Beam length

[Wowzer893]

Hello All,

Looking for some insight, me and my father are fixing up our old garage to make it more useful, we are trying to plan on putting in a beam to take the sag out of the attic, there is lots of stuff up in there too. and can't get it out of there to fix it up.

So the old part is 16x20, i was planning on running 3 - 2x8 to pick up the sag in the floor running the 20ft span, and using 2x6 as posts, and digging down to put in a concrete footing, i have done a bit of looking around and trying to find calculations to see if this will work or not, but i am way over my head in trying to comprehend them, and we are on a budget to do this, so a engineer is a bit out of our reach.

we could do it with a 6", or 8" I Beam but we where hoping to do it with wood as it would be a bit more costefictive but if shown the prof that it won't work we will have to dig deep to find some funds.

Many thanks in advance

 

[Onewolf]

Depending on how much load (lbs/sq ft) you have, you should look at the joist tables in this document: Span Tables. I don't think you are going to be happy when you see how much weight 2x8 joists can support.

 

[BlackTalon]

I don't think you will get far using 2x6s as posts/ columns... Once you figure the loads the beams will be carry to the columns you can then look at sizing the columns.

 

[David C]

Your question reminds me when I first started working. On a request from a client my boss went out to look at a failing wood beam. There was considerable deflection and some wood failure on the compression side of the beam.

On return he told me the owner builder kept saying "but its a 6x12" yes but the loads are too large, "yea, but it is a 6x12" as if a 6x12 had infinite capacity.

Your question can't be answered with the information you provided and anyone capable of providing an answer would be smart enough not to get involved. Go to a local structural engineer or you will be the guy looking at a failure saying 'yea I know but it is a 6x12.

 

[Wowzer893]

Depending on how much load (lbs/sq ft) you have, you should look at the joist tables in this document: Span Tables. I don't think you are going to be happy when you see how much weight 2x8 joists can support.

i think i grasp that chart and such, i'm going to print that out and bring it home, i have a carpenter buddy i can chat with and hopeully he will be able to tell me if i have to do it with 2x12 or whatever, thanks for this.

I don't think you will get far using 2x6s as posts/ columns... Once you figure the loads the beams will be carry to the columns you can then look at sizing the columns.

Yeah i did some more looking last night about columns and such and i think it too would be safer to just go out and buy the metal ones and be done with it.

Your question reminds me when I first started working. On a request from a client my boss went out to look at a failing wood beam. There was considerable deflection and some wood failure on the compression side of the beam.

On return he told me the owner builder kept saying "but its a 6x12" yes but the loads are too large, "yea, but it is a 6x12" as if a 6x12 had infinite capacity.

Your question can't be answered with the information you provided and anyone capable of providing an answer would be smart enough not to get involved. Go to a local structural engineer or you will be the guy looking at a failure saying 'yea I know but it is a 6x12.

Well David. many ways to approach this one. yes i may be the person who says yes but it's a 6x12, but i'm also the person who is smart enough to seek the answers needed to be able to do the work safely so that this garage we are fixing will stand for another 40 years.

Any one capable on this forum maybe would have looked at in another direction of, well why don't i spread my knowledge and inform this person on how to probably fix this situation instead of letting them fail and maybe in turn injuring a fellow board member, a person just needs to be shown in the right direction to find the answers, not all of use are carpenters, and not all of us have unlimited bank accounts for engineers, that money that would go to an engineer, would mean that i would not be getting a mill in the near future.

 

[JACDes]

but you expect / want others to give hard earned knowledge for free?


Any local competent Architect or Engineer can run the calcs. and charge you a nominal fee for the correct design to this problem.

 

[Wowzer893]

i'm just asking for people to point me in the right direction to find the information(Span charts or formula's), no one needs to sit down and do the calcs for me or anything.

is it not the basic premises around these things called Forum's to spread knowledge and gain knowledge of unknown tasks, or under takings at hand?

 

[David C]

Mr. Wowzer

I realize you don't intend to trivialize a complicated problem or belittle the expertise and experience required to answer it; but you are. The answer you seek can't be found in a table, a sentence, or a single written page. Nor can anyone with expertise simply perform a 10 minute calculation for you.

