Slugs: Nematodes for under floor boards of terrace house?

My daughter lives in a terrace house with no back garden, though there is a grass path behind yard area.

the house is about 85 years old, so probably has earth below floorboards.

she is pestered with slugs in the kitchen and hall (close to kitchen).

it is not practical to remove kitchen and seal all floorboards (where I presume slugs are entering).

Is drilling a single hole in kitchen floor and another one under the stairs then “pouring in” nematodes a possible solution?

Long term solution.
She is hoping to add an extension plus new kitchen in the next year. Is sealing all floorboards (silicone I presume) a suitable way to prevent slugs in the future?

Any other solutions to consider?

 

@ColinK The house I grew up in had earh under the boards as did another property I lived in and from what I remember it was absolutely bone dry under there and not really a comfortable place for slugs. Nematodes need damp soil to work well.
Perhaps they are coming through ventilation bricks and then into the kitchen. They could also be coming along water or waste pipes into the kitchen.

I just have this vision of a large slug going "Missus spare a few bob for a cuppa"

 

I tend to agree with Nigel it should be dry under there, there should be a good air flow under the floor.
Has there been flooding recently.
Might be worth checking all the air bricks are clear front and back.

I think what ever you do regarding killing the slugs will only have a short term effect until the damp problem is sorted out.

 

Thanks for the confirmations that Nematodes are probably not the solution for under the floor boards.

I will look again at places they might get in, including drains and air brick.

I’m guessing the solution will come when extension is done at which time part of back wall will be removed and kitchen removed.

 

Getting in under the front and rear doors?

 

I know it is not front door. No trails.
I know slugs can enter through tiny gaps.

the back door is a modern upvc door, but I will check seals.