[35015]

Post in Concrete...IS BAD PRACTICE!!!!

...My go-to for post setting is 1/4 minus,...

:grin:...Well...You can not really get..."more perfect"...than 1/4 minus gravel for a "go to" generic...never fail method...(in virtually all applications) for not only installing posts in general, but this is the "finish off" material for many current post related domestic architecture as well. I have seen it spec'd so many times on blue prints that its become common knowledge among...good builders...when facilitating any type of post work in general. There other systems that work too, and do drain better, however for most "landscape post" applications, its hard to go wrong with 1/4 minus gravel...

Excellent!!!

...I think if the wood is properly treated in a pressure tank there isn't anything you can do to it in normal construction to make it rot...

:|...Well, it's impossible to really effectively discuss someone's "I think" comments.

What I can state again (and document further) is this is...bad practice...and not something a good builder today would ever recommend to a client or student trying to mount posts. Does such practices still go on...???...of course!!! There are countless "bad practices" that plague the building arts...

Before the "1990's" the toxicity level in wood was also much higher, to the point of actually causing death and illness in children and workers that used or played on such materials. The number of winning class action lawsuits around the...very real...issue are many.

...The base of the posts are submerged in water for most of the year every year and the wall is still in great shape....

Well then...those post could be any species of wood for the most part...

The "decay line" would be very specific as wood...under water...does not rot ever. That's why we find logs from a few hundred years all the way to over 15,000 years old buried in wet mineral soils and/or under water that are actually in better condition than if just harvested and air dried...

>>>

To validate further, primary for those readers trying to figure this all out and make informed decisions, I share the following:

Will wooden posts rot in concrete?

...Simply setting the posts in concrete does create a condition that will accelerate rot in the bottom of the posts...

How do you keep posts from rotting?

...The cement does not rot your posts, the moisture does. Concrete holds moisture. If you don't allow the concrete to wick moisture out to its surrounding dirt, it will rot your posts quick. I think the best way to do posts is to use just gravel, no concrete....

Why deck posts should not be set in concrete?

...Why Deck Posts Should Not Be Set in Concrete. A deck post should always be placed on top of footing, not inside concrete because it can break. ... When concrete is poured around a deck post in this way, the post will rot due to moisture buildup by the soil. ...

The comment above by John about..."posts breaking off"...I haven't even begun to address yet in this conversation. I felt it was out of context...However, "moment shear" is a serious issue for wood post when encapsulated in concrete and subjected to either tectonic and/or wind event shear events...

Can you put deck posts in concrete?

...There are several methods for setting posts. One way is to pour concrete in the post hole, set the post on the concrete and back-fill with gravel. To help prevent rotting, this deck will have wooden posts attached to concrete footers above ground.

Note: Even the Building departments in most "Big Box Stores" officially never recommend embedment in concrete!!! Using it as a "footer" is a lesser form of placing a stone at the bottom which has been common practice for thousands of years and still is in many cultures.

We do not use OPC (ordinary portland cements) of any kind in our architectural designs for any project unless there is mitigating conditions like failure in soils load capcity...but rather the tradtional stone systems for mounting house, deck and related foundation systems...Why?...Well, for one the oldest wooden buildings in the world are built this way (7000 years undocumented and 2000 years documented) because concrete (especially modern concretes) are plagued with all types of issues, are not environmentally sustainable, are costly, and act like sponges capturing and holding moisture there by ROTTING!!! the wood the come in contact with...

 

[unburled]

There other systems that work too, and do drain better

The better the drainage, the deeper the aeration, which fuels 1/2 the microbes and it'll be damp.

Excluding eventual disposal, what's the carbon cost of concrete versus 1/4-minus?

https://www.theguardian.com/cities/2019/feb/25/concrete-the-most-destructive-material-on-earth

 

[35015]

Wow...!!!!

The better the drainage, the deeper the aeration, which fuels 1/2 the microbes and it'll be damp...Excluding eventual disposal, what's the carbon cost of concrete versus 1/4-minus?

https://www.theguardian.com/cities/2019/feb/25/concrete-the-most-destructive-material-on-earth

That is an excellent short and to the point perspective on wooden post footing method!!!

and...

WOW...!!!...What a fantastic article you shared...!!!

