Head to Head – Concrete vs Postmix

25 Replies to “Head to Head – Concrete vs Postmix”

1. Good video. Ive lost count of the amount of posts etc ive set using both, and your findings pretty much echoed what I initially found with postcrete bith when using and removing posts. I think once you understand postcrete and find the best way to use it (ie dont follow the instructions) it has its place, but I still think the 'traditional' method is better, especially for those diyers who lack experience of postcrete.

2. Thanks Stuart. Fascinating results.

3. Gold star solution is clearly a splash of accellerator in the conventinally mixed concrete.

4. Struggle to see the point in this video if you're not going to follow the postcrete instructions properly. While I don't disagree with the conclusions, I find postcrete to be an easy, quick, reliable and sufficiently strong product for many simple jobs.

5. Thanks I’m about to put a fence up and normally would use post mix but won’t now

6. Can you please just say "needles to say I had the last laugh, concrete is far superior ????

7. Things you do for Youtube video's indeed! Thank you for this in dept analysis.

8. That lever method was what I used here to remove a line of posts with repair spurs attached. Used a bag of ballast on the end of the lever to hold it down while I wedged the mushroom of concrete to stop it falling back when I reset things.

9. That was really fascinating Stuart. Who would have guessed! What about that foam stuff they use in America?

10. Very useful. Thank you for going the extra yards.

11. Hi I have put up 22 fence panels with concrete posts with postcrete 15 years ago and not one has moved I would never put wooden post in don’t last no where near concrete one’s Bernard

12. Next time, maybe try a temporary raised bed, so you can knock the sides off, and then brush/wash the dirt away, instead of having to dig again?

13. Experience and exasperation led me to the same conclusions years ago.
    Postcrete (Postmix), seems to vary in quality from bag to bag – I've opened bags that seemed to have little, if any, Aggregate and others where its the main constituent… all purchased from the same supplier. Additionally, the Aggregate seems to be composed mainly of Crushed Stone rather than the mix of Crushed Stone & Gravel you'd use in a hand mix – which has a major impact on the strength of the mix.
    As far as I'm concerned, it's an utterly worthless product alongside the quality of the timber used for making the Posts currently available.

14. I've done quite a bit of field (stob and wire) fencing and I fix my strainer posts in a completely different way. Wooden posts rot at ground level, when I replace a post the bottom of the old post is as fresh as the day it was put in because there is insufficient oxygen down there for insects and rot to exist. To stop the post rotting at ground level I use bitumen paint from 50mm above ground line to about 300mm below ground line. I use a heat gun to heat the bitumen so it really grips into the timber. After a few minutes cool time I give it another thick coat of bitumen. Then I wrap and staple heat shrink polythene over the bitumen and use the heat gun to carefully heat the polythene so it shrinks and melts the bitumen till it is squeezed out the top and bottom. The rule for this stage is keep the heat gun moving otherwise the polythene will melt and you'll get a hole. I run a wet sponge lightly from the middle up then down to squeeze out any air bubbles, but be very careful, get hot bitumen on your skin then it's skin graft time.
    I put the post in the hole making sure there is 50mm of the now bitumen sealed polythene above ground level. I back fill with soil compacting with a home made tool made out of steel section, basically 5ft (1500mm) length with a 6" (150mm) welded at right angle, so a 'T' shape. When I get about 100mm from ground level I stop backfilling with soil and use a spade to dig a square 2ft (600mm) by 2ft around the post. I find some half bricks or big stones and use a sledge hammer to smash them into the soil around the perimeter, leaving them sticking up out the soil to act as an anchor. I then mix 1-2-4 concrete using 10mm gravel and fill around the stones and pole to ground level sloping slightly so water flows away from the pole. If you're really keen you could silicone the junction between the concrete and polythene but I just paint it with more bitumen.

15. Typical, I put a fence up today and used postcrete – had the same issues as you, it was super watery, then poured more in then it was rock hard a few mm down and felt like I wasn't mixing it properly. Wish I'd have just mixed my own now ???? Great Vid as usual Stuart, albeit 24 hours too late for me lol, thanks

16. Anyone else getting replies from a probable scam posing as PD?

    Edit: Seems to have disappeared now.

17. Excellent video, Stuart! I love videos that answer questions with a little science like this. The conclusion looks pretty damning for Postcrete, though I do wonder if that much more strength is needed just to fix in a fence post when they both appeared to do a good job staying in place in your test. It's possible the Postcrete takes longer to firm-up too, though I would agree it was reasonable to expect it would be at its full firmness after ~72 Hours. Thanks for the work you put into this one!

18. Amazing video – I'm so impressed with the effort you put into making it – thank you !

19. Postcrete is really a weak product (but is is usually "Good enough").
    The far bigger concern is that putting any timbers into concrete is not a good idea long term. All posts will rot out eventually if sunk into concrete. The whole post in concrete is a scam. That goes for timber companies and postcrete etc.

20. I worked on a job with a guy and he said “full the hole up and make soup”, now I’ve never read the post mix bag but I never full the hole up, I prefer to sprinkle the bottom of hole then fill up dry and mix up in the hole. I agree the gravel in the hole first is perfect for slight drainage against rotting. Great video this, nice one.

21. Great comparison and quite surprising- thanks for sharing ???? ????

22. Another consideration is the following generation of DIYer who will need to dig out your fence posts when it's time to replace the fence and the posts have rotted. Postcrete is easier to break up while in the hole whereas concrete is a nightmare to try to remove. And since the stuff isn't structural it doesn't need to be as hard a normal concrete.

23. I was always under the impression that the more water concrete received, the better and harder it became?

24. Great video, I've never used Postcrete & after watching your video never will. I thought you went above and beyond taking those posts out after all the hard work installing them…????????????

25. Would it not be good to wrap the post in a plastic bag to protect it?

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