How to use postcrete

by Sam Wood | Last Updated: 27/07/2021

Postcrete is a fast setting concrete used to set posts for fencing, decking or whatever you need a set post for. Postcrete is popular due to how quickly it sets and for the fact that it is a lot simpler to use than concrete. But how exactly do you use it? Let’s jump into it.

How to use Postcrete

Postcrete is a lot simpler to use than concrete as you don’t need to mix it and you don’t need to add any aggregates, everything you need for the mix is already in the bag.

Supplies Needed

  • Bag of postcrete (one bag per hole is commonly used)
  • Water
  • Spirit Level
  • Something to aerate the postcrete with (E.g a metal bar)
  • Spade for digging

Step 1 – Dig Your Hole

The obvious place to start is by digging your hole for your post. A single bag of postcrete will fill a fairly large hole so you can go quite wide with your hole to make sure you have plenty of postcrete to hold the post in place.

Step 2 – Fill Your Hole One Third Full With Water

Now add some water to your hole. You want it roughly one-third full and with the water no longer draining away.

In the image I’m using a bucket to represent the hole.

Fill your hole one third with water

Fill your hole one third with water

Step 3 – Place Your Post In The Hole

Now place your post into the hole, don’t worry about getting it perfectly straight just yet.

Place your post in the hole

Place your post in the hole

Step 4 – Add Postcrete

Now comes the time to add some postcrete, keep adding it until the postcrete comes just above the water level.

Step 5 – Aerate The Mixture

Use a long pole to mix up the postcrete a little. Just jab it up and down into the mix. The aim is to just try and mix it up a little, you don’t need to swirl it around or anything.

Step 6 – Level Your Post

Now comes the time to get your post perfectly straight while the mix is still wet and moveable.

Get your Post Level

Get your Post Level

Step 7 – Keep the Post Straight As The Mix Sets

Now you need to keep the post perfectly straight while the postcrete mix sets. You can do this by either clamping or fixing it to a support structure or just holding it. Holding it straight wouldn’t be an option with concrete but due to the speed at which postcrete sets it is more possible here. I would always advise setting up support though to keep it perfectly straight. You may wobble a little while holding it which may create gaps around the post.

The Postcrete Has Just Set

The Postcrete Has Just Set

Done!

That’s all there is to it, your post is now set. The postcrete will continue to harden over the next few hours so don’t knock the post as it will still be liable to move a little.

As you can see postcrete is really simple to use. Unlike concrete, you don’t need to mix it up before use and add sand and aggregate. Everything you need is already in the bag and you just need to chuck it in the hole.

More on Postcrete

Postcrete vs concrete

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Wood by name, wood by nature. I am a fully qualified, time-served, award-winning joiner with an NVQ Level 3 in Carpentry and Joinery as well as an HNC in Construction. Beyond my joinery qualifications, I have also earned a degree in building surveying. I believe these qualifications make me perfectly positioned to provide expert advice on many different areas of DIY as well as share all of the tips I have picked up in over a decade working on building sites!