That covers stuff I have been trying to explain to clients and colleagues for decades. It will take me some time to get to read all the linked information, but what I can say is that the OPC industry has had a "strangle hold" on the building industry globally for decades (primarily since post WWII.) If it's "governmental support"...lobbyist and subsidies got stripped from it...OPC would...die out...as an industry, and make mineral based construction materials like actual stone...natural cements...geopolymers and related tradtional system viable again and competitive on the open market...

Thanks again for a great link!!!...and great advise on proper practice for placing posts!!!

 

[Steve Neul]

:grin:...Well...You can not really get..."more perfect"...than 1/4 minus gravel for a "go to" generic...never fail method...(in virtually all applications) for not only installing posts in general, but this is the "finish off" material for many current post related domestic architecture as well. I have seen it spec'd so many times on blue prints that its become common knowledge among...good builders...when facilitating any type of post work in general. There other systems that work too, and do drain better, however for most "landscape post" applications, its hard to go wrong with 1/4 minus gravel...

Excellent!!!



:|...Well, it's impossible to really effectively discuss someone's "I think" comments.

What I can state again (and document further) is this is...bad practice...and not something a good builder today would ever recommend to a client or student trying to mount posts. Does such practices still go on...???...of course!!! There are countless "bad practices" that plague the building arts...

Before the "1990's" the toxicity level in wood was also much higher, to the point of actually causing death and illness in children and workers that used or played on such materials. The number of winning class action lawsuits around the...very real...issue are many.



Well then...those post could be any species of wood for the most part...

The "decay line" would be very specific as wood...under water...does not rot ever. That's why we find logs from a few hundred years all the way to over 15,000 years old buried in wet mineral soils and/or under water that are actually in better condition than if just harvested and air dried...

>>>

To validate further, primary for those readers trying to figure this all out and make informed decisions, I share the following:

Will wooden posts rot in concrete?



How do you keep posts from rotting?




Why deck posts should not be set in concrete?



The comment above by John about..."posts breaking off"...I haven't even begun to address yet in this conversation. I felt it was out of context...However, "moment shear" is a serious issue for wood post when encapsulated in concrete and subjected to either tectonic and/or wind event shear events...

Can you put deck posts in concrete?



Note: Even the Building departments in most "Big Box Stores" officially never recommend embedment in concrete!!! Using it as a "footer" is a lesser form of placing a stone at the bottom which has been common practice for thousands of years and still is in many cultures.

We do not use OPC (ordinary portland cements) of any kind in our architectural designs for any project unless there is mitigating conditions like failure in soils load capcity...but rather the tradtional stone systems for mounting house, deck and related foundation systems...Why?...Well, for one the oldest wooden buildings in the world are built this way (7000 years undocumented and 2000 years documented) because concrete (especially modern concretes) are plagued with all types of issues, are not environmentally sustainable, are costly, and act like sponges capturing and holding moisture there by ROTTING!!! the wood the come in contact with...

Any comment anyone makes would be a "I Think" statement. What I am reporting is a lifetime of experience with working with pressure treated wood. The bottom line is I've been putting treated posts in concrete and it works. It's only the wood that isn't properly treated which won't work regardless of how it is installed.

 

[Steve Neul]

I'll blabber a bit here. Those pre 1990 chemicals were probably different than today's, and there may not have been wetland/environmental based limits on your particular application. Generally speaking currently I see two types of PT in the stores. One is labeled ground-contact. The other non-ground-contact. But I use so much reclaimed wood that the question is whether it's been treated at all (has slits all over), then I get on with the project. Post longevity also depends on whether a cut end or factory end is put in the ground, and the actual chemicals used, which have changed over the years. Like I say, just blabbering on a bit. At times I've slathered on a 1/4" layer of roofing asphalt below grade.

You are right, the older treated wood was also treated with arsenic. At the time it was the best way to make treated wood that was also resistant to insects. The only problem with it is the general public was using treated wood for raised beds for their vegetable gardens and were getting a certain amount of arsenic in their food so they had to quit using the arsenic.

I don't know if I've ever seen posts that were made for above ground. I know for a while after they quit using arsenic in the wood all of the 2x4's and 2x6's I've seen were only for above ground. Still the product may vary from place to place and someone putting posts in the ground should check to see if they are for ground contact.

 

[35015]

...Any comment anyone makes would be a "I Think" statement. ...