I also don't think it is fair to say that I don't want to "spread my knowledge and instead intend to let you fail". That's seems to be a pretty harsh accusation. I realize it is based upon the misunderstanding that your question is simply answered but still you could have said that in another way or even better asked why your beam is not easily designed. By the way I gave you very good advice which is get an expert to help you. Taking this advice is the best way to avoid "injuring a fellow board member"

But if you still want to be "shown the right direction to find the answers" that can be done very simply. Here it is:

http://www.amazon.com/dp/0071745602/?tag=atomicindus08-20

Looks like you can rent it for $69.30. Get the latest edition so that the design examples are compliant with current codes.

FYI, the design of a wood beam is beyond the ability of most carpenters and contractors.

 

[JACDes]

i'm just asking for people to point me in the right direction to find the information(Span charts or formula's), no one needs to sit down and do the calcs for me or anything.

is it not the basic premises around these things called Forum's to spread knowledge and gain knowledge of unknown tasks, or under takings at hand?

If you never used a span chart or done any structural design before why start now? But if you want to play engineer/architect go right ahead, just be prepared to accept the consequences. You already have enough information to be dangerous.

I only give professional advise to other professionals who speak the same language or a client who pays for the service, otherwise I do not get involved.
I invested too much time to give work away.

May I ask what do you do for living and how long you have been doing it? How about I come and do your job after you give me this basic information?

 

[stealthmagic27]

Wowzer are you planning on supporting only on the sides? Or in the middle also?

 

[dfiler2]

One reason i use our local lumber yard as much as I can is If I walk in and let them know what I am trying to do they will ask me the right questions and get me the proper specs I need to do the job.

 

[Wowzer893]

Mr. Wowzer

I realize you don't intend to trivialize a complicated problem or belittle the expertise and experience required to answer it; but you are. The answer you seek can't be found in a table, a sentence, or a single written page. Nor can anyone with expertise simply perform a 10 minute calculation for you.

I also don't think it is fair to say that I don't want to "spread my knowledge and instead intend to let you fail". That's seems to be a pretty harsh accusation. I realize it is based upon the misunderstanding that your question is simply answered but still you could have said that in another way or even better asked why your beam is not easily designed. By the way I gave you very good advice which is get an expert to help you. Taking this advice is the best way to avoid "injuring a fellow board member"

But if you still want to be "shown the right direction to find the answers" that can be done very simply. Here it is:

http://www.amazon.com/dp/0071745602/?tag=atomicindus08-20

Looks like you can rent it for $69.30. Get the latest edition so that the design examples are compliant with current codes.

FYI, the design of a wood beam is beyond the ability of most carpenters and contractors.

Well i won't be renting that book, i'm just trying to collect enough info, as someone above has given me a span Chart, i should be able to talk with my buddy about how far and what we are able to do, i don't have the funds to go out and get an engineer to make a drawing and tell me how to do it, so i am on my own looking for answers and asking friends their input on code, and such.

If you never used a span chart or done any structural design before why start now? But if you want to play engineer/architect go right ahead, just be prepared to accept the consequences. You already have enough information to be dangerous.

I only give professional advise to other professionals who speak the same language or a client who pays for the service, otherwise I do not get involved.
I invested too much time to give work away.

May I ask what do you do for living and how long you have been doing it? How about I come and do your job after you give me this basic information?

don't really have a choice, i have to become an engineer/architect as the money is not there to do it, that's why i'm looking for the info to do the job correctly.

I work in the Heat Treatment industry http://en.wikipedia.org/wiki/Heat_treating

feel free to ask some questions.

 

[JACDes]

If I need mold cavity made from A2 tool steel heat treated to 63 Rockwell
I use FPM heat treating and pay for their service.

I don't go on a forum and ask someone to do it for me.

I may know how to do it but I don't have the furnace, controls, etc to actually do the process. just because you have span chart does not mean you know how to use it..

That would be like me going into a dentist office and telling him how to fix teeth because I downloaded a chart online.

 

[JACDes]

funny, you have "alligator arms" to pay a pro for his service but have money to buy a milling machine?

 

[Wowzer893]

If I need mold cavity made from A2 tool steel heat treated to 63 Rockwell
I use FPM heat treating and pay for their service.

I don't go on a forum and ask someone to do it for me.

I may know how to do it but I don't have the furnace, controls, etc to actually do the process. just because you have span chart does not mean you know how to use it..

That would be like me going into a dentist office and telling him how to fix teeth because I downloaded a chart online.

