How to glue polystyrene:
A step-by-step guide

Polystyrene is a lightweight, versatile material that can be used for all kinds of projects. Whether you’re creating arts and crafts or having a go at home insulation, there’s a good chance that sooner or later, you’ll need to learn how to stick polystyrene together effectively.

The secret to success is choosing the right glue. For polystyrene, you have a range of options:

• polystyrene glue/Styrofoam glue

• craft glue

• construction adhesive

• spray adhesive

For most projects, spray adhesive is a convenient way to glue polystyrene.

Spray adhesives are versatile and very easy to use, making them a popular option for craft projects in particular. Most spray adhesives set quickly and dry transparent.

For larger projects (such as installing polystyrene foam boards for insulation), you should look for a specialised adhesive. 

These kinds of glues are generally classed as construction adhesives, and need to be applied with a cartridge gun. But they’re easy to use, and most importantly, they’ll help you to create a strong, long-lasting bond.

Before you start gluing, always check the product labelling and instructions carefully. 

We also recommend testing the glue first. Apply a small amount to a disposable surface, or a less visible part of the polystyrene, and see how it reacts. 

To glue polystyrene together, you’ll need the following:

• grab adhesive like UniBond No More Nails Original

• Paper

• Cartridge gun

• safety glasses

• cloth

Here’s how to glue polystyrene, step by step:

1. Prepare the space. The room should be well-ventilated. Wear safety glasses and protect the work surface with a piece of scrap paper.
2. Clean the polystyrene. Wipe the surface with a dry cloth. Glue adheres better to clean surfaces.
3. Check the surfaces. Ensure that at least one of the surfaces to be bonded is absorbent.
4. Prepare adhesive. Cut the tip of the UniBond No More Nails Original cartridge above the screw thread. Attach the plastic nozzle and cut it at an angle to the desired bead size. Insert the cartridge into a cartridge gun.
5. Apply the adhesive. Apply the grab adhesive in a continuous bead or zig-zag pattern on one of the surfaces.Keep the adhesive beads about 45 cm apart for optimal coverage.
6. Press together. For instant grab, press the polystyrene pieces together immediately after applying the adhesive. For a stronger bond, apply pressure for a few seconds and ensure full contact.
7. Wait for the adhesive to dry and cure. The bond will begin to form immediately, but for maximum strength, allow 24–48 hours for full curing.

For precise information about application and timing, check the manufacturer’s instructions for your chosen grab adhesive.

Tackling an insulation project on your own may seem like a daunting task, but it’s reasonably straightforward. 

To install polystyrene/Styrofoam boards, you don’t need any specialist tools. The boards are lightweight and easy to glue together.

We’ll show you the best way to glue Styrofoam or polystyrene foam boards.

First, gather your materials:

• polystyrene/Styrofoam boards

• adhesive (suitable for use on polystyrene) like UniBond No More Nails Original

• cartridge gun

• sandpaper

• white spirit

• vacuum cleaner

• utility knife

• tape measure

• gloves

Wear gloves and work in a well-ventilated space when using glue.

This is how to glue polystyrene foam together:

1. Prepare the walls. The substrate should be smooth, clean, and dry. Use a vacuum cleaner and damp cloth. If the surface is rough or uneven, use sandpaper.
2. Prepare the boards. Measure and cut the polystyrene boards, using a tape measure and utility knife. Then pre-fit the boards, checking that you’re happy with the placement.
3. Prepare the adhesive. Cut off the tip or the cartridge, then insert the adhesive in the cartridge gun. Use the knife to cut off the tip of the nozzle at a 45-degree angle.
4. Apply the adhesive. Apply beads of adhesive to the surface of the foam board. Start about 2.5 cm away from the edge. Apply a series of beads in a vertical line, about 25 cm apart. Don’t apply the adhesive too close to the edge of the board.
5. Put the board in place immediately. Press the glued side of the board against the substrate. Carefully press it into place for about 1 minute.
6. Repeat the process. Follow steps 4-7 for the remaining boards until they’re all in place.
7. Wait for the adhesive to dry and cure. Check the manufacturer’s instructions for information about cure time.