Mains water pipe

1. Check the pipe first * Make sure there are no leaks or damaged joints. * Make sure you can still access any stopcock, joint or fitting that might need servicing. 2. Insulate the water pipe * Use suitable closed-cell pipe insulation around the exposed pipe. * This protects the pipe and also gives a little separation between the pipe and the foam. 3. Fill the surrounding opening * A pest-resistant expanding foam such as Mouse Out can be used around the outside of the insulation. * Don’t completely encase the pipe itself in foam, particularly if it’s a rigid mains pipe. * Don’t rely on foam alone if the opening is particularly large. 4. For a larger hole, add a physical barrier * If there’s a sizeable void, I’d use something like galvanised wire mesh or a suitable solid cover around the pipe first. * Then seal the remaining gaps with the pest-resistant foam. * This gives you much better protection against mice/rodents than foam alone. One important point: don’t foam over a stopcock, compression fitting, isolation valve or anything that may need to be accessed. You want to seal the gap around the pipe, not permanently bury the plumbing.