Truss sag in garage?

[N8]

I believe my trusses are sagging in my garage. It's visibly evident from both inside and outside and I believe it is also the reason two of my doors are so out of whack.

At first glance there are 2 - 2x4's that run the length above the headers.
Novice question probably, but do the trusses rest on those because those are obviously dropping in the middle.

There is 2" of space above the header on either side and in the middle they almost touch the header.

Is there a way I can raise them and put in supports between them and the header, over the garage door opening, to straighten them out and relieve the sag?

I have no pictures right now which would explain everything I am sure I may not be describing correctly.
I am at work and will post some photos when I get home.

Thanks,
N8

 

[N8]

Found a picture...

 

[Gary S]

The main purpose of the header is to support the roof structure above it. When put together properly, the truss above the header can't sag unless the header sags, and that means the header wasn't designed properly. If the header isn't sagged, but the truss above it is sagging, then something isn't built correctly.
I think it is time to get rid of some of that sheetrock up there so you can take a look at the structure of the building and see what is going on.

Is the entire roof sagging like your picture shows the sag above the door? If so, your trusses aren't correctly designed, if you even have trusses up there. You might have some home-built rafters up there that won't support the load.

 

[mmhouse]

Is it just the trusses over the header that are sagging or all of them? The best way to tell would be to stretch a string at different points.

As Gary S says, the trusses should not sag if they are constructed properly. If they are indeed trusses, being over the header should make no difference unless the intermediate chords were left out of the end truss counting on the wall/header for support. Again, as Gary S says it would be best to take a look up there so you know what's going on. Post a pic if you can get one.

 

[Dan5602896]

Do you have better pictures? I'm not sure what you are saying. The only truss that should be sitting on the top plate for their entire length (2, 2x4's around the perimeter of the building are the top plate) are the two end trusses. I would measure from the floor up to the truss in various spots to check for sure.

Which direction are your trusses running? The one over the door sure looks to be sagging. For that to happen, if there is no extra weight on the truss bottom (as in using it for a joist to an attic floor) would mean the plates have lost their grip.

 

[srmofo]

look at the direction that the screws are in.

the trusses run perpendicular to the garage doors/header. Someone screwed up, big time. Thats the top plate sagging, not a truss. That top plate should be resting on the header. Thats what the header is for. Who built this garage?

 

[N8]

I found a few more photos. None of the trusses themselves.
They run spanning the 33' depth of the structure front to back perpendicular to the doors.
Can you see the sag on the outside. It only occurs over the garage doors.
Not sure if the weight of the tile has anything to do with it.

 

[N8]

Who built this garage?

It was built in the early 80's by a 'General Contractor / Drywall contractor' who spent more time smuggling drugs into the country than building houses.....

 

[mmhouse]

It appears from the photos that the headers may be sagging. And yes, it could be that the trusses/headers are not designed to carry the load of the tile...tile is heavy.

If it's the headers it may not be difficult to beef them up depending on how they're constructed.

 

[N8]

It appears from the photos that the headers may be sagging. And yes, it could be that the trusses/headers are not designed to carry the load of the tile...tile is heavy.

If it's the headers it may not be difficult to beef them up depending on how they're constructed.

Thats the thing. The headers look solid as a rock. No bow or anything out of the ordinary. It's the gap and all of the wood above the header that is funky.

 

[N8]

The main purpose of the header is to support the roof structure above it. When put together properly, the truss above the header can't sag unless the header sags, and that means the header wasn't designed properly. If the header isn't sagged, but the truss above it is sagging, then something isn't built correctly.
I think it is time to get rid of some of that sheetrock up there so you can take a look at the structure of the building and see what is going on.

Is the entire roof sagging like your picture shows the sag above the door? If so, your trusses aren't correctly designed, if you even have trusses up there. You might have some home-built rafters up there that won't support the load.

Thanks guys.
There are trusses up there. I have looked in to see if any had any breaks or signs of failure in them. They looked good to the untrained eye. I will try to grab a picture of the attic innerds later.

N8

 

[rockchucker]

That is if they ran the Sheetrock correctly! You never know. Maybe they went with the Trusses instead of across them...lol I have seen it before.


Looks bad. Tear that Rock off of the Garage Door wall and see what the real deal is. I would fix it for sure if you enjoy having a roof over your Garage.


It is just Attic Space above it right?



Looks like the Headers over the Garage Doors are insufficient. Not too hard of a Fix. definitely some work but it doesn't really look like the Trusses are to blame.

 

[Justanoldguy]

The ends of the trusses are sitting on the top plate which has sagged because there is no packers between the top plate and the header.
Jack up the ceiling with acrows and put a packer between the plate and header under every truss. That will fix it.
All the weight will then be transferred to the header like it should have been from the start.

 

[rockchucker]

Do you mean a Cripple under every Truss? Just curious...


http://www.finehomebuilding.com/how-to/articles/anatomy-stud-framed-wall.aspx



If you look at the Exterior Picture though you can see that the actual Header over each Door is sagging. You can see it in the lines of the Garage Doors and also you can see that the left Door does not close properly. I think there is more than just missing Cripple Studs in this debauchery.


