Replacing a conservatory built over a shared drain

Yenwah

We would like to replace our existing conservatory with a proper extension, however it's built over a shared drain. The conservatory was built pre 2011, so it wouldn't have required a build over agreement at the time, and I don't believe there are any manholes/inspection chambers underneath the conservatory. My question is, do you need to obtain a new build over agreement if you are replacing a structure that previously didn't require one?

ThisIsWeird

Your new extension will almost certainly require far more substantial founds than the connie. And I'm assuming that this new ext will confirm to, and be signed off by, Building Regs. 
In which case, surely 'yes'.
You'll also likely need a drains inspection, but ours only cost a little over £100 a few years back. Do you have an inspection cover on at least one side?

Yenwah

ThisIsWeird said:

Your new extension will almost certainly require far more substantial founds than the connie. And I'm assuming that this new ext will confirm to, and be signed off by, Building Regs. 
In which case, surely 'yes'.
You'll also likely need a drains inspection, but ours only cost a little over £100 a few years back. Do you have an inspection cover on at least one side?

Thought that may be the case - thanks. Yes we do have a few inspection chambers along the run. Do you think it likely that they would flat out refuse a BOA for a replacement structure?

Doozergirl

Yenwah said:

ThisIsWeird said:

Your new extension will almost certainly require far more substantial founds than the connie. And I'm assuming that this new ext will confirm to, and be signed off by, Building Regs. 
In which case, surely 'yes'.
You'll also likely need a drains inspection, but ours only cost a little over £100 a few years back. Do you have an inspection cover on at least one side?

Thought that may be the case - thanks. Yes we do have a few inspection chambers along the run. Do you think it likely that they would flat out refuse a BOA for a replacement structure?

The purpose of a build over agreement is for it to be an agreement.   Water companies don't seek to refuse, they just want their sewers built over correctly.  

Unless you have a large diameter high pressure pipe directly under your house you will get the agreement (as long as your build route complies with their guidance - and that's down to you!)

Section62

Yenwah said:

The conservatory was built pre 2011, so it wouldn't have required a build over agreement at the time, and I don't believe there are any manholes/inspection chambers underneath the conservatory. My question is, do you need to obtain a new build over agreement if you are replacing a structure that previously didn't require one?

It may have needed a buildover agreement if the drain was already a public sewer at the time. (there's a lot of misleading advice on the internet which suggests public sewers didn't exist in people's back gardens before 2011, they did)

The buildover agreement relates to the work being done, so if you are building a new structure you probably need a new agreement. Ultimately it is up to the local sewerage undertaker to decide (within the legal requirements).

Yenwah

Thanks all, makes sense 

ThisIsWeird

Ours was a shared sewer - it collected from the LH neighb, and then passed through at least one other on the RH side before bending round and joining the mains in the road.

I hadn't even realised it was where our ext was going to be - I'd always assumed it was much further down in the garden.

Anyhoo, with our Planning App, the WB got to know and sent us a letter telling us what we'd need to do - in essence have a drain check to confirm it was currently in good order, and what form of found build-over it would have. All very straight-forward, and no issues.

What would have happened if the drain had been in slightly ropey condition, I don't know. I wonder if the WB could have said "It ain't bad enough for us to replace it at the moment, but we will have to do so at some point, so you ain't building over it..."?

Fingers crossed

weeg

ThisIsWeird said:

Ours was a shared sewer - it collected from the LH neighb, and then passed through at least one other on the RH side before bending round and joining the mains in the road.

I hadn't even realised it was where our ext was going to be - I'd always assumed it was much further down in the garden.

Anyhoo, with our Planning App, the WB got to know and sent us a letter telling us what we'd need to do - in essence have a drain check to confirm it was currently in good order, and what form of found build-over it would have. All very straight-forward, and no issues.

What would have happened if the drain had been in slightly ropey condition, I don't know. I wonder if the WB could have said "It ain't bad enough for us to replace it at the moment, but we will have to do so at some point, so you ain't building over it..."?

Fingers crossed

They would probably have had you replace it at your cost.

Swasterix

On our recent extension we had to build over a near 2m deep sewer which serves roughly 6-8 properties up stream of our house. It comes through the back garden, under the extension and then bends down our alley way down to the street. 

Obviously the work involved a fairly significant excavation so I was worried that we would have problems getting the agreement. Luckily this couldn’t be further form the case. The chap from the water board couldn’t have been more helpful, helped our builder to plan the pipe work layout and even sourced the materials for a hefty discount from the water board. He visited the site a few times throughout the works and came to check once completed to sign it off. 

What we thought might be a show stopper ended up being a fairly straight forward process (for me, not for the builder!).