Thread: Post and Beam members

Here's a few pictures of a post and beam house I inspected today. (built in 1989)

If someone has experience with post and beam homes I have a few questions and welcome any other comments:

1. I know wood dry's and checks, but this crack looks excessive. The cracks are not are the base of the mortise and tenon joints, so even though it looks frightening, I'm guessing this might be ok.
What would you tell your client??

2. Floor rafter mortised into column. Does this gap require further action? How much of the tenon should be into the column?

The checking in the beam is relatively wide, but it is unlikely to be a concern, unless possibly this is a short heavily loaded beam. If the deflection was not significant I would note it but not be too concerned.

The tendon is probably ok for vertical support, especially with the diagonal brace adding support. I would be a bit concerned about the size of the gap and whether this is an indication of lateral movement. Were there any other gaps or other possible signs of movement?

Normal....and not a problem.

a buddy who has a very nice log home said one evening while the family was watching TV, a gunshot went off in the dining room. They all jump to their feet wide eyed. In the dining room, after scratching their heads, they realized that a large overhead log now had a 1/2" wide crack that hadn't been their earlier.

Originally Posted by Mark Reinmiller

The checking in the beam is relatively wide, but it is unlikely to be a concern, unless possibly this is a short heavily loaded beam. If the deflection was not significant I would note it but not be too concerned.

The tendon is probably ok for vertical support, especially with the diagonal brace adding support. I would be a bit concerned about the size of the gap and whether this is an indication of lateral movement. Were there any other gaps or other possible signs of movement?

Mark,

Thanks for the comments and quick reply.

I didn't see any other signs of lateral movement and as you noted these items although larger than normal, there was no deflection of any significance - BUT..... What do you write in your report?? No problem.?? A-OK?? Although I dislike doing this, I'm thinking of erring on the safe side and recommending further evaluation. I'm just not comfortable stating "no significant problems" or "monitor" for further movement in my report. My guess is an engineer would recommend metal bracing or connections to escape liability, but I can't make that call.

Settlement does not make much sense with this type of movement. If it moved after construction then with that much movement at that joint I would expect to see some movement at adjacent joists. Also, I would expect to see some movement at the diagonal brace.

I understand your concern regarding saying it is ok. I am a PE so I am more comfortable making those decisions. No hard in pointing out the movement, saying you do not know the cause and cannot determine whether it is a structural concern. You can followup by adding that a structural engineer may be able to provide further information (or the owner may be able to provide further information). I think it is sometimes ok to provide the information and let the buyer decide whether they want to accept the risk or pay for more information.

BTW, I enlarged the photo and noticed something stuck in the joint. did you put something there to show the size?

I would want to ascertain if the peg is broken, or it could have been constructed this way. It's not unusual to see a tenon not perfectly butted into the mortise.

Originally Posted by Mark Reinmiller

You can followup by adding that a structural engineer may be able to provide further information (or the owner may be able to provide further information). I think it is sometimes ok to provide the information and let the buyer decide whether they want to accept the risk or pay for more information.

I agree 100% with this and regularly write up things similarly. Basically, as HIs we're forced to make a call on something but there isn't always a clear cut answer. At the minimum standard according to any SOPs it's "performing as intended". But, a more specialized professional may have a different opinion and/or more information.

It's the constant gray area HIs are in.... every time we see a crack in any material we could recommend a full evaluation by a structural engineer. Or, we can just assume every crack and sign of movement is "typical settlement". Both methods are likely to prevent you from working much. The former because you're not really providing a service. The latter because you'll be too busy in court to perform any inspections.

If an inspector is calling out every crack as needing further assessment by an P. Eng, I don't think as an inspector you are assisting your client well. I suppose this is were experience plays an important role. Its the same pretty much for other systems in the house.

In this case I am not so sure I would be calling for an P.Eng, but rather a specialist who constructs log cabins/post and beam homes who is likely to be much more familiar with these type structures, if he happens to be a P.Eng that would be a bonus.