Steve, respectfully...I'm not going to debate (and detract from the OP query) your obtuse existential concepts of "I think" statements...:|

"Opinions"...do not have equal merit to shared..."facts"...

...What I am reporting is a lifetime of experience with working with pressure treated wood....

To what gain...???

Your "lifetime of experiences" are out of context on not only my 40 years of experience, but examples of which I back up my statements. Your "lifetime of experiences" are simply not supported by either observed imperial facts or the realities reflected within the industry or by research...or current architectural understanding and observation regarding the topic of posts in concrete below grade...

...The bottom line is I've been putting treated posts in concrete and it works. It's only the wood that isn't properly treated which won't work regardless of how it is installed. ...

Claiming something works Steve does not make it a fact. At best it becomes an atypical event without validation of detail or other unknown mitigating conditions that can not be confirmed or examined?

Further, the actual bottom line is...it does not work...:|

Wood in OPC with a modern PR treated, rot resistant or other species are compromised by the practice of embedment within concrete below or at grade. The...proper...modalities accepted (and reflected by research and empirical observation) as it is now within the building industry is to never embed wood inside concrete...If you chose not to accept that practice, that is your prerogative...

You are once again sharing information that is misleading and/or confusing to those that have limited experience and are trying to learn..."good practice,"...understanding and principles of placing a wooden post in the ground.

You "opinions" do not equate to "good practice" and your "experiences" (atypical at best) are moot when they are offered as a counter to the factual realities of what happens to wood (typically) in contact with the ground and concrete at the same time.

...At the time it was the best way to make treated wood that was also resistant to insects...

Actually that is not true at all...!!!

The acetylation processing of wood (as just one example) has been known since turn of the century and acetylated wood was within the building industry not that long after. The use of arsenic in wood was a choice...NOT!!!...a "best way," by any stretch of the imagination. Both industrial and economic (aka profit) choices where made by an industry that manufactured and marked such toxic products...

...The only problem with it is the general public was using treated wood for raised beds for their vegetable gardens and were getting a certain amount of arsenic in their food so they had to quit using the arsenic. ...

???...Really, the only problem was "raised beds" for gardens...!!??

There was not class action lawsuits about sick workers, children that became ill (some terminally) from this practice and use of a toxic material that did not need to exist for any other purpose than an industries "bottom line?"

Its really important Steve, that facts like this get shared on public forms where less experienced are trying to learn...as assumption of "knowing" is not the same as actually...knowing a topic well enough to offer germane advise that is both informative and safe...

 

[woodnthings]

After doing some research .....

I found several articles on why NOT to fill the post hole with concrete:

This title is misleading, it should have a ? at the end!
https://www.portersbuildingcenters.com/fill-that-post-hole-with-concrete/

I personally do not fill the holes with concrete. I put gravel in the bottom, tar or coat the part that goes into the ground then pack the soil and tamp it all around the post. :vs_cool:

 

[Steve Neul]

Steve, respectfully...I'm not going to debate (and detract from the OP query) your obtuse existential concepts of "I think" statements...:|

"Opinions"...do not have equal merit to shared..."facts"...



To what gain...???

Your "lifetime of experiences" are out of context on not only my 40 years of experience, but examples of which I back up my statements. Your "lifetime of experiences" are simply not supported by either observed imperial facts or the realities reflected within the industry or by research...or current architectural understanding and observation regarding the topic of posts in concrete below grade...



Claiming something works Steve does not make it a fact. At best it becomes an atypical event without validation of detail or other unknown mitigating conditions that can not be confirmed or examined?

Further, the actual bottom line is...it does not work...:|

Wood in OPC with a modern PR treated, rot resistant or other species are compromised by the practice of embedment within concrete below or at grade. The...proper...modalities accepted (and reflected by research and empirical observation) as it is now within the building industry is to never embed wood inside concrete...If you chose not to accept that practice, that is your prerogative...

You are once again sharing information that is misleading and/or confusing to those that have limited experience and are trying to learn..."good practice,"...understanding and principles of placing a wooden post in the ground.

You "opinions" do not equate to "good practice" and your "experiences" (atypical at best) are moot when they are offered as a counter to the factual realities of what happens to wood (typically) in contact with the ground and concrete at the same time.



Actually that is not true at all...!!!

