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 spongy and compressible so it’s useful for creating a space in concrete that can close up if needed.
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.
Did you get that? Abelflex is used to make gaps in concrete.
The gap is useful when structural engineers don’t want fresh concrete to stick to existing structures or they 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 movement or slab heave) without cracking.
Structural engineers sometimes use it with steel dowels if they want the new concrete to flex differently to existing concrete but want the surface to stay level (or flush) because trip hazards are bad.
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
walls around the outside edges of a new concrete slab.
- It has a 10mm high tear-off strip that can (should) be removed and filled with a flexible sealant.
The technical term structural engineers 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.
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 a flexible sealant.
Where Can You Buy Abelflex
A quick Google found these Abelflex suppliers in Brisbane:
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.
Abelflex is used to make gaps in concrete
So if your engineer has specified a product like Abelflex, it is there to make a gap in the concrete.