Any building could contain bats, for example in roof voids, attics, wall tops, between roofing felt and tiles, small gaps in walls, under eaves / soffits, etc
Gallai unrhyw adeilad gynnwys ystlumod, er enghraifft mewn to gwag, atigau, topiau waliau, rhwng ffelt to a theils, bylchau bach yn y waliau, o dan fondos / bondeoau, ac ati.