Your not even comparing apples to apples. your comparing apples to watermelon

I have the impact, chop saw, table saw, and material to do the job i just don't have the know on what proper 2x6, 8, 10, 12 to use.

So your saying if you had the furnace, and controls, and correct T/C wire on hand but because you didn't know how to do it you would just pay someone to do it?

 

[Wowzer893]

funny, you have "alligator arms" to pay a pro for his service but have money to buy a milling machine?

the milling machine is this, it's far from Pro grade.

http://www.busybeetools.com/products/milling-m-c-mini-110v-mt3-craftex.html

 

[Wowzer893]

Wowzer are you planning on supporting only on the sides? Or in the middle also?

i'm just hoping to put a beam in the center running the 20ft length to pick up some of the load from the attic, this old garage is built with true 2x4 and they are on just over 16" centers for them going the 16 ft side to side.

i've tried to post a pic but can't get it to work sorry

 

[BlackTalon]

So is the roof/ attic framed with rafters and joists, or is it done with trusses? If trusses, all bets are off. If the attic floor just uses joists you should be able to support with a beam; are the joists full-length vs two pieces spliced in the center?

I hope you are okay with calculating live and dead loads and applying the appropriate safety and load duration factors so you can size the beams. And for the column(s) make sure you cut through the floor and install proper footings.

Another possible option is to reinforce the joists to make them stronger by sistering additional wood to the sides. The length, etc. needed for the sistering is easy to figure out once you have drawn the shear and moment diagrams. And knowing the design loads you can then design the fastener pattern to ensure the moment gets transferred properly to the sistering members.

Also, if the joists are sagging, how do the rafters look that support the roof? If the joists were underdesigned I would wonder about the rafters as well.

If you would like better advice consider posting some photos of the rafters and joists from inside the attic. And providing a sketch of the attic floor framing would be helpful as well.

(EDIT: I took so long to write this your post above answered a couple of my questions above, 2x4s 16 inches on center is pretty horrific)

 

[BlackTalon]

Thumbing through 2009 IRC (sorry, cannot locate 2012 right now):

For 2x4 ceiling joists 16 inches on center used in an uninhabitable attic space *without* storage (10 psf live load) the max spans are ~10.5 - 11 feet assuming a grade 2 or better for most of the wood species they list. Even considering you have 'full' 2x4s, the 16 foot span is far too much even assuming no storage in the attic.

For limited attic storage (20 psf total live load), still sticking with the 2x4s 16 inches on center, the max span for most of the wood species listed, assuming grade 2 or better, is between 8 and 9 feet.

So you definitely need to support those 2x4 joists at the midspan, no ifs, ands or buts. Personally a better option if it were me would be to replace the 2x4s with 2x10s, but I believe you indicated you did not want to remove attic contents (which makes me wonder if the contents are exceeding the 10 psf allowance for 'limited storage'.

Anyway, if nothing else this reinforces your thoughts on the need to, er, reinforce.

Now let me tally my time and calculate my invoice for these preliminary engineering services...

 

[Wowzer893]

So is the roof/ attic framed with rafters and joists, or is it done with trusses? If trusses, all bets are off. If the attic floor just uses joists you should be able to support with a beam; are the joists full-length vs two pieces spliced in the center?

it's done with rafters and joists, and the joists are full length side to side, full 16ft

I hope you are okay with calculating live and dead loads and applying the appropriate safety and load duration factors so you can size the beams. And for the column(s) make sure you cut through the floor and install proper footings.

Well i'm not okay, but my buddy who is a carpenter told me to come over tonight, with the span chart i have printed out, and said we should be able to get to where we need you to be. And yes for the footings, probably do a 12" sono tube 4-6ft down, and put the bell at the bottom to make sure that it doesn't move in the spring, and fall

Another possible option is to reinforce the joists to make them stronger by sistering additional wood to the sides. The length, etc. needed for the sistering is easy to figure out once you have drawn the shear and moment diagrams. And knowing the design loads you can then design the fastener pattern to ensure the moment gets transferred properly to the sistering members.

I was actually told that this was all i needed to do by a contractor, sister them with 2x6 and all would be well, but me and my father are going to go the beam route, and if needed can sister witch ever ones are needed from there

Also, if the joists are sagging, how do the rafters look that support the roof? If the joists were underdesigned I would wonder about the rafters as well.

the roof is actually pretty good, there was a bit of sag in between the 2x4, but that was because there where on 24" centers, so 2 years ago we re-sheeted it and sister some up with 2x6, and then put some extras, in to shorten up the 24" when they where larger as well put some piece in between to get the plywood to nail correctly


If you would like better advice consider posting some photos of the rafters and joists from inside the attic. And providing a sketch of the attic floor framing would be helpful as well.

