How to fill a big gap in an internal or external wall

Task difficulty: A bit of skill required

You have a big, draughty gap around the extractor fan exit in the kitchen wall.

You will need

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Step by step process

  1. Step 1

    Step 1

    Cover all surrounding areas before you start

  2. Step 2

    Step 2

    Ensure that the gap and wall around it are clean and free from grease and loose material, then mask off any cupboard or appliances close to the gap.

  3. Step 3

    Step 3

    Moisten the surface to help the foam 'cure' and expand - a household plant sprayer filled with water is ideal.

  4. Step 4

    Step 4

    Remove cap of Polycell Expanding Foam Polyfilla carefully and, holding can away from face, shake vigorously about 20 times to mix contents, then carefully screw on required applicator nozzle (included).

  5. Step 5

    Step 5

    Hold the can of Expanding Foam upside down and direct the applicator inside the hole, apply pressure as required, shaking the can from time to time during use. The foam will expand to 2½ times the amount you start with so take care not to overfill. If using more than one layer of foam, spray lightly with water between layers. After 24 hours, the foam can be cut, sanded, plastered or over painted.

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