Home & Garden

Paver Patio -- Questions about Gravel and HPB Base (Pics Included)

  • Last Updated:
  • May 17th, 2021 10:24 pm
[OP]
Sr. Member
User avatar
Aug 22, 2009
581 posts
139 upvotes
Guelph, ON

Paver Patio -- Questions about Gravel and HPB Base (Pics Included)

Hi everyone!

I started a paver patio project last year and decided to go with an 8" compacted A-Gravel bas wtih a 1" HPB screed layer. I got to the point in the project where I've nearly completed the grading and A-Gravel base, with the exception of some fine tuning. I'm also doing artificial turf in the rear, because my yard was 99% weeds of 100 varieties, so I'm done with grass :P I've attached some pics of my plan, grading plan, and site pics.

v33 Landscape (Colour, FT) v1.png
Grading Plan v3.png
IMG_0043.jpg
IMG_0045.jpg
IMG_0042.jpg
IMG_0047.jpg

I have a few questions as I prepare for my next steps:

1.) Does it matter whether or not my gravel base (beneath the HPB) is perfectly smooth? I've seen videos where some guys use a large board to make sure that all little valleys are filled and peaks removed, but I'm not sure why this step was required. I could understand not having peaks, but wouldn't the HPB just fill in any valleys?

2.) I have a layer of woven geotextile between my compacted native soild and my compacted gravel base. Do I need any kind of geotextile between by compacted gravel and the HB screed layer?

3.) I know that HPB has to be "contained", but what exactly does this mean? WIll my gravel "contain" the HPB from below? Do I need some way of containing the HPB along the perimeter?

4.) I built a Techo-Bloc fire pit with a seating wall around it. Since I'm working in a "tight space" within the seating area to lay pavers, how am I supposed to screed the HPB? I think I'd be starting from the top-right corner of the seating area, but I won't be able to get rails in there on a 45-degree angle to match my grade. Do I just lay the stone and level them as I go?

Thanks!
7 replies
Sr. Member
Nov 6, 2014
907 posts
1558 upvotes
Woodbridge, ON
The base doesn't need to be smooth at the skreed or hpb will level it out. That said you want to have the base compacted with a gas tamper to minimize settling. Doesn't hurt to lay fabric down but weeds tend to grow in the cracks. Fabric will be a small expense and I personally would forgo it. You'll want hard landscaping edging that's staked into the ground which will help hold in the skreed and minimize shifting. Can't advise on #4.

Edging looks like this:
https://www.rona.ca/en/paver-edging-pla ... k-66635193
[OP]
Sr. Member
User avatar
Aug 22, 2009
581 posts
139 upvotes
Guelph, ON
Thanks! Yeah, I didn't see a technical reason my the base would need to be smooth, but I guess the guy with the 2x4 (i.e. checking to make sure he couldn't see light under a straight board) was just being extra careful.

I bought a gas tamper last year and I've already tamped the crap our of both the native soil and the gravel (which I did in lifts). On top of this, I think simply letting it sit over the winter should help it settle even further. I'm at the point now where I just need to fine tune my grading (so I bought a rotating laser level and receiver that I'll use shortly to confirm elevations). After fine tuing the grading, I can bring in the HPB and start the finishing work :) I was hoping to build my deck and stuff this year as well, byt lumber prices might not co-operate :(
Deal Addict
Nov 9, 2008
1744 posts
778 upvotes
Toronto
VifferFun wrote: Hi everyone!

I started a paver patio project last year and decided to go with an 8" compacted A-Gravel bas wtih a 1" HPB screed layer. I got to the point in the project where I've nearly completed the grading and A-Gravel base, with the exception of some fine tuning. I'm also doing artificial turf in the rear, because my yard was 99% weeds of 100 varieties, so I'm done with grass :P I've attached some pics of my plan, grading plan, and site pics.


v33 Landscape (Colour, FT) v1.png
Grading Plan v3.png
IMG_0043.jpg
IMG_0045.jpg
IMG_0042.jpg
IMG_0047.jpg


I have a few questions as I prepare for my next steps:

1.) Does it matter whether or not my gravel base (beneath the HPB) is perfectly smooth? I've seen videos where some guys use a large board to make sure that all little valleys are filled and peaks removed, but I'm not sure why this step was required. I could understand not having peaks, but wouldn't the HPB just fill in any valleys?

Shouldn't matter, you'll be screeding your HPB as your top layer. Just means you may have more hpb in some spots.


2.) I have a layer of woven geotextile between my compacted native soild and my compacted gravel base. Do I need any kind of geotextile between by compacted gravel and the HB screed layer?