(EDIT: I took so long to write this your post above answered a couple of my questions above, 2x4s 16 inches on center is pretty horrific)

i will try get some tonight, can't get into my photobucket to post any pictures

 

[JACDes]

Your not even comparing apples to apples. your comparing apples to watermelon

I have the impact, chop saw, table saw, and material to do the job i just don't have the know on what proper 2x6, 8, 10, 12 to use.

So your saying if you had the furnace, and controls, and correct T/C wire on hand but because you didn't know how to do it you would just pay someone to do it?

we have a small furnace, etc, but that is the issue.. it is small. We are not going to complete an order in one load. better to farm it out to a heat treat shop who has a huge furnace and get the parts back the next day, finish polish and ship to the customer.

You pay for the service and the time it saves you, plus you know it was done correctly.

if you don't know what proper size to use you pay a professional.. do overs cost more.
basic business practice some homeowners get it... most don't

 

[Wowzer893]

Thumbing through 2009 IRC (sorry, cannot locate 2012 right now):

For 2x4 ceiling joists 16 inches on center used in an uninhabitable attic space *without* storage (10 psf live load) the max spans are ~10.5 - 11 feet assuming a grade 2 or better for most of the wood species they list. Even considering you have 'full' 2x4s, the 16 foot span is far too much even assuming no storage in the attic.

For limited attic storage (20 psf total live load), still sticking with the 2x4s 16 inches on center, the max span for most of the wood species listed, assuming grade 2 or better, is between 8 and 9 feet.

So you definitely need to support those 2x4 joists at the midspan, no ifs, ands or buts. Personally a better option if it were me would be to replace the 2x4s with 2x10s, but I believe you indicated you did not want to remove attic contents (which makes me wonder if the contents are exceeding the 10 psf allowance for 'limited storage'.

Anyway, if nothing else this reinforces your thoughts on the need to, er, reinforce.

Now let me tally my time and calculate my invoice for these preliminary engineering services...

ohh i'm guessing that all the contents do exceed the 10 psf allowance, no doubt about that one. well tonight, i will try and get some pictures, and such and do a little hand sketch going. and i will def rethink sistersing up the 2x4's now that you have told me they should only be 8 to 9 ft

don't joke about those engineering services, some serious stuff right there

 

[BlackTalon]

don't joke about those engineering services, some serious stuff right there

heh heh, who said I was joking. I AM a civil/ structural engineer.

 

[Wowzer893]

we have a small furnace, etc, but that is the issue.. it is small. We are not going to complete an order in one load. better to farm it out to a heat treat shop who has a huge furnace and get the parts back the next day, finish polish and ship to the customer.

You pay for the service and the time it saves you, plus you know it was done correctly.

if you don't know what proper size to use you pay a professional.. do overs cost more.
basic business practice some homeowners get it... most don't

i haven't done anything yet, haha i am still in the planning and information gathering stage.

i can perform this task, and will. i don't have a pocket book that allows me to go out and pay for Engineering, maybe i will have to call in a favor or 2 from my contractor friends who know such information Talon has, because it looks as i have found a good portion of the information needed. but there are still holes yes, and i will keep looking.

 

[Wowzer893]

haha touche

 

[Wowzer893]

heh heh, who said I was joking. I AM a civil/ structural engineer.

haha Touche sir, you win round 1

 

[KELLHAMMER]

Wowser

I agree with many of the posters that dispensing complicated structural solutions via this forum or any other is risky business for both parties. Although, you seem set against having a local PE or an architect help sizing framing members for a structural repair. Have you even consulted one to get an idea on fees for this service? Sadly, many DIYers forgo professional advice and overdo and under do the required repair. Thus, they either spend more than or the equivalent to the said professional advice. Or end up not doing enough and all the time and materials ends up being wasted on the effort. I suspect a structural engineer may only require one hour to come to a solution. My structural engineer charges 120/ hr . You could easily burn that up on a misguided remedy in both your time and materials

 

[Wowzer893]

Wowser

I agree with many of the posters that dispensing complicated structural solutions via this forum or any other is risky business for both parties. Although, you seem set against having a local PE or an architect help sizing framing members for a structural repair. Have you even consulted one to get an idea on fees for this service? Sadly, many DIYers forgo professional advice and overdo and under do the required repair. Thus, they either spend more than or the equivalent to the said professional advice. Or end up not doing enough and all the time and materials ends up being wasted on the effort. I suspect a structural engineer may only require one hour to come to a solution. My structural engineer charges 120/ hr . You could easily burn that up on a misguided remedy in both your time and materials

there's really only 2 in our area, we are kinda remote to any cities. first one was $650, free consultation to talk about it. and then if we pay you get the drawing, cut list, and stamp.

