Overview

The Foamjoint 75mm by 25m expansion joint filler is a closed cell, cross-linked polyethylene foam roll made to fill and back expansion joints in concrete. It is fitted into the joint before the pour, then left in place as the concrete moves and settles. The foam keeps water, dust and debris out of the joint while it works as a bond breaker and a backing support for liquid sealant.

This is the 75mm wide roll, supplied as a single 25 metre length. The manufacturer part number is 70251, and the foam comes as a continuous one-piece extrusion, so there is no lamination that can split in service. It is a trade grade product for slab joints, footpaths, driveways and industrial floors.

Key Features

• Closed cell and non absorbent, so it does not soak up moisture or debris
• Cross-linked structure gives good compression recovery after load
• Resistant to fungi, insects, diluted acids, alkalis, oils and solvents
• Stable across a wide temperature range from minus 40 to plus 95 degrees Celsius
• Compatible with most liquid sealants as a backing support
• Lightweight and simple to cut or staple into place on site

Specifications

• Width: 75mm
• Roll length: 25 metres
• Thickness: 10mm
• Material: closed cell cross-linked polyethylene foam
• Manufacturer part number: 70251
• Temperature range: minus 40 to plus 95 degrees Celsius

Applications

• Expansion joints in concrete slabs and footpaths
• Driveways, patios and paved areas
• Bridge and roadway joint control
• Industrial floor joints that need a void filler
• Backing for pour-in-place liquid sealant

What You Need to Complete the Job

Position the foam vertically in the prepared joint cavity before the concrete is poured, and secure it with staples or construction adhesive where needed. After the concrete cures, finish the joint with a suitable liquid sealant, or remove the top strip where a pre-slotted zip edge is supplied. Shop the full range of concreting consumables and tools in the Concreting range, and seal the finished surface with a concrete sealer from the Concrete Sealers range. For larger jobs, the 15-pack of the same roll covers a bigger site in one order.

Frequently Asked Questions

Do I leave the foam in the joint or pull it out?

Leave it in place. The foam fills the joint, blocks debris and acts as a bond breaker so the sealant bonds to the joint faces rather than the bottom of the gap. Removing it would leave a void that fills with water and dirt and defeats the purpose of a controlled expansion joint.

Can this be used with any sealant?

It is compatible with most liquid sealants. Because the closed cell foam is non absorbent, sealant sits on top of it and cures normally rather than being soaked up. If you are using a self levelling or a gun grade sealant, the foam gives the clean back edge the sealant needs to form a proper seal.

How do I cut the foam to length?

Cut it with a sharp knife or scissors to the joint length. It is soft and easy to cut on site, and the closed cell structure means the cut edge stays clean and does not crumble. For a neat finish at corners, cut mitred ends so the strips meet flush.

What is the temperature range for this foam?

The foam stays stable from minus 40 to plus 95 degrees Celsius, which covers Australian site conditions and most industrial floor environments. It does not degrade in UV, and it resists the diluted acids, alkalis, oils and solvents commonly found on building sites.