AZEK Deck Questions - Spacing and Layout


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Old 05-02-12, 01:25 PM
J
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AZEK Deck Questions - Spacing and Layout

Hello, this is my first post and I am exciting to ask couples of questions for my deck project this year.

When I bought my new house, I installed hardwood on all floors (~1900sq) by myself. It was painful but, also was fun and saved a lots of money.

Here is my background...

Last year, I bought a AZEK boards from Craigslist with railings. They were brand new 60 x 12' boards and 25 x 16' boards and paid about $1750 + extra $900 for 10 x AZEK 5x5 post sleeves and 6 x AZEK 6' railings and some other accessories. I also purchased four more 8' railings for my deck project and Cortex hidden screws (2 x 300sq) this year. So I think that just need lumbers, hangers, and nails.

I am living in Maryland and I already got county building permit and am waiting for HOA approval. While I am waiting, I am studying myself on the Internet to avoid mistakes that I can make.


Please see my plan.

http://s6.postimage.org/7ebqxgfrl/2012_05_02_150239.jpg

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The deck is 9' high from the ground.
The post is 6x6.
The footing is 30" deep and 16" diameter (my county building code)
All lumbers (ledgers, joists, beams) will be 2x10 size with various lengths (12' 16' 20')
The deck will be installed on 12" OC.
The ledger board will be attached to house using 1/2" carriage bolts with 21" OC.
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I think that these should be fine to make a safe deck. Please let me know anything that I need to care.


My first and today's question is about AZEK board.

I know that AZEK recommends to have 1/8" spacing between boards. And, put tight at splices when it is installed above 32F. They said that contraction and expansion is minimum, but I want to know if it (no gaps) is safe at 100F in summer time. Otherwise, I will put 1/16" gap to avoid the problem. But, no gaps between boards will look better than having a gaps because I have cut boards into different lengths.

Please review my plan for deck boards layout. I was trying to minimize the wastes but if you have better idea, I will appreciate the input.

http://s6.postimage.org/72uakozbl/2012_05_02_154100.jpg

Thank you,
 
  #2  
Old 05-03-12, 09:49 AM
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I'm not familiar with Azek, so can't offer any suggestions. I do think you should initially leave a slight gap between planks, to promote drainage (and drying between planks, to minimize mold and moss growing in what will otherwise be a continuously wet environment). Also, your railing post spacing does not meet current IRC deck guidelines--the code recommends 6' maximum spacing between posts, and some of yours are considerably greater than that. If it were mine, it would be built free-standing and not attached to the house, with a 1/2" air gap--no chance of rot and/or moisture penetration into the house envelope that way. The vast majority of problems I've seen in decks over the years are related to ledger boards rotting, their attachment or improper anchorage.
 
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Old 05-03-12, 10:14 AM
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Thank you the reply,

I am sorry that it didn't finish the rail drawings so the uploaded images may not reflect my railing plan. I have 6' and 8' AZEK railing system that I will use them for my deck. My question is if IRC deck guideline recommend up to 6' post spacing, I don't know the purpose of AZEK 8' railing system.

I will put 1/8" gap between pranks. My question is about when you connect one piece to another like 12' board + 8' board. Should I give 1/16" space or just put them together tight. Even AZEK install guide say that it's okay without gap if it is installed above 32F, I would like to hear from Pros here.

Thank you again,

P.S. Here is my railing plan again.

http://s6.postimage.org/9mz46a1n5/2012_05_03_134055.jpg
 

Last edited by jay2012; 05-03-12 at 10:42 AM.
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Old 05-03-12, 11:01 AM
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I've only ever seen the butt joints on composite decks installed without a gap.
 
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Old 05-03-12, 05:03 PM
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Here's another thought (regarding your deck "footprint")--you could easily eliminate the somewhat restricting "jog" where the 2 rectangles join, by extending some of the main portion joists to cantilever all the way out to the outer edge of the smaller rectangle. Could either use a slight reverse curve, or just a simple triangle. Doing so will make the deck much more practical, giving it a far better flow. Especially if a significant number of guests with chairs, tables, grill, etc. are using it at any one time. Your present plan has a somewhat impractical "bottleneck" between the 2 rectangles, almost separating the total deck area into 2 individual spaces.
 
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Old 05-03-12, 08:35 PM
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Use a 1/8" spacing between the boards, and make the butt joints with less than 1/16" space.

The 6' railing sections can be installed full length. You'll have to cut the 8' sections in 1/2 so you can install a mid-span post, or shorten an 8' section to 6' which leaves you a 2' section that can be used elsewhere on the deck. The reason for the 2 different lengths is so that the installer has some leeway when purchasing rail kits, so he or she can minimize waste.
 
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Old 05-04-12, 05:30 AM
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Thank you mitch17, BridgeMan45, and lefty

For the design, I know that it's not the good design. The original plan was to put the stair at the corner where small and large box meet. But, due to budget and security reason, I removed the stair from the plan. But, I left the area for future stair project if I change my mind.

For the railing, I didn't know that the 6' max span rule. I thought that I could use 8' railing kit because they sell and I wanted to save some money by using long railings. Thank you lefty for the pointing out the issue. It seems that I made mistake there. Well, I need more railing then.

I currently have

12 - 5x5 - AZEK Post Sleeves
6 - 6' AZEK Primerer Railing Kits
4 - 8' AZEK Primerer Railing Kits

With my new railing plan, I think that that I need to purchase one post sleeve and one 6' rail. I will cut in half 8' rail for two ~ 4' areas.

Here is my new railing plan...
http://s14.postimage.org/5hqkwjbf5/2..._04_082533.jpg

Do you think that it should be okay with this?

Thank you,
 

Last edited by jay2012; 05-04-12 at 07:43 AM.
 

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