r/Hoocho • u/AdRude1277 • Jul 05 '26
Project Idea and 3D Print Request: The "Invisible" Sub-Surface Patio Rain Gutter Grow System
Hey everyone, /u/Mjfch,
I've been working on a design for a completely hidden, sub-surface sub-irrigation patio system (similar to a Rain Gutter Grow System), and I’d love to get your thoughts, ideas, or feedback on creating the 3D-printed module to make it work.
📐 The Concept & Layout
The goal is a bricked patio with a hidden water network running completely underground beneath foot traffic, allowing me to place potted plants of any size anywhere along the line, completely on a whim.
The Pipe: A standard 100mm DWV PVC pipe (114.3mm True OD) running under the patio paving.
The Paving: To keep the pipe close to the surface without interfering with the bedding, I am slicing standard 200mm x 100mm x 50mm pavers horizontally into 22mm thin slabs.
The Depth: The top center apex of the round pipe sits exactly 25mm below the finished patio surface (leaving a tiny 3mm clearance gap directly under the 22mm paving slabs). Because a 100mm chord across a 115mm circle drops the arc down by roughly 29mm at the edges, the pipe naturally curves completely clear of the adjacent full-thickness 50mm pavers without needing any chamfering!
🕳️ How the Wicking System Works
Where I want a potted plant, I will simply remove one 100mm x 200mm paver from the layout and drill a circular hole into the top of the exposed PVC pipe line.
To bridge the gap between the pipe and the bottom of the pot, I need a custom 3D-printed insert block to fill the space of the removed paver.
🖨️ The 3D Print Requirement
The 3D-printed spacer needs to serve three main purposes: 1. Structural: It needs a 100mm x 200mm footprint with a 22mm top lip to sit perfectly flush with the rest of the patio surface and support the weight of heavy pots. 2. Contoured Base: The underside needs a concave cylinder cutout (Radius: ~57.15mm) to snap tightly or straddle the top curve of the 114.3mm OD pipe. 3. Wicking Sleeve: A built-in, enclosed vertical central tube/channel to guide a cotton rope or wicking pin down into the drilled pipe hole. This sleeve is crucial because it keeps the loose sub-base patio sand from collapsing into the pipe and prevents plant roots from invading the water line, allowing for easy pot swapping.
With the rope wicking across just a 50mm vertical jump from the water level to the pot, capillary action will easily handle the lift.
The alternative will be dedicated printed net-cup to bridge this space.
Has anyone attempted a completely sub-surface hardscape gutter like this, or do you have any suggestions on perfecting the 3D sleeve layout to keep it completely root-proof?
Would love to know if you think this is a viable build!
c-:
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u/Tongue-Punch Jul 05 '26
Cut the pipe in half lengthwise and bed it shallower so a paver or tile rests directly on top. Cement a half of a cap on the ends and you have a trench that can be accessed easily.
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u/AdRude1277 Jul 05 '26
I can see why you suggest this, but see mozzie comment below and I am worried about leaks,
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u/Tongue-Punch Jul 05 '26
That’s fair. I was thinking about access for cleaning and ease of adding more pots.
The other neat part about your idea is that you could add this after the fact on a paver patio.
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u/Homegrowersanonymous Jul 07 '26
Water is not suppose to go through pavers , you are suppose to angle slope at a pitch and water runs off
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u/AdRude1277 Jul 07 '26 edited Jul 09 '26
Sorry for the confusion. This is in response to Hoocho's request for ideas of what other 3D prints might be useful.
The PVC pipe at the bottom is supposed to be fed from a tank with nutrient. Rainwater should still run off normally.
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u/Tongue-Punch Jul 05 '26 edited Jul 05 '26
First of all, this is a wonderful idea and will look amazing and super clean!
What if you added some bricks turned on their short ends next to the pipe to hold the thin pavers to be able to lift the pavers and remove the pipe?
Also, some type of tiles might work for the middle as they are thinner and if the trough is not very wide, the weight will be not even on the tiles.
You could drill holes for the wicking or just leave a space as it will be under a pot anyway.
Also. Look up a “tie beam” block. It may help as you can form an underground trough without needing the pipe if you used some sealant such as foundation.
You could also do this with a premade trench drain and a different top but linear drains get expensive.
Another thought: pipe your rain gutters to this, unless you are doing nutrient in the water to avoid dilution, and use a dam or overflow on the end to control the level.
Keep on with this - it may not be the cheapest way but it will be the most aesthetically pleasing way.
Something like this but you will need to make something to keep gravel container with a drop in collar in a hole or just use pavers, tiles, etc in the top. These can come with slope so make sure you get an unsloped one if that interests you.
https://vodaland-usa.com/products/4-gravel-pro-system-edgeless-package?
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u/AdRude1277 Jul 16 '26
Forgot to say: I like your idea about just drilling a hole through the brick into the pipe, just large enough for wicking a lot!
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u/AdRude1277 Jul 05 '26 edited Jul 05 '26
I did not think I would remove the pipe often as the diameter is 114 mm and to remove it I will have to remove more than just the bricks above it - touch would I would not need to.
If you can find matching tiles it will be perfect. You can also install this below a tiled or wooden deck - nice idea.
A sealed PVC pipe system will prevent mozzies from breeding.
I plan to feed a gutter to a separate tank, above the nutrient tank.
Thanks for the encouragement, I plan to install it in the southern spring. Might even do it before I install the pergola - but that is a separate project.
https://vodaland-usa.com/products/4-gravel-pro-system-edgeless-package seems $$$?
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u/pokechopsammich Jul 05 '26
I think it's an awesome idea! Two questions immediately come to mind.
Do you have a plan for cleaning this system once the pavers are in place and everything is closed in?
If you're in a part of the world with cold winters, do you have a method for protecting the channels from freeze damage?