bridging over drain in foundations?

[leekr]

Have just dug down to the depth required for my footing for my new porch (2.2m x 1.4) and have found that they is a drain pipe running half and half at the bottom of where my concrete is to be layed. Whats the best way to bridge over this?
Also they is a pad of concrete about 4inch thick at one end of the trench if any one can shed any light on this for me.

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• leekr
• 12 Apr 2014
• 2

Untitled

• leekr
• 13 Apr 2014
• 1

Untitled

• leekr
• 13 Apr 2014
• 1

 

[tony1851]

Just leave a gap in the concrete by putting a couple of boards either side of the pipe. Make sure the concrete top surface is at least 50mm above the top of the pipe.
When you start bricking, put a couple of short p.cast concrete lintels over the gap.

(I'm impressed by the quality and strength of your trench shoring, by the way )

 

[leekr]

should I dig any deeper either side of the pipe to expose it?

 

[tony1851]

should I dig any deeper either side of the pipe to expose it?

As long as the underside of the concrete is no higher than the bottom of the pipe, it will be fine.

 

[conny]

should I dig any deeper either side of the pipe to expose it?

As long as the underside of the concrete is no higher than the bottom of the pipe, it will be fine.

So are you saying his footings should be as deep as the underside of the pipe?

 

[leekr]

The pipe is half out the ground now. So I'll just dig another 2inch down to be safe. Thanks

 

[ban-all-sheds]

So are you saying his footings should be as deep as the underside of the pipe?

At least.

 

[tony1851]

should I dig any deeper either side of the pipe to expose it?

As long as the underside of the concrete is no higher than the bottom of the pipe, it will be fine.

So are you saying his footings should be as deep as the underside of the pipe?

Yes; the general rule is that if a foundation is within 1m of a pipe, the underside of the foundation should be at least as deep as the invert of the pipe.

 

[tony1851]

The pipe is half out the ground now. So I'll just dig another 2inch down to be safe. Thanks

Don't dig down much more than that because the earth immediately under the pipe can then fall away, leaving the pipe unsupported.

 

[noseall]

The pipe is half out the ground now. So I'll just dig another 2inch down to be safe. Thanks

Don't dig down much more than that because the earth immediately under the pipe can then fall away, leaving the pipe unsupported.

Ah come on now Tony you know that's a bit daft.

How many times have you seen instances where there are drain pipes criss crossing trenches unsupported? I've lost count. Repairs are not that difficult either.

What are we talking here - 600mm?

I suggest digging any friable non-virgin material out of the trench no matter what, including any of the pipe trench back-fill.

 

[leekr]

Thanks for the help people. Has anyone got any idea what the concrete pad at the back of the trench could be. My guess is its something to do with the drain?

 

[ban-all-sheds]

Has anyone got any idea what the concrete pad at the back of the trench could be.

The foundations for your house.

 

[tony1851]

Don't dig down much more than that because the earth immediately under the pipe can then fall away, leaving the pipe unsupported.

Ah come on now Tony you know that's a bit daft.

[/quote]

Yes, you're perfectly right - I don't know whatever came over me, giving rubbish advice like that.

In future, when old cement-connected salt-glazed pipes are involved, I'll suggest digging all around them; using them as steps to get up out of the trench, and encourage them to drop hammers and other tools on them.

How stupid of me not to remember all that!.

 

[noseall]

In future, when old cement-connected salt-glazed pipes are involved, I'll suggest digging all around them; using them as steps to get up out of the trench, and encourage them to drop hammers and other tools on them.

How stupid of me not to remember all that!.

What, and you think that all ground-workers are going to leave a column of soil beneath all pipe runs irrespective of depth of pipe and depth of trench!

Dropping weighty objects on clay pipes will cause damage no matter what.

Dig it out, expose it and wrap it. Put a half batt under it if you need to, though I doubt you will.

Chill out Tone.

 

[tony1851]

[

Chill out Tone.

I'm cool enough, thanks.