2nd one wanted to come and vist first, okay, and then wanted $725 (Included travel from his office to us, drawings, cut list, and stamp)

 

[404]

Hello All,

Looking for some insight, me and my father are fixing up our old garage to make it more useful, we are trying to plan on putting in a beam to take the sag out of the attic, there is lots of stuff up in there too. and can't get it out of there to fix it up.

So the old part is 16x20, i was planning on running 3 - 2x8 to pick up the sag in the floor running the 20ft span, and using 2x6 as posts, and digging down to put in a concrete footing, i have done a bit of looking around and trying to find calculations to see if this will work or not, but i am way over my head in trying to comprehend them, and we are on a budget to do this, so a engineer is a bit out of our reach.

we could do it with a 6", or 8" I Beam but we where hoping to do it with wood as it would be a bit more costefictive but if shown the prof that it won't work we will have to dig deep to find some funds.

Many thanks in advance

So to start off with I am not a structural engineer, nor am I your engineer. Some of this is incomplete or vague.

All that said, it is possible to get an overkill solution without that much work. What I do (in my benighted ignorance) is to look at the ratio of the length of the beam to the height. The width of the beam is important to prevent the beam from twisting or rolling over in the middle but does not do a lot otherwise. The main thing in beam strength is the height of the beam. The beam gets stronger as the cube of the height. So a beam one foot high has a strength of one, lets pretend. A beam 2 foot high has a strength of 2 * 2 * 2 (multiplication) which is 8.

So now for your beam. If I was doing this ( and I was part of doing this for a garage in Vermont, I would make a beam that was a glued and screwed sandwich. The web would be 3/4 plywood and the truss could be 2 x 8. This beam is going to be 2 feet high, to use plywood a half sheet at a time.

I will make a sketch and post in a little bit, my magnificent wife just brought me lunch.

 

[BlackTalon]

there's really only 2 in our area, we are kinda remote to any cities. first one was $650, free consultation to talk about it. and then if we pay you get the drawing, cut list, and stamp.

2nd one wanted to come and vist first, okay, and then wanted $725 (Included travel from his office to us, drawings, cut list, and stamp)

Those are good prices considering they include stamped drawings and for one of them a site visit. Can burn 2-3 hours on the calcs easily (ha, I've already burned 2, as I started messing with options for solid wood beams), plus another 2 hours on drawing. You get to ~$750 pretty quick.

On a side note, if you go with a solid wood beam it will need to be pretty beefy. Also, you need to restrain the beam ends from rotation and also secure the compression flange to the joists for lateral stability -- otherwise beam sizing will increase even more. Chances are this will get beyond what your carpenter friend is willing to stick his neck out on. Also, where I live you would need a permit for this work, which would include needing a stamped drawing. And frankly if someone is looking to eventually buy your place they (or their inspector) might get nervous about the beam/ column installation and want supporting information so they know it is okay. We've been hired by real estate agents several times to perform calcs on undocumented structural 'upgrades', and they don't always comply with codes -- that can be a deal-killer.

 

[JACDes]

Wowser

I agree with many of the posters that dispensing complicated structural solutions via this forum or any other is risky business for both parties. Although, you seem set against having a local PE or an architect help sizing framing members for a structural repair. Have you even consulted one to get an idea on fees for this service? Sadly, many DIYers forgo professional advice and overdo and under do the required repair. Thus, they either spend more than or the equivalent to the said professional advice. Or end up not doing enough and all the time and materials ends up being wasted on the effort. I suspect a structural engineer may only require one hour to come to a solution. My structural engineer charges 120/ hr . You could easily burn that up on a misguided remedy in both your time and materials

that is the going rate....

