# Building an extension near a main drain



## raven

Hello, 
I'm wondering are there any building regulations wrt how close you can build an extension near a main drain (servicing a large number of houses within the same estate)? The drain is running through the property (there's a legal right of way for it apparently). There are no manholes involved as far as I can see. Could you build up to it, perhaps with the side path around the house being build over it?
We'll get an engineer to look obviously, but would like to hear as many opinions as possible.. 
Any advice or experience appreciated.
Thanks...


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## Allen

Don't forget that drains have a finite life and will have to be replaced at some stage.  This will require access for a digger with room to work. This includes storing the excavated earth beside the trench, etc.


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## sallins

Be very careful and get yourself good engineering advice. Bear in mind that the trench that was excavated for installation of the drain could have been quite wide and poorly backfilled. This could impact on the width and depth of your extension footing. In this regard, as a rule of thumb only, the nearest point of the footing to the drain should be below a 45 degree line extending from 300 mm below the bottom of the drain. You should also check with Local Authority regarding right of way


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## DBK100

Dublin City Council will not allow you to build within a distance of 3m of a public sewer.
This will usually be enforced via a refusal of planning permission or a condition attached to a grant of planning permission.
I am aware of many cases where home owners have built extensions as exempted development and have built right over sewers  -  as there was effectively no one there to police the work.
This is not to be recommended. The council may need access to maintain or replace sewers at a later date, or, you may well find that a neighbour who applied for permission and was refused could report you to the enforcement department.
You could be left with an ugly building site on your property and a building contractor who is entitled to claim against you for loss through any building contract you may have entered.

DBK100
http://www.mesh.ie


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## onq

+1 What DBK100 and others have advised, except to say you may need legal advice as well as any engineers comments.
If you're unwise enough to purchase a building part or all of which has been built over a public sewer you could end up with no building at all.
Quite where this possibility will leave you with your insurance company I don't know, but its something to keep in mind even when only advising on purchasing land.

A Report I issued back in 2007 after speaking with another Council in the Greater Dublin Area referred to a study that seems to be offline or superseded, so I rang up Dublin City Council today at: 01-2222155

         Drainage Section, 
Floor 2, Block 1, 
Civic Offices, 
Fishamble Street, 
Dublin 8.
 Opening Hours  9:30 - 13:00   14:00 - 16:30

[broken link removed]

I was referred to Version 6.0 of the code which I was informed is the current version - a bit worryingly, it is still termed a Draft:

[broken link removed]

------------------------------------------------------
_
Greater Dublin Regional Code of
Practice for Drainage Works
Cód Cleachtais Réigiúnach
Mhórcheantar Bhaile Átha Cliath
le haghaidh Oibreacha Draenàla
Version Draft 6.0

"6. BUILDING CLOSE TO A PUBLIC SEWER.

In order to protect the public drainage infrastructure on or adjacent to a site, the following conditions will apply:

6.1. *No building may be constructed over the line of a public sewer; as per the Public Health Act 1878*. The Local Sanitary Authority requires a minimum clear distance of three metres to be maintained between sewers and all structures on site, including basement and foundations. Details of overhanging structures such as balconies must be agreed with the Local Sanitary Authority. This minimum clear distance will be increased if the sewer is greater than 3m deep or is greater than 375mm in diameter. See GDSDS Technical Documents on New Developments for more information.

6.2. Foundation layout shall be submitted for the written approval of the Local Sanitary Authority, to show that no extra building load will be placed on the sewer.

6.3. A sewer condition survey (CCTV) of the sewer shall be carried out at the Developer's expense both before and after construction, to the requirements of the Local Sanitary Authority. Any damage to the sewer shall be notified to the Local Sanitary Authority and rectified at the Developer's expense. For further information and guidance see the Greater Dublin Strategic Drainage Study, Volume 2, New Development Policy._"

------------------------------------------------------

My *Bold* above - there is no grey area here whatsoever.

As recorded in my old Report I was informed colloquially that      the Public Health Act 1878 prohibits the erection of any building over any sewer of an urban authority.
While the Health Act of 1947 consolidated and repealed the legislation in this area, the older Act is still relied on by the Local Authority to enforce this requirement.
I was also informed that, where a drain collapses, the Council may use the Public Health Act 1878 to demolish any building over it to carry out repairs as required. 

