New OSB sub-floors: slight movement and creaking noise

[kreutz]

Builders in our flat are replacing floor joists and sub-floors as the old ones were sagging and loud. The new OSB boards are 25mm thick. They finished the job and I have to now sign it off.

Pretty much all of the floor seems to be OK, i.e. it is even and quiet, but there are a few spots where OSB sub-floor boards meet where slight movement can be felt when walking. In the case of one of them, it makes a creeking sound which is audible enough. The builder says that it is normal and that, once we put glue and the parquet flooring, it will stop moving. It sounds to me like that's not right. It is a big job to redo and I should've kept a closer eye on this in hindsight, but it would be great to hear an opinion from a professional about this: should I get them to redo it or should I sign it off?

Thanks.

 

[Deleted member 174758]

No, it's not right IMHO. Creaking in the sub floor won't normally be cured by glue in the floor above. You always need to sort things like this out before installing the finished floor. The cure might be as simple as some extra screws (assuming that they screwed the sub floor and didn't nail it) and/or some glue between the OSB and the joists in the affected area.

 

[kreutz]

Thank you.

I have told them to redo the two worst parts.

Most of the rest of the floor seems pretty solid but you can hear a slight crack or two occasionally in random parts of the floor (usually can't replicate it if you step on the same area again). Would that be normal or is that also poor workmanship? Not expecting them to redo it, would just be good to know how badly I've done.

 

[Deleted member 174758]

I am a foreman joiner, so when I or my lads put in a floor I always take the time to walk the floor so that I can check for creaking, level floor, etc. That is pretty normal. AFAIK OSB should be treated the same way as chipboard - glued to the joists and screwed down adequately with all short ends fully supported on extra woodwork, as required. If that has been done then any sounds will possibly be coming from the joist to masonry/stud wall connections which might be a bit more awkward to fix