 

[Wowzer893]

Those are good prices considering they include stamped drawings and for one of them a site visit. Can burn 2-3 hours on the calcs easily (ha, I've already burned 2, as I started messing with options for solid wood beams), plus another 2 hours on drawing. You get to ~$750 pretty quick.

On a side note, if you go with a solid wood beam it will need to be pretty beefy. Also, you need to restrain the beam ends from rotation and also secure the compression flange to the joists for lateral stability -- otherwise beam sizing will increase even more. Chances are this will get beyond what your carpenter friend is willing to stick his neck out on. Also, where I live you would need a permit for this work, which would include needing a stamped drawing. And frankly if someone is looking to eventually buy your place they (or their inspector) might get nervous about the beam/ column installation and want supporting information so they know it is okay. We've been hired by real estate agents several times to perform calcs on undocumented structural 'upgrades', and they don't always comply with codes -- that can be a deal-killer.

Yeah those where only quotes too i should add, they weren't firm lump some. you pay this and you will have your drawing.

in the end i just want to try and do this right. i have thought already about the rotating factor, i am going to get the welding shop in town here to fab me up some plates, that will enclose both ends and then leg them straight through with all thread, and then all thread on the bottom. basically 2 C's out of like 1/4" plate or 1/2" plate, leaning towards the 1/2" plate

But i will see what happens tonight and see how far we get, and if we do not feel confident in our decision i guess i will have to give an engineer the grand and get this drawing.

You are right about real estate people though, my family friend is one, and he has had to do this before, that's where i got the contacts from.

 

[Wowzer893]

that is the going rate....

that is the going rate is around here, but everywhere you talk too is a 4 hr min, and you don't get a drawing, stamp or cut list. someone once told me don't know if it's true is every time an Engineers stamp hits the final page is $50

 

[bczygan]

OK Wowzer893,
First, what's your first name. I like to talk to people by name for this kind of thing. Mine is Bill.

You have gotten the typical range of answers for this kind of question.

Usually some rule of thumb answers like "Use a 2x12", along with a lot of admonitions to hire professional help or you will be damned to eternal perdition.

Professionals will hesitate to help because of liability and they do it for a living and expect to get paid.

Amateurs may have some knowledge, but may not have enough experience to see any critical conditions you have. And they may not know to gather enough information to make informed judgements.

The problem with diagnosing and designing over the web, is that it is hard to determine all the existing conditions.

But it can be done.

It will require that you do a lot of legwork.

We MUST have extensive photos and measurements. Enough to determine the existing conditions completely. We need to be able to examine the entire structure from peak of roof to foundation. We need size and spacing and condition of all the structural members. We need to know the loads you intend to impose on the structure.

We also need to know if you are going to do this work without a permit, or if you intend to meet all the local jurisdictions requirements.

And you need to determine the quality of the advice you are getting to sort out that that is a partial answer, that which is wrong, and that which is complete and meaningful.

I am an Architectural Designer, not a registered Architect or Engineer, but I have designed and rehabbed structures similar to what you describe.

Give us the information we need, and we can advise you. It's not rocket surgery.

Start with as many photos as you can and measurements of everything.

Bill

 

[Wowzer893]

Hello Bill.

My name is Drew.

and not a problem i'll take some photos tonight, and get some dimensions as best i can and get it posted up

 

[BlackTalon]

that is the going rate is around here, but everywhere you talk too is a 4 hr min, and you don't get a drawing, stamp or cut list. someone once told me don't know if it's true is every time an Engineers stamp hits the final page is $50

We pay ~$20k/ year for our Errors and Omissions insurance. We also carry general liability, etc. And we have professional society memberships, health insurance, rent, office equipment costs, vehicle costs, etc. etc. etc. Similar to an auto mechanic, the hourly rate we charge for any given level of engineer is essentially 2.5 times their salary; that is what it take in order for us to stay in business. So I am surprised to hear the 'stamp hitting the page' is only $40

Even the engineers who are on-man operations who work out of their homes have E&O costs, general liability costs, and other overhead expenses.

I suspect you don't have a good understanding yet of the design liability that the engineer assumes. Heck, think of it as an insurance policy -- for $750 someone else (i.e., the engineer) takes essentially all the liability off your hands if it comes crashing down and kills someone because it was under-designed... Now if it crashes down because someone did not follow that design when installing...

