Thread: Modular trusses don't look right.

This just doesn't seem right to me. The large gap is insupported at the midsection of the roof. Can someone comment on this please?

Thank you.

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The gap is there for the hinge to rotate. Sometimes they cut a kerf on the framing members instead to allow the two pieces to come together. Its part of an engineered system, and is common in truss design for homes that need to broken down and transported.

Sorry, could you clarify that a tad? I'm trying to envision the hinge you mean. Does something go through those circular holes?

EDIT...Oh, I didn't see that there are two overlapping metal pieces there, is that right? What, do the trusses fold up for transportation? I'm picturing them folding up into a nice little bundle, like a folding drying rack. :~)

The hole is the hinge. They didn't want the overhang sticking out when the house was driving down the road. So they use this connector to allow that portion of the roof to be folded over on to the other part of the roof.

Here's another photo of a similar hinged truss...

I assume that when ther get into position that can't travel any further, therefore are locked in place.

Thank you for your help.

Russ

Modular home truss - thats what they look like.

You need to look at the manufacturer's installation manual, as they sometimes require the installation of 2X plates or scabs as bridging over the hinges. These plates will be of specified length and call for fastener size/spacing/number...........Greg

While I do not see a whole lot of manufactured housing I think something is wrong.

I simply cannot see how the hinge would perform under a wind or snow load without some contact between the wood truss components.

I have attached a brochure/flyer from a hinge plate manufacturer.

Charles

Originally Posted by Charles Gifford

While I do not see a whole lot of manufactured housing I think something is wrong.

The PDF you attached is from MiTek, and they several hinged trusses.

One of those has engineered specs that allow up to 1" gap between upper chords. They also state the sheathing running across the framing affects the strength, read it here:

The "final word" will be the home manufacturer's installation manual. Some will require "bridging" and some won't-doesn't really matter what the hinge specs call for..............Greg.

Originally Posted by Gregory Booth

You need to look at the manufacturer's installation manual, as they sometimes require the installation of 2X plates or scabs as bridging over the hinges. These plates will be of specified length and call for fastener size/spacing/number...........Greg

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Originally Posted by Gregory Booth

The "final word" will be the home manufacturer's installation manual.

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Maybe, or, maybe not. If this is built as a site built home, then the rules will change.
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Originally Posted by Gregory Booth

doesn't really matter what the hinge specs call for..............

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That's all fine and good, but we don't often find installation manuals in the attic of the homes we inspect.

But I agree that the manufacture should have the specs on the entire assembly and all sub-systems.

Engineered components and systems (with approved documentation) are allowed even if we don't like the "look" of the finished product.

Dom.

The design of the hinged area of the truss in post #5 seems like it makes more sense than the one in the OP. The latter looks like it would hardly have any play. I suppose if that's all one needs, it's fine.

From the pdf files it looks like trusses are often hinged simply for transporting large trusses more easily, nothing to do with modular housing necessarily. Perhaps that's the case with the OP, since Russell mentions them near the midsection of the roof. And unless the sheathing was taken off first, I can't see how they would fold over as described by Robert: "They didn't want the overhang sticking out when the house was driving down the road. So they use this connector to allow that portion of the roof to be folded over on to the other part of the roof."

It does seem like the OSB doesn't overlap the joint enough to impart much strength.

Russell, do you have any photos of the whole house, roof, or attic? Are the hinges only in the "midsection"? Where are they exactly?

Originally Posted by Kristi Silber

The design of the hinged area of the truss in post #5 seems like it makes more sense than the one in the OP. The latter looks like it would hardly have any play. I suppose if that's all one needs, it's fine.

From the pdf files it looks like trusses are often hinged simply for transporting large trusses more easily, nothing to do with modular housing necessarily. Perhaps that's the case with the OP, since Russell mentions them near the midsection of the roof. And unless the sheathing was taken off first, I can't see how they would fold over as described by Robert: "They didn't want the overhang sticking out when the house was driving down the road. So they use this connector to allow that portion of the roof to be folded over on to the other part of the roof."

It does seem like the OSB doesn't overlap the joint enough to impart much strength.

Russell, do you have any photos of the whole house, roof, or attic? Are the hinges only in the "midsection"? Where are they exactly?

Although sometimes there are hinged sections to permit larger eave overhangs, the primary purpose of hinging HUD Code and Modular homes is to permit steeper roof planes. With pitches much beyond 3:12, sectional home floors of nominal 12',14' or 16' widths are just too high to transport. There are many configurations of hinging. I have installed the exact same model home, by the same manufacturer, with entirely different hinge methodology........Greg.

Modular:

Modular Buildings - Structural Engineering

HUD & Mods:

manufactured home truss design? - The Inspector's Journal Forums

http://www.inspectionnews.net/home_i...ss-plates.html


An example truss drawing of a 4/12:

http://www.homanlumber.com/HINGE%20TRUSS.jpg

There can be multiple hinges. Pictured hinged top chord.

Post 2 in this thread has a nice image of a hinged roof being lifted into place.

These photos are relevant. I always hated this design for trusses and these photos show why. first time I actually saw them 'failing'. Would like to know from structural engineer if this type of truss has been discontinued.

Originally Posted by Ernie Simpson

These photos are relevant. I always hated this design for trusses and these photos show why. first time I actually saw them 'failing'. Would like to know from structural engineer if this type of truss has been discontinued.

Those hinges didn't fail on there own - they had help!

The sheathing doesn't extend from one side of the hinge to the other.

Do the hinges somehow lock in place once fully extended?

Originally Posted by Kristi Silber

The sheathing doesn't extend from one side of the hinge to the other.

Do the hinges somehow lock in place once fully extended?