The acetylation processing of wood (as just one example) has been known since turn of the century and acetylated wood was within the building industry not that long after. The use of arsenic in wood was a choice...NOT!!!...a "best way," by any stretch of the imagination. Both industrial and economic (aka profit) choices where made by an industry that manufactured and marked such toxic products...



???...Really, the only problem was "raised beds" for gardens...!!??

There was not class action lawsuits about sick workers, children that became ill (some terminally) from this practice and use of a toxic material that did not need to exist for any other purpose than an industries "bottom line?"

Its really important Steve, that facts like this get shared on public forms where less experienced are trying to learn...as assumption of "knowing" is not the same as actually...knowing a topic well enough to offer germane advise that is both informative and safe...

You just can't believe everything you read, even from a manufacturer. Here is 10 4x6 posts set in concrete which have been there for 30 years which are currently 18" under water. Neither the posts nor the 2x6's have been treated with any other preservative. It's not just this retaining wall, every post on my place is set in concrete including the posts to my shop. It works. If a post set in concrete fails it's because it wasn't properly treated which would fail anyway.

 

[Pineknot_86]

Didn't see this but you can insert either end into the hole.:wink: OK, good advice here.

 

[Gus64]

I found several articles on why NOT to fill the post hole with concrete:

This title is misleading, it should have a ? at the end!
https://www.portersbuildingcenters.com/fill-that-post-hole-with-concrete/

I personally do not fill the holes with concrete. I put gravel in the bottom, tar or coat the part that goes into the ground then pack the soil and tamp it all around the post. <img src="http://www.woodworkingtalk.com/images/smilies/vs_cool.gif" border="0" alt="" title="Vs Cool" class="inlineimg" />

I was thinking after reading all opinions that what the heck did we do before the internet, haha! We just would put the posts in the ground one way or the other and it would be 'live and learn'! I did initially buy bags of concrete then returned them for bags of modified stone. If I didn't ask you folks I would have gone with the concrete option. The stone packed tight around the 4x6 and now I will decide if I will cut off a foot or two of the 4x4 (16' post attached to 4' of a 4x6 which is in the ground 4 feet deep) which I will attach to it. I really don't know what to expect after I mount this whole contraption but will of course 'live and learn' and gladly share my results here on these great forums. Thanks!

 

[Pineknot_86]

The 4x4 posts for my pool deck are in concrete. I have lived here over 23 years. So far, so good.

 

[35015]

Statistical...No...It does not work...

You just can't believe everything you read, even from a manufacturer...

No...:|...one "can't believe everything," they read...Nor has anyone here suggest they should...

...If a post set in concrete fails it's because it wasn't properly treated which would fail anyway....

That is not only obtuse it is a false assumption without any form of logical validation? "If a post set in concrete fails it's because" it has began to decay...or has suffered an event to cause failure...which could be anything from a car hitting it to fugal presence...or other factors...plan and simple.

Beyond that is the point of this aspect of the discussion...What has, in many cases clearly advanced that decay compared to exactly the same wood types...in exactly the same soil and biome types...that have not begun to decay at all, or not as rapidly?

The point you continue to labor over is the false conviction that this isn't exacerbated by the concrete embedment. That is no longer a point of assumption within the building arts, as enough empirical evidence is out there to the contrary. Enough, in fact, to make Architects, Contractors, Lumber Distributors, Building Supply Stores, Pole Building Manufactures, many Local Building Departments and related architectural facilitators clearly stating (as in this conversation) it is...BAD PRACTICE.

Again, if you (or anyone?) chooses not to accept that, or agree with it, that is your prerogative...

 

[Steve Neul]

No...:|...one "can't believe everything," they read...Nor has anyone here suggest they should...



That is not only obtuse it is a false assumption without any form of logical validation? "If a post set in concrete fails it's because" it has began to decay...or has suffered an event to cause failure...which could be anything from a car hitting it to fugal presence...or other factors...plan and simple.

Beyond that is the point of this aspect of the discussion...What has, in many cases clearly advanced that decay compared to exactly the same wood types...in exactly the same soil and biome types...that have not begun to decay at all, or not as rapidly?

The point you continue to labor over is the false conviction that this isn't exacerbated by the concrete embedment. That is no longer a point of assumption within the building arts, as enough empirical evidence is out there to the contrary. Enough, in fact, to make Architects, Contractors, Lumber Distributors, Building Supply Stores, Pole Building Manufactures, many Local Building Departments and related architectural facilitators clearly stating (as in this conversation) it is...BAD PRACTICE.