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent persons should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.
My best advice is that you should retain a competent building professional to advise you on these matters.


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## GreenFlag

i know  couple of people who built rear extensiosn and the builder built over the drain (ie the drain runs along the middle of the extesnion) . i think they used concret lintols etc to protect drains and put in access for drain maintenace (roddin i think is the term).

otheriwse would it not mean that most of the houses in dublin older estates would be unextendable?


is there anything in exempt development guidliens that makes reference to drains?


GF


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## onq

GreenFlag said:


> i know  couple of people who built rear extensiosn and the builder built over the drain (ie the drain runs along the middle of the extesnion) . i think they used concret lintols etc to protect drains and put in access for drain maintenace (roddin i think is the term).
> 
> otheriwse would it not mean that most of the houses in dublin older estates would be unextendable?
> 
> 
> is there anything in exempt development guidliens that makes reference to drains?
> 
> 
> GF



*DRAINS:*

The issue is whether its public or private, GF.

PUBLIC

If its public you cannot build over it legally - people may have done so illegally.

PRIVATE

If its private and on your land:


You can build over it.
If you damage it you pay for it.
If you cause an interruption in other people's use of the drain, they may have a claim against you - especially if it backs up and covers their site in raw sewage!
If you want to relocate the drain and there are leases granting a right of way to other house to use the drain
(i) you may need permission to move the drain
(ii) this may affect the existing lease
(iii) you may have to bear the cost of amending all the leases you affect​
If you do build over it you have to protect it.
This is where the lintels you say come in, along with other measures where the drain may be affected by the foundation.
Usually lintels are appropriate where the drain passes through the rising wall of the extension.
The foundation must be below the pipe in such a situation and the lintel carries the weight of the extension to either side and down to the foundation.
You should make sure that there is a gap or soft fill just above the pipe to allow for settlement.
The pipe should be bedded in cement and haunched all around to protect if from the new weight of the slab above it.
Where the pipe runs beside the foundation and close enough so that its likely to be affected by the foundation load footing additional measures will be required to protect it.

All of the above works should comply with the Building Regulations.
Here's a link to Technical Guidance Document H - "Drainage and Waste Water Disposal" - see pages 15-17 inclusive therein:

http://www.environ.ie/en/Publicatio...ng/BuildingStandards/FileDownLoad,1649,en.pdf

*EXEMPTED DEVELOPMENT*


In general drainage works need permission.

Development is described as works carried out on under or over the land and this includes drains.
As far as I know laying drains is not exempted development except in the case of supporting works done as part of exempted development, such as an exempted development extension to a private dwelling.
You cannot go into a field and start laying drains for a commercial for example.
You may find exceptions to this advice, but that's the general position.

FWIW

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.


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## Loz

Hi there, I wonder if I might resurrect this thread. My house has a kitchen extension that was built approx. 1-1.5 metres from a sewer manhole servicing a number of houses on the terrace in Dublin 5.

My neighbour has extended the back of their house even further - the manhole in my garden is right beside their extension (so both houses may have built too close to the manhole). 

I want to extend on the 1st floor on top of my kitchen now, but I'm afraid to apply for planning as they will discover the extensions built too close to the manhole - both mine and my neighbours.

Some information before my questions:
- neither houses got planning permission for the extensions. The extensions are both about 20 years old and were knocked up by family members who could lay blocks... 
- I technically inherited the house under sad circumstances,  so I was not responsible for building the extension myself without planning, nor was I in a position to get a builder survey before 'purchasing' per se.

My questions are:
1. How do I know if this is a Public sewer or a Shared Drain? My fear is that it's a public sewer.

2. Are there any exceptions to the 3m exclusion zone for building close to public sewers?

3. How easy is it to get the council to agree to move it?

Any advice would be greatly appreciated. Many thanks.


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## Leo

Maintenance of shared drains is the responsibility of the householders served by it, it would follow that moving it would have to be paid for by the householders also. 

Regarding the planning issues, because the existing structures are there so long, you can't be made knock them down. Chances are you'll have to knock yours anyway unless an engineer is satisfied (and is prepared to sign-off) that your foundation and wall structure is sufficient to hold the weight of the proposed first floor extension.