Just my .o2 though.

 

[WNYflyer]

The ends of the trusses are sitting on the top plate which has sagged because there is no packers between the top plate and the header.
Jack up the ceiling with acrows and put a packer between the plate and header under every truss. That will fix it.
All the weight will then be transferred to the header like it should have been from the start.

As as justanoldguy said that looks like that is the case. If they are true trusses find the truss panel point (joint where verticals and diagonals of the truss meet at bottom chord) nearest the doors and jack the trusses up at that point. Kind of like the jacking point on your car. Probably want to build a jacking frame of some kind to move the trusses up at the same time.Then shim with lumber and perhaps some steel shims between the top plates and the door header.

Is always preferable to shim at the spot the trusses sit on the top plate and especially if the roof is true clay tiles that are quite heavy. All load then transferred to the door header then to side jambs then to foundation as it should be.

 

[Gary S]

Thats the thing. The headers look solid as a rock. No bow or anything out of the ordinary. It's the gap and all of the wood above the header that is funky.

That's good news. There should be no gap between the top of the header and the bottom of the plate that the trusses sit on. That gap should have short cripple studs every 16 inches to keep it correct under load. If the header is straight and the roof above it is sagged, all you need to do is jack it back up straight and install short studs to hold it in place.

 

[GarageEnvy]

I'm not an engineer, architect or general contractor but I have seen a couple of these as an appraiser and there were some common causes. In one case the house was originally designed for wood shake roof and the owner re-roofed with tile. In another case the structure was not originally designed for the load of sheetrock. In a third case (and this is probably the only one of it's kind) a guy decided he might want to pull engines one day so he threw in a giant steel I beam across the trusses before sheetrocking over it. I've also seen quite a few DIY storage lofts (including in my own home) that caused sag. I suspect it may be one of the first 2 cases for you.

 

[wbrian63]

I don't see any sag from the outside at the top of the garage doors - at the eaveline, sure, can't miss that.

I've attached a pic from earlier in the thread to show what Justanoldguy is talking about - and I think he's hit it. There are no cripple studs between the top of the header above the garage doors and the plates that form the top of the walls, at least from this view. Over the man door is probably no big deal, but the span of those big garage doors is a problem.

Easy fix - but spread the load across all of the trusses with some sort of beam. You might try a 2x6 "on the flat" with multiple jacks down the length - the trusses adjacent to the man door need a lot less lifting than the trusses mid-span over the garage doors.

 

[N8]

If the header is straight and the roof above it is sagged, all you need to do is jack it back up straight and install short studs to hold it in place.

Thats what my mind kept telling me.
The plan I had devised in my head prior to asking the question was this:
Take a 6" x 6" x 20' beam and place it under the joists closest to the plate.
Use four or five jacks too lift & straighten it out.
Determine correct gap and place spacers (steel or wood) in to maintain gap & secure.

 

[N8]

I don't see any sag from the outside at the top of the garage doors - at the eaveline, sure, can't miss that.

I've attached a pic from earlier in the thread to show what Justanoldguy is talking about - and I think he's hit it. There are no cripple studs between the top of the header above the garage doors and the plates that form the top of the walls, at least from this view. Over the man door is probably no big deal, but the span of those big garage doors is a problem.

Easy fix - but spread the load across all of the trusses with some sort of beam. You might try a 2x6 "on the flat" with multiple jacks down the length - the trusses adjacent to the man door need a lot less lifting than the trusses mid-span over the garage doors.

Thanks wbrian.
You type faster than me! Those are exactly the problem spots.

I'll let everyone know what I come up with.

 

[wbrian63]

You don't need a 6x6, it will be too rigid to conform to the arcing sag of the top plate. Use a 2x6 or 2x8 "on the flat" and multiple jacks as you planned. Even with 24" spacing on the trusses and a jack placed between two trusses on the 2x6 or 2x8, you should be able to lift the structure without failure. Of course, a jack directly under the truss is better - the 2x lumber will carry the force across to the adjacent trusses.

Go slow - don't try to lift it all at once, you'll crack the sheetrock (which may happen anyway, as it's had to "stretch" over time as the plates sagged.

 

[N8]

You don't need a 6x6, it will be too rigid to conform to the arcing sag of the top plate. Use a 2x6 or 2x8 "on the flat" and multiple jacks as you planned. Even with 24" spacing on the trusses and a jack placed between two trusses on the 2x6 or 2x8, you should be able to lift the structure without failure. Of course, a jack directly under the truss is better - the 2x lumber will carry the force across to the adjacent trusses.

Go slow - don't try to lift it all at once, you'll crack the sheetrock (which may happen anyway, as it's had to "stretch" over time as the plates sagged.

Thanks again.
Would steel spacers or wood spacers be preferable for the gap?

This space is part of a much larger garage.
My gut tells me to start from the middle and work my way out. (to the right)
That would be from the building spit shown at the height changes on the elevation.

