Why would a laminate floor dip at the edge near an supporting wall when heavy item placed on it.

We are looking to buy a house but noticed where the laminate sits at wall edge next to a set of French doors the floor laminate splits down showing a 5/6 Mum gap around 1cm long. The grove seems to slip out on the lock and does this at both sides where the cabinet stands.

Any ideas why this might be. Current owners didn’t lay the floor and are not sure if the floor is cement or suspended plus they do not know what underlay was used.

Any advice about what might be the cause and if it’s a problem to start clear or or something that won’t be costly to correct

  • It sounds like an uneven or improperly secured floor beneath the laminate. But without knowing where the house is located and it's age we also can't make an educated guess of what might be beneath the laminate. Jun 5, 2018 at 12:01
  • Cheers it was build in 50s in pinchbeck area not much more help I know thanks for your comments :)
    – Natasha
    Jun 5, 2018 at 18:19
  • 1cm long? I don't understand. A photo would really help.
    – isherwood
    Jun 6, 2018 at 15:25

2 Answers 2


Often people install laminate floors on a foam based underlayment. It's possible the heavy object is compressing it sufficiently to cause the gaps.

Examples: https://www.homedepot.com/b/Flooring-Flooring-Tools-Materials-Surface-Prep-Underlayment/

  • This is what came to mind for me as well, but I don't understand the "1cm long" thing.
    – isherwood
    Jun 6, 2018 at 15:25

As far as I can guess using this site and assuming it's the ground floor, construction will either be a suspended timber floor or a ground bearing concrete floor.

If it's a suspended timber floor it could be wood rot, insect damage or a damaged sleeper wall. If the joists were mounted to the wall it could also be a failed mounting point.

If it's a ground bearing concrete floor it could be subsidence (though less likely as I would assume other damages would be visible to the house) or again wood rot or insect damage if a wooden underfloor was laid over the concrete.

If it's an upper floor the construction will most likely be a suspended joist floor and the issue could be caused by wood rot, insect damage or a failed mounting point.

If you really like the house, given it's age, it might be worthwhile to have a building inspection executed and indicate that you already saw this issue so they'll already have something to look into.

I do have to note that I'm no expert in this area but I'm just making educated guesses based on available information.

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