Good question - I used HPB as my base and screed layer, and had geotextile between it and my sub base (soil). You don't really need to compact HPB - it self compacts to something like 96% as soon as you lay it. You will want to run a compactor across your stones once you've laid everything to settle them into the HPB though (consult your paver manufacturer for guidelines). I'd be somewhat concerned of the fines in your A-gravel washing out, causing your HPB to settle into the gravel, so maybe geotextile is a good idea...? Is there a reason you didn't go with just HPB?


3.) I know that HPB has to be "contained", but what exactly does this mean? WIll my gravel "contain" the HPB from below? Do I need some way of containing the HPB along the perimeter?

HPB is "runny", in that it needs an edge to prevent it from continuing to "flow" out the sides. This is typically just the edge of the soil where you havent excavated and are meeting your pavers with an existing grade/surface (driveway etc)

4.) I built a Techo-Bloc fire pit with a seating wall around it. Since I'm working in a "tight space" within the seating area to lay pavers, how am I supposed to screed the HPB? I think I'd be starting from the top-right corner of the seating area, but I won't be able to get rails in there on a 45-degree angle to match my grade. Do I just lay the stone and level them as I go?

Get smaller screen rails (I used 3/4" EMT conduit pipe, you could just cut them into smaller lengths with a hacksaw and use any smaller, flat straight edge to screed

Thanks!
Some answers to your questions!

Sidenote - your whole yard is basically going to be hardscaped. Are you concerned about water management at all / does your municipality allow this? At least in Toronto, artificial turf is considered hardscaping and you need to have a minimum % of softscape in your backyard and front yard. Be careful.
Sr. Member
Feb 26, 2019
501 posts
469 upvotes
Ottawa
Does that artificial turf heat up in the sun? Looks like it could get hot back there. I’d personally add more plants to cool things off.

Nice work on it though. Ambitious project.
Deal Addict
Apr 26, 2003
1750 posts
835 upvotes
GTA
That's a serious sized job that you're DIY'ing. Koodos to you for undertaking this.

Did you draw up that grading plan yourself?
[OP]
Sr. Member
User avatar
Aug 22, 2009
581 posts
139 upvotes
Guelph, ON
jacquesstrap wrote: Some answers to your questions!

Sidenote - your whole yard is basically going to be hardscaped. Are you concerned about water management at all / does your municipality allow this? At least in Toronto, artificial turf is considered hardscaping and you need to have a minimum % of softscape in your backyard and front yard. Be careful.
Water management has been top of mind throughout the project, which is why I was really careful about the grading. I'm not touching the grading along the perimeter of the property (which are small swales), and everything drains to the large swale in the rear which has a storm management drain system (where the trees area). I'm pretty sure the municipality allows artificial turf since many people are installing it, but I'm being a little more cautious by leaving the boundaries.
dottawat wrote: Does that artificial turf heat up in the sun? Looks like it could get hot back there. I’d personally add more plants to cool things off. Nice work on it though. Ambitious project.
My neighobours installed turf two years ago and haven't noticed it getting hot or anything. They've loved it so far. Thanks! I had helical piles installed for a future deck and the installer said it was the rockiest soil he's ever encountered. It was brutal to dig! And I also hand dug a trench the length of my house for a gas line for the fire pit.
exrcoupe wrote: That's a serious sized job that you're DIY'ing. Koodos to you for undertaking this.

Did you draw up that grading plan yourself?
I actually had TONS of help from a retired landscape architect who I met in an online forum, and he just seems to enjoy helping people with their landscape projects! He's the nicest guy ever -- even gave me his cell so we could go discuss the plans. I took elevation measurements on a 5FT x 5FT grid and then he designed the contoured grading plan to work with it. He's extremely detail-oriented (which I like), so I'm trying to do everything right with his help :)
[OP]
Sr. Member
User avatar
Aug 22, 2009
581 posts
139 upvotes
Guelph, ON
jacquesstrap wrote: Some answers to your questions!

Sidenote - your whole yard is basically going to be hardscaped. Are you concerned about water management at all / does your municipality allow this? At least in Toronto, artificial turf is considered hardscaping and you need to have a minimum % of softscape in your backyard and front yard. Be careful.
Sorry, I didn't realize until not that you had responded within the quote in bold text! Thnaks for your thoughtful answers.

To answer your question, I went with an A-Gravel base for a few reasons:

  • It's cheaper
  • I already bought a gas plate compactor
  • I needed A-Gravel for the base of my artificial turf anyways (so I could compact one continuous surface)

I used HPB as a leveling bed for my wall stones, and I found it really nice to work with, especially when I was super picky about getting my wall to hit a very specific grade with my digital level haha! I initially had woven geotextile between the A-Gravel and the HPB, but found it super slippery so I pulled the fabric out. I'm hoping that the HPB doesn't sink into the A-Gravel -- that' would suck haha!

Thanks!

Top