Horizontal crack in floor joist just above middle

[mrbodge]

After pulling up some boards bodge discovers there is a floor joist which has a horizontal crack beginning inside the wall running along it for at least 9 feet (could be much longer, cannot see any further). This crack is about 3mm thick. He can't see how far it goes without ripping up more boards (and that seems excessive). Tried to take photo but current camera lacks the ability to focus properly to take the shot.

Being a little bit crazy I jumped up high in the air and landed on it. Didn't make any noises, move or anything. Is this a problem that needs solving?

 

[ladylola]

True a photo would help but I'd hazard a guess that it's nothing to worry about. It sounds like a shake that is common in timbers especially if they have been put in green or wet. It's caused by drying out which causes stresses.Have you tried sticking something into the crack to see how deep it is and what is the size of the timber, I'm taking it that the crack is on the vertical face of the joist? As there wasn't any movement or cracking when you scienctifically applied a load it's unlikey to be a problem. If the timber is an upstairs joist then any failure (pre test!) would show up as cracking to the ceiling.

 

[mrbodge]

Not tried sticking anything in but the timber is massive to give an accurate scientific definition. Nothing bad happened before I knew it was there so decides it is as the lady says, a "shake".

Yes it's on the vertical face.

I'll measure it properly when it's not 3am

 

[Burnerman]

The bigger the timber, the bigger the shake.....if you could look at the end grain you'd probably see that it came from the centre of the tree.
John

 

[mrbodge]

Now I have a proper camera to get proper advice, here is the crack in question.

Untitled

• mrbodge
• 15 Jul 2010
• 1

 

[ColJack]

FAIL!!.. try again..

Untitled

• mrbodge
• 15 Jul 2010
• 1

don't use the bb code, use the net code.. or better still click under the reply window where it says "Show My Images" and just click the picture you want to insert.. no need for the img tags..

 

[big-all]

if you think of an "H"beam you only need around 20 -30% off the centre core to be intact for the full strength to be present accross the full height
that 3mm gap will probably taper to zero within 15 to 20 mm
hense ColJacks inteligent question to find if the timber has fully split along the grain

 

[mrbodge]

I'll have to pull up more boards to be sure but it looks like it stops and starts again, like the crack finishes, then another one opens up.

I don't want to pull up any more boards than necessary, so I went a long way further down and yes the crack had extended from the wall all the way along 3/4 towards the other wall. It stops and restarts in close proximity to each other at points, though mostly it's not very thick (part I photo'd is the thickest)

I'd say it does appear to run along the grain. On the other side of the building (where I lifted a board 3/4 towards the far wall. it has had another "joist" (I don't know if you would call it a joist, but great big bit of timber the same size as a joist) bolted onto it. I think they call that "sistering"? This joist extends about 1/3 of the way along the entire length of the joist with the crack in.