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Can you cut a H4 treated pine post?

Finding My Feet

Can you cut a H4 treated pine post?

Hi Team,

I am wanting to replace a 30 yo hardwood gate post with a 88mm square section H4 post. it is out of the ground by 140cm. and carries a gate weighing about 20-25kgs.The top of the post has a decorative round top (matching the pickets) plus two grooves below the rounded top. My questions;

1. About how deep in the ground should I concrete it in?

2. From an OH&S perspective, is it OK to cut the shape into the top of the post with respect of the H4 dust?

3. If so, can Bunnings make this post up as a special order?

Thanking you,



Amassing an Audience

Re: Can you cut a H4 treated pine post?

Hi @102028 


First a tip to get that old  post out once the gate is off: Pre rock the post if  possible.

Get your car jack put it beside the post use  one or two big G clamps on post sides (just above jack lift lug) and lift post via jack against the clamps touching the post post where the G clamps are. Method two drill 12m hole and put the biggest big bolt  or steel through. (note bolt will bend  allways keep  people clear of a loaded jack). Reset clamps and lift again the other side if possible until people can lift it out.


As a general  rule for any post bury 1/3 of the total length a bit less  for use with concrete footing,  so your post is 140 cm tall from  ground so that is 2/3  so 1/3 is 70 cm in ground. Use of concrete bury (50cm to 70) cm of post Paint post end with Bitumous  paint or  any paint to help increase its life span underground.  


Re H4 dust just use dust mask  as  most important and enclosed (buttoned) clothes so it  dosnt go in your shirt etc . Do not panic if it does as it is not lethal in a direct way.


Bunning does have a cutting service for materials, Maybe in store Kerfing cutting you wood with  decoritive grooves they may do but  please check with @EricL  @MitchellMc 

Bunnings Team Member
Bunnings Team Member

Re: Can you cut a H4 treated pine post?

Hello @102028 (Ian)


Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thank you for sharing your question about changing your timber post.


If you are after exactly the 88x88 posts they come in 1.8m, 2.4m, 3.0m, and 3.6 meters lengths. Just to be on the safe side, I would bury the post not less than 500mm into the ground. Is the top of the post a separate decorative attachment? From a safety point of view, it would be better to transfer this feature rather than cutting into the H4-treated post. Would it be possible for you to post a photo of the top of this post to give our members a better idea of what it looks like? We can then make recommendations on how to proceed.


The H4 post can be cut at the store, but only straight cuts to reduce the height of the post. Please remember to wear safety gloves, goggles and a dust mask when cutting into H4-treated timber.


If you need further assistance, please let us know.




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Re: Can you cut a H4 treated pine post?

Thanks Mitchell and Eric,

At this stage I plan to use a 1.8M H4 post in-ground about 60-70cm and cut the top off the old hardwood post and drill, dowel and glue it to the top of the new post. The challenge will be holding the drill square. I might look at using a bench or pedestal drill to assist.


Thanks again for your advice,

Regards, 102028

Re: Can you cut a H4 treated pine post?

Hi @102028 


The  top bit is just decoration just cut it off square glue it to post top with liquid nails.  That will be so strong no dowels needed . at the join just fill and sand with your favorite filler and  paint over.  


But if you still keen to dowel  mark an X  in both post centres and drill centre . if one hole is a little crooked no foul just over size the hole and use glue as filler. Just make sure posts bits are square and level to each other.


have fun


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