant work being done (assuming the policy obliged you to) and you have legal cover on the policy.