A phone call to your local planning office should give you an indication of how they'll treat it. You can also request a consultation meeting with a planner.


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## kceire

Rear drainage is a civil issue, not a planning issue. You need to satisfy yourself that the system will operate normally after your works.


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## Carlitos081

Hi all, we are sell agreed with a property and we found out that there is a sewer in the garden. We are planning to build an extension that is exactly 3 mt from the sewer. Because it is really close to the minimum distance, we would like to have it written in black and white. Who will be the entity that can do it?


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## Leo

Carlitos081 said:


> we would like to have it written in black and white.



What exactly are you looking to get in writing?


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## Carlitos081

Leo said:


> What exactly are you looking to get in writing?


We want to extend the property and the extension will be at only 312cm from the center of the man hole where a sewer of 300mm is in place. I'm aware of the rule "*the drain should be below a 45 degree line extending from 300 mm below the bottom of the drain*" and because it is really close to that limit and I can't know precisely where the sewer is, I would like to get Irish water to confirm that I can extend where I want to with a document, plan permission or other kind of paper that I can go ahead with the work. I don't really trust Architects and builders as in the end the responsibility and the damage remain to me.


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## Leo

Carlitos081 said:


> I would like to get Irish water to confirm that I can extend where I want to with a document, plan permission or other kind of paper that I can go ahead with the work.



As you currently don't own the property, they are very unlikely to provide you with any such documentation. 



Carlitos081 said:


> I don't really trust Architects and builders



You probably shouldn't be looking at purchasing a house that requires the services of both professions so.


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## cremeegg

Carlitos081 said:


> I don't really trust Architects and builders as in the end the responsibility and the damage remain to me.



The responsibility should lie with their insurers.


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## Carlitos081

Leo said:


> As you currently don't own the property, they are very unlikely to provide you with any such documentation.
> 
> 
> 
> You probably shouldn't be looking at purchasing a house that requires the services of both professions so.


I don't understand why I shouldn't buy this house, I think Irish water should give such type of approval written on a paper. In the end I'm trying to do the right thing


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## Leo

Carlitos081 said:


> I think Irish water should give such type of approval written on a paper.



They will to the owner of the property if they are furnished with plans of the proposed works, and those plans contain sufficient detail for them to determine if it's likely to cause an issue or not. Without detailed plans, they'll likely just refer people to the guidance documentation (example). 



Carlitos081 said:


> I don't understand why I shouldn't buy this house



The point was if you have no trust for builders and architects, why would you buy a house that would require you to avail of their services?


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## Carlitos081

Leo said:


> They will to the owner of the property if they are furnished with plans of the proposed works, and those plans contain sufficient detail for them to determine if it's likely to cause an issue or not. Without detailed plans, they'll likely just refer people to the guidance documentation (example).
> 
> 
> 
> The point was if you have no trust for builders and architects, why would you buy a house that would require you to avail of their services?


The point is that Irish water has a sewer that they own and for which they created rules to be respected, so I'm expecting support from them in order to determinate if the owner of the land(I'm not but I'm sure I can get the owner to delegate me) can do the work he wants


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## Leo

Carlitos081 said:


> so I'm expecting support from them



It's likely they will only deal with the owner of the property, and they may require an excavation to confirm the exact location of the sewer. Do you have detailed drawings of the proposed extension? Whoever is preparing the construction drawings for you will be familiar with Irish Water requirements. I presume you have read this.


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## kceire

Carlitos081 said:


> The point is that Irish water has a sewer that they own and for which they created rules to be respected, so I'm expecting support from them in order to determinate if the owner of the land(I'm not but I'm sure I can get the owner to delegate me) can do the work he wants



They will, but not at this early stage.
I had to do it for a client this year.

You need drawings of the proposed extension.
You need to accurately plot the sewer line, depth, cover and invert on paper relative to the extension.
It may also need a CCTV survey (We did) to determine its condition.
Then you need a Chartered Engineer to state that they will over see the works.
We had to undertake to  expose the pipe on site and allow an inspection from the Local Authority Inspector but we were allowed to build 300mm away from the main line (225mm sewer).

Point is, they will deal with you once you have plans and a plan of action. They will not and should not give a blanket letter stating they will allow you to build near it now based on your lack of information and word.

If you don't like this, then you buy a different property or you budget for not building the extension.


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