Originally Posted by Matt Fellman

At the minimum standard according to any SOPs it's "performing as intended".

One way to look at it is this way: Is that tenon intended to be in the mortise, or is it intended to be out like that?

I doubt the person who constructed that tenon over cut it like that. Is the beam cut too short? (possibly, but doubtful) Did the walls separate? (that is the big question) Did the beam shrink that much in that long dimension? (I doubt it)

Logs shrink in diameter, not length. It could have been very well cut short and the tenon maybe fully seated and the peg fine. Can't tell from just a picture. The question is what did the other tenon at the opposite end look like?

Thanks all - great to bounce this off peers.

My lesson learned - Just like we do with this newsletter - "If you don't know the answer ASK the experts". _ and thanks for YOUR answers.

And the answer IS: We do not know all the answers AND we could not possibly know all the answers. It is perfectly OK to recommend further evaluation when you don't know the answer.
I agree we shouldn't do it all the time, but when in doubt - DO IT! (That's what I did in my report)

Originally Posted by Raymond Wand

Logs shrink in diameter, not length.

Typically, yes. but reaction wood (from a leaning tree or a tree growing on a hillside) can shrink significantly along its length. But having said that, it probably would not shrink as much as shown in the photo. My first guess would be lateral movement, but then I would expect to some movement at adjacent joists.

Due to the relatively decent focus and resolution of the photo, zooming in on the photo to 400% shows evidence that the end of the beam was in contact with the post, i.e., that it has pulled out by the mount of the gap.

Also looks like there may have been a leak above - was there?

Looks like a 3/8 tube when the photo is enlarged?
The joist does not appear to be pegged but just pocketed into the beam which would be in keeping with the other joists.

Originally Posted by Jim Abram

This is clearly a settlement issue .

Not "clearly" ... you "assume" that to be the case.

Clearly - Definition and More from the Free Merriam-Webster Dictionary
- clear·ly adverb \ˈklir-lē\
- : in a clear manner : in a way that is easy to see, hear, or understand
- : in a way that is certain : without doubt

Its not settlement either, its either been pulled due to as Mark said, or it was built that way, but it ain't settlement.

I do have my thoughts on the probable cause.

Some Facts:

1. The checking crack of that beam is on the opposite side of the rafter gap.
2. You can see pegs used to secure the girt beam on the post have moved outward into the gap space. They are not flush.
3. The color of the wood inside the gap is lighter than the rest.

My thoughts:

The lighter color of wood at the gap would indicate that this occurred after installation. If the joist was designed to have a tight fit with no gaps, then why have the pegs protruded? It couldn't fit tight with those pegs protruding. I think the checking caused the large beam to twist or move in a manner that caused the pegs to protrude which pushed the rafter out.

With that said, From an inspectors point of view it is not as important why it occurred but what to do about it. The bottom line is the client needs to know if that gap is "NO Problem", Requires "Further Evaluation" or "Requires Repair". Pick one.

Originally Posted by Jim Abram

Since you do not understand what settlement is the definition is posted below :

Settlement in a structure refers to the distortion or disruption of parts of a building due to either; unequal compression of its foundations, shrinkage such as that which occurs in timber framed buildings as the frame adjusts its moisture content, or by undue loads being applied to the building after its initial construction.

Wrong again. I do understand the term 'settlement', but I don't think it applies to this situation.

I would like to hear Mark Reinmiller's explanation of Lateral settlement because he is a P. Eng and you are not.

Originally Posted by Jim Abram

Raymond - You constantly display that you do not understand the topics discussed . After fifty years of doing structural designs , construction and repairs , I have a fairly good understanding of the subject.
Why you are so mean spirited is beyond me . Your personal attacks are untrue and unwarranted and are totally uncalled for.

I understand perfectly that you think you are superior.
Where have I attacked you and what is untrue?
I won't even talk about you talking down to me and others.

