×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

New second Floor

New second Floor

New second Floor

(OP)
Hello,
I am doing a residential design/build project where we are adding a second floor to an existing split-leve house. The addition is above an existing 4-car garage that is 27'x33' with 8' clg. ht. and pre-fab roof trusses.

My question is this, what sort of a floor system should I use? I am thinking of using 16" wood I-Beams, but since their max. span is about 21' that requires me to have a bearing wall in the center, but I don't know what size LVL beam to spec. Also, those LVL beams will be EXPENSIVE, and the homeowner will Freak when I tell them how much they cost.


Any other Ideas of accomplishing this task?

Thanks!!

RE: New second Floor

Use more 16" beams than you planned on. Hire an engineer.

RE: New second Floor

haynewp is right, hire an engineer. If the homeowner "freaks" about the cost of the engineer, replace the existing homeowner immediately with a fly-rod.

-Mike
www.sewellgeneralcontracting.com

RE: New second Floor

Realise that after hiring an engineer, he may require you to strengthen/underpin existing foundation below the new addition (or conclude that it is not possible).  Most homeowners only think of cost associated with what's "visible".  Existing foundation may not have been designed to carry the additional floor loads.

RE: New second Floor

jrtm76,

A 24" deep open web floor truss spaced at 24" o.c. without any additional roof loads would clear span the 27'-0" without any additional load bearing requirements in the center as long as the floor loading is 40#psf live and 15#psf dead.

Contact your local truss manufacturer, they will normally provide you with all of the truss layouts and engineering requirements as part of the selling price for the trusses. The cost should be about $95 each...

RE: New second Floor

(OP)
Thank you guys for all the suggestions.
I contacted a local truss designer and they are suggesting a 20" deep open web truss at 19.2" o.c.
There is actually an engineer looking at the foundation today, he already suggested we reinforce it and the homeowner has agreed to it.

Again, thank you all.

RE: New second Floor

Another concern you should have in addition to having floor joints that will support the design loads, you should also consider if the existing footing will support the new loads.

RE: New second Floor

(OP)
Yes, that has been considered and a structural engineer was hired to design reinforcement to the existing footings.

RE: New second Floor

I am in the process of pricing two ways to add a second floor to a family house that has million dollar views (from the roof).  Since my husband has built butler buildings cheaply in our citrus groves, I asked several metal building companies to give me a price on adding a second floor around and over the existing house.

Of course the first floor roof will have to be removed and covered while the second floor structure goes in, but the prices are much much less from the metal building companies.  Oh, and before you gag, realize that you can clad a metal building in any finishes you want and make it look just like any residence.

Oh, and a metal building can be built in 7 days.  This is a lot quicker than conventional construction which adds months and frustration.  I will keep you posted...we are considering filming the project and submitting to THIS OLD HOUSE...

RE: New second Floor

I don't like pre-engineered metal buildings personally.  They aren't in it to supply a good quality structure imho.  They want to sell metal.  Always remember, you get what you pay for.  It's cheaper now by all means but it will show at some point.  Hopefully it won't take a design event to do so.

RE: New second Floor

I've also had some bad experiences with pre-engineered buildings.  They have much higher allowable deflection and drift limits than typically would be used for good design.  The cost numbers always sound more attractive becuse you are getting FAR from a complete package...I always hear their advertisements on the radio and wonder how many people sign up not knowing that glazing, foundations, finishes and HVAC are not included...

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources