Why is water ponding on our plant floor instead of reaching the drain?

Water ponds on a plant floor because the floor no longer falls towards the drains. In most cases the slab has not moved and the drains have not moved — the room has. Partition walls get added, a line gets relocated, one room becomes two, and drains that were in exactly the right place for the original layout end up in a corner the water never reaches.

The floor is still doing what it was poured to do. It is just doing it in a room that no longer exists.

How do you know the slope is the problem and not the drain?

The clearest test costs nothing: wash the floor and watch it. If the water clears on its own, the drains are fine. If someone has to walk it out with a squeegee, the fall is wrong somewhere between where the water lands and where it is supposed to go.

In a roughly 2,000 square foot production room at a food-processing plant in south Etobicoke, there were three drains and none of them were doing much. What the plant had settled into was three or four people with squeegees, permanently pushing water across the floor towards the drains after every wash.

That is the detail worth sitting with. Nobody had specified a squeegee crew. It accumulated because the floor stopped working and the shift had to get the room clean anyway. Add up three or four people doing that after every wash-down and the floor defect has a labour number attached to it that nobody has ever put on paper.

Why not just move the drains?

Because moving a drain is a much bigger job than reshaping a floor. Relocating a trench or point drain means breaking the slab, cutting into the drainage line, re-tying it and making good — a deeper excavation, a longer shutdown and a lot more that can go wrong inside a fixed window.

In that production room we left all three drains where they were and re-sloped the floor to them. We shot levels across the room first to work out how much fall was needed and how much the edges had to come up, then built the slope in ordinary concrete and finished the top in food-grade material.

Our opinion, and it holds in most rooms we have looked at: the drain is rarely the thing that is wrong. The floor around it is. Re-sloping is the cheaper answer often enough that it should be priced first, before anyone opens up a line.

What actually goes wrong when water sits?

Standing water encourages bacteria, and the dirt that settles into a puddle is a bacteria trap. In a food plant that is not an aesthetic issue. These plants are inspected, and ponding gets written up as something the plant has to act on, with a deadline. A floor defect becomes a compliance item.

The rooms are also washed down, power-washed and effectively flooded on a regular schedule to keep them clean. A floor that cannot clear that water on its own is fighting the cleaning regime rather than supporting it.

Which layers have to be food-grade?

Only the top. The concrete doing the shaping is buried and sealed under the finish, so it can be ordinary material. Over it goes the food-grade system — a base coat and a top coat, with a non-slip broadcast where the room needs it. We go through this in more detail in which floor repair layers have to be food-grade, because it is the single most common thing plant managers get quoted wrongly.

The finish also has to survive what the room does to it. That is why these rooms get a cementitious urethane or polyurethane floor system rather than a general-purpose coating — the same approach we used across the new production room floor at the same plant.

Does this apply to buildings that are not plants?

Directly, in garbage and compactor rooms. What comes out of a compactor is not pleasant, it needs to be washed away quickly, and on a flat floor it simply sits there and generates the odour complaints that reach the property manager. We have re-sloped those floors and finished them the same way we finish utility and process room floors, and the garbage room restoration work we have done in high-rise buildings is the same principle in a different building type.

If a room is hosed down and the water does not leave on its own, the floor is the problem — plant or condominium, it makes no difference. More questions of this kind are answered on our FAQ page.