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Pergola - for shade and rain

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  • Aug 28th, 2018 8:36 pm
[OP]
Newbie
Sep 1, 2010
68 posts
6 upvotes
GTA

Pergola - for shade and rain

I am planning to build pergola 12 x 18 ft over raised deck.
  • Trying to avoid digging holes for pergola posts. Just wondering if attaching 6x6 posts with deck frame ok? Did anyone use this approach?
  • Should I go with 4 posts on 4 corners or two posts and attached with wall on other side?
  • Not sure if city permission required in case of attached with home wall, I am in Ajax?
12 replies
Deal Addict
Dec 14, 2011
1463 posts
517 upvotes
London
18 feet? 4 posts is not near enough unless you are going to get some heavy duty beams. You are asking for sagging and weakness. I would not skip some extra support just because you want to avoid digging or aesthetic concerns.

By "raised deck" how raised is it? Do you have a staircase? This just adds to the challenge.

How does a pergola stop rain? I've never had one (and don't care for them).

I'd probably just get a really nice retractable awning installed professionally.
Deal Guru
User avatar
Mar 23, 2008
10320 posts
6588 upvotes
Edmonton
We have a pergola over the deck at our place. The deck is 12 x 16, and the pergola "covers" about half it. The "covers" is in quotes because as far as any kind of sun/rain shelter goes, it's about as useful as a window screen.

Ours has 4 posts at the corners, with about an 8' span between. The posts are 4x4. Frankly, the whole thing is wobbly as shit (not my design, just haven't taken it down). But I think a large part of it's instability is due to the lack of braces on the top. The bottom is lag-bolted to the joists of the deck.

This would have done wonders across the top:
https://diy.stackexchange.com/questions ... m-wobbling

And you can easily find your answer about the building code by calling the building department at the city office.

C
Deal Addict
May 23, 2009
2271 posts
793 upvotes
Mississauga
Sounds like you are describing a roof rather than a pergola. A pergola wont stop rain and decent shade needs some sort of fabric over the top. In Ajax, any roof/pergola structure attached to a 2ft or higher raised deck needs a permit. A roof that will keep rain off also has to handle snow and ice load. Your existing deck might not have been built to accommodate the additional load.

For building over a 18x12 deck size you need more than 4 posts for a freestanding; more than 2 if attached to your house. If attaching it to the exising deck, you also want to examine the construction of your existing deck. What is the existing footing and framing of your current deck? Attached to house foundatation etc.
Deal Addict
Jul 29, 2006
4011 posts
818 upvotes
Are you thinking of a polycarbonate covering over your deck?
Newbie
Sep 12, 2017
63 posts
36 upvotes
Have a look at the TojaGrid product. They're modular and easy to install.

CHM.
Jr. Member
Oct 14, 2017
115 posts
22 upvotes
Bought it. Pricey, but ridiculously easy and quick to assemble.
CanadianHandyman wrote: Have a look at the TojaGrid product. They're modular and easy to install.

CHM.
[OP]
Newbie
Sep 1, 2010
68 posts
6 upvotes
GTA
Yes, agree. Probably I would need 3 +3 posts or 3 + wall attached.
Drakestar wrote: 18 feet? 4 posts is not near enough unless you are going to get some heavy duty beams. You are asking for sagging and weakness. I would not skip some extra support just because you want to avoid digging or aesthetic concerns.

By "raised deck" how raised is it? Do you have a staircase? This just adds to the challenge.

How does a pergola stop rain? I've never had one (and don't care for them).

I'd probably just get a really nice retractable awning installed professionally.
[OP]
Newbie
Sep 1, 2010
68 posts
6 upvotes
GTA
May be poly-carbonate or water proof fancy cloth. Fist challenge is pergola or some sort of structure.
nx6288 wrote: Are you thinking of a polycarbonate covering over your deck?
Deal Addict
Jul 29, 2006
4011 posts
818 upvotes
a3dview wrote: May be poly-carbonate or water proof fancy cloth. Fist challenge is pergola or some sort of structure.
not sure how the cloth would hold up over the winter. But I can tell you my poly held up just fine. It's been 2 winters now and the thing still looks brand new.
Jr. Member
Oct 23, 2010
173 posts
45 upvotes
Brampton
I built a sort of pergola outer frame (12x12) on my deck. 2 outer 4x4 (should've gone with 6x6 for asthetics) lagged into deck frame and the 4 rafters attached to 4x4s lagged into the brick. Its very sturdy. Ordered square coolaroo shade sail off amazon. It gives me lots of shade and some shelter from rain. The sail comes off before winter. Still needs some finishing work but happy with the results so far.
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[OP]
Newbie
Sep 1, 2010
68 posts
6 upvotes
GTA
Your "sort of pergola outer frame" is interesting and good idea if shade is only requirement.
Did you install DIY or hire someone? Approx cost?
Attaching to wall style is strange but interesting. Hopefully is is strong enough during high winds etc.
ablessa wrote: I built a sort of pergola outer frame (12x12) on my deck. 2 outer 4x4 (should've gone with 6x6 for asthetics) lagged into deck frame and the 4 rafters attached to 4x4s lagged into the brick. Its very sturdy. Ordered square coolaroo shade sail off amazon. It gives me lots of shade and some shelter from rain. The sail comes off before winter. Still needs some finishing work but happy with the results so far.
Jr. Member
Oct 23, 2010
173 posts
45 upvotes
Brampton
It's diy. The deck itself is freestanding (pylex screws for footings). I didn't want to install a ledger board over my sliding door for just 2 "beams". I did the 4x4 against the brick to match the outer posts instead (still have to trim them down abit) It's not a load bearing structure except the weight of the 2x6s. Have had some high gusts here and there since putting it up and it hasn't budged. Even had a pelting of hail 2 weeks ago. The railing gives it a solid feel so no need for upper bracing. I'll take the shade sail and PVC lattices off before winter though.

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