Rafter Crack

1090 Views 18 Replies 6 Participants Last post by Nealtw, Mar 4, 2020

DIYDood

Discussion Starter · Feb 28, 2020 (Edited by Moderator)

Hey everyone,

Hoping to get a professional opinion. Yesterday we noticed a crack in one of the rafters. What I would like to know, is if this will cause serious damage and needs to be fixed immediately? Will sistering the rafter be sufficient, or at least until I can get a professional out to repair it? What can I do to repair it and prevent it from splitting any further?

Not sure what caused it originally, but it might just be age. In California. Thanks in advance for your help.

Picture for reference:

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Nealtw

· #2 · Feb 28, 2020

DIYDood said:
Hey everyone,

Hoping to get a professional opinion. Yesterday we noticed a crack in one of the rafters. What I would like to know, is if this will cause serious damage and needs to be fixed immediately? Will sistering the rafter be sufficient, or at least until I can get a professional out to repair it? What can I do to repair it and prevent it from splitting any further?

Not sure what caused it originally, but it might just be age. In California. Thanks in advance for your help.

Picture for reference:

That does not look like a rafter, can you take some pictures from different angles so we can see what you a looking at.

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Windows on Wash

· #3 · Feb 28, 2020

That is a pretty darn good sized crack.

Nealtw

· #4 · Feb 28, 2020

Windows on Wash said:
That is a pretty darn good sized crack.

Lower grade lumber with knots on the edge the other one has one too with a crack starting.

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Old Thomas

· #5 · Feb 29, 2020

I would sister another to it with as long a member as I could get in there. Jack up the cracked one if it needs to be pushed back in place. Look down the length of the new one and put the crown up. Screw it together or better yet through bolt it and forget about it.

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bob22

· #6 · Mar 1, 2020

Looks perhaps More like fascia than rafter. Who males rafters out of 3/4 (as it looks to me)?

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Nealtw

· #7 · Mar 1, 2020

bob22 said:
Looks perhaps More like fascia than rafter. Who males rafters out of 3/4 (as it looks to me)?

More pictures would help. :smile:

bob22

· #8 · Mar 2, 2020

Sorry, does look like 2x on second viewing. Wonder what is above that to cause the failure?

123pugsy

· #9 · Mar 2, 2020

bob22 said:
Sorry, does look like 2x on second viewing. Wonder what is above that to cause the failure?

Looks like a knot crack as already mentioned. Doesn't take much to crack.
Sister away.

DIYDood

Discussion Starter · #10 · Mar 3, 2020

More pictures! Thanks for the help already

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DIYDood

Discussion Starter · #11 · Mar 3, 2020

As far as I know it's just the roof on top. We don't get snow loading, so that isn't it. There is a window offset about 6" to a 1'. It might get some loading from that weight.

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DIYDood

Discussion Starter · #12 · Mar 3, 2020

bob22 said:
Sorry, does look like 2x on second viewing. Wonder what is above that to cause the failure?

As far as I know it's just the roof on top. We don't get snow loading, so that isn't it. There is a window offset about 6" to a 1'. It might get some loading from that weight.

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Nealtw

· #13 · Mar 3, 2020 (Edited)

DIYDood said:
As far as I know it's just the roof on top. We don't get snow loading, so that isn't it. There is a window offset about 6" to a 1'. It might get some loading from that weight.

Is this the right side up?

It appears to have the weight of the wall, the roof and the skylight from above all on this, Rafter? Joist? Beam?
I am not an engineer but that should have been at least 2 or maybe 3 ply to carry the load.

Do you know why the 2x4s were added ?
Can you tell us what this building is?
Can you measure the length of that timber?
Is this an attic space or?

maybe a picture from a distance outside so we can get a good view of what we are looking at.

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DIYDood

Discussion Starter · #14 · Mar 3, 2020

Nealtw said:
Is this the right side up?

It appears to have the weight of the wall, the roof and the skylight from above all on this, Rafter? Joist? Beam?
I am not an engineer but that should have been at least 2 or maybe 3 ply to carry the load.

Do you know why the 2x4s were added ?
Can you tell us what this building is?
Can you measure the length of that timber?
Is this an attic space or?

maybe a picture from a distance outside so we can get a good view of what we are looking at.

Here are the farthest out pictures I have (attached, and unfortunately rotated 90* counterclockwise). They are from either direction of the crack.

To answer your questions:

Do you know why the 2x4s were added? No
Can you tell us what this building is? It is a bakery/factory.
Can you measure the length of that timber? Not readily, as it's high up. I would guesstimate ~20'
Is this an attic space or? It is not used for anything. It's just the roof/skylight.

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Nealtw

· #15 · Mar 3, 2020

DIYDood said:
Here are the farthest out pictures I have (attached, and unfortunately rotated 90* counterclockwise). They are from either direction of the crack.

To answer your questions:

Do you know why the 2x4s were added? No

Can you tell us what this building is? It is a bakery/factory.

Can you measure the length of that timber? Not readily, as it's high up. I would guesstimate ~20'

Is this an attic space or? It is not used for anything. It's just the roof/skylight.

The 2x4s are there to hold the top of that lower divider wall stiff.
I would think that whatever size the cracked one is it is over spanned. And should have been at least doubled. I think an LVL of the same height should be put beside the cracked one.

It is serious and not something you want to leave for the next big wind or anything.

DIYDood

Discussion Starter · #16 · Mar 4, 2020

Nealtw said:
The 2x4s are there to hold the top of that lower divider wall stiff.
I would think that whatever size the cracked one is it is over spanned. And should have been at least doubled. I think an LVL of the same height should be put beside the cracked one.

It is serious and not something you want to leave for the next big wind or anything.

Can you go into more detail on this: "I think an LVL of the same height should be put beside the cracked one."
What is an LVL?

We're definitely going to get it fixed ASAP, just need to know what we're in for and what ROM cost we should be expecting.

Nealtw

· #17 · Mar 4, 2020

DIYDood said:
Can you go into more detail on this: "I think an LVL of the same height should be put beside the cracked one."
What is an LVL?

We're definitely going to get it fixed ASAP, just need to know what we're in for and what ROM cost we should be expecting.

LVL is beam that looks a little like plywood with layers. They are 1 3/4" thick and come in heights that match lumber measurements.
Most lumber yards carry them up to 40 ft long, they just rough cut it to close to your length.

The biggest part of the job looks like scaffolding at both ends just to measure it. doing the install is just details to work out. For sure a 2 man job.

Nealtw

· #18 · Mar 4, 2020

You do have hangers so the 2x4 under it can come off

The new beam will be nailed to the old 4 nails every 16 inches.

And you can add a full 4" hanger under both of them.
There will be a bit of a sag that should be lifted out so you start at the end with the crack
https://www.homedepot.com/p/Simpson...anger-for-4x8-Nominal-Lumber-HHUS48/205227141

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Nealtw

· #19 · Mar 4, 2020

To lift is you need 2 2x4s nailed together in an L shape for stiffnes that will reach the floor. Lean it into the beam and hammer it over.

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