# Forum Home Renovation Cladding  Weatherboard install  butt or 45deg joins?

## ChocDog

Ive seen it recommended to use a 45deg join, as opposed to a butt join, when joining weatherboards.  
But Ive had a look around the neighborhood at new builds as well as old homes and havent found any 45deg joins yet. So whats the story? Is it recommended best practise that no-one does, or are the cons to this method. So to you old school chippies out there (Im looking at you inter6/ringtail) and you new-skool cologne loving builders (metrix!), or anyone else for that matter, if time wasnt a concern, which method do you recommend? 
Cheers.

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## OBBob

I did 45 degree joins on the last place and it worked well. One advantage is that it's not as obvious if the joint moves a bit.  
Interested to hear what the current norm is too.

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## Oldsaltoz

Yes every new home I have seen has butt joints, however, I suspect the 45 degree cut would be used on any joints, simply because it will be stronger with a bigger area for adhesion. 
Good luck and fair winds.   :Smilie:

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## r3nov8or

The problem with 45 degree cuts exposed to the weather is that it creates a fine sawn point that is more susceptible to water intake and therefore rot than a 90 degree cut. That's why you also won't see any weatherboard home with mitred corner boards either anymore - they all have a vertical square corner profile with the boards butted into it at 90 degrees.

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## OBBob

Hmm ... my place had huge eves, which mitigated that I guess. I used the square block on the corners.

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## r3nov8or

Well, there's always moisture in the air, then there's blown rain, washing the house etc. Modern paints are great these days, just that 45s add to the possibility of water intake. A 'spliced' 45 join can also look better and blend the join whereas a great butt join depends on the two ends being perfect and the boards exactly the same thickness. There's always pros and cons. My dear departed Dad always said don't use a 45 outside, so I don't  :Smilie:

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## Bloss

> Well, there's always moisture in the air, then there's blown rain, washing the house etc. Modern paints are great these days, just that 45s add to the possibility of water intake. A 'spliced' 45 join can also look better and blend the join whereas a great butt join depends on the two ends being perfect and the boards exactly the same thickness. There's always pros and cons. My dear departed Dad always said don't use a 45 outside, so I don't

   :What he said:  and my dear departed told me that Dad too . . . and on that bit of advice at least, I listened . . .  :Redface:  blocking on the corners and butt joints long runs . . .

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## OBBob

Well gee guys ... where was this thread when I did mine! I recall it being a fair PITA to cut them at 45 ... ha ha ha. From this point forward I shall no longer bother.  :Smilie:

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## intertd6

Normally butt joints are used on WB's, on the odd occasion I have seen external corners mitred ,  mitred joins are used trims & fascias externally as the norm, so if someone wanted to spend the extra time on mitering all the joints I couldn't see a problem with it.
regards inter

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## ringtail

Now that I feel old, my 2 cents. Butt join. With a hardwood board you will get shrinkage across the board but next to nil along its length. 45ing , IMO could lead to ugliness with hardwood boards if they shrink differently, which they will. Apart from that, it's just not needed, is time consuming and offers no real benefit. Of course, oil based primer all round before installation and slop it on the endgrain  :Wink:

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## ChocDog

Brilliant. Many thanks for the directions guys. 
 Sounds like its butt joining all round on my baltic pine WBs. My understanding is no sealant at the joins; just paint any fresh cuts (I've already undercoated all sides....). And a bead of sealant where they meet the WB stops.  
I'm sure I read in one of those Alan Staines books to mitre the joins on WBs. I've noticed a few things in those books dont always seem to be the best advice.

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## OBBob

Yes!

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## ChocDog

Bingo, thats were I read it. Cheers Bob.

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## r3nov8or

Some have given reasons as to why mitred joins aren't better. A book says they are better, but doesn't say why (that I can see). Make your choice and be happy  :Smilie:

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## freebaser

Interesting that many of the butt joins at my place have warped and opened up a bit but the ones that had been cut on 45 degree angles were mostly still sitting well after many years. Once the water gets into the joint both types seem to separate and look ordinary after many years. When replacing boards, I found a few butt joins in my old weatherboards that had been placed mid span between the studs - so they were basically hanging in the air held together by paint - no surprise that they moved over time.

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## fredgassit

Would all of the advice above apply to Hardiplank?

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## fredgassit

Would all of the advice above apply to Hardiplank?

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## goldie1

hardies used to recommend caulk but now flashing behind and no caulk  http://www.jameshardie.com/d2w/techn...t-flashing.pdf

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## fredgassit

Thanks Goldie1.

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