Patio level - protruding manhole cover? Drainage?

[RubberJ]

Hi.

I've had my house renovated and I'm moving onto the back yard as a DIY project because, well, the money had to run out sometime. It's only a small back yard, about 2.5m x 6m. Double french door now open onto the short edge, and more from the kitchen along the long edge. The other long edge is the fence to the neighbour's, the short end is the fence and gate to the back street. Although the decision hasn't been made about paving, it may be slate tiles, so it will possibly be mortared in.

Due to the changes in planning laws over time I now have a brick manhole in the centre of it that wasn't necessary before I had the renovation: 1200 x 750, covered with a concrete slab and inset with a square manhole cover. I've been digging up the site to level it and it appears the manhole cover is level with one brick below the DPC. I've read around and know that ideally any solid surface should be 150mm, two bricks, below the DPC. Sites such as pavingexpert.com show various methods to drain paving areas higher than 150mm above the DPC, including channel drains and linear drains.

My questions are: how should I drain the area? Do I NEED to drain the area (it certainly wasn't before with no apparent ill effects)? I haven't got a concrete base, just hardcore and the clay/earth that the builders dug through to find my drains (pretty much the whole yard!). I could slope towards my wall and use a linear drain (I have a surface water drain I can run into in one corner) but how can I accommodate the manhole into the slope?
Added to this is the fact I'm getting a new fence this week and I need to set the base level for it first. My neighbour's old patio is only a brick and a half below their DPC so ideally I should be starting there at the fence line, but I can't slope towards the neighbours or just on to the street (those planning laws again).
Basically, any pointers appreciated, or else I'll make it up as I go along based on what I find on Google or in the Reader's Digest DIY Manual! (This is generally how I get through these things - I haven't done so badly so far. Usually. )

Thanks in advance for any help.

Cheers.

 

[r896neo]

if it's a brick built chamber just knock off one course of brick and reset the cover.

An area that small a flowerbed or even 6 inches of gravel along the fence line would do for all but the heaviest showers.

Linear drains would also work but best not to fall it toward the building unless you have no choice.

 

[RubberJ]

It is brick built, but it's topped with a 6" concrete slab...

 

[r896neo]

oh

In that case if the manhole is too much work then create a flowerbed along the edge and fall it towards that or gravel edge as i mentioned above.

Or fall it out out the back gate but to comply with the suds legislation just put in a linear drain at the gate to catch it and pipe that to the drain or a soakaway

 

[RubberJ]

We were thinking of just paving, all planting in pots/boxes. But I think falling towards the back gate sounds like the preferred method, I'll put the linear drain there. Thanks for the help.
How can I allow for the slope with the manhole cover? Just let it sit at a slight angle with respect to the rest of the paving? Or I suppose I could replace the cover with one that you can put paving inside, then build up the mortar and slope that to match the rest...?

 

[r896neo]

If your game to have a go reomving the old one you may be able to find a shallower cover. A recessed one will not work as they are extra deep, nearly 90mm usually. A galvanised cover and frame may be as little as 30mm deep.

Sloping the paving up to suit will look awful in such a small space. The various dry area and gravel trap arrangements which allow you to be closer to dpc level do work if detailed correctly but really are a last resort.

In your case it sounds like either lower the manhole cover or live with the hump and slopes around it