Rain water soak away

[David WE Roberts]

I don't know if my rain water drainage is to a soakaway. However...... Having just unblocked a rainwater down pipe at the top where it met the guttering, and found it full of mud and moss (our North facing roof seems to be almost a 'green roof' - there is moss growing around nearly every tile) I was pondering on how much crap had gone down the pipe before it became blocked.

Which led me to pondering about soak aways in general.

If you keep washing muck down into them they must silt up eventually. So how do you deal with this? Should there be a gulley and 'U' trap before the soakaway to catch rubbish which can then be removed? Or do you have to plan to dig the garden up every 20 years or so and clean out the soakaway?

Cheers

Dave R

[Tim W]

David WE Roberts wibbled on Wednesday 30 December 2009 18:50

That would be the easiest to maintain way.

Once, I made a hollow chamber soakaway with a paving slab base, brick wall with gaps between some bricks and paving slabs sitting on top. This was in a lawn 4" under the surface, so if one remembered where it was, it was a fairly simple matter to lift the sod and clean it. However, it would take a lot of blocking up being a chamber type.

Can't do that here as there's clay 12-18" down so not much depth of soil to drain into. I'm thinking of burying long lengths of perforated pipe 12" down or just above the clay layer. In that case I will certainly be installing u- traps with access lids as perforated tube will block relatively easiliy and be nearly impossible to clear.

[The Natural Philosopher]

The latter really.

[David WE Roberts]

In which case the next question is "How do you find the soakaway?".

Presumably by digging up the pipe run and following it along.

I am now hoping I never have to tackle this particular problem :-(

[OG]

My MIL's house built in the 30's seems to have recently blocked its soakaway from the porch. The plan is to cut into the downpipe and insert a diverter to pipe the rainwater down the side of the house and into the outside drain where the kitchen and bathroom grey water pipe outfalls are.

That's the plan anyway.

[Roger Dewhurst]

Fill the soakhole with coarse gravel and then lay filter cloth on top of the gravel. Periodically clean the filter cloth.

R

[js.b1]

Milk crates.

Plus there is a formula for what size soakaway based on %age free area somewhere, based on area of roof being served and so on. Probably Paving Expert or similar.

[Dave Liquorice]

Check what the MIL's water board are charging here for. If it includes surafce water in the sewerage charge fair enough but if not the bill could increase (if they found out...). Or if there is no surface water entering the sewage system she might be entitled to a reduction in the bill...

[The Natural Philosopher]

Its marked on the plans?

[David WE Roberts]

Errr.....which particular plans would these be? I don't have any for my 1930s semi. Are you saying that someone else will hold a set of definitive plans? Including any changes to soakaways since the 1930s?

[The Natural Philosopher]

Building control SHOULD have them.

But if its that old..dig up and mark the location on a new plan, and file the plan with the house deeds!

Normally, when a soakaway is full of mud, it hardly matters where it is, because you are faced with a complete dig up and make new situation anyway.

so get digging new drains!