- - - Updated - - -

Originally Posted by Jim Abram

Raymond - You constantly display that you do not understand the topics discussed . After fifty years of doing structural designs , construction and repairs , I have a fairly good understanding of the subject.
Why you are so mean spirited is beyond me . Your personal attacks are untrue and unwarranted and are totally uncalled for.

I understand perfectly that you think you are superior.
Where have I attacked you and what is untrue?
I won't even talk about you talking down to me and others.

Originally Posted by Jim Abram

Raymond - You constantly display that you do not understand the topics discussed . After fifty years of doing structural designs , construction and repairs , I have a fairly good understanding of the subject.
Why you are so mean spirited is beyond me . Your personal attacks are untrue and unwarranted and are totally uncalled for.

Jim,

Do you even read your own posts?

Do not understand the topics discussed ...
Mean spirited ...
personal attacks ...
untrue ...

You accurately described yourself and your posts - all evidenced in the one post of yours quoted above.

Behavior and Modeling of Wood-Pegged Timber Frames | ? Lee - Academia.edu

Behavior of Mortise and Tenon with Shoulder and Knee Brace

The addition of the knee brace caused several changes in joint behaviour. First, the compression force induced in the knee brace by the loads caused a tensile force in the beam at the joint. This tended to pull the tenon and shoulder out of the post. The result was either a peg failure in bending or shear,a block shear failure of the portion of the tenon between the upper peg and the end of the tenon, or a splitting failure of the tenon at the upper peg hole. Knee-brace response was highly dependent on the degree of contact between the ends of the knee brace and the faces of the beam and post. If a gap was present at either face, all knee-brace force was carried through the peg at that end. This led to peg damage similar to that discussed previously. Relatively little horizontal movement occurred in the beam/column joint until the knee brace went into bearing at both ends. Then, horizontal movement increased rapidly with increasing load. In the majority of cases, white oak specimens reached the maximum load of 67kN (15,000 lb) without catastrophic failure of any component.Douglas fir and eastern white pine specimens generally failed in bending or a combination of bending and shear between the knee brace attachment point and the roller supported end of the beam. Further details are available in Sandberg et al.(1996)

Originally Posted by Jim Abram

Since you do not understand what settlement is the definition is posted below :

Settlement in a structure refers to the distortion or disruption of parts of a building due to either; unequal compression of its foundations, shrinkage such as that which occurs in timber framed buildings as the frame adjusts its moisture content, or by undue loads being applied to the building after its initial construction.

I'm not sure where that definition comes from. As a structural engineer I use the term settlement to refer to foundation settlement. Lumber shrinkage causes movement, but I would not refer to that as settlement. Floors sag, which is deflection. I would not call that settlement either. Some people refer to all movement as settlement.

Using your definition, then any movement could be called settlement. Then you would be correct, but your answer would be the same as saying the gap was caused by movement. Does not tell us much.

Yes it does matter, you yourself said so.

Not all settlement and movement requires repair, but then what's in a definition if one can't tell the difference? That's a rhetorical question btw.

Originally Posted by Jim Abram

Raymond - Give it up, you are just making more of a fool of yourself.
If you use English in your posts ,maybe what you are trying to say could be understood.

Well I wouldn't want to argue with you, that's for sure, because I'm not a know it all, that's a title reserved for you.

Originally Posted by Jim Abram

Raymond - Give it up, you are just making more of a fool of yourself.
If you use English in your posts ,maybe what you are trying to say could be understood.

Yet another post containing just what you complained about others posting.

Jim, apparently you just don't get it ... "it" being basically everything ... based on your posts here.

The Troll is everywhere ... do not feed the Troll.

I just got the report from a structural engineer that evaluated the beams and joist connection.

They reported that the checking crack was significant, greater than 3/4 inch throughout the length of the member and that the Mortise and tendon flush framing has gaps greater 1 inch.

The conditions warrant repair which consists of steel plates to flitch beams together, fastened on either side of centerline checks. The gaps in the mortise and tendon require the installation of steel angles to provide adequate lag bolt fastening. The steel flitch plates need to be notched around the flush framing of joists and around the steel angle connection.

