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New composite deck: Framing and Pillar options

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[OP]
Newbie
Nov 6, 2011
37 posts
4 upvotes
Toronto

New composite deck: Framing and Pillar options

Hi,
I am planning for a small suspended deck that's attached to the house. Deck size: 12ft x 5.5 ft. Suspended height: 9-10 ft. Location: GTA.

I want to do composite for lower maintenance. So far, I am leaning towards getting Trex Transcend or Select, but I have some concerns about the framing options. It looks like most composite decks use PT wood for the frame. While I am ok with the frame and joists being in PT as they will be covered, I am wondering what are the options for the pillars. The pillars will be 9-10 ft and the deck is facing west, so they will get a lot of sun. I would like the pillars to last as long as the floors/railings, and I do not want to get to a situation where 15-20 years from now, the pillars need to be replaced while everything else still looks good.

I am planning to go to deck masters in the next couple weeks to ask for their advice, but I would also like to get opinions from someone who is not trying to sell me something :)

I noticed that Trex makes steel framing (Trex Elevations), anyone has experience with these?
33 replies
Deal Guru
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Sep 1, 2005
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Markham
dyatsin wrote: Hi,
I am planning for a small suspended deck that's attached to the house. Deck size: 12ft x 5.5 ft. Suspended height: 9-10 ft. Location: GTA.

I want to do composite for lower maintenance. So far, I am leaning towards getting Trex Transcend or Select, but I have some concerns about the framing options. It looks like most composite decks use PT wood for the frame. While I am ok with the frame and joists being in PT as they will be covered, I am wondering what are the options for the pillars. The pillars will be 9-10 ft and the deck is facing west, so they will get a lot of sun. I would like the pillars to last as long as the floors/railings, and I do not want to get to a situation where 15-20 years from now, the pillars need to be replaced while everything else still looks good.

I am planning to go to deck masters in the next couple weeks to ask for their advice, but I would also like to get opinions from someone who is not trying to sell me something :)

I noticed that Trex makes steel framing (Trex Elevations), anyone has experience with these?
Wood is much more rigid than composite and being vertical, it should last a lot longer than 9-10 yrs. Alternatively you can make concrete pillars but it's more expensive.
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Mar 31, 2013
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Courtenay, BC
you could use wood for the actual load bearing strength, then "wrap" the post with trex that matches your decking............
Deal Fanatic
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Oct 19, 2008
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GTA
phantomfj wrote: you could use wood for the actual load bearing strength, then "wrap" the post with trex that matches your decking............
Yep, the big brands have matching fascia that's often used to wrap the outer rim joists. You could us the fascia to wrap posts but should take care to design to not trap water.

One thing about the composite fascia, it moves a lot with temp differences so can't be nicely mitered at corners....needs an overhanging butt joint.
[OP]
Newbie
Nov 6, 2011
37 posts
4 upvotes
Toronto
gr8dlr wrote: Wood is much more rigid than composite and being vertical, it should last a lot longer than 9-10 yrs. Alternatively you can make concrete pillars but it's more expensive.
Thank you. I was trying to avoid going concrete as I do not like the look. But you have a very good point with the pillar being vertical, so it would not retain water and last longer.
phantomfj wrote: you could use wood for the actual load bearing strength, then "wrap" the post with trex that matches your decking............
Zamboni wrote: Yep, the big brands have matching fascia that's often used to wrap the outer rim joists. You could us the fascia to wrap posts but should take care to design to not trap water.

One thing about the composite fascia, it moves a lot with temp differences so can't be nicely mitered at corners....needs an overhanging butt joint.
Good idea! Yes, I am now leaning towards going PT + composite fascia's. I expect it would cost a lot less than Trex Elevations.
Do you know whether I should wait for the wood to "dry" for a few weeks before putting the fascia's?
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Oct 19, 2008
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dyatsin wrote: Good idea! Yes, I am now leaning towards going PT + composite fascia's. I expect it would cost a lot less than Trex Elevations.
Do you know whether I should wait for the wood to "dry" for a few weeks before putting the fascia's?
Definetly should allow the posts to dry, split etc. Hate to throw a wrinkle in your plans but a deck 9-10' high is going to require diagonal bracing btw the posts and rim joists.
[OP]
Newbie
Nov 6, 2011
37 posts
4 upvotes
Toronto
Zamboni wrote: Definetly should allow the posts to dry, split etc. Hate to throw a wrinkle in your plans but a deck 9-10' high is going to require diagonal bracing btw the posts and rim joists.
Thanks for the heads up! The deck at my previous house had these, and I was hoping to avoid these.

