Best wood for fence posts

simeon_, Oct 16, 6:41am
Have options to get macrocarpa fence posts and rails. it isn't treated would this be more durable(last longer) than treated pine. Have alot of fences to renew. some posts are still ok but think I'll just start fresh . best technique for strong posts?

apollo11, Oct 16, 7:00am
No, I don't think you can bury macrocarpa. OK for rails though.I'd use H5 if the posts are in contact with the ground ie you are using a rammer around them, otherwise H4 posts are fine with concrete.
For a stronger fence, don't skimp on the number of posts, and put a good couple of spades of concrete in the hole before you put in the post (so the base is fully encapsulated. Overfill the hole with cement and smooth it off angled away from the posts so that water won't sit around the base of the post.
Don't leave the posts out in the weather for too long without rails as they can twist.
Use a sealer on any cuts. Use a capping rail to stop your palings warping out.

simeon_, Oct 16, 8:14am
Thanks.So every two metres for strong fence?Any specific cement . thinking the mix in the wheelbarrow stuff is best? What depth hole is best .I'm thinking of sourcing a hole borer for the posts also. best size for that? 250mm?

tintop, Oct 16, 8:25am
Before you decide exactly what spacing to use - scoot down to a timber yard and check what length rails are available. Probably 2.4m spacing will be more economical - suits 4.8 and 6.0m long rails.

\While bagged dry mixed concrete is convenient, it is expensive compared to using builders mix and cement.

newtec1, Oct 16, 9:08am
Normaly 2.2 spacing is the preferred spacing.You may find 2.4 is stretching it a bit and the rails will drop over time.You can get 4.4 rails for economy and don't chose what looks like a cheaper option of 75x 50,go for 100x 50 it will be worth it.100x 75 post are adequate,but if you have any doubt chose 100x100 and a min of 600mm into the ground with conc. Ready mix is the cheaper option for conc and you can mix it in a barrow if you don't have a mixer.Not that hard if you have the time and energy,i have done plenty that way.

newtec1, Oct 16, 9:12am
As for the timber,no macrocarpa can't be treated and won't last anywhere near the same as H5 pine.AS has been said don't leave them standing without the rails as they will twist and turn and become as usefull as petrol on a fire.

smallwoods, Oct 16, 9:36am
Ok, this will get some people replying.
YES you can use Macrocarpa quite effectively as a post and rail fence.
IF you know what you are doing.
You will need a hot and cold bath to treat them if not already treated, using creosote(either full strength or thinned with diesel), Heating the first lot up and then dipping into the cold solution to seal.
A shorter lifespan can be gained from using waste engine oil the same way.
Main thing is to re-dry the posts after treating or you will be as black as a gollywog.
The H5 CCA treatment is a high water ground condition treatment, H4 is your normal in ground treatment.
The closer your post the straighter the fence will stay.
Also, if the Macro is from your district (same soil type) it will (may) have a natural durability gene in it,.
From the old native days, posts off the farm where the trees were grown lasted longer than those from afar.

newtec1, Oct 16, 9:46am
And who has the ability and resources to treat Mac the way you described.If you live on a farm maybe,but in the city it is easier to buy treated pine. i worked in a sawmill where OB Kauri came in for treatment for use in out door furniture,so it's not only pine that gets treated,but you do need to have the resources to do it.

smallwoods, Oct 16, 7:24pm
OP was asking for the options as he could get Macro, not whether feasable.
Respondents said he couldn't use it, which they are wrong, he can if treated correctly. Can't see why you would go to H5 in a residential area (if that is where they are?) unless boggy ground conditions.
Anyways just gave them options, what they do with it is their call.
System can be done out of 200ltr drums cut in half.

tintop, Oct 16, 8:09pm
Where can you get creosote nowdays ?

omamari, Oct 17, 7:41am

smallwoods, Oct 17, 8:07am
Heaps of rural supplies stores still hold or get creosote.

cantabman1, Oct 17, 8:16am
Mr Pinetree Meeds says terrorised fence posts are the answer. lol

golfdiver, Oct 17, 8:24am
Mahogany is good for fenceposts

omamari, Oct 17, 5:42pm
Teak's better

cantabman1, Oct 17, 6:23pm
If you really want to know , it is Totara. But you will have a hard time finding much except maybe washed up on the beach, W/Coast.It will outlast anything else .

newtec1, Oct 17, 8:17pm
They used to use totara for house piles directly into the soil but over time they would rot at ground level when they were exposed to air and moisture,not in the ground itself.

golfdiver, Oct 17, 8:49pm
Totara isn't that good, we replaced thousands of them when I was farming. Puriri is pretty good in the ground, it was used decades ago for footing and breast blocks in swamps and lasted well. H5 pine will be as good as you will get theses days

newtec1, Oct 17, 8:55pm
Yep,H5 pine will outlast any other timber,even heart Kauri.Native timbers don't have arsenic and copper pumped into them and when exposed to moisture and air will eventually rot away.

trade4us2, Oct 17, 9:12pm
I had Totara piles but after 130 years the house had sunk down 600mm!

newtec1, Oct 17, 9:19pm
That's disgusting,130 years.get onto the council pronto.

johnny231, Oct 19, 5:44am
None of the fences you see use H5 as suggested unless they are 125mm house piles. What you need is 100mm x 100mm H4 fence posts. This is what you'll be directed to at the timber yard. I am a landscaper and this is all that is used for domestic fences.

bestie1, Oct 19, 7:50am
If you're building your fence in invercargill use treated pine.
There's various companies supplying macrocarpa fencing but you really you want to be building your fence closer to central Otago to use it.
Macrocarpa fence posts are used routinely in central. . different climate

comadi, Aug 27, 4:14pm
Correct, H5 is over kill for a fence; H4 100 x 100 or even 100 x 75 is fine.
Have the 75 mm thickness in line with the fence line.
And don't put cut ends in the ground.