Wow! The client also advised that they walked. (OH my! I killed another deal )

Originally Posted by Ken Amelin

I just got the report from a structural engineer that evaluated the beams and joist connection.

They reported that the checking crack was significant, greater than 3/4 inch throughout the length of the member and that the Mortise and tendon flush framing has gaps greater 1 inch.

The conditions warrant repair which consists of steel plates to flitch beams together, fastened on either side of centerline checks. The gaps in the mortise and tendon require the installation of steel angles to provide adequate lag bolt fastening. The steel flitch plates need to be notched around the flush framing of joists and around the steel angle connection.

Wow! The client also advised that they walked. (OH my! I killed another deal )

That much checking could significantly reduce the strength of the beam. The repair may be a conservative approach, but sometimes that is necessary because you cannot really evaluate the remaining strength of the beam. One inch of movement at the mortise is excessive. I certainly agree for the need for repair to that joint. The cause of the movement is still a mystery.

Originally Posted by Jim Abram

Since you do not understand what settlement is the definition is posted below :

Settlement in a structure refers to the distortion or disruption of parts of a building due to either; unequal compression of its foundations, shrinkage such as that which occurs in timber framed buildings as the frame adjusts its moisture content, or by undue loads being applied to the building after its initial construction.

If you are going to post a quote, please include the source of the quote. As you may know from reading other topics here, when things get very dicey and technical---folks post the source of their information that supports their position. Otherwise there is no way to determine the authenticity of the position, or the supporting information. Thanks in advance.

Originally Posted by Ken Amelin

I do have my thoughts on the probable cause.

........If the joist was designed to have a tight fit with no gaps, then why have the pegs protruded? It couldn't fit tight with those pegs protruding. I think the checking caused the large beam to twist or move in a manner that caused the pegs to protrude which pushed the rafter out......

Ken, in some forms of post & beam construction, the pegs are normally left protruding (this is what I have seen in the Northeast). I have included a picture of this. However, it would be difficult for the pegs to be forced out because they normally protrude from both sides in this form of the constructions. If not protruding, they are cut flush on both sides of the beam.


mortise-and-tenon-joinery.jpgmortise-and-tenon.gif

Originally Posted by Jim Abram

Rich - This is not a Doctoral Thesis presentation......

But Jim, how can I tell if you are trying to slosh me with BS unless you quote your source? While I know you wouldn't try that, some may. So, tell us where you you are getting your stuff from, that's all. No big deal. BTW, as it wasn't clear, which book were you referring to in your reference?

Dictionary of Architecture by Henry H. Saylor,
A Concise Dictionary of Architectural Terms by John Henry Parker,
Dictionary of Architecture and Construction by Cyril Harris, or?

Originally Posted by Rich Goeken

Ken, in some forms of post & beam construction, the pegs are normally left protruding (this is what I have seen in the Northeast). I have included a picture of this. However, it would be difficult for the pegs to be forced out because they normally protrude from both sides in this form of the constructions. If not protruding, they are cut flush on both sides of the beam.


mortise-and-tenon-joinery.jpgmortise-and-tenon.gif

Rich,

The pegs are located within the joint and have protruded within the gap of the joint, not on the side of it as your photo shows. (see my pic). And they do not go through the entire way. They are there for connection of the spliced beam sitting on the post. It's a 4-way connection.

Originally Posted by Jim Abram

The definition comes from the Architecture Dictionary.

But, does it matter what you call it ? Both movement and settlement are issues that require appropriate repairs. The issue in this instance is there is not enough information to determine the cause and every possibility should be considered.

In most cases movement due to shrinkage or deflection do not require repair.

Originally Posted by Ken Amelin

Rich,

The pegs are located within the joint and have protruded within the gap of the joint, not on the side of it as your photo shows. (see my pic). And they do not go through the entire way. They are there for connection of the spliced beam sitting on the post. It's a 4-way connection.

