Depth of drainage under driveway

[SarahG]

Our drainage is 600mm under the drive and has been signed off by building regs. We are trying to get our warranty certificate, but they are saying we need some chartered professional to confirm acceptance as it is close to the surface. The building inspector says he can't comment and our architect is retired. What should the depth be, is 600mm acceptable or does it need a concrete top? The connection to our mains is 615mm so was not possible to go lower.

[Russell griffiths]

Put a concrete strip over it. 
the pipe needs to have a good covering of the correct gravel

the concrete needs to be wider than the trench and place it’s load on virgin ground both sides of the pipe. 
look up a drawing for this. 
get it done and send evidence in. 

[saveasteading]

2 hours ago, SarahG said:

has been signed off by building regs

It is quite clearly laid out in the building regs, so if you have done it according to that then you should not need another party to confirm it. 

 

 

 

Edited Wednesday at 18:09 by saveasteading

[SarahG]

4 hours ago, Russell griffiths said:

Put a concrete strip over it. 
the pipe needs to have a good covering of the correct gravel

the concrete needs to be wider than the trench and place it’s load on virgin ground both sides of the pipe. 
look up a drawing for this. 
get it done and send evidence in. 

Yes this is an option, the builder as far as they are concerned have sign off and have completed work, so this is extra required for warranty company and will cost at least £1k to pull up drive, cut membrane and lay concrete. Really don't want to pay for that and also don't want to rip up my new drive for something that building officer says I don't need.

 

@saveasteading we have a 600mm deep trench, so if 300mm is what we need we are already double that. I will call warranty provider in the morning and see if I can talk to someone, they never seem to call me back.

[Mr Punter]

Sounds like your warranty company are being dickheads.  Is this Protek?

[Russell griffiths]

I didn’t think the driveway was finished, in that case look up the regs, if it complies then what argument do they have. 

[saveasteading]

12 hours ago, SarahG said:

already double

The important issue is that it has a proper bed ans surround of gravel or concrete. That arches the load from above and protects the pipe. Got an photos during construction of did the bco see it at that stage?

[Adrian Walker]

I presume that you have photographic proof of the construction by the builder?

[SarahG]

Yes it is Protek. I have sent them the photos, but they disagree and think there should be protection i.e a concrete slab above the drain, as it looks like around 300mm deep at the drain connection, going down to 600mm. The BCO didn't check it at the time, he said if he had would have asked the same, but he signed it off anyway. Which is frustrating as had he got them to do it we wouldn't be in this situation. I did speak to a nice chap, an engineer at Protek and I think really my only options are to get the builder back at my own expense and get them to pull up the drive and add the protection or I ask Protek to make an exclusion. I am not sure what implications that has in terms of getting a mortgage, which I need to do asap. We have no current plans to sell, but in 5-10 years who knows. I am not sure if it is ok to have exceptions or not, and also maybe we do need this protection so now I am worried about that.

[Mr Punter]

You may be far better to get it excluded and get the policy in place.

[saveasteading]

54 minutes ago, SarahG said:

looks like around 300mm deep

That's the issue then.

 

what would be worst case if there was damage at that location?   so you get it sorted in that unlikely evet.

what could cause damage there? is there heavy traffic?

I'd accept the exclusion and if by some tiny chance anyone has a problem in 5 years then you do the concrete thing.   same cost much delayed.