Supporting A Crawl Space

[D45]

The family room is above the crawl space and I feel the family room vibrates a ton and is noisy

In the crawl, there is a large beam running under a portion family room, but an even larger portion of the floor is "unsupported" and the floor joists are just sitting ontop of the foundation wall

The basement is half poured basement (8 foot ceilings) and half crawl (about 3-4 feet high)

My thought is to run some 2x6s (4x4s? 2x8s?) under the entire span of the family room floor, evenly spaced out and parallel with the other beam

Lay down some thick 16"x16" concrete pavers, buy 3 adjustable columns and three concrete column bases

Seems cheap, easy and should be effective.................any thoughts?

 

[kaymccampbell]

Just extend the beam and put a couple posts under it with bases. One post at the joint.
What kind of beam is already there? Wood? Steel? Other?

 

[D45]

The beam is already running wall to wall, can't extend it

The supports under the wooden beam (look to be 2x10s) are round steel columns, which don't look to be adjustable

I think another beam, parallel to the main beam, to help support ad isolate the noise/vibrations would help

The main wooden beam is only about 4-5 off one wall, leaving the remainder of the family room floor joists unsupported for a good 12+ feet

I think that another beam evenly spaced out (from the beam to the wall) over the family room floor seems logical.......

 

[bczygan]

Anything you can do to cut the span of the joists or beams, will make them less bouncy.

Bill

 

[D45]

Will the size of the beam matter at all?

Obviously the larger the better, but with that comes price

Will 2x6s work or are they too small for support?

 

[givemethewillys]

Wouldn't putting x braces or blocking under the family room span stiffen it up considerably?

 

[DTE]

My living room floor bounced like what you are saying yours does, and I split the difference with the center beam under the house and added 2 more that I built out of 2 x 10's bolted together and used 3 adjustable post's on each one. Might be a little more than needed but I very seldom have to do things over. ( it stopped all the bounce also )

 

[kaymccampbell]

Gotcha. Then make an identical beam to the original poorly placed main beam and split the remaining open span with it. Support it the same way and you should minimize your floor bounce.

 

[Richard Cranium]

use a couple of 2x10s sistered together.

 

[ddawg16]

Post some pics?

 

[dfiler2]

The main wooden beam is only about 4-5 off one wall, leaving the remainder of the family room floor joists unsupported for a good 12+ feet

Assuming you mean 4-5 ft on one side and 12 ft on the side that seems weak, then yes, supporting that side would probably help a lot. What are the floor joist made of? Your first idea is probably the best and if the joists are dimensional lumber you may need to shim on top of the beam to make sure you are contacting all of them. If the joists are at least 2x 10's you might be able to install some metal bridging at the 6 ft mark that would help a lot.

http://www.strongtie.com/products/connectors/nca-tb-ltb.asp

 

[D45]

Assuming you mean 4-5 ft on one side and 12 ft on the side that seems weak, then yes, supporting that side would probably help a lot. What are the floor joist made of? Your first idea is probably the best and if the joists are dimensional lumber you may need to shim on top of the beam to make sure you are contacting all of them. If the joists are at least 2x 10's you might be able to install some metal bridging at the 6 ft mark that would help a lot.

http://www.strongtie.com/products/connectors/nca-tb-ltb.asp

yes that is what I tried to describe.........floor joist are wood

From the looks of it, they are either 2x10s or 2x12s, I will try to measure real quick

Thanks for the link........not sure those would work that well, since there are already braces in there, angle cut wood

 

[D45]

Gotcha. Then make an identical beam to the original poorly placed main beam and split the remaining open span with it. Support it the same way and you should minimize your floor bounce.

This is what I am leaning towards, simple and effective

 

[D45]

My living room floor bounced like what you are saying yours does, and I split the difference with the center beam under the house and added 2 more that I built out of 2 x 10's bolted together and used 3 adjustable post's on each one. Might be a little more than needed but I very seldom have to do things over. ( it stopped all the bounce also )

I wonder if I would need 2 or 3 adjustable columns........I would be making a sistered beam probably around 25 feet long

 

[D45]

I just measured the area....

The floor joists are 2x10

The current beam is about 6 feet off one wall and the span to the other wall is about 13 feet

Here are some pics:

 

[trukkins10]

My last house was just like that. I sistered all the joists to stiffen it up. Very noticeable when done. My reason was to lay tile tho.

 

[D45]

My last house was just like that. I sistered all the joists to stiffen it up. Very noticeable when done. My reason was to lay tile tho.

Sistered each joist to each other? As in bracing each other? I wonder if I should do this first, before the beam.......

