How to glue Styrofoam: Your DIY guide for insulation and repairs

A range of adhesives that can be used to glue Styrofoam together, so you will want to choose the one suitable for your specific project.

Standard white glue will work with many small applications, such as decorations and school projects. However, it may not be ideal for more permanent repairs since it is not as strong as some of the other options.

Spray adhesive works very well for most applications involving gluing Styrofoam. It’s great for bonding large surfaces together, such as Styrofoam blocks or boards, but less so for bonding small areas.

Another choice is foam board adhesive or Styrofoam glue. This type of construction adhesive is made for bonding Styrofoam and polystyrene products, especially for installing insulation boards. It is perfect for construction projects since it can be applied quickly and will hold up to the conditions at the building site. Styrofoam glue is also available in smaller packages for hobbyists and household repairs.

The two most common methods for gluing polystyrene foam together are spray adhesive and foam board adhesive.

Spray adhesive is the right choice if you want to bond larger areas. You can quickly and easily apply an even coat over both surfaces. Spray adhesive will not drip or run, so it is easy to work with. First, set up a workspace and gather your materials:

• spray adhesive compatible with Styrofoam
• scrap paper or plastic to cover your work area
• personal safety equipment
• clamps, tape, or another means to keep the pieces firmly in contact until dry

Here are the basic instructions for gluing Styrofoam:

1. Set up in a well-ventilated area with adequate lighting.
2. Cover any areas that might get overspray on them.
3. Wear nitrile gloves and safety glasses.
4. Ensure the Styrofoam parts are clean, free of dust, and that they fit together correctly.
5. Apply spray adhesive to both surfaces. Shake the can about a dozen times and spray an even coat on both surfaces to be joined. Hold the can vertically if possible.
6. Press the parts together. For a temporary bond, join the parts immediately after spraying. If a stronger, more permanent bond is desired, allow the glue to become tacky before pressing the surfaces together. (See the label for more details.)
7. Allow the glue to cure. Ensure the glued area is undisturbed and in firm contact until the glue has completely dried.

Polystyrene foam boards are quite popular for building insulation. They generally provide more R-value per inch than fiberglass and other loose-fill insulation. Also, foam boards are very easy to work with. 

Here’s how to glue polystyrene foam boards together:

1. Clean the area where the insulation boards are to be installed. Use a vacuum or damp cloth to ensure both the substrate and surrounding area are clean and dry.
2. Cut the board to size. Use a tape measure, utility knife, and straight edge to cut the boards to the desired size and shape. Pre-fit the boards before applying glue.
3. Apply the adhesive. Use a caulking gun to apply the adhesive to the foam board surface. Cut the tip at a 45° angle and puncture the foil seal. Start about 2–3cm from the edge of the board and place a series of beads about 25cm apart. Avoid applying glue too close to the edge of the board.
4. Press the board into place immediately after applying the glue. Press the board firmly against the substrate to ensure a good bond.
5. Wipe away excess adhesive with a damp cloth before it dries. If dried adhesive is discovered later, use a sharp blade to carefully scrape it away.
6. Use mechanical fasteners (nails or screws) on all boards to improve adhesion and hold the insulation board in place until it is dry.
7. Allow the boards to completely dry before covering them with the finish material. Consult your product’s instructions for information about drying and curing times. Note that your adhesive may need extra time to cure in damp conditions and low temperatures.

When you need to do a quick Styrofoam repair, reach for Loctite Extreme Gel. This high-viscosity formula can fill gaps and works great on porous surfaces like foam. It will bond to nearly any surface and contains our unique Flextec formula, ensuring it never becomes brittle. Constant flexing, vibration, temperature fluctuations, and moisture are no problem for this advanced adhesive. You can use it for indoor and outdoor applications.