MortarThePoint

Neither Floplast nor Osma make a 22.5 degree bend in 110mm, but Brett Martin does: Single Socket: https://direct-drainage.co.uk/products/110mm-single-socket-22-5-bend-b5071-underground-drainage-pipe-fitting Double Socket: https://direct-drainage.co.uk/products/110mm-double-socket-22-5-bend-b4051-underground-drainage-pipe-fitting

Looking closer on site, the 160mm pipe is closer to the corner of the house than I thought, so I think I can use the setup below that looks pretty reasonable. May be better to use a 160x160x160 junction to keep all inverts level. I don't think I have to have the optional rodding access as the bends on that branch will be 30 degrees or less meaning I could rod the branch and the 160mm main section through the top Inspection Chamber (I.C.). If space allowed, it would probably be nice to have it after the lower bend and focused on rodding just the 160mm main section. Still interested how people would tackle the original challenge though, but that's relegated to curiosity now rather than necessity.

It's just surface water from gutters and all below ground

So do you cut a hole in the smaller rectangular grid? I was thinking of perhaps having the shoe over that part meaning the square section could be easily removed.

When they put in the drive and the rainwater pipe across it, the ground workers asked if I wanted a 110mm pipe or 160mm pipe. It seemed like a small additional cost to go with 160mm pipe. I now need to connect two 110mm pipes to it. They are coming in opposite directions each at 90degrees to the 160mm pipe forming a T shape. Rodding access on each 110mm pipe will be about 3m away via 4D960 chambers. Some options to connect are shown below. It's right at the front of the house, outside a bay window, so I'm keen to have something discrete. Using the equal tee (6D193) feels like a bodge, but a blockage here feels unlikely given the step up on pipe diameter. The two 6D198 feels less like a bodge as could provide rodding access, but doesn't have level inverts. The rodding access could go via a 110/160 reducer to decrease the size of the rodding eye. Floplast 6D900: mixed 160/110 chamber plus 2no 45 bends 6UR928: 160mm chamber plus 2no 45 bends or the naughty option on right where the central channel isn't used 6D193: 160mm 90 tee plus 2no 110/160 adapters. Feels like a bodge as no access but could add a second to the outlet with the branch facing up to allow access. Level inverts benefit 4D960: 110mm chamber plus short pipe, 2no 67.5 bends and 110/160 adapter Level inverts benefit SP230: A wildcard option is to use a soil pipe double branch and allow rodding access. Would need a short length of pipe and a 110/160 adapter into the 160mm pipe. I have one of these spare. Feels like a shame to have the combined flow in a 110mm section of pipe even though it would only be about 200mm worth. Level inverts benefit Polypipe 160/110 branch: allows rodding access via a 160mm 45 bend technically compliant down to 600mm depth I think Would prefer a ring seal version 6D198 or 6D218: two of these have the benefit of having 110mm side ports. 6D198 would need 2no 45 bends but have a smoother flow.

This is what Floplast show as an example in their brochure for downpipes with shoes:

I tried disabling the DHCP server in the Router menu hoping that DHCP requests would make their way to the original router, but sadly not. It isn't obvious how to have it act as a switch. There is a Bridge option, but it says it only supports one device at a time and has to use mobile data. With it acting as a Router (inc DHCP server) I can happily RD to a machine on the other network as well as shared drives

For the two turns, I think I'll use Osma 4D960 plus two bends as I've identified a cheap source and didn't like the look of their 90 bend chamber (4D918) and the total cost of that was looking like £100+ each. The first corner can be achieved with a total turn of 2x22.5=45 if I bring the pipe out from the house at 45 degrees. Despite all being level invert, it says to always use the main channel rather than make the turn with the chamber's 45 inlet. I loved the look of the Polypipe SFA7 option but it's too expensive.

Made a few calls. Polypipe suggested that Bottle Gullies are the standard approach. Wavin (Osma) said it was down to taste and Bottle Gullies are probably the easiest and neatest. I said I liked the idea of hopper and rested bend and that seemed ok but may be less roddable. In terms of joining the main run of pipe, it's standard to use a tee, as long as the main run is roddable (ie chamber at is ends). It's looking like I'll go with an Osma 4D960 with 2x45 bends at each corner of the house, straight runs between those and then Y-tee branches to each hopper or gully.

Brett Martin's B2803 is a 90 degree 280mm inspection chamber, but the exits have a sharp 45 bend with the channel being straight within the inspection region. Osma's 4D918, on the other hand, has the bend in the inspection region. Osma have a useful selector, a copy attached. Slightly bigger though, 315mm vs 280mm. Here's some information about their Multi-Base IC range. The Osma 4D918 looks a bit silly from above, but there is a straight alternative (4D910) that could be used with 45 elbows. Even the smaller (250mm) Osma 4D960 could be used with two 45 elbows. Brett Martin B2803: Osma 4D918: Osma 4D960: F0026752_0001.pdf

That makes for an about 15,000mm * 1/60 = 250mm drop from the stack's rested bend to the tee by the 450mm chamber which has an invert of 600mm. That means the rested bend can have an outlet invert (600mm - 250mm) = 350mm below the surface. That works about perfectly to have the Floplast rest bend at the bottom of the stack (D571, dimensions below). If it was available in black, I'd consider having the collar sticking out of the ground meaning the invert could be at just 300mm below the surface. The orange stuff isn't UV stable and would catch the eye, but I guess I could spray paint it black if I needed to.

Good advice, I'll take a look this evening when the wife isn't watching the awful movie she currently is. It will save her subjecting me to it's sequel.

Looking at table 3.1 in Part K it looks clear that the minimum height for internal elements in a single family dwelling is 900mm. A block of flats however would require 1100mm as would an external balcony of a family dwelling. I just got spooked by a call with Richard Burbidge where they said I need 1100mm even for a singe dwelling. I checked with my BCO to make sure and he says 900mm. -----

Looks smart, but I'm using a shoe rather than pipe straight in so I'll use something with a grate on the top surface

I'll have to check my levels, but may struggle to get a rested bend in and have a good gradient as well (1:40). The longest run is going to be about 28m so 1:40 would need 700mm which may be optimistic even from the surface let alone a rested bend. Most of the run will be under paving so can be near the surface.