rafter depth too great for ridge beam on one side

[CheckItOut]

House was built in 2005 and I know the ridge depth must be as great as the cut end of the rafter but wondered if there was an exception that I was not aware of. Rafters on one side of the redge board were fine but no the other side. You could nail an extension on the bottom of the ridge but without the opposite rafters applying "pressue" agains it, I don't know that it would really do any good.

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[caryseidner]

Why are the rafters on the left side and, the first two on the right side of the ridge a different size (2x10??) then the other rafters (2x12??)?

[Mark P]

I’m sure someone is going to blow me out of the water for saying this, but I would not make an issue of it. You have an equal amount of force being exerted on both sides. If there are no other symptoms (bowing, cracked joist, sagging, etc) I would not even mention it. If there are some problems that could be attributed to the roof framing I would mention it. I do find it odd that the rafters change for 2x10 to 2x12 and the 4th and 5th from the front of the picture look like they may have been sistered or doubled up, I am interested why that is and seeing more pictures. Was this an add on garage?

[Michael Brown]

Can we make those pics a little smaller please?

3600 x 2700 pixels is just a little overkill by a couple thousand pixels [:-bigeyes

Michael

[kurt]

Originally posted by AHIS

I’m sure someone is going to blow me out of the water for saying this, but I would not make an issue of it.

I would not be that person. It isn't right, but you'd have a hard time making a tight case that it was bad.

It's wrong, but it isn't bad.

[CheckItOut]

Originally posted by AHIS

I’m sure someone is going to blow me out of the water for saying this, but I would not make an issue of it. You have an equal amount of force being exerted on both sides. If there are no other symptoms (bowing, cracked joist, sagging, etc) I would not even mention it. If there are some problems that could be attributed to the roof framing I would mention it. I do find it odd that the rafters change for 2x10 to 2x12 and the 4th and 5th from the front of the picture look like they may have been sistered or doubled up, I am interested why that is and seeing more pictures. Was this an add on garage?

This was not over a garage - main portion of the roof. No bowing or other issues. I climbed the roof and it looked great.

[CheckItOut]

Originally posted by admin

Can we make those pics a little smaller please?

3600 x 2700 pixels is just a little overkill by a couple thousand pixels [:-bigeyes

Michael

I wanted to make sure you could tell the species of wood involved [:-slaphap

I tried to shrink it, and did by a lot, but guess not enough.

[hausdok]

Hi,

I've fixed the photo. Please, People. Try to make your photos as small as possible before you post them. There are plenty of free image resizer tools available on the web that work great. If you've got XP, just go to Powertoys for Windows and download their image resizer there.

ONE TEAM - ONE FIGHT!!!

Mike

[stubrooks]

It is not correct. Do you have the design plans and specifications? Are the rafters supposed be 2x6 or 2x10? Could be the light but it looks like some sistering or buildup of rafters may have been done to use existing materials or fix other botched workmanship. Was that done within standards of either code or good construction practice? Built in 2005 - Have there been any heavy wet snows there since it was built? Ice storms?

You observed "unusual" construction involving the rafters that make up the roof support structure. IMO, It would be advisable to include what you saw in your report that you considered unusual, why it would be considered unusual, and possible issues both short and long term. You could then suggest that it may be in the client's best interest to consider assessment by a structural engineer. (Oh, this is in NC, can you do that still?). To me, this is not making a big deal out of it.

If that house was 50 years old and everything still looked good, you could add that fact. Short point is, don't blow it off - you made an observation - report it.

Sorry if it sounds like I'm lecturing. Not intended.

[SonOfSwamp]

Not to be all contrarian, but a couple years ago I looked at tornado-damaged houses as part of an investigative-reporting job with a local TV station.

When an inspecting unit starts looking at big-time failures, he learns that it's stuff like these rafters that split and detach under high wind (or snow) loads.

I know, I know. Tornados tear up everything. But if the house is built right, it's a little less likely to break at the weak points. In the tornado-hit neighborhood I visited, details like these were the difference between houses that were damaged, and houses that collapsed and killed people.

For a real lesson in half-ass building, go see some tornado houses. We found garages walls not bolted down (they flew), big porch columns with no fasteners (they collapsed and took porches with them) and a whole lot of split rafters (bad joinery and overcut birds' mouths) that broke and let roofs go flying.

I'd probably write something like: The ridge board isn't deep enough to allow proper attachment of the rafters. Under high wind and/or snow loads, this could cause problems, maybe even failure. Hire a person with good experience in roof framing, and make the repairs he recommends.

