foundations over sewer pipes

[a13exf]

Hi,

i'm in very early stages of considering applying to extend the front of my house but don't want to go the expense of planning applications etc if the sewer pipes under my house are going to make building costs prohibitive.

the image below shows two 150mm diameter pipes (brown and blue drawn to scale) and a 150mm exclusion zone in turquoise either side of them according to the water company's requirements for no foundations in that area.

you will see the dark black box indication where the outside wall of a single story extension would go.

could someone advise what kind of work would be required to build the extension in the position shown? would i be able to get away with lintels over the drains etc? my concern is the top right corner in the image which has the corner of the extension and front wall sitting on top of the extension.

 

[^woody^]

Depth?

 

[freddiemercurystwin]

So is the position of the drains on your plan show the actual confirmed position or a position copied from a water company plan or other similar plan? Also what is the depth? And are you confident a front extension will get planning as they are usually resisted.

 

[a13exf]

Other houses on the street have similar extensions at the front already. i'm quite confident the positions of the pipes are quite accurate based on measurements i've made on features like manhole outside my property etc.

depth is around 1.2m down from top left corner (rough estimate based on depth at nearest manhole)

 

[^woody^]

depth is around 1.2m

Then it's feasible

 

[wessex101]

That will have to be one hell of a lintel to span that exclusion zone on the front elevation. More like a reinforced concrete ground beam maybe with pads either side, still feasible though if slightly more expensive.

 

[a13exf]

that was my worry, costs involved outweighing the benefit.

I know it's like asking how long is a piece of string but, given the position of the sewer pipes. Anyone able to roughly estimate total build cost of this? including an RSJ due to the living room wall being knocked through.

 

[wessex101]

£18,763.24 plus VAT give or take 10p

 

[^woody^]

I can't see any significant cost in bridging those pipes over and above a normal 1.2m deep strip.

 

[pilsbury]

£18,763.24 plus VAT give or take 10p

Not a bad price....... I'm not happy about the give or take 10p. If we agree a price, we agree a price.