Large hole in joist!

[paulwright1972]

The previous occupier of my house wasn't too clever. He or she has roughly cut a section approx 7 inches wide and 75% through a joist in kitchen ceiling/bathroom floor. It's starts about 10 inches away from the wall and is right where I'm planning to put the bath....

I'm thinking of squaring out the hole and fitting as tight as I can with another piece of joist. Then put a steel plate on each side of the joist, extending 6 inches or so past each end of the gap. Drill through in several places and bolt up with M10 bolts.

Is this a reasonable way to go or is there a better way?

Thanks.

 

[Shytalkz]

At least it's close to the bearing, so the bending stresses are not great. However, the section left to deal with shear is not very much!

Don't bother infilling the notch, that won't replace the strength lost, without clever glueing and screwing; use a 38mm wide timber x joist depth, take from face of bearing to 300 past the notch (even better if you can get it onto the wall), bolt either side at mid depth with 2M8 bolts set 50 from the end of the new timbers and 50 back from the face of the notch ie 4 bolts in total. Cheaper than messing about with steel plate as well.

 

[^woody^]

Check out this notch which I happened across the other day (note the date is wrong!)

Untitled

• ^woody^
• 16 Jun 2008
• 7

Stupid contractors had did it a few years ago when they installed a shower tray. Fortunately the joist stayed up

 

[Shytalkz]

Now that, viewers is a notch!

 

[noseall]

that is a chasm.

 

[paulwright1972]

That bears an uncanny resemblence to the 'notch' I have, although somewhat neater.

Is the remdial work suggested above still appropriate/adequate for this problem now you see a photo?

 

[Shytalkz]

Yep that will be fine.

 

[paulwright1972]

Thanks very much the quick reply.

I'ts amazing how some people don't realise what they are doing isn't such a good idea!

 

[Adrian80]

Sorry to piggy back on an old post:

But, i can kind of see why people want to notch out a joist and fit a waste pipe for a shower tray, or something. (I actually want to fit a shower tray and the waste will have to cross a couple of joists)

Clearly there are notches and notches, but if you notch out a joint to fit a 32mm waste pipe is there anything you can do to reinforce the joist after.

Possibly put noggins between the adjacent joist, so it spreads the load a bit more?

 

[Shytalkz]

Just bolt another piece of timber either side, the depth of the remainder of the timber.

 

[Adrian80]

Cheers Shytalkz,

I see where your going! Reinforce the remainder of the timber.

Cheers

Adrian

 

[joe-90]

Just bolt another piece of timber either side, the depth of the remainder of the timber.

Very technical I must say. No minimums in regard to remaining timber? No 'calculations' re bending moments? Is your name John Wayne?

 

[Shytalkz]

Technical enough. Not that you would understand.