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Can you take a look at the following link and answer the questions at the bottom of the sheet? Your answers will allow me to accurately model the loading and size your beam. Thanks
Would it be a New Beam #5?
The beam is closest to the center, #3 and supports only the asphalt shingled 4/12 roof. We have run lolly columns to the foundation of this one story with a basement house.
Will it also support the ceiling and drywall?
Are you still there?
Yes. What we have done is to remove a semi-load bearing wall between the kitchen and living room and, had originally put in two 12" x 1.75" microlams bolted together, but it does'nt seem like quite enough as we are getting about a 1/2" sag. we also cut away the trusses above the kitchen and put in vertical supports from the plate that sits on the beam to the top of the trusses.
We are putting a cathedral ceiling in the kitchen.
We were looking at a beam roughly 4" x 10" at 15 lbs/ft. Do you think this will be enough? I can send you a picture if you like.
You have to be very careful about cutting truss members. The internal truss members are designed specifically for the configuration they were shipped to the job site for. You can not just cut out sections and replace that with new elements.
Truss members all have different forces in them. Some members are in compression and some members are in tension. When you cut out an internal member, the entire force distribution in the truss will change.
On another note, most pre-manufactured trusses are not designed to have bearing points at their midspans
I would not recommend that you do this until you have talked to the truss manufacturer that fabricated your trusses and get them to analyse the new configuration and agree with your modifications.
What city are you close to in VA so I can look at your design snow load requirement?
This is an older house ca 1950 with the trusses built on site and nailed together with plywood plates. The previous owner had already removed the wall and made half the room a cathedral ceiling. It sagged a good 1 1/2". we are trying to fix the problem. let me send you a picture. We are in Manassas.
You can attach it to the chat window with the icon in the toolbar
Can you give me an address we can sen a picture from an I phone?
The trusses are 24" oc and we realize it may take a little while to figure this.
I just got the picture, let me print them out
Before we get started I’d like to point out that a Professional Engineer’s standard of care typically includes a site visit to assess field conditions and get an overall understanding of the structure. This can obviously not be accomplished through the internet. The information provided here is meant for planning purposes only (general sizing and budgeting) and is based on the information provided by you. All loading cases considered are for vertical loads only, no lateral analysis has been completed. The information should be verified by a professional engineer who can visit the site to ensure that potentially important information has not been overlooked or omitted.
One problem I see is if you go to a steel beam, connections will be harder to accomplish between your timber members and your steel beam
We have thought of that, and I have worked with I-beams before. We are sending more pictures to try to give you a better grasp. We will probably have some small holes drilled to attach wood tot he bottom to aid in drywalling. I appreciate the lateral support issues you have mentioned.
I can actually see the sag in the beam in one of your pictures. A big issue is that you have a sag in your beam with only Dead Load on it. The snow load for your area is 25 psf, when that is added you will really have sag and possible cracking and failure
Another issue is your roof rafters in the cathedral ceiling side are way over-spanned.
Are you going to sister in some deeper roof rafters that can span your approx. 13' with a 25 psf snow load on top of your Dead Load?
I just printed off 8 pictures. I am leaving my office right now. I am going to have to put some thought into this. I will be able to give you some advice for planning and budgeting purposes, but when all is said and done, you will really need to have an engineer come out for a site visit and give you the final guidance.
I am going to switch over to the Q&A format and we can continue with the e-mail process. When I come back online, I will send you an e-mail to tell you I am back, so check your e-mail periodically (use the e-mail account that you gave to JustAnswers). You do not need to rate any answer yet until we are complete and you are satisfied. Thanks.