# setting deck posts (4x4) in concrete anchors/piers



## kenmac (Feb 26, 2009)

I set mine on top of the concrete & installed the anchors.. I don't like & didn't use 4x4 . Being that tall . I would use 6x6


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## amakarevic (Apr 12, 2007)

thanks. 6x6 makes sense. also, for a deck that size, do you think 4 posts will be enough (also on one 10 ft side of the rectangle, the deck anchors to the house) or should i go with more, e.g. 6 or even 7 (one in the center) ?


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## kenmac (Feb 26, 2009)

Mine bolts to the house on the back side. my deck is 24' x 12 ' . I used 4 6x6 post


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## Gary in WA (Mar 11, 2009)

Here is the new minimum deck code, anything more will be better: http://www.lancova.com/deckinfo.pdf

Gary


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## bigmark77 (Sep 7, 2011)

I see most posts on the internet say not to encase 4x4's in concrete. I need to build a 6' x 6' x 10' tall free standing structure. I need it to be stable and not fall over for risk of injury. How can I secure these posts to footings and have sheer resistance?


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## oh'mike (Sep 18, 2009)

Posts need to set on piers and not contact the earth at all---use Simpsom post attachments---

Codes vary a lot---so check ----no buried posts in this area.----Mike---


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## Millertyme (Apr 20, 2010)

I agree. There really is no debate here. You just don't put wood into concrete. Especially support members. Its that simple. People who are doing it are doing it wrong. Use the anchors. They work great and are real easy to use. They also give you a little bit of wiggle room in case your centers are off a little (within reason). If you ledger it to the house on one side, 4 4x4s holding a support beam will be sufficient.


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## Knucklez (Oct 21, 2007)

my deck is fully floating, 36" high. i used 4x4 post on simpson strong tie ancor into concrete pier. i was also worried about lateral movement due to no ledger.. but when i installed hurricane ties between all beams & joists it made a HUGE difference. deck is absolutely solid with no movement whatsoever.

for 10' long span, .. in MY AREA .. you can use a post on each end as long as a) beams are double 2x10 and b) we are talking about outside beams only (inside beams would need 3 posts).

Knucklez


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## dpach (May 12, 2009)

I used 6x6 posts with the adjustable Simpson Strong Tie anchors. They are attached to the piles with J-shaped stainless steel threaded rod. Building inspector was very happy with the system.

I would never put wood in concrete (concrete holds moisture, which wood likes to soak up).

Keep up posted with what you do.


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## Knucklez (Oct 21, 2007)

dpach, what is the diameter of the concrete with respect to the 6x6 post? in my area, the diameter would have to be 12" (double width of post) which is a lot of concrete for a large deck! 

.. but concrete is cheap :thumbup:


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## amakarevic (Apr 12, 2007)

dpach, this is one bada$$ looking deck. i love the trailer space underneath. congratulations!!


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## dpach (May 12, 2009)

Knucklez said:


> dpach, what is the diameter of the concrete with respect to the 6x6 post? in my area, the diameter would have to be 12" (double width of post) which is a lot of concrete for a large deck!
> 
> .. but concrete is cheap :thumbup:


The piles are 12" wide, and 12 feet deep. Yeah, it was about $1100 to have guys come in and drill, form and pour them (including concrete) but worth every dollar to make sure this deck never moves.


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## dpach (May 12, 2009)

amakarevic said:


> dpach, this is one bada$$ looking deck. i love the trailer space underneath. congratulations!!


Thanks. Took over a year to finish (had 5 mths of snow and rain where I couldn't do a darn thing). Worked out great for the snowmobile trailer.


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## amakarevic (Apr 12, 2007)

dpach said:


> The piles are 12" wide, and 12 feet deep. Yeah, it was about $1100 to have guys come in and drill, form and pour them (including concrete) but worth every dollar to make sure this deck never moves.


12' deep ???!!! why so deep, for god's sake ?? i mean, they only need to reach the frost line. i don't imaging the frost line goes deeper than 6' in the north of Alaska, much less anywhere else.


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## Clutchcargo (Mar 31, 2007)

I like the look of the beam. 
That doesn't look like PT... is it?
Is that beam configuration (2-6x6's stacked?) as strong as a triple 2x12?
And is there any reason to not build a beam like that?


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## dpach (May 12, 2009)

amakarevic said:


> 12' deep ???!!! why so deep, for god's sake ?? i mean, they only need to reach the frost line. i don't imaging the frost line goes deeper than 6' in the north of Alaska, much less anywhere else.


Actually, our frost line only gets about 6 feet, but we have really heavy gumbo/clay soil that when wet (like this year), it swells and puts a lot of sideways pressure on piles. This can often cause the piles to get "sucked" up as the soil heaves even though they are below the frost line, and end up with voids under them. By going 12 feet (only cost $400 more for the entire job), it gets down passed the gumbo to better hardpan soil. This thing will never move.


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## dpach (May 12, 2009)

Clutchcargo said:


> I like the look of the beam.
> That doesn't look like PT... is it?
> Is that beam configuration (2-6x6's stacked?) as strong as a triple 2x12?
> And is there any reason to not build a beam like that?


