Entire floor moving

[JBAG]

Hey all, just finished plastering and painting the main bedroom in our 60's era house, then pulled up the carpet and noticed something disturbing!!
In one corner of the room the entire floor (boards and joists) moves up and down about 5 or 10 mm. :oo::oo::oo:
The only access hole is on the opposite side of the room so I can't look in there without ripping up the floorboards.
Any ideas on what this means and how to fix it???

[jiggy]

could be a number of things from really simple to really nasty.You should be able to get access from room to room under the house. It might be just a missing packer under a bearer or a sunken pier , it could also be termite damage.Let us know how it looks or take pics.

[JBAG]

Cheers,
I'll have to have another look but when i pulled up the boards where the inspection hole is I don't reckon there would be anywhere near enough room to get in there.

[jiggy]

Are you planning on re-carpetting or using the existing floorboards ?You may end up having to cut out a section of boards where the problem is .!

[Bloss]

You have no choice really you have to create access to see what is the problem then to fix it. Likely a failed pier/stump/bearer through subsidence, rot or simply poor workmanship. Might be as simple as using some packing, might need a new hole, stump etc. But you can't tell until you take a look. If you cut carefully you can remove floor boards along a joist centreline and they can be replaced and carpet will hide.