 

[bczygan]

We pay ~$20k/ year for our Errors and Omissions insurance. We also carry general liability, etc. And we have professional society memberships, health insurance, rent, office equipment costs, vehicle costs, etc. etc. etc. Similar to an auto mechanic, the hourly rate we charge for any given level of engineer is essentially 2.5 times their salary; that is what it take in order for us to stay in business. So I am surprised to hear the 'stamp hitting the page' is only $40

Even the engineers who are on-man operations who work out of their homes have E&O costs, general liability costs, and other overhead expenses.

I suspect you don't have a good understanding yet of the design liability that the engineer assumes. Heck, think of it as an insurance policy -- for $750 someone else (i.e., the engineer) takes essentially all the liability off your hands if it comes crashing down and kills someone because it was under-designed... Now if it crashes down because someone did not follow that design when installing...

And the prices quoted above are great deals for that service and protection.

The difficult thing is to convince a client that they need to spend more on the design than for the materials....

Professionals of all kinds get the bucks for a lot more than the time spent for a job.

 

[404]

The (2x8) means a board nominal dimension. The no ( ) means 2 ft by 4 ft 3/4 plywood.

So here is the sketch. This pic is the (2x8) truss inside the plywood sheets.
In reality this is (2x8) laid flat fitted together.

The lower (2x8) should be continuous. The height of the truss is 2 feet. Make the length as you need but keep the angles of the truss the same.

Imagine this being laid flat on a flat floor for assembly.
The bottom layer is the upper and the lower (2x8) only.
Then 2x8 sheets of plywood along the length.
Then the (2x8) laid flat truss.
Then another layer of 2x8 sheets of plywood
Then the upper and lower (2 x 8) only.

There will be joints between the plywood sheets, offset them 2 to 3 feet between the 2 layer of plywood.

This should be glued, screwed to clamp the glue, and then nailed for shear.

The glue should be rated for continuous loading, which used to leave out the common yellow glues, not sure if that is different today.

 

[bczygan]

The (2x8) means a board nominal dimension. The no ( ) means 2 ft by 4 ft 3/4 plywood.

So here is the sketch. This pic is the (2x8) truss inside the plywood sheets.
In reality this is (2x8) laid flat fitted together.

The lower (2x8) should be continuous. The height of the truss is 2 feet. Make the length as you need but keep the angles of the truss the same.

Imagine this being laid flat on a flat floor for assembly.
The bottom layer is the upper and the lower (2x8) only.
Then 2x8 sheets of plywood along the length.
Then the (2x8) laid flat truss.
Then another layer of 2x8 sheets of plywood
Then the upper and lower (2 x 8) only.

There will be joints between the plywood sheets, offset them 2 to 3 feet between the 2 layer of plywood.

This should be glued, screwed to clamp the glue, and then nailed for shear.

The glue should be rated for continuous loading, which used to leave out the common yellow glues, not sure if that is different today.

Just curious how you can design or engineer anything without knowing the existing structure and loads that will be imposed?

 

[Wowzer893]

We pay ~$20k/ year for our Errors and Omissions insurance. We also carry general liability, etc. And we have professional society memberships, health insurance, rent, office equipment costs, vehicle costs, etc. etc. etc. Similar to an auto mechanic, the hourly rate we charge for any given level of engineer is essentially 2.5 times their salary; that is what it take in order for us to stay in business. So I am surprised to hear the 'stamp hitting the page' is only $40

Even the engineers who are on-man operations who work out of their homes have E&O costs, general liability costs, and other overhead expenses.

I suspect you don't have a good understanding yet of the design liability that the engineer assumes. Heck, think of it as an insurance policy -- for $750 someone else (i.e., the engineer) takes essentially all the liability off your hands if it comes crashing down and kills someone because it was under-designed... Now if it crashes down because someone did not follow that design when installing...

I am well aware of what it takes off my shoulders, we work with foster wheeler almost on a weekly basis, I am right now working on a project and I'm pretty sure their bill now is around 100, 000 and we are only in the first stages of revision, this is for an oil and gas project.

And the prices quoted above are great deals for that service and protection.

The difficult thing is to convince a client that they need to spend more on the design than for the materials....

Professionals of all kinds get the bucks for a lot more than the time spent for a job.

Honestly it's not that I don't want an engineered drawing and stamp, it's that I can't afford it. I need to be in the 1000 to 1500 range for this aspect of the remodel.

But tomorrow in the light I will take some photos and get some measurements and hopefully be headed in the right direction