Downspout Gully Designs

[Triassic]

I need to fit down spouts and rainwater pipes.   I’m running the 110mm rainwater pipes away from the building and into Soakaways, all straight forward and easy to install.
 

What I’m not sure about is the gully the downspouts discharges into. Should these be a simple plastic grid type, with a shoe on the end of the down pipe, or should the downspout go directly into the gully?
 

Thoughts, pictures, best practice ideas most welcome.

[Temp]

Our rainwater down pipes are 80mm and the drains 110mm. We didn't want gullies and ended up using rubber adaptors that connect the two and stop stones entering. We have never needed access for rodding but could remove the lower section of 80mm down pipe if necessary.

 

[LA3222]

Something I'm looking at now too. I intend on fitting the downpipes next week and want to run them into the ground so there no grids etc on show.

 

From what I can see it looks like I need to use P trap gully as these can take a 110mm pipe in the top (i have a connector on the  ottom of my down pipes that sits over a 110mm pipe).

 

However p traps are not rodable so I'm putting rodding eyes in for each run.

 

Bottle gullies look better in practical terms as they can be taken apart to clean but the you have the grids on show ?‍♂️  

 

I may have missed something though - hopefully this thread will tease that out of more knowledgeable members.

[LA3222]

seeing @Temp post made me think why bother with gullys? Just put a 90 degree bend at the bottom? I'm running my rainwater to a harvesting tank which will have a silt trap and the gutters will have leaf protectors - food for thought.

 

I think @Triassic  it comes down to what you want the look at the bottom of your downpipes to be?‍♂️

[Oz07]

Gully with grid to take waste or rainwater. Can be taken apart without downpipes being in the way. I suppose you should shoe it and not cut out the grid but has a leaf guard at the top. Sits on fins which keep the water flowing

[Oz07]

I don't trap where connecting to S/W

[Triassic]

We’re on a septic tank so waste and rain water are separate. 
 

Do I need to use 100mm orange/brown rigid pipe or can I connect the downspout direct to 65mm twin wall flexible, routed to a rock filled soak away?  I only ask as I have a load of twin wall left over from another job and it needs using up.

[Temp]

1 hour ago, LA3222 said:

seeing @Temp post made me think why bother with gullys? Just put a 90 degree bend at the bottom? I'm running my rainwater to a harvesting tank which will have a silt trap and the gutters will have leaf protectors - food for thought.

 

That's what we have, just 90 degree bends with a short length of 110mm up to ground level.  80mm down pipe fits inside with the rubber boot covering the gap. Needed to use plumbers lube to get the rubbers in place on the down pipes but seems to work fine for us. Sorry I can't remember where we got the rubbers.

 

We do have a filter that stops leaves getting into the rainwater tank but no silt trap. The tank is just for garden and car use so not an issue. Quite a lot of silt in the tank after 13 years. 

 

[Triassic]

Thanks all for the input. I’m going to pipe my downspouts directly into The 65mm twin wall pipe and run these to a dry brick constructed soak away chamber. I’ll cover each one with a small paving slab, if I then have problems with silt I can uncover the slab and clean the chamber.
 

With the amount of rainwater we’re getting, sometimes in huge deluges, I’m considering a French drain around the house to keep the foundations dry. Is this something anyone else has done?

[LA3222]

37 minutes ago, Triassic said:

Thanks all for the input. I’m going to pipe my downspouts directly into The 65mm twin wall pipe and run these to a dry brick constructed soak away chamber. I’ll cover each one with a small paving slab, if I then have problems with silt I can uncover the slab and clean the chamber.
 

With the amount of rainwater we’re getting, sometimes in huge deluges, I’m considering a French drain around the house to keep the foundations dry. Is this something anyone else has done?

How deep you putting the pipe? I am thinking of putting the start of the run at maube 100mm of cover so that when I get to the end I'm not having to go too deep.

 

I know that a typing less than 600mm deep should be concrete covered but this is next to the house,  ot going to be walked on, will have some plant pots at best on it so unless I'm missing a trick minimal cover shouldn't be an issue?

[Triassic]

All of my rainwater drains are under grass or paths, so I’ll be keeping the pipes fairly shallow at the house end, probably starting at 150mm deep. The longest drainage pipe will be 6m long.

[Temp]

3 hours ago, Triassic said:

 

With the amount of rainwater we’re getting, sometimes in huge deluges, I’m considering a French drain around the house to keep the foundations dry. Is this something anyone else has done?

 

In part. Our house is on a gentle slope and is split level. On the up hill side of each change of level we put a French drain under the house to route water out sideways to surface water drains.

[scottishjohn]

10 hours ago, Triassic said:

All of my rainwater drains are under grass or paths, so I’ll be keeping the pipes fairly shallow at the house end, probably starting at 150mm deep. The longest drainage pipe will be 6m long.

just hope they don,t freeze --and then you get a thaw at surface --then rain --where is the water going to go ?

thats one of the reasons you have them at 600mm down

[joe90]

11 hours ago, Triassic said:

I’m considering a French drain around the house to keep the foundations dry. Is this something anyone else has done?

Yes, our ground has very high water table so when the trench was dug fir the foundations and the blockwork was up to DPC we backfilled the outside with 50mm stone and ran a pipe from this to a nearby ditch. We did the same with the garage and it works very well.

[LA3222]

40 minutes ago, scottishjohn said:

just hope they don,t freeze --and then you get a thaw at surface --then rain --where is the water going to go ?

thats one of the reasons you have them at 600mm down

Why is freezing an issue? If the pipes have the right fall on them, any water within should flow out so any slight residual water within freezing would not be sufficient to damage  or block the pipe? 

[Triassic]

2 minutes ago, LA3222 said:

Why is freezing an issue? If the pipes have the right fall on them, any water within should flow out so any slight residual water within freezing would not be sufficient to damage  or block the pipe? 

I’m not too concerned with freezing, if it’s that cold everything outside will be frozen and as you say, “ if the pipes have the right fall ......”