Building an extension over an existing drains

[bondaneka]

Could anyone offer me some advice please? I am planning to have a further small extension built on the back of my kitchen extension (see photograph) to provide a utility room/downstairs toilet. The existing lean-to conservatory will be demolished as will the old back door extension (behind the green shed ). A new wall will be built to replace the current outer conservatory wall, the existing roof will be removed and a full width roof will replace it.

I would like to build a 2400 x 2200mm extension on the back of the house (for the utility room) from where where the kitchen window is now. Unfortunately (see other photos) there is a drain about 500mm from the existing back wall near enough under the current kitchen window. The main drain therein goes diagonally under the house with the flow going away from the house (still diagonally), under a boundary wall into next' door's garden where only a very short distance away there is another drain cover on their patio. The drain pipe is not very deep.

Given the location of the drains, should I give up on this idea and instead plan the utility extension on the conservatory side of the house (drain free). I understand that it may be difficult/ill advised to attempt to build over the existing drain? I should perhaps mention that the wall of the house (opposite side to the conservator) forms the boundary with my neighbour and that the conservatory is on the south side of the property hence my reason for not really wishing to have the further extension on that side.

Any advice very gratefully received. Many thanks.

(I have posted this message on a Screwfix forum - didn't know this one existed - so apologies to anyone who ends up reading it twice).

 

[jeds]

You can build over a drain but it needs to be properly designed and if the drain is public you need permission before you start. So the first thing to establish is whether the drain is private or public? Basically, any drain serving two or more properties is public but only from the point that the second property joins the line. So, if the drain does your house and then shoots off along the road and another joins the line your bit will most likely be private. On the other hand, if the drain comes from another house onto your land and your house joins the line then the main line will be public but the line from your house to the main line will be private.

 

[theprinceofdarkness]

I built an extension over a manhole and drains. You need to bridge the drains with a cast in lintel fro m foundation to foundation and replace the manhole cover with a screw down one. At one corner I actually had to bridge over the drains on to a padstone out side the extension. Just get the levels right so you can't see it. A plan of the area would be useful.
Frank

 

[bondaneka]

Thank you both for your replies - much appreciated.