Building over drains / strip foundations

[vards01]

I am hoping someone can give me some advice on how to go about the following.
I currently have a dilapidated lean-to, which I plan to take down and build a solid lean-to which will house a washing machine and tumble dryer and general items I do not want in the house. The problem I have is that the drains run right underneath where I am going to build.

Currently it is what I can only describe as a couple of inches of concrete placed over the top, I will be breaking all this up, and I have the idea of building a dwarf wall around the perimeter (dotted green line) then making up some timber frame sections and cladding with weatherboard/insulating and lining internally with ply.

I would like to put the dwarf wall on a standard strip foundation, but concerned about what I will need to do to prevent possible collapse of the drains (shown circled in light blue). This will be a very light weight structure, so maybe I am over engineering it slightly.

Any advice would be much appreciated.

Thanks in advance, Ian

Untitled

• vards01
• 19 Dec 2010
• 1

 

[vards01]

would rebar placed withn the strip foundation surfice?

 

[^woody^]

Bizarrely, if this was some sort of conservatory or something not requiring building control approval, then you can do what you like with the building over the drains

However if building control is required for the extension work, then you will heed to place proper footings and bridge over the drains

Depending on drain depth and ground conditions though, a normal strip foundation above the drains can sometimes be OK - but never acceptable to building control

 

[vards01]

Well I really hope this does not require BC, guess I'll have to give them a call.

 

[^woody^]

You don't need to call them if the work can be kept of their remit

 

[maltaron]

Is the sewer private? It appears to serve at least next door and may be a public sewer, in which case the sewer authority will be involved (and this can be a nightmare). Do a search for Building regulations H4, this will give all the info you require.

 

[vards01]

The drain serves 4 properties, mine is no2 in line, I will check out the building regs, but now thinking I may just put down another 4" slab with some threaded rod in and bolt down the timber sections, as oppose to a dwarf wall. As bricking up around the pipe and putting a lintel over seems way over kill and costly, for what is a glorified shed.