Bouncy floor - fix?

[Gowardo]

Hi guys,

Hope all is well I am refurbishing a property and one of the floors is quite bouncy on an upstairs room. I've already taken all carpets out and therefore managed to lift a few floorboards to see what the state of the joists is.

The joists seem in good enough condition, although it seems as though they have already been strengthened with criss-cross timbers at a very sporadic distance of about 4 feet apart.

This is a back bedroom we are talking about and the joists rest on a load bearing wall below. I have a feeling the house has moved slightly in time causing the joists come ever so slightly loose, hence the bouncing.

What would you do if this was your floor? I'm thinking of removing a bunch of floorboards and simply install some additional bridging like so:

Do you think that should fix the problem?

Thanks in advance!

 

[foxhole]

If you mean they have noggins like those in the pic then this is normal practise and part of the original build, though I don't like that particular method a it's not very strong.This is to prevent twisting and warping , will not take any bounce out of the floor, what size timbers are installed?

 

[freddiemercurystwin]

And what is the span and what are the gaps between each joist?

 

[gregers]

herringbone.

 

[Gowardo]

Thanks for your responses fellas.

Full joist length/span is probably about 4 meters (I'll measure more precisely this evening) and I think joists are about 70mm wide with a pretty standard gap of around 400mm.

Any idea how I can get around the bounce?

At a bit of a loss to be honest!

Thanks in advance all

 

[foxhole]

Missing a dimension there, what depth?

 

[AronSearle]

Firstly it is not likely a structural issue, just a quality issue.

Half a dozen ways to skin a cat.

One option is to remove existing floorboards and screw and glue T&G plywood flooring, ensure you have glue in the T&G and the face of the joist. Creates a diaphragm action which will stiffen up the floor.

Obviously this is pretty permanent, I'd personally put up with a bit of bounce as long as it doesn't creak n squeak.

 

[Gowardo]

That would be a good idea normally, but I was looking to sand the original floorboards, so that's gonna be a no I'm afraid. Do you think I can achieve a similar result by installing some bridging in between joists or should I not bother? Mind you, like you say the bouncing is not a huge bother, but it is considerable. While there is no creaking or squeaking, it does bother me and would love to get it done before finishing the room.

Thanks for all the advice!

 

[freddiemercurystwin]

Ahh well, little point contributing any more without the depth of the joists.

 

[Gowardo]

Ahh well, little point contributing any more without the depth of the joists.

You are absolutely right sorry fella - I will get these posted to you guys tonight. It's been a mad week Thanks again for all the advice so far.

 

[AronSearle]

Do you think I can achieve a similar result by installing some bridging in between joists

No, and in fact they could cause cracking noises as they won't stop joists flexing but will mean more things rubbing.

As someone said above, the noggins (those bridging pieces as you call them) are just to stop joists twisting, and once the floor layer is on they become somewhat redundant anyway.

 

[Will..]

Mid span support via RSJ or box lintel or steel plates bolted to the side of the joists. No other option I can think of off the top of my head.

 

[Deleted member 174758]

As someone said above, the noggins (those bridging pieces as you call them) are just to stop joists twisting, and once the floor layer is on they become somewhat redundant anyway.

As I'm currently installing some really large replacement joisting in an existing building I've got to disagree. Without solid strutting (or "noggins" as incorrectly stated above) you will still get a degree of flexing of the floor, or "bounce", even if you glue and screw the plywood in place (think sprung dance floors to get my drift - you never strut them). With solid strutting in addition the floor will be a lot more rigid with less tendency to "bounce". It's how I'd approach iot - that or timber herring-bone strutting which is lighter.