I just double checked and while the joists in the basement are braced/connected to each other, but NONE of the joists in the crawl are braced

 

[dfiler2]

The odd thing here is that the joists don't seem to be the same from one side of that duct work to the other. There could be a header and if that the case I would put another beam like the one on the left directly under the header and as you suggested earlier use some adjustable metal columns. I would get an LVL the right length and dimension, it may be easier to get 2 LVL's and overlap them in the center unless you can get some strong friends to help lift a full length one into place into place. Two beams would require more posts.

After looking a little closer it does look like the 2x10's on the right are one piece. I think 2 x 10 are good for about 15 feet but your getting close to the limit, the reason i bring this up is the bridging would probably do a lot and you do the beam later if they didn't do the job you wanted.

 

[D45]

You can see that there are 2x10s overlapping each other and sitting ontop of the beam

They are 2x10s on both sides of the duct

 

[trukkins10]

Glue and screw 2x10 to each joist. You don't need to do the entire length, just 80%. What this does is minimize the deflection of the floor.
What "vibrates" in the room? Do you have hardwood flooring? That could be the cause of noise from echoes.

 

[D45]

Carpeting on the floor

Not sure what is underneath, other than plywood

The floor seems loud like it vibrates when my daughter jumps around and plays hard in there

 

[D45]

So should I beam support it or first try the metal joist braces first?

 

[kaymccampbell]

Beam support it.

 

[Shiftless]

Assuming you mean 4-5 ft on one side and 12 ft on the side that seems weak, then yes, supporting that side would probably help a lot. What are the floor joist made of? Your first idea is probably the best and if the joists are dimensional lumber you may need to shim on top of the beam to make sure you are contacting all of them. If the joists are at least 2x 10's you might be able to install some metal bridging at the 6 ft mark that would help a lot.

http://www.strongtie.com/products/connectors/nca-tb-ltb.asp

Beam support it.

And support your beam with adjustable screw posts. That way you can fine tune them as time goes by and your soil moisture changes and or minor settling occurs. Even a sixteenth can cause squeaks. Worked for me!

 

[Kaizen]

first thing i'd do is have your daughter or an adult jump around and look for flexing. i'm guessing that beam isn't doing it job. if you see any flexing jack up the beam and repeat. if that isn't the problem i'd sister something to the existing. depending on space I might use 3/4 inch plywood screwed and glued in to cover the bouncy areas. then cross bracing....even 2x12's cut 15.25 long should fit between them. off set them so you can nail through the existing joinst into the end of the brace.
last determine if its just the noise that's bugging you. not sure if that's a cold zone but safe and sound or spray foam will deaden the foot falls

 

[D45]

What's the possibility those current support columns are in concrete....... Or removable?

I wonder if some adjustable columns would help out better for the old beam

I think for $0.75, I'll try those bridging braces first on the long 13 foot long portion to see if that helps at all and also throw some on the other side of the duct

 

[DTE]

I wonder if I would need 2 or 3 adjustable columns........I would be making a sistered beam probably around 25 feet long

If your spanning 25 ft I would probably use 4, I can't tell from the photos but I guess the beam under there now sits in a pocket ? you don't have a pocket for the new one so you will need a post at each end and then you would still be spanning a pretty good distance and buying one more post should not be much of a factor. I also added some hurricane straps along with toenailing the beam in place. You will probably find some sag in your floor so you might have to raise it a little a that time. You will be glad you fixed it when your done. We were doing a pretty extensive remodel when I fixed ours and ended up with the original 3/4 sub floor, 3/4 plywood and then 3/4 oak flooring with the beams installed I guess you could drive a truck on it now .

 

[D45]

Yes, the current beam is sitting in a concrete pocket with steel shims

Thanks for all the help guys.........

Would it be worth it to spend the extra time/little money and staple some paper faced insulation in there while I am at it?........assuming the make insulation for 2x10 cavities

Rigid foam?

Foil?

 

[kaymccampbell]

Insulating would make the floor warmer. No guarantees how much.

 

[D45]

Ok, I got inside the crawl this weekend and cleaned out three large garbage bags full of old wires, foam, and misc junk

The current beam I thought was "sistered" together, but there are actually THREE 2x10 boards screwed together.......yes, just screwed together.

Should I bolt them all together, evenly spaced down the run?

Each floor joist for the crawl has 16" OC, which are also 2x10 boards

The crawl is approximately 23'6" long and 20' wide

I would first like to insulate the open areas between the 2x10 joists..........suggestions here on what will be simple, cheap, and effective?

How much insulation will I need? Obviously I will need a 15" wide section.......whats the diff between a "roll" and a "batt"

How thick of insulation should I get?

