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How to pave side of house and ensure run off?

dweller1

Hi all. I have the side of my house to pave. i have a 30cm gravel zone from the house that must remain for termite inspection. this leaves a 130cm gap between the edge of gravel and a retaining wall approx 50 cm high. i intend to pave.

the area will be clear to allow a 7.5 cm gap below hte weep hole to the top of the paver, below the paver will be 7 cm of road base and 3 cm sand base. i know i need a 1to 2 degree drop for run off (approx 1-2cm over a meter). i also am aware that i need to have run off from both the house and the retaining wall to a center line drain.

My concern is that over such a small distance of 130cm (meaning only 65cm of each side of the center drain) it is difficult to get run off in both directions to the center line using even relatively narrow pavers of 20cm.

Can i slope the road base at 1cm drop and have the sand level thus the top of the pavers will be level? the variation of sand will only be 2.5 to a max depth of 3cm.

Any ideas would be welcome.

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EricL

Hello @dweller1

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your paving project.

Your proposed plan is very sound; however, it's functionality relies on the condition that the water will immediately pass through the pavers and into the sand. If the surface were gravel or smooth pebbles, then water would permeate the surface and pass through the sand and into your pre-built channel drain.

Pavers act as a barrier and hold water on the surface for quite some time (depending on the type of paver of course), but typically water does not pass through a paver immediately which can cause issues. If enough water gathers on the surface, it will become a puddle and will fall into the direction where the pavers are directed to. If the surface is flat, then you'll have larger puddles which will not automatically drain away. If a strong enough downpour occurs the water will drain into the area of least resistance which is the gravelled area near your house wall.

As an alternative, I propose building a fall away from the house and installing an https://www.bunnings.com.au/everhard-3m-easydrain-compact-polymer-grate-and-channel_p4770469 close (but not right next) to the retaining wall. This will facilitate rainwater drainage even in severe conditions. I would suggest a 50mm concrete buffer on each side of the drain so that rainwater properly flows into it. If you can share a photo of the side of the house where the paving will be laid down, we'll try to render a picture of the layout using AI to give you an idea of how it can all be set up.

Let me call on our experienced members @Dave-1, @Nailbag, @Noyade and @DIY4Knuckleheds for their recommendations.

If you have any other questions we can help with, please let us know.

Eric

Dave-1

Good Morning @dweller1

I was thinking a picture would be nice when I started reading your ideas :) Once I sorted out what you were intending to do I was well on the way to thinking a slope away from the wall, pretty much what @EricL has suggested. The 20mm pavers sound like thick tiles? Or are the thin sandstone type? Whichever way water does like to pool when it rains and then seep away slowly so having a route that it prefers would be a good idea.

Dave

MitchellMc

Hi @dweller1,

I didn't realise Eric had replied, but I'm thinking the same.

I think there are really two separate drainage issues to consider here:

Surface water running off the pavers.
Subsurface water.

In regard to your question about sloping the road base but keeping the sand and pavers level, I wouldn't recommend it. Road base is porous, so any water that passes through the pavers will simply infiltrate into it rather than travel across the surface of the road base to your drain. The slope only becomes effective where water is flowing over a relatively impermeable surface.

Similarly, if you slope the paving from both sides towards the centre but don't have a surface drain at the low point, you'll likely end up with water ponding there until it slowly seeps through the paver joints.

My recommendation would be to simplify the design by sloping the paving in one direction only, away from the house and towards the retaining wall. Then install a surface channel drain along the base of the retaining wall. This way, any rain falling on the pavers runs away from the house and is captured immediately by the drain. Any water that seeps through or behind the retaining wall can also discharge straight into that same drain.

You'll still have some water that penetrates through the pavers into the road base, so if groundwater or seepage behind the retaining wall is a concern, I'd also consider installing a subsurface agline beneath the paving layers to collect that water and direct it to the stormwater system.

Overall, I think this approach is simpler to construct and less likely to create drainage issues than trying to create a crown and drain to the middle over such a narrow width.

Please let me know if you have any questions.

Mitchell

dweller1

thanks everyone for feedback. here is a picture of the side of the house. the gravel near the house has been removed to allow access but will be placed back in once paving is complete. cheers

Dave-1

Morning @dweller1

Reading @MitchellMc's words brought to mind when I had to redo my storm water.

I ended up with a trench down the middle of the side path with gravel surrounding the pipe. I had a slight slope away from the house and a clay top to above the gravel.

One thing I noticed immediately is the reused pavers (20mm thick ish) dried fast and the water coming through the bricks to under the house dissapeared.

The gravel wicked the water and subsurface water towards the trench dip and then follows it downhill.

Stormwater rectification stage 1

Stormwater rectification stage 2

Just to show how it worked (forget about all the digging :) )

Just saw you picture, I would definently go for a drain just a little off the fence retaining wall.

Dave

dweller1

thanks again for the feedback. it sounds like the way to go. a question though about the surface channel drain. can i then connect that into the existing center drain or do i need a plumber to fit it? just want to ensure things are done correctly. cheers

MitchellMc

Hi @dweller1,

Yes, a surface channel drain can typically be connected into your existing stormwater drainage, but that connection should be carried out by a licensed plumber. Since you'll likely need a plumber for that part of the project anyway, I'd recommend discussing the overall drainage design with them before you begin. They can advise on the best way to connect the channel drain and whether any additional subsurface drainage would be beneficial.

Please note that plumbing work, including connecting drainage to the stormwater system, must be completed by a licensed plumbing professional for safety and compliance.

Here's an AI-rendering of what it could look like.

Mitchell

dweller1

well, that certainly is impressive. i just need to leave the 30cm from the house for the gravel to allow termite inspection, but that is impressive. much appreciate the image and thoughts to follow up.

dweller1

out of curiosity, what type and size are those pavers in the picture? thank you

MitchellMc

Hi @dweller1,

The closest we would have would be the https://www.bunnings.com.au/tuscan-path-600-x-400-x-20mm-bluestone-paver_p0129309 or https://www.bunnings.com.au/tuscan-path-600-x-400-x-20mm-charcoal-porcelain-paver_p0129321 .

Mitchell

EricL

Hello @dweller1

It's great that my teammate has given you a great render of the side of the house. Just in case you are curious about what it would look like with a lighter coloured paver, I've placed a sample image also rendered in AI. I used the Brighton Masonry 400 x 200 x 40mm Cream Mypave 424 Paver. Please note that this has a rougher finish than the rendered image. I recommend visiting your local store so that you can see the actual finish of the pavers.

If you need further assistance, please let us know.

Eric

ChatGPT Image Jul 22, 2026, 02_50_57 PM.png

dweller1

Eric, what is the brown edging near the house? is that timber or something else. thanks

EricL

Hello @dweller1

Yes, it is a 100 x 25mm 4.8m Wet H4 Treated Pine Sawn Garden Edging. The timber garden edging can be stained if you wish to have a darker finish. You also have the option of using thin pavers in a dark grey finish.

Eric

dweller1

thanks, the info here has been excellent