patio and rain drains

ds1980

Firstly thanks or maybe not thanks to blackshirtuk!

So basically at present or new patio will sit flush with the top of the rain drains directly outside the extension. This isn't a problem but i now realise that had we installed the brickslot aco then we'd have been able to raise the patio that little bit extra to help reduce the step out of the extension.

Barring taking it all out and doing again i was thinking of just laying about 75mm of the new slab (possibly 600x600) on top of the rain drain. Aco didnt want to comment as it not designed for that but they didnt say woahhhh hold up cowboy! Should i have any reservations about doing this? I can't really think that it'll cause any problems and the rain can just fall into the gap between the render plinth and slab? I was also think that i could potentially find a 10mm slot like channel that i could attach to the back edge of the slab if required? Potentially i may have probs if they needed cleaning?

here's a pic and if anyone has any thoughts on whether this can be done it would be greatly appreciated.



ta

timbo29_2

Hi ds1980

I might be getting the wrong end of the stick here but I think there may be a slot product that you could use this scenario.

If you have a look at the slot drainage on the following website
pavingexpert dot com threshold01.htm

There is a 'L' shaped piece that may fit over the existing channel?

Let me know how you get on as i'm looking to do something similar soon

Thanks
Tim

timbo29_2

Hi ds1980

I might be getting the wrong end of the stick here but I think there may be a slot product that you could use this scenario.

If you have a look at the slot drainage on the following website (will need to google following) pavingexpert dot com threshold01.htm

There is a 'L' shaped piece that may fit over the existing channel?

Let me know how you get on as i'm looking to do something similar soon

Thanks
Tim

ds1980

these are the types of drains but not quite what ill need to do although there is diagram showing paving placed directly under the door sill. this is basically what ill be doing but perhaps with the added bonus of some additional drainage taking surface water away to a drain? Mmmmmm

zaax

It this going able to cope with a heavy thunderstorm down pour - an inch a minute?

You should be sloping the patio away from the house / door. Also you have breached the damp proof course on the right of the door.

ds1980

?

no breach that's an extra grate on top of drain and even if it wasnt would 10mm make a difference? What im trying to understand is that the current DPC is there to prevent "rising damp" but drains etc are to stop rainfall from getting in? so not really sure why theres the 6 inch rule anyway as long as theres somewhere for ground water to run off?

The existing rain drains all slope towards the garden. Reading Part M it appears that they now require level access? Ive emailed BC for their input. Id assume a rain drain would have more than inch a minute output over a brick drain which has 90% less surface area for rain removal? no idea?

heres a pic of what im currently proposing to do. Bit rough but it'll mean we lose couple inches off the height? Forget to label the drain which is the brown thing

wealdroam

ds1980 wrote: »

so not really sure why theres the 6 inch rule anyway as long as theres somewhere for ground water to run off?

The 'six inch rule' is there to minimise the possibility of rain hitting the ground and bouncing,splashing up to the wall above dpc.

ds1980

i get that, so why does part M now say that they want flush thresholds and the drains that are available for said job have much smaller inlets than what i currently have? Question is can i do as im intending? I dont see how it can be any worse than fitting a flush drainage system at DPC height?

blackshirtuk

Hi,
Firstly thanks for the thanks!!

I think the idea of the drain is to take the water away that is hitting the doors and running down to the cill. The water in ours then runs away to a soakaway in the garden,

our patio runs slightly down towards the garden from the drain so I don't believe the drain is for the patio.

In your diagram i would be worried that all the run off water bypasses the drain and goes on to the patio.

the slot drain i showed you does come in 2 parts maybe the top part could replace the grill on the drain? Sorry don't know if you can buy it separately. But Would achieve what you want to do.

ds1980

unfortunately not. Spoke to Aco and theyre different sizes.

That makes sense now although changing whats there to a brickdrain will have the same affect then it appears due to the cill size?

So they either stay as is or become redundant? If i put the brick drain i think ill be able to bring it forward from the existing anyway.
The current raindrains go down the side of the extension to the drains so i should be able to bridge the slot drain to the rain drain no probs. id only need another 8 m across the back so that may be the easiest solution

something like this? Just need to know what to do under the cill....concrete gradient like yours? If i put down some geotextile or something while it sets will that be ok to go on top of rain drains rather than remove them all?

something like this and assume i only nee dthem to go under the cill and not right across the patio?