I am leaning towards "unfaced" insulation

 

[D45]

I plan on using this to secure and hold the insulation

http://www.menards.com/main/buildin...4421524998-c-5776.htm?tid=1857063589970250474

100 pieces for $12.23

 

[D45]

Unfaced Insulation:

(R11) 3-1/2"x15"x40' : $7.69 ROLL
(R19) 6-1/4"x"15"39' : $14.97 ROLL
(R21) 5-1/2"x15-1/4"x93" : $16.29 BATT
(R25) 8-1/2"x15"x18' : $10.99 ROLL
(R30) 10"x15"x22' : $9.99 ROLL

 

[ssdave]

Install insulation and support it with the wires you linked to. I would use unfaced fiberglass batts. Cheapest and easiest to install.

Then, follow kay mccampbell's advice. She's got it right, without a lot of weird overkill ideas.

Go into the space, and split the remaining span, using a double 2x6 or 2x8 beam to support the floor joists. You don't need a huge beam, if you put 4 supports or so under it, the length it is spanning is trivial, at only 5 or 6 feet between supports. The smaller you make the beam, the easier it will be to install. You can either use metal adjuatable supports, or just use 4x4's and pound tapered wedges in to adjust the height to be fully supporting the beam. If the beam doesn't support all the joists, you can shim under the high ones so that the beam supports them also.

This isn't all that complex of a problem. Your floor isn't failing, it's just got more flex/bounce than you need. Supporting it in the middle of the unsupported length will reduce the flex to 1/4 of what it was before you supported it; that should easily solve the bounce/flex problem.

One thing you might look at for the base to sit on the dirt is precast concrete deck supports. They make some that have a groove that you can put a 2x6 in. These might be an easier way to put in the base. Put those in at 3 feet o.c, put a 2x6 on edge in the groove, put a 2x4 flat on top of it and nail it, and then put your support posts between that and the beam. Your original ideas will work fine also, this just might be an easier way with similar cost.

 

[D45]

Thanks for the info

I know the original beam is a triple 2x10 beam, and like you said,, the floor isn't falling apart, just needs more support..........I am thinking that a couple of 2x8 boards (I will "sister" two together), running the 23'6" span will suffice

I will get a total of four adjustable columns.....that I will need to find some thick concrete blocks or sit under the posts, or get concrete deck supports?

http://www.menards.com/main/buildin...441476595-c-5647.htm?tid=-5863498471560104930

or these

http://www.menards.com/main/buildin...4441455602-c-5647.htm?tid=6483008166910711820

 

[matt_i]

If you sister beams, look for GRK-RSS framing screws in your Home D. They need a T30 bit in an impact driver, but never has such a strong grip been available in a wood screw.

 

[D45]

I am familiar with those screws, very good idea

I was going to spend the time and drill holes and bolt them all together, but I might change my mind now and just use those GRK screws

•High tensile torque and shear strength (5/16" diameter screw equivalent to 1/2" lag bolt)

 

[ssdave]

I like using the inexpensive deck support blocks you referenced, but use them at close spacing as they don't have a lot of bearing area. Then, put a 2x6 in them, with another 2x4 nailed crosswise in a T shape on top. Then, support from that to the beam under the floor. The bond beam blocks aren't made for putting a board in them, they will probably split if you try that. You can use solid CMU's, two of them, and put a piece of plywood on top before you start in with your posts.

If you don't use the deck support or two solid CMU's, you need to use 16x16 patio blocks, probably 2 or 3 thicknesses under the support posts. A single thickness is too light, and will crack under much load. They really aren't much better stacked, they're not the right thing for the job, but they do work. The deck supports are much stronger, although they need spaced closer, say 4' o.c., or even 3' o.c. if the ground is real soft. They really aren't supporting much permanent floor load, they're more just dampening the vibration in your case, by supporting peak loads as someone jumps or walks on the floor.

 

[benjamintmiller]

All of these suggestions that you sister every floor joist should not be followed.

As ssdave said, adding another beam parallel to the first in the middle of the span will make the floor 4x stiffer. Sistering every joist will make it 2x stiffer (and cost a fortune, comparatively).

If your floor does not have diagonal bracing between the joists, this is the first thing I would try. This will spread the load out between joists and stiffen it considerably.

 

[D45]

This is odd, because while there are not any diagonal braces in the crawl, the rest of the basement has them..............just cut corners I guess

Yes, I was not referencing every floor joist getting sistered together, I guess I worded and explained it wrong

I do plan on adding another beam parallel with the other beam

The current beam is about 6' off the wall, leaving approximately 13' span to the other wall. I plan on putting the new beam also 6 feet off the wall.

By doing so, I will have both beams 6' off each wall, and then everything will be evenly spaced and supported

 

[bzinsky]

considering this is just to remove bounce, I would be trying to keep this as simple as possible.

I'd honestly would just lay a few 2x4's in the dirt and bang some 2x4 posts between the joists and the 2x4, probably wouldn't even use screws.