Well, the third type is floor hatches.

Well, the third type is floor hatches. They can have completely different sizes and design features. Highlight two types of these hatches — not filled and filled. The first are finished with a gypsum water moisture -resistant sheet. Lined with laminate, linoleum, tiles. The latter — have a hatch cover, which is usually filled with a solution of expanded clay, cement, boiled boards or foam. Also, floor hatches are made with a shock absorber and without it.