Hangers?

Specific Inspection Topics Structural Inspections
1

Fellow HI’s.

            Here is question I can not find an answer for. Did an inspection yesterday at a house (I guess you could call it that) that has manufactured wood I beams installed. The question is.....is there a certain type of hanger used for wood I beams or is a hanger just a hanger? Any help would be greatly appreciated.
2

Beams!!! or joists???

Beams are usually supported from below.

Joists go on hangers.

3

i’d check manufacturer’s directions.

lots of different hangers out there.

some can be used for engineered or non engineered applications.

some can only be used for one or the other.

any pics?

try these sites

http://www.strongtie.com/products/Category_list.html?source=topnav

or

http://www.tamlyn.com/index_files/TopMountHangersforWoodIJoist.htm

4

Here is a picture. These are looking at the joists from below on the first floor. This had to be the worst house built I have ever seen.

5
  1. Usually, regular joist hangers can be used. Always check with the manufacturer, but LP OSB I joists are OK with it.
  2. Make sure that the just didn’t toenail the suckers.
  3. Check spacing between joists. Usually 16" OC, but can also be 24" OC. Again check with manufacturer.
  4. They usually allow 2-3", once in a while, to handle a partition wall above or some such.
  5. All the infor is usually printed right on the joist.
6

ok- somebody give me a quick class on how to install a picture…I have had a brain cramp from looking at the IBC book today.

7

See following tutorial:

http://www.nachi.org/tutorials/tutorial.php?width=770&height=480&tutorial=mb-attachments

8

Hi. John;

In most cases with joist hangers, it depends on what kind of joist we are talking about. In cases of regular stick building, with conventional joist or rafters, regular lumber yard hangers will suffice.

In cases with structural Engineered Lumber framing, it is most appropriately designed with the system from an Engineer or Architect, where it will be specified for it’s use. If not, then maybe contacting the Manufacturer of the product, and usually their recommendation to specific hangers will be listed with the design of the floor system or roof system.
Most of the hangers manufactured are of a long line of designers and can only be qualified and selected by Engineers of the Manufacturer or a Structural Designer if involved.
I added this link for your review of the many possibilities of uses.

http://www.strongtie.com/

Hope this helps.

Marcel

9

Typically, conventional joists use a face mount flange hanger and I-joists use a top mount flange hanger:

ITT-top_flange_cwp (Small).gif

U-face_mnt_cwp (Small).gif

10

These are just three example; therefore, there needs to be some engineering involved. I would think.

[

](http://www.strongtie.com/products/connectors/HTU_PT.html#gallery)

Marcel :slight_smile: :)](“http://www.strongtie.com/products/connectors/HHB-GB-HGB_GLULAM.html#gallery”)

11

Just a fact to point out, When inspecting newer houses with MFG. I joists for floors, when installed they need to be installed slightly lower than the beam to allow for expansion and contraction, so if you see flooring in a newer home buckling check the I joists in the basement. Many times a builder will install them flush to the main carrying beam and they tend to expand pushing the sub floor up.

12

Watch out for nailing. Find many that have not been fully nailed.

13

Actually what I meant to say is the main beam that the I joists are attached to tend to shrink thus making the joist push the sub floor up. Here in NE we buy kiln dry lumber which I believe is dried for about 30 minutes and then out in the yard up for sale, always green and worse in the winter because it freezes in the yard and doesnt dry until the heat goes on.

14

Peter, you can correct me if I am wrong, but the last Project I did with TJI’s or I joist, it was reccommended that the underlayment span the girder beams by 1/4". Not backing it up with a link is my downfall I guess. Sometimes they are not readily accessible. The theory or fact behind that is, since the carrying beam of the floor structure is more of a massive volume, it tends to shrink less than the members attached to it. So, therefore, shrinkage if existing in the floor members perpendicular to the main supporting beam exist, the 1/4" will compensate without creating a bump in the flooring material.

JMHO.

Marcel

Marcel :slight_smile: :slight_smile:
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15

Marcel, not sure if we are on the same page, I was referring to the joist not the sub floor or underlayment. I was referring to an I joist that is connected to a stick framed carrying beam that is usually made out of 2x10s the I joist will not shrink but the main carrying beam will thus pushing against the sub floor. Your thoughts?

16

Peter, with top flange hangers beam shrinkage won’t matter, the Joists will still be in the same position relative to the top of the beam. I’ve never seen I-joists installed on a beam in which the tops of the beam and joists were supposed to be flush without using top flange hangers although I’m sure someone somewhere has decided to use up those hangers that’ve been stashed away in his garage and save $25.

All in all, we don’t have to confirm compliance to engineering. I called one roof system in which the framers had nailed truss-bearing hangers with siding nails (40% smaller diameter and a different alloy) but unless it looks bad or you know it’s wrong, why call it?

Joist layout would be called out by an engineer and it might be 12", 16", 19" or 24" on center (center to center, not in between). Unless the floor or roof exhibits exfcessive deflection, joist spacing is not our problem. If it does, then call out excessive deflection. -Kent

17

Kenton, out here it is rare to see top flange hangers. Most everything is hung with typical joist hangers, hence the problem with shrinkage. Competition in the building trades is very high here and the per square foot costs are relatively low compared with the work involved, so the faster they go the more money they make, quality takes a back seat.

18

I would imagine that if one would use TJI joist that the center beam would be of a type of LVL or if one choses to use 3 two x’s they would still use the top beam mount hanger, and this would allow a 1/8" gap between the top of the carrying beam in relation to the top of the tji’s which would prevent any bump in the floor system. This is usually the common hangar to use in this type of framing.

JMO

Marcel

19

Your correct Marcel, it should be done this way but many times is not. I have seen tgi’s attached to a triple 2x10 main carrying beam with regular joist hangers, if the tgi’s are flush to the top of the main 2x10 beam and it shrinks because it was green when installed, then the tgi’s push against the sub-floor pushing the finished floor up, even if it’s only a little bit it’s noticed.

20

Well it’s true, practices and attitudes about what’s OK vary a lot from one part of the country to the next. As long as it’s safe and it works it’s hard to argue with.