Would the composite fascia boards be strong enough to be used for the braces?
[OP]
Newbie
Nov 6, 2011
37 posts
4 upvotes
Toronto
dyatsin wrote: Would the composite fascia boards be strong enough to be used for the braces?
Nevermind, I just looked them up, and they are only 1/2-5/8 thick!
Would be floor boards be strong enough to be used for braces?
Deal Addict
Aug 18, 2009
1577 posts
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Toronto
dyatsin wrote: Hi,
I am planning for a small suspended deck that's attached to the house. Deck size: 12ft x 5.5 ft. Suspended height: 9-10 ft. Location: GTA.

I want to do composite for lower maintenance. So far, I am leaning towards getting Trex Transcend or Select, but I have some concerns about the framing options. It looks like most composite decks use PT wood for the frame. While I am ok with the frame and joists being in PT as they will be covered, I am wondering what are the options for the pillars. The pillars will be 9-10 ft and the deck is facing west, so they will get a lot of sun. I would like the pillars to last as long as the floors/railings, and I do not want to get to a situation where 15-20 years from now, the pillars need to be replaced while everything else still looks good.

I am planning to go to deck masters in the next couple weeks to ask for their advice, but I would also like to get opinions from someone who is not trying to sell me something :)

I noticed that Trex makes steel framing (Trex Elevations), anyone has experience with these?
I'm in a similar situation and looking to do a raised deck as well. Have you gotten any quotes or are you planning on doing it yourself?
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Oct 19, 2008
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dyatsin wrote: Nevermind, I just looked them up, and they are only 1/2-5/8 thick!
Would be floor boards be strong enough to be used for braces?
No, composite deck boards can't be used as framing member. When I build a deck I use 6x6 posts and 4x4's for diagonal bracing. You could cover 4x4's in fascia after framing inspection.

Fascia I've used to 'skin' rim joists wasn't even 1/2" thick, it was 1/4 or 3/8....can't recall.
[OP]
Newbie
Nov 6, 2011
37 posts
4 upvotes
Toronto
VertigoM wrote: I'm in a similar situation and looking to do a raised deck as well. Have you gotten any quotes or are you planning on doing it yourself?
I am planning to get a contractor to do it. No, I have not gotten any quotes yet, I am planning to ask for quotes in the next couple weeks.
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dyatsin wrote: So far, I am leaning towards getting Trex Transcend or Select....... the deck is facing west, so they will get a lot of sun.
This is a good read, I always tell clients to research carefully to make their own decision on deck boards with careful consideration to how hot some brands of composite get. I installed Azec on a deck one summer and the boards became too hot to handle without gloves.....I was sweating like a w#ore in Church while screwing decking down.

https://boston-decks-and-porches.com/20 ... -deck-get/
[OP]
Newbie
Nov 6, 2011
37 posts
4 upvotes
Toronto
Zamboni wrote: This is a good read, I always tell clients to research carefully to make their own decision on deck boards with careful consideration to how hot some brands of composite get. I installed Azec on a deck one summer and the boards became too hot to handle without gloves.....I was sweating like a w#ore in Church while screwing decking down.

https://boston-decks-and-porches.com/20 ... -deck-get/
Thanks! I decided not to go with Azec for that same reason, from what had read, they are hotter. but this site actually shows the numbers. Very useful!
I guess I will go look at Timbertech (Legacy) and Trex in the store to see which one I like better. Looks like they have comparable temperatures for the lighter colors and I think both of them would have enough scratch resistance for my needs.
Deal Addict
Nov 17, 2012
2803 posts
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Toronto
I'd just stick with wood. If you want, use cedar and make it all nice and pretty and smell good to boot. Clear protectant on it once every few years and that's it.

Not a fan of composite decking boards. Too hot and they degrade over time.

As others have said - they're NOT for structural work. Just flat decking.

If you're going to use them I'd reduce the joist spacing to make sure they're well supported. Adding a couple extra joists to the deck will cost a few bucks and avoid any sagging of the composite deck boards between the joists.
Deal Addict
Mar 22, 2017
1079 posts
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West GTA
Be wary when using composite about how hot it gets - it can be EXTREMELY hot, much hotter than wood, and can make your deck unusable/dangerous in direct sun on warm days. Not all composite is equal in this so it's worth looking into it.

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