Again, if you (or anyone?) chooses not to accept that, or agree with it, that is your prerogative...

The fact of the matter is I have had around 80 treated posts set in concrete on my place. If there was an issue with them rotting I would know it. Even when the storm destroyed one of my buildings the posts remained so there wasn't any trace of rot. I just dug them up and re-used them and set them back in concrete.

 

[unburled]

The fact of the matter is I have had around 80 treated posts set in concrete on my place.

It just occurred to me that a big benefit of encasing the post in concrete is that chemical leaching is reduced.

 

[Steve Neul]

It just occurred to me that a big benefit of encasing the post in concrete is that chemical leaching is reduced.

In my case the posts are not encased in concrete. I dig the hole and set the post in. Then I plum the post with stakes and when it's all set I back fill the hole with cement. In the end of the post is still in contact with the ground. In any case there wouldn't be enough of the chemical leach into the soil to hurt anything.

 

[woodnthings]

Come on guys .....

The fact of the matter is I have had around 80 treated posts set in concrete on my place. If there was an issue with them rotting I would know it. Even when the storm destroyed one of my buildings the posts remained so there wasn't any trace of rot. I just dug them up and re-used them and set them back in concrete.

In my case the posts are not encased in concrete. I dig the hole and set the post in. Then I plum the post with stakes and when it's all set I back fill the hole with cement. In the end of the post is still in contact with the ground. In any case there wouldn't be enough of the chemical leach into the soil to hurt anything.

All this arguing and pontificating, 55 posts later, come to find out the posts are not encased in concrete, only set in or backfilled at the bottom and the ends are touching the soil.



I guess words do have a specific meaning after all. :nerd2:

 

[Steve Neul]

All this arguing and pontificating, 55 posts later, come to find out the posts are not encased in concrete, only set in or backfilled at the bottom and the ends are touching the soil.



I guess words do have a specific meaning after all. :nerd2:

Well, it was just an assumption the post was only back filled. I don't know of anyone that would pour cement in a hole and then put the post in. It's difficult enough to put a 16' 4x6 post in the ground without worrying about knocking dirt in the hole while you are doing it. Posts are heavy.

 

[woodnthings]

Backfilled VS encased?

Well, it was just an assumption the post was only back filled. I don't know of anyone that would pour cement in a hole and then put the post in. It's difficult enough to put a 16' 4x6 post in the ground without worrying about knocking dirt in the hole while you are doing it. Posts are heavy.

OK, here we go again. If you set the post in the hole, end resting on soil or gravel, THEN fill the entire hole or "backfill" it to the top. it WILL be encased in concrete.

There are folks who will pour a small amount of concrete into the hole, let it set up, THEN put the post on top.

I understand your definition of backfilled to mean to the top... right?

I've never hear the word backfilled as applied to posts, only foundations. Could be just me, tho? :|

 

[Steve Neul]

OK, here we go again. If you set the post in the hole, end resting on soil or gravel, THEN fill the entire hole or "backfill" it to the top. it WILL be encased in concrete.

There are folks who will pour a small amount of concrete into the hole, let it set up, THEN put the post on top.

I understand your definition of backfilled to mean to the top... right?

I've never hear the word backfilled as applied to posts, only foundations. Could be just me, tho? :|

Yes, except for the bottom, the post is encased in concrete all the way to the top and sometimes more. When the posts get wet they swell a bit and tend to crack the concrete. The cracks don't seem to affect the grip the concrete has on the post but in recent years I've starting putting a form around the top of the hole and put rebar around the post to help reduce the cracks. Then one building which has a concrete floor the posts were put in the ground flush to the ground level and then the floor was poured around the posts.

 

[35015]

It just occurred to me that a big benefit of encasing the post in concrete is that chemical leaching is reduced.

What I have read (and considered) on that aspect of this topic the only thing this does is slow down and/or concentrate not only the toxins within older wood posts but adds whatever toxins are within the concrete itself. Many fail to realize (or choose to ignore?) the toxicity of the concrete additives themselves and/or the industry itself at large. This was reflected in the article you shared which I am still digesting and others have thank me for sharing with them...I pass that on to you for bring it to my attention...:laugh2: