Al and Robins 20x30 1 1/2 near Lake Eufaula, OK

Started by ajbremer, May 09, 2011, 04:01:01 AM

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I will probably hang my joists from the beams with hangers and avoid the problem. Im doing wuat i csn to eliminate waste


You'll like the Advantech.  It will withstand a lot of moisture.  I put some down early this year and left it exposed to weather, and after a month or more I still did not have fibers poking up like you would get with regular OSB. 

It will also make that deck nice and tight.  Glue it down too. 

"Officium Vacuus Auctorita"


Monday Morning - October 3rd, 2011 Oklahoma, USA

I contacted 'Advantech' this morning (Huber Engineered Woods: and talked to two different people at two different times with various questions.

I mentioned that it's getting toward Winter here in Oklahoma and I'm about to put my sub-floor on. I told them I wasn't sure if I'll have my roof on in four weeks or four months and I wondered if their product would withstand the winter for that long. The guy said: "Sure, that's what it's made for, guaranteed to be like new for up to 300 days exposed to all weather." He said almost all Lowe's has the product but the two big Lowe's near me has only the 23/32 thickness and they said that it is the most common.

I also asked him about screws or nails and using glue on the joist. He said to use #8 screws minimum and use glue on the joist but not a water based one because Advantech is water resistant. He mentioned that Strong-Tie has a stand up screw gun/tool that people use to screw in Advantech panels. Strong-Tie even mentions that it's 'Advantech Approved'. They also have thicker panels at 7/8, 1.00, and 1 1/8.

Both Lowe's places near me sell the 23/32 4x8's for $23.48 a sheet. Oh ya, I also asked him what he thought the most common finished floor used to go on the sub-floor and he said probably carpet first and then hardwood flooring.

He also mentioned that when it snows and when there's ice buildup it is a good practice to get it off instead of letting it stay on. He said not to use salt to melt the ice or snow. He also said that any product that is 'pet-safe' is safe for Advantech. He did mention that Advantech is also good for people with pets.

I'll be doing the countryplan jig before ya know it...well, I think I'm going to record a tune on my guitar while on top of the sub-floor instead of doing the jig thingy...stay tuned.
Click here to see our 20x30 and here to see our 14x24.


What's holding up the ends of the floor joists?


Nails into the floor joist through the rim joist and joist hangers. There is a girder in the middle where they lap.
Click here to see our 20x30 and here to see our 14x24.


I didn't see joist hangers in the pics. I was just concerned nails might not be enough. I've never seen one done with steel posts like this. Interesting idea. Are you going to put angle braces on the posts? Go Sooners!


He has 4" angle iron running full width and welded to the posts that they are sitting on. I think thats what you mean


The angle is on the outside of the posts under the rim 2x's

Air and end nailed is the support the joists have at the sides


enlarged section of the above photo. (upper right of photo)

Looks like there are some joist hangers (good!)
Looks like many of the joists are hanging on nails driven through the rim and into the end grain (not good!)

With nails in the end grain there is likelihood of the joist end failing before the nail fails.

If the 4x4 angle could have been notched around the steel posts and welded in place it could do double duty as a joist support.
Just because something has been done and has not failed, doesn't mean it is good design.


Further to the joist attachment question. According to the
IRC joists framed into the side of a girder must be supported by an approved hanger. Alternatively a ledger strip may be used; minimum size 2x2". Looks like the nails into the end grain are more for holding the rim in place rather than to support the weight on the joist. Hence the engineered hangers.

And a question.  i don't have an answer for this... just a suspicion.
it's about the large amount of overlap in the center of the joist span.

The IRC states there should be a minimum of 1.5" of bearing surface and a minimum overlap of 3 inches with a minimum of three 10D nails, face nailing the joist overlap. I do not see any mention of a maximum overlap amount. But my reference framing books all illustrate something like a maximum overlap of around 12 inches. The question that comes to mind is this... can there be too much overlap? Can the floor loading cause the ends of the overlap to move upwards as a floor load makes the joist deflect down in the center of the span?  Like I said I don't know the engineering answer. Myself, I would have cut those ends shorter and used the cutoffs for blocking or something.

I should mention it is good to see proper use of solid blocking over the girder with bridging elsewhere.

And for now, my last "I wonder..."   I wonder if the undercoating applied to the steel embedded in the concrete may have a detrimental aspect? It may prevent the concrete from bonding to the steel. Maybe, I dunno?  Would the rubbery coating allow the steel to slip within the concrete? A question for a trained engineer?

Just because something has been done and has not failed, doesn't mean it is good design.


Okay, an answer to the overlap question.... long overlaps may produce squeaky floors.  Typical instructions in framing courses are to limit the overhang on lapped floor joists to 6 inches or it may end up being a squeaker.   

And another question re the undercoating. This may act like a lubricant to allow the steel column to push down through the concrete. Is there a flat steel plate under the post and angle sections to prevent this movement? 

Just because something has been done and has not failed, doesn't mean it is good design.


I belive he was concerned with the lime in the concrete eating away at the steel. So which condition is worse? Personally i would have stuck to wood but thats me. Im actually considering coating my pt posts with it too but i will have a foot on the bottom. Im also conserned wit it possibly trapping moisture in.


As for using wood over steel I recently removed some fence at the farm that was standard unpainted steel pipe posts (drill pipe) 22 years embeded in concrete I busted it off and the metal is still in good shape and reuasable. In my area dry intense sun (west texas) most wood posts would of needed replacing long before that, of corse I am comparing fence posts to a more protected foundation posts. If you look back I think some of the posts that Al used had spikes built in to the sides that would prevent them from moving in the concrete.


Not to question the builders methods I just wanted to save some future grief. There are things you can skimp on and things you can't. Don't skimp on structure. We've had members whose houses have failed in the past. I don't want to see that again. Do what you think best, please don't get the idea I am trying make trouble. If I'm seeing it wrong that's fine.


The angle iron pieces with stud like things in the inside of the angle are apparently steel reinforcing corners that are cast into concrete columns to protect the corners from damage. Yes they would be anchored well within the cast concrete.

Things like the square posts though could slip because of the undercoating. If the end of the 4 inch x 4 inch post is open at the bottom end then there is actually only about 4 square inches of area bearing on the concrete or whatever is below, if the wall thickness is 1/4".  A 4x4 wood post, on the other hand has a bearing area of 16 square inches.

Just because something has been done and has not failed, doesn't mean it is good design.


I think that's all any of us try to do Scott, it's not to pick as much as it's to give things to think about for future builders.
The studded steel would be well supported in the pier, the unstudded steel should probably have a foot on it and a good thickness of concrete footing under the steel to prevent it "punching through".

The thread has moved on but in reference to the Advantech question;
23/32" ply is what we commonly refer to as 3/4", plenty adequate for a typical subfloor, most sheet goods are 1/32" under in thickness. The maximum allowable span rating is stamped on most panels. It generally looks like a fraction, I can't recall but it'll be around 32/48. The higher number is the max distance the panel can span between rafters, the lower number is the max span that the panel could span between floor joists. I glue and nail with ring shanks, we keep the deck swept clean after every storm and I generally paint the floor with cheap oil based garage floor paint or, if they have some, mismixed oil based paint from the paint dept. Not necessary but cheap insurance. The stand up screw gun probably wouldn't be worth it for a single job, I don't own one and recently put down another 2000sf of decking with a cordless handheld. Useful for production work but marginally usefull for a one off.


Tuesday Morning - October 4th, 2011

All these comments are great and I thank you all.

I did the best I could with what I knew and with what I had when I first laid the steel into the ground. Yes, there were a few corner post, possibly 2 out of 4 maybe - can't rightly remember, that had a foot on them causing them to be more stable in the concrete. The 4 corner post are primed 4"x4"x3/16 steel post. The 2 posts in the middle of each outside length are 3"x3"x1/4" galvanized post. I remember handling those two3x3 thicker post and they seemed sturdier than the corner post. Then, all the other 9 post are the 4"x4"x3/16 (I think they were 3/16 and not 1/4) posts. I think all but 2 of those angle iron post had the protrusions coming out of them. I was told that they were engineered to fit into concrete.

I did spray a light coating of undercoating to each post because I thought that the concrete would interact in a bad way with the steel. I also had the opinion that the steel would somehow rust more without the coating because of possible moisture that could somehow get into it. I didn't think of putting concrete under the steel to prevent the post from 'punching through' but there are metal feet on a few post, the protrusions on others, and I remember putting a thin piece of steel on top of the rock for something for the post to sit on but I can't remember if I did that to every post. I often wondered how much concrete settles down into the rock on the bottom before it dries? Is it to thick to do that or does some 'concrete juice' run down into the rock and hold it together just a little?

I put one bag of rock into each hole, then set the post on the rock and then poured the concrete in. I didn't know and/or realize about any of the 'punch through' theory. If I could go back, I would have maybe drilled a couple 1/2" holes through the metal post near the bottom and put about a 6" or 8" rod through it, then the concrete would have more to hold onto?

As far as joist hangers go, I'm still putting them in. I initially put the joist in by nailing through the rim-joist to hold them up. Yesterday I added 4 more joist hangers. The Simpson Strong-Tie 2x12 hangers that I'm using (LUS210Z) have a capacity of around 1000 lbs all the way around (uplift, floor, snow, and roof). There are 4 joists where a hanger can't go because it's where they connect to the post. I will put brackets under these locations. I'm glad this was pointed out to me.

Now, about the overlapping length of the joist. I didn't know there was a maximum and that too long is not good. I see Don's point about the ends going up if the middle goes down. Should I cut them off? The reason their long like that is because they are 12 footers and I didn't think I needed to cut them. I guess I thought things would be stronger with more wood there.
Click here to see our 20x30 and here to see our 14x24.


I would cut off the excess. Three inches overlap is code minimum overlap. You would likely be fine to have six inches of overlap and face nailed with minimum of three true 10D nails. 16D nails with ends clinched over even better.

Here's some commentary on concrete from PEte my engineer friend...

Regarding steel in concrete, reply #136... concrete and steel are really quite compatible, ever hear of rebars in concrete, they work really well together. The concrete takes compressive stresses very well and the reinforcing steel takes the tensile forces, and controls cracking in tensile regions of the member. Actually, normal concrete chemistry tends to inhibit steel corrosion. You knock the concrete off the rebar, or off the fence posts mentioned in reply #137 and the steel will be in fine shape. We do require concrete cover around the reinforcing steel; generally 1.5" clear when the concrete is formed, such as beams, columns and the like, not exposed directly to ground or weather; at least 3" clr. when the concrete is cast directly against soil w/o forming, and at least 2" clear when a formed surface is finally in contact with soil; and a few others. The idea is to protect the steel from soil chemistry, environmental chemistry and moisture.

You will see old concrete structures, undersides of bridges for example and road salts, where the surface concrete has spalled away and the reinforcing gages are exposed. What has happened here is enough moisture has gotten to the reinforcing steel, along with some salts, maybe because of excessive concrete cracking or constant wetting with salts; this causes rusting of the steel and the rusting process causes a many fold expansion of the volume of the steel as it turns to rust, and this expansion exerts high expansion stresses on the outer concrete lays, causing them to spall. And, at the very least where a post come comes up out of a pier, the surface of the pier should be sloped away from the post so it will drain moisture rather than hold it. There is still some chance that moisture can get in around the post and cause rusting or rot. And, concrete does tend to hold moisture so there is some considerable debate about wooden posts in concrete being susceptible to rot. Maybe the cracked interface or joint between the post and the top surface of the concrete should be caulked to prevent moisture from getting down along the post in this crack.

Regarding bond between concrete and steel.... you don't want excessive rust on the rebar or steel and you certainly don't want any manufacturing olds or lubricants on the steel, both must be cleaned off before the rebars are installed. But, a certain amount of rust on rebar or plain steel is actually good, and improves bond because of the roughness it causes. Deformed rebars actually get a good share of their bond strength from the mechanical actions of the deformations against the concrete Smooth steel has very little bond strength in concrete, and sometimes bond breakers are used intentionally. Some metals are reactive with concrete and can't be used in concrete
Just because something has been done and has not failed, doesn't mean it is good design.


Further commentary of my own. I think I've said this once or two places before. This is not necessarily directed at any one person; it is just being broadcast to anyone who reads this. Many believe everything they see illustrated on the internet as good and proper

When not sure of how to go about some aspect of construction it is always better, IMO, to ask the question before materials are purchased, before any tools are lifted. This is especially true when dealing with unconventional, non traditional materials and methods. It is also frequently best not to wait to ask a question on Wednesday if the coming weekend is when the related task is to carried out. Sometimes it takes a while for good replies to come along.

Let me add that similarly every detail of the build should be thought out and drawn before any tools are lifted. The only area where I had some difficulty with my cabin was the one area that I had not made detailed plans before getting too far along the project. Well, I made one other error in judgement but I have a fix planned and will detail that for all to see in a while.

And one more time I'll ask about diagonal bracing in the X and Y directions. ???

Just because something has been done and has not failed, doesn't mean it is good design.


Tuesday Night - October 4th, 2011

Started to shorten my 'too long' joist lapping. My joist overlapped as much as 2 feet and as you've read I've learned that they should only overlap about 6 inches. I did nail them so I not only had to cut them but also pry them apart ever so gently. I've repaired 3 joist so far and I've got a system down now so it's not a hard thing to fix and make right. It's even hard to tell that it was once longer.

I adjusted the circular saw so that it almost breaks through the excess lap but doesn't touch the joist behind it. Then I use a nice short hand saw to cut away the final very thin layer. It all looks much nicer too. Thank you Don and everybody.

Of course I will post pics as soon as possible. I took a picture tonight but it was just too dark.
Click here to see our 20x30 and here to see our 14x24.


On the post bottom "punch through" problem. I think I have a clearer mental picture now. From what PEte has said and what we now know about the construction there is a risk of the posts slipping down in the pier concrete, the steel is smooth with a bond breaker of undercoating and there is no footing under the steel. Where there is a foot on the post it sounds as though it is only the size of the post, and that steel has no protective concrete cover. The fix that is coming to mind right now would be to weld angle iron tabs to the posts on top of the concrete piers to prevent them from being able to slide down within the pier.