If you're talking about my beam (didn't really say), what you see is a little deceiving. It is actually triple 2x12 pressure treated, wrapped with cedar with 1/2 inch spacing between the cedar and beam for drainage. I wanted to hide the ugly green pressure treated lumber so it would match the rest of the deck. Might be a little overkill, but I think the finished product looks much better than the ugly green.

Here's a pic of it before the rim joists and beam were wrapped in cedar.

I've had people also ask about the stair being code with no support half way up on an 10 tread step, but they too are also deceiving as they are not just 3 cedar stringers. They are actually 3 2x12's pressure treated with 2x12 cedar on the outside for cosmetics/added strength. Another pic of them is below. There's actually 5 stringers in a 38" span, and the building inspector was more than pleased.


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## amakarevic (Apr 12, 2007)

BTW, how wide is the deck? i really wanna know how long the girders are and if they are 2x10.


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## dpach (May 12, 2009)

amakarevic said:


> BTW, how wide is the deck? i really wanna know how long the girders are and if they are 2x10.


The deck is 14.5 ft from ledger to rim joist, with a 2.5 ft cantilever, so ledger to beam is 12 feet. And they are 2x10 pressure treated. All joists/rimjoists are blueskinned also to prevent rot under the deck boards.

Code for 2x10's is 14 feet, so inspector was happy with 12 foot span.

2x10 pressure treated joists are hurricane tied to beam and in joist hangers on the ledger.

The inspector said he wished all decks were overbuilt like this (just seems to be the right way to build it to me).


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## amakarevic (Apr 12, 2007)

ledger to rim joist is actually the depth (length of joists shown with blue stuff on top of them), i was asking about the width (how long are the girders?)


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## dpach (May 12, 2009)

amakarevic said:


> ledger to rim joist is actually the depth (length of joists shown with blue stuff on top of them), i was asking about the width (how long are the girders?)


The deck is 19 ft wide. The girder (we just refer to them a beam) is triple 2x12 pressure treated screwed and glued, and blueskinned. There's approx. 6.33 ft between the 6x6 beam posts.


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## amakarevic (Apr 12, 2007)

what is "blueskinned" ?


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## dpach (May 12, 2009)

amakarevic said:


> what is "blueskinned" ?


 
Blueskinned is the blue covering that is over all my joists/beam. It is a rubberized material with a tar-backing that sticks to your joists. It protects the tops of the joists from rotting. The most common rot problems on decks is the tops of the joists under the floor boards around the screw holes that go into the joists.

When screws go through this material, the tar backing seals the screw holes so moisture doesn't rot the wood. Plus, the blue rubber "skin" sheds water that would normally sit under the floor boards on top of the joists.

It cost me about $250 to do the entire deck (including the additional adheasive that was recommended to me). It has its own sticky side (tar side), but the adhesive really helps keep it on.


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## Knucklez (Oct 21, 2007)

> It has its own sticky side (tar side), but the adhesive really helps keep it on.


 dang... wish someone had recommended extra adhesive to me cause my first strip didn't stick. ended up not even using the blueskin because i was annoyed (i'm talking about a shed project, not a deck).

what type of adhesive did you use?

Knucklez


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## Clutchcargo (Mar 31, 2007)

Why did you go with Blueskin instead of something like Grace IWS?


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## dpach (May 12, 2009)

Knucklez said:


> dang... wish someone had recommended extra adhesive to me cause my first strip didn't stick. ended up not even using the blueskin because i was annoyed (i'm talking about a shed project, not a deck).
> 
> what type of adhesive did you use?
> 
> Knucklez


 
Actually, Bakor (the company that makes blueskin) has an adhesive just for Blueskin. It was on the shelf at HD right beside the blueskin.


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## dpach (May 12, 2009)

Clutchcargo said:


> Why did you go with Blueskin instead of something like Grace IWS?


The Blueskin actually has a little thicker "tar" on the underside which a contractor told me seals better around screws. Grace IWS does fine around roofing nails which go straight in, but he suggested using Blueskin, and it was the same price. So I went with the one that someone had first hand experience with.

I'm sure IWS would also work fine, but I just preferred a little more tar for around the screws.


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## woodworkbykirk (Sep 25, 2011)

6x6 posts are code in most areas now in my region the only thing 4x4's are allowed for are hand rail posts, not for structural posts. based on the dimension of your deck 3 posts wills suffice

the best method is to set your concrete and let it cure. from there use the post brackets that dpoche showed earlier. you simply set them in a straight line and anchor the bracket tothe concrete with tapcons or concrete wedge achors. that bracket will support the load but will also allow air flow up under the post so it wont rot like setting the post directly into the concrete will


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## Msradell (Sep 1, 2011)

Is that a garage door on the end of the building behind the deck? If so what do you use that building for that you no longer needed that door to be usable?


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## dpach (May 12, 2009)

Msradell said:


> Is that a garage door on the end of the building behind the deck? If so what do you use that building for that you no longer needed that door to be usable?



Not sure what you're seeing....the brown building on the far side of the deck is an 8x12 shed with twin swing-out doors on the end. That's where I keep 2 snowmobiles for the summer, and garden furniture, hoses, etc for the winter.

It will be torn down next summer and rebuilt with a normal peak roof, 9 foot walls, and then sided to match the house.

Hope that was what you were referring to.

I also have a 24 x 28 garage with 10 foot walls and twin 8x9 insulated doors that sits just behind where I stood to take the pics.


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