Postfix Rapid Setting Post Concrete, 20kg Bag, 5 to 10 Minute Initial Set

Postfix is the quickest way to set a post solid in the ground without mixing concrete. Pour it dry into the hole, add water, and the post is held within minutes. This rapid setting post fixing concrete comes in 20kg waterproof plastic bags. It is factory blended to give a high quality concrete, with an initial set of 5 to 10 minutes depending on conditions. The supplier states a typical compressive strength of more than 20N/mm² at 28 days. Fencers, landscapers, builders and homeowners use it for timber, concrete, metal and plastic fence posts, gate posts, washing line poles, rotary dryers, bird tables and play equipment.

Why it works

No mixing

Because the concrete is factory blended, there is no measuring of sand, gravel and cement and no mixer to clean. It goes from the bag straight into the hole, which saves time on every post.

Rapid setting

The initial set is 5 to 10 minutes, depending on conditions. The post can be let go quickly instead of being propped for hours, so you can move straight on to the next hole.

Strong enough for fencing and gates

A typical compressive strength of more than 20N/mm² at 28 days is plenty for fence posts, gate posts and garden structures.

Cleaner than wet concrete

Pouring dry from the bag keeps the work tidy around patios, lawns and borders. There are no barrows of wet mix to wheel across the garden and no mixing board to clean, which matters on small jobs where only a few posts are being set.

Waterproof bags

The bags are waterproof plastic rather than paper, so they can be stored outside or on site without turning to stone in the rain.

Where it's used

• Timber, concrete, metal and plastic fence posts
• Gate posts and fence support posts
• Washing line poles and rotary dryers
• Bird tables and children's play equipment

Specifications

Choosing the right option

This listing is a single 20kg bag. The choice is how many bags you need, which depends on the post size and hole size. The supplier's guide includes:

Multiply the bags per post by the number of posts and round up. Gate posts usually need a larger hole than fence posts.

Installation, use & care

Follow the instructions on the reverse of the bag. Dig the hole, stand the post in it and hold it plumb with a spirit level. Pour the dry postfix around the post and add water as directed. Keep the post upright until the initial set, 5 to 10 minutes depending on conditions. Wait for the concrete to harden fully before hanging gates or loading the post.

FAQ

Do I need to mix it?

No. It is factory blended. Follow the instructions on the reverse of the bag.

How fast does it set?

The initial set is 5 to 10 minutes, depending on conditions.

How many bags per post?

It depends on post and hole size. A 100mm post in a 200mm x 600mm hole needs about 0.75 of a bag.

What can I set with it?

Timber, concrete, metal and plastic posts, gate posts, washing line poles, rotary dryers, bird tables and play equipment.

Can I store it outside?

It comes in waterproof plastic bags, which protect it from rain.

Ordering & delivery

Sold in 20kg bags, priced per bag. A minimum order of 15 bags applies, shown when you add to basket. Bagged concrete is heavy, so delivery charges and lead times are shown at checkout.