All About Abelflex ( A Story about Joints)

What is Abelflex?

The technical (confusing) answer:  Abelflex is a closed cell, cross-linked, 100% polyethylene foam expansion joint and space filler strip.

This means that Abelflex is a plastic foam that has bubbles in it that aren’t linked so water can’t run through it.
It’s made from the same sort of foam used to make pool “noodles” – so it’s buoyant. The air bubbles mean it is compressible so it’s useful for creating a space in concrete that can close up if needed.

Abelflex Roll
Abelflex comes in a roll

So Abelflex is simply the proprietary product name for a foam filler that is 100mm high x 10mm thick or 150mm high x 10mm thick. It comes in rolls up to 25m long and is used in concrete work.

What is Abelflex Used For?

The primary purpose of Abelflex is to create a gap in new concrete. So Abelflex is cast into the concrete and left there.

The gap is  useful when we don’t want fresh concrete to stick to

Picture of Abelflex in concrete slab
Abelflex around a column

existing structures or we want the fresh concrete to expand or shrink freely without affecting (pushing on) adjacent structures (including walls, other concrete, brickwork and pipework).

Abelflex also allows new driveway and patio slabs to rotate slightly (if there is slab heave)  without cracking.

We sometimes use it with steel dowels if we want the new concrete to flex differently to existing concrete but we want the surface to stay level (or flush).

Finally Abelflex is often wrapped around pipes before concrete is poured so that the pipes don’t break if there is slab heave or ground settlement.

Specific Feature of  Abelflex

The specific features that make Abelflex useful on site are:

  • It has an adhesive backing which makes it perfect for sticking to
    Picture of Abelflex roll
    Abelflex in a roll

    walls around the outside edges of a new concrete slab.

  • It has a 10mm high tearoff  strip that can (should) be removed and filled with flexible sealant.

The technical term we use for the gap made by Abelflex is an Isolation Joint.

 One Useful Tip

The tear-off strip on top of Abelflex is there for a reason that is often overlooked. The tear-off strip needs to be removed after the concrete has cured and the remaining gap filled with flexible sealant (Sika-flex or similar).

If you see Abelflex and it hasn’t had the strip removed and filled with sealant – that is a builder’s defect! When a concreter is tasked with installing a carport slab or walkway slab, once the concrete is poured and cured the concreter never comes back. If Abelflex is used and a sealant joint is not installed, the job is only half done. Get your builder or your concreter to install the Abelflex joint properly.

Why?

Abelflex DOES NOT seal the gap between a structure and a walkway slab. If you don’t seal the gap between a concrete slab and an existing structure, water can run down the gap and into the footing and could result in slab heave. If your builder hasn’t done everything within their power to prevent slab heave, then they could be liable for repairing your house. For the sake of installing some sealant, please make sure the tear-off strip is removed and replaced with flexible sealant.

Where Can You Buy Abelflex

A quick Google found these Abelflex suppliers in Brisbane:

Blackwoods

Lyndons

Don’t forget that Abelflex is a proprietary name. Other manufacturers supply similar products that are acceptable – particularly if their features match the features specified above. A typical example of a similar product is the product available from Parchem called Jointflex.

13 thoughts on “All About Abelflex ( A Story about Joints)”

  1. Matt
    Great information. What is the best non mechanical means for removing ableflex that has been incorrectly stuck in concrete. We tried acetone and it does not work. Your answer will be appreciated.
    Many thanks.

    Roger

  2. Hi Matt, I want to use abelflex for a different purpose than joint seal. In particular a little flexible box to protect some camera equipment and need to glue it together. Do you know or can you recommend a way to bond different pieces of abelflex together? thank you

  3. Hi, i have recently built a new house and wanted to do concreting around the house. The concretor has not put joint foam at one complete side. He said that slab was irregular so foam is not required. He has concreted to hide the slab. I am doubtful if this is actually the right practice. Could you please help me here?

      1. Thanks Matt.
        That’s a really informative manual, especially for someone dealing with this for the first time.
        Much appreciated.

  4. Well explained! It is ideally suited for joints in sidewalks, driveways, streets, and single- and multi-level floor slabs. Due to its unique self-sealing characteristic, no subsequent joint sealing is required.

    1. Thanks for the comment Perci. Unfortunately I disagree about the self-sealing characteristic of Abelflex. This is a common misconception – extra sealant IS required when Abelflex is used. Abelflex and its competitors come with a tear off strip that should be removed and filled with joint sealant. That is their real benefit – they make it easy to install joint sealant where they have been used in a joint.
      Without joint sealant you DO NOT have a water seal.
      Check out these links for information from the manufacturers.
      http://www.parchem.com.au/public/pdfs/data-sheets/Jointflex-TDS.pdf
      https://www.tilersonline.com.au/files/data-sheets/davco-Abelflex%20Datasheet%20v1.1.pdf
      Matt Cornell

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