 

[WNYflyer]

Thats what my mind kept telling me.
The plan I had devised in my head prior to asking the question was this:
Take a 6" x 6" x 20' beam and place it under the joists closest to the plate.
Use four or five jacks too lift & straighten it out.
Determine correct gap and place spacers (steel or wood) in to maintain gap & secure.

In general sounds like a plan. I would cut out the ceiling drywall at the end of the trusses to expose the connector plate that should connect the top chord to the bottom chord (roof rafter to attic floor joist). If you cannot put your jacking beam fully under that plate and have to come farther into the garage such that you are jacking on the bottom chord of the truss only then don't do it. You may only succeed in jacking up the bottom chord locally and perhaps busting it and in all the while the truss doesn't move. If need be perhaps you can reinforce the bottom chord from the end of truss to the first truss panel point to take the jacking loads. Again if that roof is true clay tiles then need to be especially careful because of the weight. Don't really know if the above will work because don't know the loads, etc. but it is one of the right ways to attempt/do it.

In theory, you also maybe able to go up in the attic and measure up the truss dimensions, lumber size and grade and sketch that up. Then take that info to a real lumber yard and tell them what you roof is made of and the location on the trusses you want to jack and they maybe (throw them a few $) able to run in on the computer to see if your trusses are okay for your jacking scheme. Never done that before but in theory may work and may save you a lot of trouble.

 

[ZRX61]

Maybe you just found the location of the lost stash...

 

[N8]

Maybe you just found the location of the lost stash...

LOL... Trust me I have been looking for that for awhile!
No cash or other "incidentals" yet.

I almost thought I had and underground bunker in my back yard.

Turned out to be a 3' 4' x 18' curved tunnel 3' underground that my dogs dug up.
But thats a whole other story.

 

[scottzilla]

Header in above photo is "Packed out"; no cripples used. The lvl butts up against the top plate and the end gable truss sits right on top of the lvl. I don't see how this header could ever sag.

I'm no expert but you may have to replace your header (lvl would be nice) and secure points above it.

 

[Justanoldguy]

I'm no expert but you may have to replace your header (lvl would be nice) and secure points above it.

Replacing the header is a really silly overkill idea for a very simple solution. JM2CW

 

[srmofo]

[IM


I'm no expert but you may have to replace your header (lvl would be nice) and secure points above it.

The issue is that there is a space between the lvl and the top plate. Why replace everything when you can just add wood.

Personally I would measure the gap at the ends to find what size my "filler" needs to be. Then start at the edge and work across. If its more than 1.5", Then I would work one way then back again, trying to avoid lifting too much at one time.

I think if you start in the middle then you would be trying to lift the entire load at once vs little by little as you work across it. Same concept as when you install the top plate. You dont nail it in the middle then try to staighten it. You just start at one end and have a helper push/pull while you nail it down straight.

Either way good luck

 

[OccupantRJ]

If you will make some wood wedges and use 2 opposing each other to provide parallel surfaces, you can use these to place in the gap several places where needed, jack as you see fit, and do it in small increments to reduce stress on the trusses and ceiling as you work. As you jack, just keep pushing each pair of wedges together to make them thicker, and you will have complete incremental control against a sudden drop. When you reach your goal, the wedges can then be nailed into place and left there, or remove each pair to install vertical grain blocking.

RJ

 

[N8]

I finally found some time to go up and take some photos from the inside.

<img src=http://www.bandbspeed.com/images/garage/g%20(1).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(2).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(3).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(4).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(5).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(6).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(7).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(8).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(9).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(10).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(11).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(12).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(13).JPG>

<img src=http://www.bandbspeed.com/images/garage/g%20(14).JPG>

 

[rodnok1]

I agree with the others that there should be short studs between the header and the double top plate. I'd jack it up slowly adding shims and spacers over a period of time until it's level again. With all that weight over the doors I'd be tempted to install alot of spacers over those doors. Poor construction, lucky it wasn't 4 inches of sag and collapse.

 

[Justanoldguy]

The packers/shims/spacers only need to be directly under each truss landing point.
That is where the load is being transfered to the beam.

 

[CraigFL]

To me, in post #7. it looks like the roof sags(not the header) in the middle of each big door opening. Asphalt/fiberglass shingles weigh about 280#/SQ while true clay tile is 1000#/SQ almost 4 times as heavy. Even after you spread the load out over the header, you may find some sag now in the header. Hopefully, you're not at an elevation where snow load is a consideration.

 

[N8]

Hopefully, you're not at an elevation where snow load is a consideration.

The previous owner may have had some "snow" problems and thats what landed him in prison.
I digress. I have seen nothing more than an inch of snow here in 13 years so I am cool there.
I will keep tooling around and work out a solution.
Thanks again guys for all the help.

 

[DuluthMN]

It was built in the early 80's by a 'General Contractor / Drywall contractor' who spent more time smuggling drugs into the country than building houses.....

Rip out all sheet rock asap. There may be enough leftovers hidden in the walls to pay for your entire next build.

 

[Torque1st]

This picture seems to show the left side with a double top plate directly bearing on the door header.