Planning error

[Elppin]

Hi,

New to the forum, and hoping someone might be able to offer a little help?

We've just begun a single-storey extension across the back of our property.

The plans show the waste/sewer pipe extending up the length of the garden, however once the digging had begun for the foundations it was found that there was no pipe work where shown on the plans.

After some further investigative digging, it was found that although the pipe next to the house started off in that direction, it ended 4m from the rear of the house, and then joined a pipe running parallel with the rear of the house that serves all of the houses on our side of the road.

The pipe is approx. 1.2m underground, and so was not previously uncovered by the 1m trench required for the foundations.

The problem is that the extension we're having built is exactly 4m deep, so the new rear wall of the house falls exactly on top of this previously unknown pipe.

Building inspector has been out and says that we now need to move the wall 50cm away from the pipe. I don't want to reduce the room size, so the only option is to make the room 50cm wider.

This has implications in terms of:
1. Time
New plans have to be submitted for the new larger size 8-10 weeks).

2. Costs
Albeit I appreciate that we will ultimately benefit from the larger size room, we are presumably looking at unplanned costs for the larger room (extra brickwork, larger roof etc), new plans to be drawn up and submitted, repeat Building Regs fees, cost to dig foundations in new location and to replace the exposed pipe with plastic (we apparently now have to do this as the pipe has been disturbed).

3.Other
There are ramifications in terms of leaving the site unattended whilst plans are approved (planner has said ok to dig foundations, but recommends not pouring concrete until new plans are approved). Builder is very reluctant to leave the trenches open for that length of time - understandable as the weather is likely to cause issues.

Should we build the new larger foundations and fill with concrete to stabilise everything, but knowing that if the new plans are refused it will be money down the drain?

The rear garden is obviously also trashed which will prove challenging with two young children.

Is the architect that drew up the plans responsible here? Surely he should have obtained copies of the original plans to confirm where the sewer lines ran?

I have no idea what our next course of action should be. The architect is visiting site tomorrow, and will no doubt discuss options with the builder.

Any help offered will be very gratefully received!

Elppin

 

[freddiemercurystwin]

The architect should have used 'best endeavours' to locate any services that may have affected the build. Its hard to tell on a forum whether or not he has used best endeavours or not.

The way you have described the drainage working (ie a shared pipe running parallel to the rear wall) is extremely common. Manholes in the rear gardens up or down the run are a big giveaway but often they are historically under flower beds (or even buried) so that's not necessarily any use. It seems hit and miss as to when the Waterboard do a search for existing drains in the vicinity or not as part of a planning app so that cannot be relied upon either. There are various other methods of finding out, from looking at historical records or old planning apps in the area, looking at the searches in your deeds, asking the neighbours etc or even just pay the Waterboard for a search. I have had surveys commissioned before now when I've run out of all other options. At the end of the day he must have had some reason to assume they went off away from the house as your plans indicated (though God only knows what). There is always a way.

As you say any costs spent on a foundation further away would be money down the drain so I would look to avoid any new works until new permissions are gained.

 

[Architexeter]

Im going to assume your house is an attached house so PD only covers 3m extensions and you had to get Planning Permission for your proposal. There is the new Neighbour Consultation Scheme which is up to 6m and could well save your bacon in this instance, its not quite like PD as your neighbours can object but the planners cannot get involved unless they receive a neighbour objection. Do you get on with your neighbours? Can you find out if they are ok with a 4.5m extension? If so you may feel more confident proceeding down this route prior to approval.

Regarding the shared sewer, this is now the property of your local water authority and as such they need to be notified of a "build over" and can insist on a condition survey so they can choose whether to replace it prior to the extension construction. You will need to have foundations down to below the invert level of the sewer. Get your Architect to submit a "Build Over" application with the new plans ASAP

Regarding BC fees, I cannot see them wanting a new payment here and I should hope that your Architect amends the drawings at no cost including a revised application for the Neighbour Consultation Scheme if you/they feel it is their screw up. Normally an Architect will show the drainage layout as indicative and subject to site checks by the contractor.

It may be something you wish to discuss with the planning department once you have some revised plans so you can get their thoughts on it too should one of the neighbours object.

Once you have the above you can then make an informed judgement as to whether to proceed before a decision is issued.

 

[jeds]

Before starting work you should have applied for permission to build near or over this drain from your local drainage authority. In order to do that the exact location, depth and status of drains should have been properly investigated. What steps did your designer take to identify drains and what advice did he give on this? I don't accept he didn't know the drains were there. As freddy says, the arrangement at the back of your house is extremely common and if he didn't know exactly where they were he should have known they were at least somewhere near. It's not difficult to locate drains like this and any decent surveyor would have done so. Bottom line is; if he'd done his job properly you wouldn't now be in this mess.

As above, follow the prior approval procedure for the additional depth of your extension under permitted development and you should be ok.

PS. Your builder is correct. Foundations should not be left exposed for long periods of time.