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Need help with question on base for interlocking and pergola

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  • Jun 20th, 2017 11:07 am
Member
Sep 7, 2008
280 posts
6 upvotes

Need help with question on base for interlocking and pergola

Hello, we are planning to do interlock ourselves on an area of ~2000 sq ft ( walkway and patio) and have a few questions below. Hoping someone can shed some lights into this as well as sharing your experience. Much appreciated!!! We are located in east end Toronto
1) since the area is quite large, where can we buy reasonable price and quality geotextile and HPB. I heard it that it is cheaper at aggregate yards than garden centers or landscaping places..
2) we are thinking to build 6 inches base. Is this sufficient for walkways and patio?
3) can we make 3 inches of granular A crushed stone and 3 inches of HPB as we heard that HPB is more expensive? Or we have to build 6 inches of HPB
4) Also we want to a pergola as well on the interlock patio. The size is 16Wx16Lx12H ft we are thinking. How many posts do we need. Do we have to pour concrete for the base and how thick is needed?

Many thanks...
23 replies
Member
May 28, 2017
204 posts
65 upvotes
1 post every 8 ft would be fine. What you can do is dig a hole at least 4 feet then put in 1/2 bag of cement and level it down. Then put your post in there and fill with gravel.
Deal Fanatic
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Nov 19, 2004
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Cambridge, ON
If the pioneers is going to extend to the pergola posts, put the posts in first since you will need to dig the holes below the frost line and bury the posts. For a 12' high pergola, you are going to need 16' posts since approximately 4' will be below ground.

Even if the patio is going to be within the post perimeter, I'd still do the posts first just to avoid any mess once the patio is in.

As for depth, you will get all sorts of responses. I think we did ours 6-8" (slope to account for). Good enough for a patio. I'd just use hpb for the whole thing.
Deal Addict
Dec 17, 2007
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Alliston, ON
You should go minimum 8" deep for the interlock. 3" base of granular A, tamp it, then the rest HPB tamping it every few inches.

Don't forget to take into account the height of your pavers when you dig. If the stones are 3" thick and you only dig out 6", that only leaves you with a 3" base. It's better to go a bit deeper when you dig it out now, then have stones shift in a few years and wish then that you had gone deeper.
Member
Sep 7, 2008
280 posts
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don242 wrote: If the pioneers is going to extend to the pergola posts, put the posts in first since you will need to dig the holes below the frost line and bury the posts. For a 12' high pergola, you are going to need 16' posts since approximately 4' will be below ground.

Even if the patio is going to be within the post perimeter, I'd still do the posts first just to avoid any mess once the patio is in.

As for depth, you will get all sorts of responses. I think we did ours 6-8" (slope to account for). Good enough for a patio. I'd just use hpb for the whole thing.
Thank you all for your insights.
@don242 "If the pioneers is going to extend to the pergola posts..." could you please elaborate as i am not sure I understand this :-(

Any ideas where to buy the geotextile and HPB with reasonable price? Thanks
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Nov 19, 2004
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tockty wrote: Thank you all for your insights.
@don242 "If the pioneers is going to extend to the pergola posts..." could you please elaborate as i am not sure I understand this :-(

Any ideas where to buy the geotextile and HPB with reasonable price? Thanks
Sorry, that should have read "patio", not "pioneers". Bad case of auto correct.

I can't remember how much hpb we got, but the price varied based on amount. We paid $255 delivered for up to 11 cu.yds. from a garden center, but we are in Cambridge so not sure of places in your area.
Member
Sep 7, 2008
280 posts
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don242 wrote: Sorry, that should have read "patio", not "pioneers". Bad case of auto correct.

I can't remember how much hpb we got, but the price varied based on amount. We paid $255 delivered for up to 11 cu.yds. from a garden center, but we are in Cambridge so not sure of places in your area.
Thanks for your prompt response! Would you use 4x4 or 6x6 for the post?
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Nov 19, 2004
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tockty wrote: Thanks for your prompt response! Would you use 4x4 or 6x6 for the post?
I'd definitely go with 6x6 posts. Our pergolas are much smaller and we still used 6x6. A bit more cost but you will definitely appreciate it after.
Sr. Member
Jan 3, 2013
719 posts
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Winnipeg
A 12 ft Pergola with 4x4 posts would be a death trap especially on a windy day.

Have you considered putting the posts on ground hogs? Here in Winnipeg if you buy four or more they're each $146 supplied and installed for 8ft deep.
Member
Sep 7, 2008
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zeon64 wrote: A 12 ft Pergola with 4x4 posts would be a death trap especially on a windy day.