The hinges do not "lock" - they act as a simple pivot point. In this type of application, there is frequently blocking (see that wedge?) installed between the horizontal chord and the movable "rafter". Then a plywood gusset or 2X bridging/sistering along the rafter would be applied to hold it all together. Where the heck is that dang installation manual? ...........Greg.

Originally Posted by Kristi Silber

The sheathing doesn't extend from one side of the hinge to the other.

My thoughts exactly.

Most of the photos I see posted here provide for a hinge joint in the sheathing by meeting the sheathing over the pivot point or close to it, I don't recall having seen many, if any, photos showing the sheathing overlapping truss to truss so it can be nailed to each truss and 'lock' the pivot point in those hinges in place so it cannot move or pivot.

Originally Posted by Jerry Peck

My thoughts exactly.

Most of the photos I see posted here provide for a hinge joint in the sheathing by meeting the sheathing over the pivot point or close to it, I don't recall having seen many, if any, photos showing the sheathing overlapping truss to truss so it can be nailed to each truss and 'lock' the pivot point in those hinges in place so it cannot move or pivot.

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It's Not Required !
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Originally Posted by Billy Stephens

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It's Not Required !
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http://www.inspectionnews.net/home_i...t-esr-1397.pdf

From ESR-1397
- 4.0 Design and Installation
- - 4.1 (blah, blah, blah) The sheathing attached to the cords must comply and be installed in accordance with Section 5.5 of this report and the applicable code.

- 5.0 Conditions of Use
- - 5.5 Lateral translation of the truss chords across the hinge joints must be prevented by sheathing attached to the truss chord members continuously across the joint as prescribed by the applicable code or by other means acceptable to the code official. The higher compression value given in Table 1 may be achieved by the installation of a single piece of sheathing continuously across the joint and connected to each chord member at the joint by nail penetrating through the sheathing and into the chord section at a location not more than 3 inches (76 mm) from the chord end at the hinged joint, or by other special measures specified by the building designer and acceptable to the code official.

Either the sheathing is run continuously across the joint "or by other means acceptable to the code official" ... "or by other special measures specified by the building designer and acceptable to the code official".

Billy, you really should look before you leap.

You gotta make sure the training net is still down there before you try out for those harder moves.

Originally Posted by Jerry Peck

Either the sheathing is run continuously across the joint "or by other means acceptable to the code official" ... "or by other special measures specified by the building designer and acceptable to the code official".

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So Sheathing is Not Required.
* what's hard to understand about that?

Originally Posted by Billy Stephens

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So Sheathing is Not Required.
* what's hard to understand about that?

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Like so many required things in the code ...
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*what's hard to understand about that?
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The code has requirements - that is what they are called - and there are exceptions to those requirements ...
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*what's hard to understand about that?
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Your antics and posts have become boring lately - just one silly post after another,
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with you usually inserting some silly graphic
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and your use of periods to separate things
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like in this post.
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Originally Posted by Jerry Peck

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Like so many required things in the code ...
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*what's hard to understand about that?
.
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The code has requirements - that is what they are called - and there are exceptions to those requirements ...
.
*what's hard to understand about that?
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Your antics and posts have become boring lately - just one silly post after another,
.
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with you usually inserting some silly graphic
.
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and your use of periods to separate things
.
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like in this post.
.

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I like Periods.
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I like Graphs.

If You Don't .
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So What.

You Bore Lots of Folks.

.Get Over Your Self.
.* see attachment of Silly Graph.
.

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Originally Posted by Billy Stephens

* see attachment of Silly Graph.

A "bite me" graphic was the best you could do?

Get Over Your Self.

Agreed ... get over your self.

Originally Posted by Jerry Peck

A "bite me" graphic was the best you could do?

I was Running Short on Time.

Agreed ... get over your self.

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Well at least We both Agree on Something.
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Hi to all. I have been a member for a couple months or so. Although I'm not any type of formal inspector, I want to get into this field.

I have worked in the modular housing industry for over 25 years. Not double wide trailer type homes with low pitched a roof. We build mostly custom homes with many different roof lines.

I was the supervisor in the framing department and dealt with these hinge trusses for a long time.

The hinge plates are very reliable and for them to fail, it takes allot. If you ever had to remove or repair one of these trusses or plates you would know what I'm saying. Usually a broken plate is broken from transportation (forklift) before the roof is built or from house erection (possible crane lifting roof).

The gaps between the fixed part of the truss and the hinge upper (top cord) is common when the roof needs to be over hinged for an attached knee wall to be pulled out into place. Some truss designs have no gap.

As for the sheathing seam being right at the hinge point. My last manufacture stopped the sheathing on the lower section of truss a couple of inches and over hang the upper section by the same (allowing a little sheathing gap).

Hope this helps.

Originally Posted by Jeff Smith

Hi to all. I have been a member for a couple months or so. Although I'm not any type of formal inspector, I want to get into this field.

I have worked in the modular housing industry for over 25 years. Not double wide trailer type homes with low pitched a roof. We build mostly custom homes with many different roof lines.

I was the supervisor in the framing department and dealt with these hinge trusses for a long time.

The hinge plates are very reliable and for them to fail, it takes allot. If you ever had to remove or repair one of these trusses or plates you would know what I'm saying. Usually a broken plate is broken from transportation (forklift) before the roof is built or from house erection (possible crane lifting roof).

The gaps between the fixed part of the truss and the hinge upper (top cord) is common when the roof needs to be over hinged for an attached knee wall to be pulled out into place. Some truss designs have no gap.

As for the sheathing seam being right at the hinge point. My last manufacture stopped the sheathing on the lower section of truss a couple of inches and over hang the upper section by the same (allowing a little sheathing gap).

Hope this helps.

Great information, thanks for posting Jeff.

And welcome!