OK, misunderstanding. I thought you were talking about somewhere else in the house along with the pictures. You are saying that the pegs used to fasten the cross-beam timber (that are on the top) are damaged. Usually that can only be seen from the top. Were they that bad that you could see them from the side? Were they sheered or does it appear that the tendon was cut too small on that beam? Just curious.

I noticed the structural engineer's report said massive support issues. Just the cracked beam would make me walk away.

Originally Posted by Ken Amelin

I just got the report from a structural engineer that evaluated the beams and joist connection.

They reported that the checking crack was significant, greater than 3/4 inch throughout the length of the member and that the Mortise and tendon flush framing has gaps greater 1 inch.

The conditions warrant repair which consists of steel plates to flitch beams together, fastened on either side of centerline checks. The gaps in the mortise and tendon require the installation of steel angles to provide adequate lag bolt fastening. The steel flitch plates need to be notched around the flush framing of joists and around the steel angle connection.

Wow! The client also advised that they walked. (OH my! I killed another deal )

Wow! Indeed. But......I think a second opinion might be appropriate. Engineers are like the rest of us and not all know as much as others.

Lon

Thats my feeling too fwiw.

We don't know the species of wood, dimensions, or whether the checking was there prior to installation or a historical perspective from the current owners.

Originally Posted by Jim Abram

Ken - This is exactly why a structural engineer does not belong in a residential dwelling . I think that MA for years did not require an engineer for anything in a building under 40,000 cu/ft. I think that might still be the case . I know you are done with this one and will probably get additional business from this client. Keep the engineers number handy if you want more repeat business.
I can just picture the flitch plates and bolts and angle irons as decorative features. There are numerous way to address this issue without making this lovely house look like a recycled factory building.

Jim,

Although I agree that the engineer went overboard, -- I really don't care. That's their profession their license and their liability. I don't have their credentials and don't wish to criticize.

Like our profession we get stirred up if a Realtor tries to criticize our findings and recommendations. It's not their business, not their license and not their liability - so (I tell them to) butt-out.

Originally Posted by Jim Abram

Mark - That is entirely dependent on the severity of the shrinkage or deflection.
If the deflection of a beam has caused doors to become misaligned to the point that they are not operable, of course the deflection requires repairs.

Are you saying that if a door binds, then you must reinforce the floor system?

Originally Posted by Rich Goeken

But Jim, how can I tell if you are trying to slosh me with BS unless you quote your source? While I know you wouldn't try that, some may. So, tell us where you you are getting your stuff from, that's all. No big deal. BTW, as it wasn't clear, which book were you referring to in your reference?

Dictionary of Architecture by Henry H. Saylor,
A Concise Dictionary of Architectural Terms by John Henry Parker,
Dictionary of Architecture and Construction by Cyril Harris, or?

A little search yields that it derives from Wikipedia
Settlement (structural) - Wikipedia, the free encyclopedia
It references: Curl, James Stevens (2006). A Dictionary of Architecture and Landscape Architecture (Paperback) (Second ed.). Oxford University Press. p. 880 pages. ISBN 0-19-860678-8.

The attempt to use strict word interpenetration by definition will wield two people at odds when in fact they really are not. English is very fluid and often needs terms qualified before a word can be interpreted correctly.

The problem is that the term Settlement differs in application. In a standard built home settlement is about foundation support movement that translates through the structure. When applying it to Log construction or Post and Beam construction there is an added dimension to the use of the term "settlement". Logs and beams will shrink. Many will say that the logs have settled when they really are saying that the logs have reduced their size (shrinkage) causing the vertical distance to reduce over time. Which can be a cumulative amount of 6" to 8" or more. Post and beam is a little different in its dynamics of shrinkage due to construction method. All wood expands and contracts over time. Wood, once it has reached its final stage of drying will still expand and contract, just in smaller amounts. I think you guys are all correct though just not qualifying terms as they are applied to specific material and construction method.

You build a house, standard stick, using green wood there will be settlement of the walls due to vertical shrinkage. Yet there may be no settlement of the foundation. So you could say that "the house has settled and there is no settlement". It would be confusing yet factually correct. Ain't english grand????

