Quick answer: for normal fencing work, we recommend rapid-set Postmix. We would choose traditional concrete when suitable concrete is already being mixed elsewhere on the job, or when the project specifically needs a conventional concrete footing.
Customers often search this as Postcrete vs concrete, Postcrete or concrete or is Postcrete as strong as concrete? Postcrete is the Blue Circle/Tarmac product name; Wern-Wood sells our own 20kg rapid-set Postmix.
For normal fence posts, use Postmix
Our reason is simple: it is quicker and easier. A post can be set in around 5-10 minutes with rapid-set Postmix rather than turning the job into a separate concrete-mixing job.
You also work one post at a time without mixing a wheelbarrow batch, which is much easier on normal fencing jobs, repairs and awkward-access work.
Use traditional concrete when you already have it
If suitable concrete is already being mixed elsewhere on the project, or you have enough left from another job, there is no reason to waste it. That is the main situation where we would deliberately use traditional concrete instead of Postmix.
We do not choose traditional concrete for ordinary fencing because we think it is automatically better. For this job, Postmix is simply faster and more convenient.
Is Postmix as strong as concrete?
For a fence post, the practical question is not only material strength. The footing size, depth, ground conditions, post section, wind exposure and how much movement happens while the mix is young all matter.
A correctly sized Postmix footing is suitable for most normal fence posts. A badly sized or shallow footing can fail even if the material itself is good.
Postmix sets quickly, but it still needs time to cure
The bag may set in around 5-10 minutes, but that does not mean the footing has reached full strength immediately. Keep temporary supports in place for as long as practical and avoid unnecessary movement early on.
For rails, we would normally be comfortable starting after about an hour where the job allows. We know contractors who move on faster and others who leave posts for 24 hours. Our advice is to give it time and avoid cracking the fresh footing by moving the post too much too soon.
Gate posts need more support than fence posts
Gate posts take much more leverage than ordinary intermediate fence posts, especially on the hinge side. Give them a more substantial footing and more Postmix rather than treating them like a standard fence post.
See our Postcrete / Postmix quantity guide for practical buying quantities.
When concrete may be the better choice
- Suitable concrete is already being mixed on site.
- The footing is part of a larger concrete job.
- The specification calls for a conventional concrete mix.
- You have unusual load, exposure or structural requirements and have designed the footing accordingly.
Our rule
Normal fencing job: use Postmix. Already have suitable concrete on site: use the concrete you already have.
Shop Wern-Wood 20kg Rapid-Set Postmix or read How to Use Postcrete / Postmix for Fence Posts.
