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Old 08-14-2019, 12:34 AM   #16
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Re: Sagging joist


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Originally Posted by viper View Post
Yes, I cannot accurately assess the loads with the info given but if the 4x4 is not adequate, the same or close sized Ibeam (overkill) will certainly carry the load.

In some cases, if a piece of lumber appears to hold, it is assumed to be OK but you need a lot of extra margin so creep does not sneak in.
perhaps you could assess the load better if you asked questions like what is exactly above this, just a floor or a wall and if a wall i , what is above it that wall. How long the crawlspace has had this hole in it before the sag was noticed .
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Old 08-14-2019, 06:33 AM   #17
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Re: Sagging joist


Nobody would use double 2x4 as a mid beam supporting 2 joists, esp on flat. 4x4 is one piece lumber, half inch thicker than doubled 1.5" lumber, and span of only 2 joist bays, so makes sense to the experienced people. It would take a lot of force to bend that short piece of 4x4. Anecdotally, there seems to be many patio roofs with 4x4 headers, not that they are adequate, but not collapsing either.

To throw in a monkey wrench, I wonder if that treated 4x4 would twist?
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Old 08-14-2019, 12:34 PM   #18
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Re: Sagging joist


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Originally Posted by carpdad View Post
Nobody would use double 2x4 as a mid beam supporting 2 joists, esp on flat. 4x4 is one piece lumber, half inch thicker than doubled 1.5" lumber, and span of only 2 joist bays, so makes sense to the experienced people. It would take a lot of force to bend that short piece of 4x4. Anecdotally, there seems to be many patio roofs with 4x4 headers, not that they are adequate, but not collapsing either.

To throw in a monkey wrench, I wonder if that treated 4x4 would twist?
Hi sorry very novice person here, are you saying this should be good? Haha

To be clear, this is in basement. We have 2 floors plus a finished attic space (3rd floor).
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Old 08-14-2019, 03:46 PM   #19
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Re: Sagging joist


I will just say, when I see anything having to do with foundations, basements, and such, what I don't ever want to hear from any installer is "this should hold".

I calculate this stuff for a living but it can be very difficult to assess with a couple pictures, and I just like seeing jobs getting done right. Too many horror stories and the same synonymous word is always used...."contractor"......

At the end of the day, here are the questions that SHOULD be at issue AND getting a proper answer. If they don't, the whole job is guess IMO.

1. What are the loads (vertical and possibly lateral forces) being presented at the location of concern and what is the lumber being used currently?

2. What is the capacity of the repair element?

I know some people feel all this stuff is overkill, but for people that do this for a living, this could be a 30min riddle. Sometimes steel is recommended (as I have done) not as the only means to carry the load, it is to mimic the performance of the concrete.

You are talking about a 3 story house so it will be important to know if there is a load supporting wall above that concrete footer? If so, there is no way I would fly that job without some hard numbers.


In jobs such as this, I have used a load cell on a jack as an element is lifted so there is no guesswork on the loads. I can imagine about every contractor in America throwing a baby fit about using a load cell for "piddly work" but it takes 5min.
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Old 08-14-2019, 03:59 PM   #20
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Re: Sagging joist


Quote:
Originally Posted by viper View Post
I will just say, when I see anything having to do with foundations, basements, and such, what I don't ever want to hear from any installer is "this should hold".

I calculate this stuff for a living but it can be very difficult to assess with a couple pictures, and I just like seeing jobs getting done right. Too many horror stories and the same synonymous word is always used...."contractor"......

At the end of the day, here are the questions that SHOULD be at issue AND getting a proper answer. If they don't, the whole job is guess IMO.

1. What are the loads (vertical and possibly lateral forces) being presented at the location of concern and what is the lumber being used currently?

2. What is the capacity of the repair element?

I know some people feel all this stuff is overkill, but for people that do this for a living, this could be a 30min riddle. Sometimes steel is recommended (as I have done) not as the only means to carry the load, it is to mimic the performance of the concrete.

You are talking about a 3 story house so it will be important to know if there is a load supporting wall above that concrete footer? If so, there is no way I would fly that job without some hard numbers.


In jobs such as this, I have used a load cell on a jack as an element is lifted so there is no guesswork on the loads. I can imagine about every contractor in America throwing a baby fit about using a load cell for "piddly work" but it takes 5min.
There are hints here that can be looked at.

No damage except for floor sagging, would be the first one.

If this fix fails over time, will it be instant or will the home owner have a year or two to see it and get it fixed.

If he had asked before the fix was done would the answer been a little different, yes.

Would the answer have included steel, no it would have been a flush beam with a 2x4 jack on each side. giving him a bigger access hole while making it stronger than what he has.



Is there a need to hire an engineer and get a written report for $1000, no.


Is it worth upgrading before there are signs of failure, no. May never happen.
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Old 08-14-2019, 08:17 PM   #21
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Re: Sagging joist


Sorry, that was half in jest. I do mean that your carpenter did a good job and the 4x4 frames will support those floor joists. 4x4 treated posts have a reputation for twisting as they dry, but in longer lengths posts.

I'm not an engineer. As such, I can't give you the formulaic numbers. You can search for some of the numbers. Search with words such as "how many pounds to stress break a 4x4 #2 grade douglas fir/southern pine". Round about way to check is to look at the span chart of treated 4x4 lumbers, maybe as a beam or a header. Look for doug fir/south pine. Look at the deflection rating. L/360 and /480 are both acceptable in this case. Look at the spans published. Published spans probably will not include 2 joist bays worth, about 36" max in your case. If max published is 4 or 6', I would assume 36 belongs in the accept area.
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