Laminate floor trouble?

[LastTwoBraincellsFightingFor3rdPlace]

The flooring in my lounge is looking dreadful. There’s darkening all around the perimeter of the lounge, underneath the rug too. It has been like this since we moved in. It’s not wet to the touch and it has been like this since we moved in.

Does anyone know what could have caused this?

Obviously, the floor will have to be replaced, but I want to ensure that this doesn’t happen again.

It’s laminate and I’ll be replacing it with hardwood floor this year (hopefully!)

Photo attached

That looks like it is absorbing damp from the sub-floor. I wonder what is underneath it and whether there is was an impermeable membrane laid.

How old is the house?

When the floor was laid, there should be a damp proof layer then the underlay then the laminate. Maybe they forgot the damp proof layer? Do the boards feel spongy?

It’s a Victorian terraced house, I’m afraid I don’t know specifically how old it is.

The previous owners had a leak, and all of downstairs got ripped out and replaced. The laminate is around three years old.

No, not at all - they’re solid and dry to the touch.

Oh, I wonder if the sub-floor was replaced with cement and did not dry out properly before the laminate was laid...

Obviously I don't really know, but you may find out when you lift the laminate prior to laying the new floor.

(The worst thing would be if they put in a cement floor without a damp proof membrane...)

Oh, dear 😭