Bedroom Floor "bouncing"

[petewood]

Are you sure that noggins will take the bounce out of the floor, I would have thought that once the floorboards are fixed to the top of the joists this would stop sideways movement, and if the joists are flexing vertically then neither noggins nor herringbone would stop this. I reckon that the best way to stop the bounce would be to fix extra timber down the side of the joists. If it can't be fitted right to the ends then fit them as long as possible.

I wouldn't have thought that small notches out of an 8" x 2" would have weakened them to any great extent.

 

[masona]

The idea of the noggins is to stop the joists twisting but does make the floor more rigid.

eg: If you have 3 joists without noggins and stand on the middle joist which will bend because of the weight, so if you put in noggins, the middle joists will not bend as it would spread across the load therefore making more rigid and less bounce over a bigger area.

The joists should always be at the shortest span, if it's the other way round, the longest span will give you more bounce.

 

[petewood]

I take your point but I would think that these joists must be running the long way, even I could walk along an 8" x 2" at 2.5m long without it flexing noticeably.

 

[roblatus]

One side of the room the wall is an external wall. No problem there. However at the other side of the room is an internal solid wall which is built on top of the floor. There is a joist that runs parallel to this wall and quite close to it. I don't see how i could get a noggin in between this joist and the next one which is essentially at the other side of the wall.

I wouldn't worry about that for now because the weight of the wall may make that last joist rigid anyway. There's nothing to stop you using a L-shape bracket on top of the joist and fixed to the wall with screw/rawlplug.

ok excellent. Thanks for the help. this is a job that i will be doing for sure now. I think the wall on top of the floor has maybe contributed to the slope that is also present in this rooms floor. It was on my survey when i got the property, it said that the slope was due to the timbers settling and had happened a long time ago but surely a wall built on top of the floor in such a way without a supporting wall underneath must have contributed to this slope?

If i can somehow remove a couple of boards that run under the wall then i may try and get some sort of noggin in between these two joists that the wall sits over as i was hoping this may help give a bit more support to this area too.

 

[masona]

Forgot to mention, if you do away with the floorboards and renew with 18mm plywood sheet with screws, that will make it even more rigid as it bond all the joists together over a larger area.

 

[Bylough]

All good advice here. May I add though- forget the angle iron idea, unless you want to have a built-in lightning conductor!!

 

[Bylough]

Or get Radio 1 on your telli !!

 

[roblatus]

All good advice here. May I add though- forget the angle iron idea, unless you want to have a built-in lightning conductor!!

Is this for real???


Surely things like your tv aerial or satallite dish would be more prone to a lightning strike?

 

[roblatus]

Are you sure that noggins will take the bounce out of the floor, I would have thought that once the floorboards are fixed to the top of the joists this would stop sideways movement, and if the joists are flexing vertically then neither noggins nor herringbone would stop this. I reckon that the best way to stop the bounce would be to fix extra timber down the side of the joists. If it can't be fitted right to the ends then fit them as long as possible.

I wouldn't have thought that small notches out of an 8" x 2" would have weakened them to any great extent.

I have had a quick look at some of the notches. I would say they where about 1-1.5 inches deep by about 3-4 inches long.

 

[masona]

I have had a quick look at some of the notches. I would say they where about 1-1.5 inches deep by about 3-4 inches long.

Should be okay, another improvement would be if you have joists bedded in the wall, if so, you can make a small thin wedge to tighten it up if there're loose.

 

[JDLDIY]

How deep were your joists? Notches like that wouldn't cause much flex in 8" timber joists over such a short span. Mine flex a little but the span is wider at 3m and the joists are only 6" deep by a slim 2"!

As Masona said above sometimes the joists need repacking into the wall with slate/timber. If they still "bounce" as mine do, well I intend to bolt on more 6" x 2" timber to the middle sections (about a metre long) using carriage bolts, timber connectors between the pieces of timber and big washers. I think the holes shouldn't be drilled in line. I might also reinforce the sections of timber where notches have been cut with bolted on 4" x 2".

 

[roblatus]

How deep were your joists? Notches like that wouldn't cause much flex in 8" timber joists over such a short span. Mine flex a little but the span is wider at 3m and the joists are only 6" deep by a slim 2"!

As Masona said above sometimes the joists need repacking into the wall with slate/timber. If they still "bounce" as mine do, well I intend to bolt on more 6" x 2" timber to the middle sections (about a metre long) using carriage bolts, timber connectors between the pieces of timber and big washers. I think the holes shouldn't be drilled in line. I might also reinforce the sections of timber where notches have been cut with bolted on 4" x 2".

The span is 4m.


ie the joists run across 4m and this is where the bounce is.

 

[JDLDIY]

Ah, sorry I thought you'd meant that the span was across the 2.x dimension.

 

[roblatus]

Ah, sorry I thought you'd meant that the span was across the 2.x dimension.

sorry for any confusion


I guess the notches i mentioned would be more likely to cause the bounce accross the 4m span rather than 2.5m then?

 

[JDLDIY]

How deep are your joists?