My wife and I recently bought our first home, and it’s 1919 story&half bungalow. The upstairs attic has great potential for a master siute with a full set of stairs and good head room. But, the floor is under framed with 2×6 joists that mearsure 5 1/4″ tall with spans of 12-13′ and one area is spanned 15′. would sistering on 2×6’s for the 12′ joists and sistering on 5 1/2 LVL’s for the 15′ span be adequete? I would love to hear what you think or any advice would be appreciated?
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You'd be better served by sistering 2x8
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
feet , eyes , head
feet one of the last things a person thinks of when buying a place, whats under my feet unless it bounces so bad the glued on pictures on the wall shake
Piffin is right, 2x8 minimum
eyes, are thee any windows and at what height..... eyes.... vision.......a clue
looks really nice, wow this is neat our first home,
first time buyer, go back a second time and SEE it agin (eyes)
look at another home, and then go back again
head
so lets say you have to sister in 2x8 you just rasied the floor a few inches
head......what are you lookiing at ...exposed rafters......old 2x4 lets see
insulate, not to code, drywall. loose another 1/2 inch
what.......... insulate to code with venting, lets just assume we are going fiberglass r-30
now those 2x4s have to be sistered up to 2x10 ( with air flow)
so lets see, we lost 2 inches in the floor, 6 inches in the ceiling
how attractive is that attic now
the only reason I say this is that my bro did the same thing as you might be ( against my suggestions of lvl's and rigid foam, due to he didnt want to touch the roof)
the house was built with a open attic area with 1/2 inch plywood floor and stairs ( not to code)
by the time they got done, nothing to the floor other then pariticle board and carpet,and the roof up to code with vents, the ceiling at the ridge ( vaulted) was less the 6 feet
and he is 6'3
thats at the ridge
the sidewalls are a joke to him, all he can do is walk down the middle of the "new bedroom"
hes out of state, the contractor said it would work
saved money wiht no permits
now the living room ceiling is all cracked up ( new bedroom above)
DUHHHHHHHHHHHHHHHHHHHHHHHH
take a second look
get a "real" builder in for advice
then see where it goes
Edited 4/29/2005 9:12 pm ET by Isamemon
I owned a house with a situation nearly identical to yours and I did stiffen the floor by sistering onto the existing 2x6 joists with more 2x6. I also added solid blocking and glued down a new plywood subfloor. Of course you probably would be better served by sistering on 2x8 but in my case I didnt want to lose any headroom either above or below. There are a number of other ways to stiffen your floor that I'm not all that familiar with but the discussion pops up here on breaktime occasionally and you'll find that info in the archives if you so desire.
I'll add that this was my own house and would most likely not do this on one of my jobs. Sometimes you have to work with what you have. A lot of the older houses I work on have framing that is overspanned and undersized. The standards were different back then. You might want to reconsider that King Sized Waterbed up there.
Tom
Edited 4/29/2005 11:40 pm ET by mcfish
I've got a similar situation with my 1880-era summer home in Newfoundland, Canada but I would like to avoid sistering the existing 2x6 joists with additional joist material. Are there any other alternatives? The traditional style of these houses called for open joist bays. The upstairs floor boards act as the ceiling for the downstairs and the joists all have a decorative camfer on the edges. I would like to keep these design elements but the upstairs floor is pretty bouncy. Last summer, I removed a 1" board wall between two tiny upstairs bedrooms to make one reasonable-sized bedroom. I didn't think that wall was doing much but I guess it did help stiffen things a bit. Anyway, the situation is now somewhat worse. Are there any other ways to stiffen that upstairs floor? Thanks for any suggestions you folks could offer.
Chip
Congratulations on buying your first home!!
We had almost the same situation. 1924 bungalow 24' wide with the load bearing wall at about the 13/11 point. Virgin growth 2x6's 16 oc between the main level & the attic. We decided to make the attic a "suite" for our two young girls. A couple of low shed dormers really added a lot of light & made it a nice space. But headroom is minimal. 7:12 pitch roof gave us under 7' at the peak. We certainly didn't want to do anything to reduce what little height we had.
First question to deal with are codes. Do you have them and/or will you follow them. I know it's a sin to say so, but lots of things that are not technically to code work perfectly well, as long as you're doing your own work, not someone else's.
Sistering deeper joists would be best - and most direct solution if you are not too concerned with headroom. If you are, and the floor is not outrageously bouncy as it is now, sistering 2x6's might be enough (even one on each side of each original joist?) to make you feel comfortable. Topping it with a good stiff subfloor material will add a lot of stiffness, too.
What's your ceiling material on the main level? Ours was plaster & lath that we wanted to keep, so excessive vibration was a worry. We glued & screwed as much as possible to avoid causing damage. If, by chance, that ceiling isn't precious to you, another intriguing option might be to strip the ceiling to the joists and glue and screw plywood to the underside as well as the attic floor to create a (I forget the proper term) sort of box beam effect for the entire floor which is astonishingly strong and wouldn't even necessitate sistering additional joists.
Finally, The solution we went with involved incorperating the knee wall (which pretty much ran the entire length of both sides of the attic) as a structural element. We anchored the top & bottom plates really well, then sheethed it with 1/2" plywood (glued&screwed) before drywall to create a sort of 30" beam running perpendicular to the joists and this really locked everything together. Is it to code? No. Is it bouncy to walk on? No more than any other floor in the house. Did we crack the plaster ceiling? No - and that's a good sign there isn't excessive flexing. It's been four years for us and no problems.
I would make it a point never to put a king size waterbed up there though.
Good Luck.
Edited 4/30/2005 10:26 pm ET by NannyGee
spans of 12-13' and one area is spanned 15'
According to Span-Calc 2002 you might get 13' with 2x8 16"OC at 30lb live load (attics and sleeping quarters.) At 12"OC you might get 15'.
SamT
You could sister the existing 2x6's with new 2x6; this will effectively give you 4x6 nominal for calculation purposes. A 2x6 SPF SS-grade (good luck finding any new ones!) is good for 9'6" on 24" centers if my memory serves. A 4x6 would be good for a substantially increased span, but you will have to have it calculated as that is not a standard size you will find in any table.
You need to plug in the joist spacing, too. There is a difference for acceptable scantlings among the three most common spacings of 12", 16", and 24".
Another option to sistering would be to insert additional 2x6 joists between the existing ones, halving your joist spacing. So if you were on 24" centers, you would wind up with 12" centers.
Lastly, glue-N-screw for a new subfloor of ¾ ply on top of the joists will definitely give you a stiffer floor deck. Whether it would meet code or not would be something your engineer would have to determine in conjunction with the local inspector.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
It would seem polite to offer some response to the advice you have gotten here.
Maybe he's over at HD...asking them what they think of our advice?
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
Reading this thread makes me really glad that all of my floor joists from the basement to the attic are 2x10s with a 14' span. I don't go down to 2x6s until I get into the rafters in the attic.Phew!
You won't find too many floors framed in 2x6 unless the house is pretty small or very old or both. Having a max span of under 10 feet, they're not real useful on houses wider than 20 feet unless there are multiple beams used to hold them up.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?