# Forum Home Renovation Sub Flooring  Advice needed on best way to fix rotted end of joist (pics included)

## activeman

Hi all, 
I was hoping that you could help me out with this (see attached pic)   
What is the best way to repair the ends of the joist, considering that the part of the joist out of shot is in good nick? Do I do the same again here, or cut a bit out to splice? (ive attached a diagram with two methods that I am thinking of)   
I was thinking that option 1 is neater overall, but may come to issues when I lay the deck on top.
What are your thoughts? 
Cheers
Rob

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## r3nov8or

I would cut back to the next bearer and install a new joist, of the right grade and dimension for single span. Keep the good parts of the old joists for the 'next' project.

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## activeman

I was hoping to not have to do that  :Frown:  
I should add that the rotted section is about 200mm long, and that the good part of the joist is several metres. 
However, if they need to be sistered over a bearer, then so be it. I'll do it. Just be nice not to have to if I don't have to.

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## r3nov8or

"several metres"? What are the dimensions of the joists, and the actual span? "several metres" seems too far for safety from what I can make of the picture.

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## activeman

> "several metres"? What are the dimensions of the joists, and the actual span? "several metres" seems too far for safety from what I can make of the picture.

  span 1700mm
joists are 100x50x several metres (3000 - 4000mm) 
its an old place, hence those measurements (from what I've been told) 
so ive got 200mm rotten ends of 3000 - 4000 mm joists, and I hoping I don't have to replace the whole joist just because of rotten ends. 
cheers, rob

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## r3nov8or

I would replace the bearer to bearer 1700 span as suggested earlier, but someone else may suggest what you propose is ok.

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## Bloss

> I would replace the bearer to bearer 1700 span as suggested earlier, but someone else may suggest what you propose is ok.

  OOPS must have been dozing  . . . :Redface:  
Why woud you not simply run new short lengths of joist running across the first inner line of bearer and cantilevered over the outer bearer with the bolts through over that inner bearer?

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## ringtail

Just had a quick memory refresh of the AS. All joins in joists must be over a support. They can be butt joined with 30 mm min end bearing or scarfed. Lapping of joists in line is not permitted and drawings 1 & 2 would not comply unless the original joist still sits on the bearer. Even then its a bit of grey area in this case. Cutting back to next bearer is the sensible thing to do IMO

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## r3nov8or

Bloss, I think you've misunderstood, because this is about cutting back joists, not bearers.

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## shauck

Or, could you stick a stump in and cut back the rotten section and join over new stump? Just as much work and cost probably.

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## Moondog55

Surely there must be "Legal" alternatives that allow joists to be splinted?
Could they be perhaps sistered vertically on a short section on a joist hanger off the bearer?

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## r3nov8or

The AS says "Where cuts are used they shall be located centrally over the support, so that each side of the cut section is adequately supported". It then shows a picture of the various methods of joinign over a bearer. Stretching the definition of 'support' could mean a joist hanger, but they aren't free, and with the nails and bolts and time might just cost as much as 1.7m of a new joist anyway.  
It's a bit like NASA investing millions inventing a ball point pen that writes in space, and Russians just using pencils.  :Smilie:

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## Moondog55

Personally I think what is in the picture is "Strong enough"  it looks to have at least 30mm of bearing surface over the bearer and I would only muck about if I was getting it inspected.
you should see my garage roof

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## Bloss

> Personally I think what is in the picture is "Strong enough"  it looks to have at least 30mm of bearing surface over the bearer and I would only muck about if I was getting it inspected.you should see my garage roof

  mmm - remind me not to get you to do work at my place . . .  :Wink:  Why muck about - just whack some new short joist lengths in . . .

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## ringtail

> mmm - remind me not to get you to do work at my place . . .  Why muck about - just whack some new short joist lengths in . . .

  
Agree, totally.

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## Gaza

sign on front of moondogs garage

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## Bloss

> sign on front of moondogs garage

  LOL - but we all know Cecile keeps him on the straight and narrow . . . . :Cool:

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## Cecile

> sign on front of moondogs garage

   :Rofl:  
You don't know how true this really is!

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## shauck

> You don't know how true this really is!

  I am not responsible for anything that Moondog says!  Just for what he does.

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## Moondog55

Iwasonlyytrying not to overbuild

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## Gaza

> Iwasonlyytrying

  Thats. a Long word

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## activeman

Thanks for all the replies.    

> OOPS must have been dozing  . . . 
> Why woud you not simply run new short lengths of joist running across the first inner line of bearer and cantilevered over the outer bearer with the bolts through over that inner bearer?

  Because I hadn't thought of that very simple solution. Cheers.

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## Bloss

> Iwasonlyytrying not to overbuild

  Doing it right is called 'building'  :Wink:   :Smilie:   :Cool:  - well that's what my Dah taught me - but we're just joshin' with ya . . .  :Tongue:

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## barney118

> Just had a quick memory refresh of the AS. All joins in joists must be over a support. They can be butt joined with 30 mm min end bearing or scarfed. Lapping of joists in line is not permitted and drawings 1 & 2 would not comply unless the original joist still sits on the bearer. Even then its a bit of grey area in this case. Cutting back to next bearer is the sensible thing to do IMO

  I visited a pole home the other day and under the outer bearer 2 x 290 x 45 on each side of the wood pole checked in was a sight, until I spotted the join on a bearer not over the post butt joined using a gang nail plate that was bent around the bottom and 2 sides 50mm up 100 mm long on the top and bottom of the bearer. ( I will take a pic next time) and this was supporting a 2 storey outer clad wall  :Shock: .  
I agree on others cut it back 1700 to next bearer and join as per pic you have supplied.

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## ringtail

Yep get a pic for the she'll be right thread

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## Bloss

> Yep get a pic for the she'll be right  . . .

  Until it's not . . . thread  :Frown:

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