Second Story Addition

Ebola

Situation:
Home Owner wants to add second floor. First floor ceiling joists are 2x8 over 13'10" span. Ceilings are older plaster-over-stucco-over-sheetrock (appx. 12 lbs/sqft).

So:
Ceilings need to come out, and span tables call for at least 2x10 No. 1 Southern Pine joists. I worked it at 60LL 20DL 360DF just to be sure because there will be some stone work in upstairs baths.

But is there a better way to reinforce existing joists (angle iron, flitch, sistering) as opposed to removing entire ceiling structure? Lots of wire, plumbing, hvac to deal with. ie will sistered 2x8's sub for 2x10's otherwise house will be uninhabitable while work takes place.

neolitic

My trick is to set 2X4 blocks on
the top plate between the ceiling joist
then run my new floor joist on top
of those to isolate the 2nd floor from
the old 1st floor ceiling.
Saves a lot of time and mess if your
conditions allow it.

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Ebola

Thanks for responding. I see what you mean, but this would still necessitate lifting/detaching the roof. What the home owner wants (really) is to prep the old ceiling and get it structurally capable of supporting the new second floor without actually adding the second floor yet. That will be done later when weather permits in a modular fashion -- prefab walls, etc., rip off old roof, crane up new second story, attach trusses, reroof, sheath-- wham bam thank you ma'am

neolitic

I can't see yours, but I have done
just that, by removing a strip of deck
at the bottom of the roof.
Had to tarp the whole roof at night
but with most of the roof in tact
it wasn't hard to keep the snow out.
Of course I was keeping the job moving,
not letting it sit through the winter.

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Aaron111

I suggest telling landlord to tear out and re Joyce the floors ......

Joe Carola

Why does the ceiling have to come out? There's no reason for it to come out when sistering new joists. I used to add the 2x4 blocks on the outside walls and then sister joists, but that doesn't solve the problems with wires/plumbing/hvac. No need to strengthen existing ceiling joists because the new 2x10's will take the weight of the second floor.

Since your adding 2x10's that means your existing stairs are coming out and you have to add a new set of stairs. What we always do now when changing stairs is add a plate to the top of the existing joists and run I-joists full length across the entire house and start the new floor above the old joists. This way nothing is in the way.

Doing this adds at least 2 risers to the new steps but it makes everything alot easier and the first floor stays protected and people can still live in the house if there isn't alot of work going on the first floor.

You frame the new stairwell opening and open up the existing ceiling joists later after the addition is done.

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neolitic

Joyce says she doesn't remember you.

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DaVinciRemodel

I think Joyce remembers him! That's why there's an "inspector" doing this job. I wish my inspectors would do this for me - work and pass inspection - one call does it all.

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neolitic

Missed that, must be my pain meds.

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eisert

I worked on a job in Minneapolis a couple of years ago that was the same as you describe. Second story addition, a ton of mechanicals in the way. Electricians, plumbers and hvac came in first and did all of their work. Then we craned off the roof and craned in a structural floor panel. Demo and new floor completed in about 8 hours. The floor panels spanned the entire width of the house (roughly 30 ft?), were about 5 feet wide, 1 1/2 inches thick. Extremely heavy. Can't remember what the panel product was called though. If you would like the builders name, send me an e-mail at eisert.steve@gmail.com. I'm sure you could contact him and he could give you some info on the product.