Would appreciate suggestions on best way to reinforce floor joists
under a wood floor (I want to support heavy loads, reduce vibration,
make floor as rigid as possible).
Joists are 2x6 on 16" centers, lighter than average 2x8 construction
and could use some help. House is 2 1/2 yrs old.
I've tried some jack posts supporting short extra 4x4 beams across the
underside of several joists. But using posts (in a fairly new and
still-settling house) creates high spots in the floor, requires
contant readjustment. I would prefer strengthening the joist
structure itself if possible.
Thanks in advance to anyone who cares to comment.
A house is 2 1/2 years old and used 2x6 for floor joists?
What is the span? I would check building codes for your area, we use 2x6 for
wall joists, and at least 2x8 or larger for floor joists. Most builders
today use engineered beams for floor joists.
Either way I would daughter additional 2x6 joists of the identical length
and fasten securely to the original joists.
You don't mention how heavy the load is, that you want to support. You
also don't mention the length of the span for these joists. A 2X6 on
16 centers will span little more that 8 feet.
In addition, you don't mention what type of "heavy load" you will be
carrying. If it's "normal living" stuff like a refridgerator or a
piano, then you can probably add more 2X6's, so that there will be one
every 8 inches. That will substantially increase the load bearing
http://southernpine.com/ That's a website that has charts for
effective load bearing capacity of joists, based on grade, size, span,
and other factors.
And you should also add bridges between the joists. These can be the
old style diagonals, or solid bridging. Bridging spreads the load from
each joist, to the ones that are near it, effectively strengthening
the floor system.
email@example.com (Art) wrote in message
i have a similar question. one of my bedrooms floor will rattle a dresser if you
walk heavy or jump a
little. will cross bracing fix this. joist are 2x8 with a 16ft span, looks like
old pine built in 1962.
<< Joists are 2x6 on 16" centers, lighter than average 2x8 construction and
could use some help. House is 2 1/2 yrs old. >>
Don't waste time and money on this jerry-built dud, Start planning now to dump
it and move as soon as you can. You may have to sell at a loss since disclosing
faults is required in many locales. Just dry your tears and remember your tax
accountant can make it less painful next year.
Before you shop for a new house, start making a a check list now of things you
want, things that are signs of shoddy wiorkmanship and present the list to your
realtor when you're ready to go. This is no time for sentimentality. Good luck
Hi again and thanks to all who replied. I'll have to choose between
the "sister" joists attached lengthwise to the joists or the cross
braces between joists--it's helpful to know either of these will
strengthen the floor.
I appreciate those who worried I was cheated, but it's not the case.
The house is otherwise strong and sound with a secure foundation. For
most folks with normal furnishings it would be zero problem. My heavy
items are storage cabinets, bookcases, media racks, and related stuff
all in one large room or studio--that's the room that needs the
I forgot to mention another method I used successfully in a smaller
upstairs room in another house, which was a layer of 3/4" plywood
screwed and glued to the subfloor under the carpet. That worked
really well. (Current house is single story, hence the jackposts.)
I asked my carpet contractor to do the same in this house in that one
room, but after the carpet was laid and all my furniture was in, I
discovered he had used 5/8" chipboard instead of good 3/4" ply. This
is softer and doesn't add enough rigidity. I could always empty the
room & try again, but maybe doing the joists will be simpler.
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