Originally Posted by Garry Sorrells

A little search yields that it derives from Wikipedia
Settlement (structural) - Wikipedia, the free encyclopedia
It references: Curl, James Stevens (2006). A Dictionary of Architecture and Landscape Architecture (Paperback) (Second ed.). Oxford University Press. p. 880 pages. ISBN 0-19-860678-8.

The attempt to use strict word interpenetration by definition will wield two people at odds when in fact they really are not. English is very fluid and often needs terms qualified before a word can be interpreted correctly.

The problem is that the term Settlement differs in application. In a standard built home settlement is about foundation support movement that translates through the structure. When applying it to Log construction or Post and Beam construction there is an added dimension to the use of the term "settlement". Logs and beams will shrink. Many will say that the logs have settled when they really are saying that the logs have reduced their size (shrinkage) causing the vertical distance to reduce over time. Which can be a cumulative amount of 6" to 8" or more. Post and beam is a little different in its dynamics of shrinkage due to construction method. All wood expands and contracts over time. Wood, once it has reached its final stage of drying will still expand and contract, just in smaller amounts. I think you guys are all correct though just not qualifying terms as they are applied to specific material and construction method.

You build a house, standard stick, using green wood there will be settlement of the walls due to vertical shrinkage. Yet there may be no settlement of the foundation. So you could say that "the house has settled and there is no settlement". It would be confusing yet factually correct. Ain't english grand????

Had someone say to me once... "Communication at its best----is a hazardous process!"

Originally Posted by Ken Amelin

Jim,

Although I agree that the engineer went overboard, -- I really don't care. That's their profession their license and their liability. I don't have their credentials and don't wish to criticize.

Like our profession we get stirred up if a Realtor tries to criticize our findings and recommendations. It's not their business, not their license and not their liability - so (I tell them to) butt-out.

I disagree. With knowledge that a long experienced HI accumulates, you do have standing to criticize a licensed professional and the same is true for an experienced agent regarding what a HI might do. Over and over, we see licensed professionals make mistakes, show poor judgment, or who are incompetent. A license, whether for an engineer or HI, just proves that he/she passed the relevant test, sometimes on their tenth try. No where on anyone's license is immunity from criticism bestowed upon them.

Originally Posted by Lon Henderson

Wow! Indeed. But......I think a second opinion might be appropriate. Engineers are like the rest of us and not all know as much as others.

Right, it's a house, not a bridge or a skyscraper.

A good log home builder or the original builder could make nearly invisible repairs to that structure to satisfy most engineers, IMO.

Originally Posted by Lon Henderson

I disagree. With knowledge that a long experienced HI accumulates, you do have standing to criticize a licensed professional and the same is true for an experienced agent regarding what a HI might do. Over and over, we see licensed professionals make mistakes, show poor judgment, or who are incompetent. A license, whether for an engineer or HI, just proves that he/she passed the relevant test, sometimes on their tenth try. No where on anyone's license is immunity from criticism bestowed upon them.

Lon, fair enough, but when you are a professional and criticize another profession what does it really mean?? Not much. Only kibitz. If you truly disagree with someone, I say "PUT IT IN WRITING" and sign your name along with your license #. Now that means something. Otherwise whiners not welcomed.

Expert witnesses contradict one another in the courtroom on behalf of the respondent and plaintiffs. Both are professionals.

Fair comment on the engineer is open for comment, but since we don't know the qualifications of the engineer .. Well just say'n, but maybe much like home inspectors he was covering his backside.

Fair comment/discussion is whining?

Originally Posted by Ken Amelin

Lon, fair enough, but when you are a professional and criticize another profession what does it really mean?? Not much. Only kibitz. If you truly disagree with someone, I say "PUT IT IN WRITING" and sign your name along with your license #. Now that means something. Otherwise whiners not welcomed.

Just did that with an electrician (minus the license # since we don't have any) and the electrician corrected his "repair".