This is some further commentary that I think is worthwhile.

In terms of lateral strength of this foundation the following things come to mind. I make no claims, one way or another, about the adequacy of this foundation system.

1. He was digging in very firm, free standing soil, and was digging fairly good sized piers, fairly deep; so the piers may be fairly good as relates to vert. loads and lateral bearing against the soil due to wind, etc. However, only about 3' deep still makes them fairly tippy. Deeper would be better as the piers try to act like cantilevers up out of the soil. Also, the lot is quite flat, holds water, and got pretty muddy in some of his early posts, so at some times the upper foot or so of soil may not offer much lateral resistance.

2. The steel posts cantilever up out of the conc. piers about 4' above grade, so that is a fairly long cantil. at which height the entire lateral load on the building is imparted.

3. The 4" sq. tubes are good cross sections in both compression (as columns) and in bending against the lateral loads, but their connections up at the floor framing system are suspect for transmitting the lateral loads.

4. The 4x4 angles may be marginally o.k. as cantilever compression members for gravity loading, but are quite susceptible to twisting and buckling due to canti. bending in combination with the compressive loads. They are an unstable member when used as a beam or beam-column.

5. Someone showed and suggested some knee braces below the floor framing system and to the pier members and that would seem like a wise idea.

The fix that comes to mind to me here is to weld another piece of angle to each of the angle iron posts to form a square tube. This would involve considerable welding, I doubt they would need to be continuous welds though. I could tell in one pic that the welder was burning the galvy, you sure don't want to inhale much of that at all. As I've said before steel is not my strong suit so take all this for what it's worth.

I agree with Don, good planning is critical. I spent a good bit of today cursing a pair of hips that I set about a degree off. Doesn't sound like much till the error accumulates over about 28'  d*


Quote from: ajbremer on October 04, 2011, 08:22:00 PM
Tuesday Night - October 4th, 2011

Started to shorten my 'too long' joist lapping. My joist overlapped as much as 2 feet and as you've read I've learned that they should only overlap about 6 inches. I did nail them so I not only had to cut them but also pry them apart ever so gently.

Al, once you cut through the ends you don't need to remove the end that is now an extra. Just leave it The cut disconnects it from the main section. Also your method of cutting almost through with the circular saw and cpmpleting with a hand saw is a good one as you don't want any weakening kerf cuts in the main joist.

Just because something has been done and has not failed, doesn't mean it is good design.


Ok, Don - thanks again. I'm gett'in off work now and heading right to it.
Click here to see our 20x30 and here to see our 14x24.


"4. The 4x4 angles may be marginally o.k. as cantilever compression members for gravity loading, but are quite susceptible to twisting and buckling due to canti. bending in combination with the compressive loads. They are an unstable member when used as a beam or beam-column."

"The fix that comes to mind to me here is to weld another piece of angle to each of the angle iron posts to form a square tube"

Whilst i agree with the comments above that an angle iron is not a recognised post or beam member

being that the angle is welded to the adjacent posts by a full 4x4x1/4" angle iron and welded both sides

pretty sure it won't be going anywhere but

If worried about twisting just make it a triangle and stitch weld

but I think he mentioned it was 4x4x1/4" being just less than 4ft from top of concrete to the welded joint

I would imagine the compression required to twist and collapse one of those posts would require a rather high point load

The building with its size - gives you a rough 87000lbs weight with 30# snow- full loft and floor

If you divide it equally amongst the 15 posts it comes out to be about 5800# per post

yes i know thats a basic way of doing it - and each post will have varying loads - fine double it
and we'll call it 12,000#

anyone know the compresive strength of that angle iron before twisting ....?

before we start internet over engineering !


Wednesday Night - October 5th, 2011

Hey, great information UK4x4 - thank you sir.

I've often wondered where a total weight chart for typical houses exists. Where do they come up with these weights. how bout metal roof vs. shingle roof, different sidings, light planks instead of drywall on the inside, man and woman occupant instead of family of 6, no bathtub, waterbed, small hot water tank, etc., etc. There's a lot of variables going on when it comes to weight, that's my guess. I do realize though that someday I may not own this house and a huge family with a different life style may move into it and it has to be safe for them too.

Also, as UK4x4 mentioned: Every post in the system is welded to the 4"x4"x.25 angle-iron that runs the total distance around the perimeter and down the middle. It all acts as one unit. Everywhere a post touches the angle-iron, there is a weld: bottom, top, back, front...all sides.

I'm over half way done cutting off my excess joist lappage to 6" like Don said. Here's a pic of it:

As I said in a previous post, I set my circular saw just short of going into the next joist and then I use a real good short hand saw. Here's a pic:

And lastly: "By the light of the moon may all good 'Dollar Store' hammers lay their heads once and forever!"
Click here to see our 20x30 and here to see our 14x24.