Have you considered putting the posts on ground hogs? Here in Winnipeg if you buy four or more they're each $146 supplied and installed for 8ft deep.
Thank you all for the feedbacks
@zeon64 this is the 1st time I ever of this :-( you meant this one, right?Image
Can you please share pros and cons between the post buried in cement 4ft in the ground vs groudhog anchors? Many thanks
Member
Sep 7, 2008
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if we are going to bury the 6x6 posts into concrete 4ft deep underground. What is the diameter of the concrete that we should pour. As well, should we use sonotube for this?
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Nov 19, 2004
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tockty wrote: if we are going to bury the 6x6 posts into concrete 4ft deep underground. What is the diameter of the concrete that we should pour. As well, should we use sonotube for this?
I'd go with a 10" diameter hole. Don't bother with sonotubes for this. Gravel at the bottom of the hole, put in post and add concrete.
Member
Sep 7, 2008
280 posts
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don242 wrote: I'd go with a 10" diameter hole. Don't bother with sonotubes for this. Gravel at the bottom of the hole, put in post and add concrete.
Thanks so much don242! do you know any lumber yards in east end toronto other than typical big box such as HD, Rona. I am sourcing materials for the pergola as well as garden shed. We like the cedar for the pergola and pressure treated wood for shed. I had called Lumber guy and central fairbank lumber but they said they don't stock the cedar. I am not sure if we should go with PT wood for both pergola and shed?
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Feb 10, 2006
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Whitby
From your base standpoint, I would opt for just using HPB only. The cost difference shouldn't be too much per yard . Definitely source your material from a stone yard if possible. You may be even able to swing a cash no tax kind of deal, atleast that was openly available for my purchase. In terms of Geotextile fabric, I would get that from a landscaping yard (Arnt's is an example by me, but I am sure you have other options).

A 6" base is more then sufficient for a walkway/patio. I do know that the interlock manufacturer's may suggest a deeper base depending on your soil composition (sandy or clay).
Member
Sep 7, 2008
280 posts
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azn_dan wrote: From your base standpoint, I would opt for just using HPB only. The cost difference shouldn't be too much per yard . Definitely source your material from a stone yard if possible. You may be even able to swing a cash no tax kind of deal, atleast that was openly available for my purchase. In terms of Geotextile fabric, I would get that from a landscaping yard (Arnt's is an example by me, but I am sure you have other options).

A 6" base is more then sufficient for a walkway/patio. I do know that the interlock manufacturer's may suggest a deeper base depending on your soil composition (sandy or clay).
Thanks! we are looking at permacon and they recommend between 6~8 inches base if i recalled. We are planning to buy 80mm thick pavers for driveway as the style we like have biggest piece of 19 1/2 x 13 inches. Should we also use the same thickness for patio and walkway as well or we are good with 60mm for the same style.
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Feb 10, 2006
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Whitby
tockty wrote: Thanks! we are looking at permacon and they recommend between 6~8 inches base if i recalled. We are planning to buy 80mm thick pavers for driveway as the style we like have biggest piece of 19 1/2 x 13 inches. Should we also use the same thickness for patio and walkway as well or we are good with 60mm for the same style.
I would buy what you like the best and just make sure to account for the correct depth + paver thickness when digging.

I would also recommend sealing the pavers once you are all done, it brings out the colour in them and keeps them looking new for the few years that it lasts. A small investment.
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Sep 7, 2008
280 posts
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Thanks! We really like the smell of cedar; hence plan to use it for pergola but it seems not many places stock them. We plan to bury the posts this weekend and not sure if we can wait. PT woods is readily available.
Deal Addict
Dec 17, 2007
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Alliston, ON
Go to peacock lumber, they stock cedar posts. Or you can just clad the posts in 1x6 cedar trim after.

I wouldn't bury the post in ground. I'd pour a pier and mount the post to it using some like these Simpson post mounts
Deal Addict
Sep 17, 2002
1091 posts
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we installed our 12 x 12 timber frame pergola a few years ago (actual size end to tend is about 16ft) so when approached the city for permits - they suggested to pour 4ft deep with concrete and add a post mount. Cheaper than finding a 16ft beam in our case as ours is about 11ft tall.

you just have to measure twice and secure it as posts will shift.

Watch out for carpenter bees/ants - suggested getting insecticide and spray it yearly.....minimum.

Also, do your stain ahead of time and apply whatever coats plus 1 - plus 1 b/c you don't want to do it in 5 yrs.
Deal Addict
Mar 5, 2012
2045 posts
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Guelph
OP, minimum 12" diameter holes for 6x6 posts, 10" is way too tight, two inches of concrete on each side of a big tall post like that isn't enough, and that's in a perfect world where you've dug the hole exactly center. Unless of course you're going with anchors instead which will be more forgiving.

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