Crumbling underlay for laminated flooring

[dustnbones2]

I'm in the process of removing lino and hardboard. I noticed though there is underlay in the adjacent kitchen that looks like it's crumbling.
What is this stuff made of and why is is crumbling like this? Also, is it a health hazard as I need to remove is part before the lino can be laid

 

[Deleted member 174758]

How old is the building?

 

[dustnbones2]

How old is the building?

1930s I think

 

[opps]

The existing top flooring in your image is laminate flooring. When you say lino, do you mean laminate?

The sheets under the existing laminate looks like a fibreboard.

Wickes Wood Fibre Laminate & Wood Flooring Underlay - 10.03m² - Pack of 20 | Wickes.co.uk

Wickes Wood Fibre Laminate & Wood Flooring Underlay - 10.03m² - Pack of 20

www.wickes.co.uk

 

[dustnbones2]

No I mean the layer below the laminate which you identify as fibreboard.

 

[foxhole]

Fibre board is easily damaged only good under compression .