WJ

[randynavarro]

Walter?

Is that you?

[John Dirks Jr]

Originally posted by randynavarro

Walter?

Is that you?

...ditto, where ya been....at?

[SonOfSwamp]

Tis I. I had troubles interacting with the website. After lurking a while, I dumped all my cookies, and I could interact once again.

WJ

[hausdok]

Yeah,

I always feel better too after I toss my cookies. []

It's good to have you back, Old Friend.

ONE TEAM - ONE FIGHT!!!

Mike

[kurt]

Tornado resistant construction isn't dependent on rafters bearing on a ridge.

Collar ties, properly spaced and installed, are what keep roofs from blowing apart in high winds. Lottsa folks think collar ties are what keep rafters from spreading apart. They're not. They prevent uplift during high winds. Uplift is what causes the roof to blow apart.

This roof may or may not have collar ties; the pic doesn't show anything. Were there collar ties?

Overcut birds mouths, inadequate connection between rafters and walls, or other connections would make a big difference in whether a house would stay together, or blow apart. That's why galvanized steel rafter ties to walls, or other metal fasteners, are required in hurricane zones.

While I agree w/the assessment that crappy construction makes houses blow apart in high winds, this particular "defect" isn't likely to make any difference. It's all the other stuff that'll make it fail.

Of course, when the lawsuits fly in, all the experts will point to everything and anything that's minutely incorrect to illustrate how the builder was at fault. That's what happened when the porch collapsed in Chicago, anyway. Teeny little defects that really don't mean anything, all of a sudden start meaning a lot to the attorneys, because they can use them to show negligence.

[SonOfSwamp]

Not that evaluating tornado houses is really a part of HI work, but my take-away from that investigation was: "Things that aren't fastened right sure do break easy when the house starts twisting."

Most of the roofs (which were on the ground when I saw 'em) came apart at the overcuts, halfass toenails, etc.

It's just a little something that sticks in my mind these days -- if the builders had done more things right, the roofs might've stayed put, the brick-tieless brick veneer might not have fallen on the nice lady in the van, the paralyzed woman might still be walking and the folks who ended up dead might've walked out the front door, rather than being dug out of the rubble.

That said, the rafters in the pic wouldn't bother me much. But I'd write 'em up anyway...

WJ

[kurt]

A lot of things done right would make houses damn near indestructible in high winds.

Simple things like gluing framing together instead of relying on (really crappy) nail connections. Glue joints, properly applied, are stronger than the wood pieces they connect.

We built an experimental house 30 years ago that only used PL200 construction adhesive, and only enough tiny nails to hold everything together until the glue set. When it came time to take it apart, we couldn't. Even the bulldozer ended up just pushing around the entire box.

We had to burn it down to get rid of it. We hired the local fire dept. to use it as a "test burn".

Point being, houses are built really stupid. We have a world of technology and product out there that allows us to build perfect structures, but we still rely on techniques that were crude >100 years ago.

[caryseidner]

I framed many of roofs with 20' Doug Fir 2 x 12's on 7/12 or greater slopes and when they are running at that angle the vertical dimension is gonna be at least 1-1/2" taller (my framing square is in storage and I don't feel like doing any sketches right now, so please give me a little latitude here) than if it were laying horizontal. Never saw a 2 x 14 before and we never used any engineered timbers for a the ridge. Maybe I was trained by a crappy carpenter.

For some reason the rafters were changed from 1 dimension to a larger dimension. Maybe the rafter run length increased and the larger rafter was needed for the span. Maybe some goofy architect wanted a taller fascia. Maybe the carpenter had extra lumber left over from another job he (or she) was trying to use. Maybe 20 other things. I don't think its a problem....unless I WAS trained by a crappy carpenter.

[Brandon Chew]

When a rafter is loaded by the weight of building materials, snow, and wind blowing against the roof plane, it wants to bend and push against the ridge. When the cut edge is only partially bearing against the ridge, it sets up shear forces in the rafter that run parallel to the grain. Wood is weakest in shear parallel to the grain.

The roof framing will look fine until a great enough load is applied to the roof that causes the rafters to split along their length starting at the ridge. Whether or not those rafters will be OK under the required design load conditions is something for an engineer to figure out.

House was built in 2005 and I know the ridge depth must be as great as the cut end of the rafter but wondered if there was an exception that I was not aware of.

There is no exception under the prescriptive code (IRC). Plans detailing the rafter-ridge connection that are stamped by a licensed design professional would be acceptable in lieu of the prescriptive code.