Suspended floor bounce

[Lesley72]

Hi we have a suspended floor.  We used Omnie tor2 ufh floorboards with 6mm ply.  The tiler used a crack mat and then we had 120cmx60cm porcelain tiles put down. The tiles keep cracking and the tiler said there is too much bounce in the floor. Any ideas how we can fix this bearing in mind we have ufh and although the ply had a pattern on showing where was safe to screw this has now been covered by the crack mat screed. Please help.  

[Dave Jones]

what is the suspended floor makeup ? joist sizes and centres ?

[Lesley72]

  On 18/03/2024 at 17:13, Dave Jones said:

what is the suspended floor makeup ? joist sizes and centres ?

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@Dave JonesOur builder said he built as per our architect spec which was 

“Structural floor to be in timber floor joisting. Install 200 x 50mm C16 floor joists at 400mm centres. Joists are not to be built into walling but are to be supported on restraint type joist hangers.
Joists to have one row of herringbone or diagonal strutting - Herringbone strutting to be at least 38mm x 38mm; solid strutting to be at least 38mm thick and at least three quarters of the joist depth.
Notches in joists to be no deeper than 0.125 times the depth of the joist and should not be cut closer to the support than 0.07of the span, nor further away than 0.25 times the span. Holes should be no greater than 0.25 times the depth of the joist; should be drilled at the neutral axis; and should be not less than 3 diameters (centre to centre) apart; and should be located between 0.25 and 0.4 times the span from the support” ??

Edited March 18, 2024 by Lesley72

[Dave Jones]

whats the span and what flooring went on top before the tiles ?

[Lesley72]

@Dave Jones 6mm ply Omnie board,  then the tilers crack mat   Span is 3200mm new extension which joined onto an existing kitchen suspended floor which spans 2300mm 😬

Edited March 18, 2024 by Lesley72

[Dave Jones]

surely there was a proper floor first. 6mm isnt going to support anything. 

 

22mm caberdeck or equiv is standard.

[Lesley72]

@Dave Jones apologies there was routed chipboard system we bought from Omnie which then had their 6mm ply put ontop.  

[joe90]

  On 18/03/2024 at 18:48, Lesley72 said:

there was routed chipboard system we bought from Omnie

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But what depth? And if routed then structurally weakened 🤷‍♂️, as @Dave Jones says

  On 18/03/2024 at 18:31, Dave Jones said:

22mm caberdeck or equiv is standard.

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[Dave Jones]

whats the span of the 4 x 2 joists

[Lesley72]

  On 18/03/2024 at 18:53, joe90 said:

But what depth? And if routed then structurally weakened 🤷‍♂️, as @Dave Jones says

 

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@joe90 The TorFloor 2 Standard system
comprises of a 22mm chipboard deck
panel with a 6mm woodfibre cover panel
with bonded layer of AL HEX aluminium
diffuser foil.

[Dave Jones]

the long and the tall of it is the joists are not man enough if you have 22mm boards on them and then another 6mm ply and you have deflection.

 

would never use 4x2 unless its a very short span, 2m max.

[Lesley72]

@Dave Jones thank you so much. What can we do to fix it? 
 

 Can we just now not have tiles due to deflection?  If not what type of flooring can we use that won’t crack? 

[joe90]

https://omnie.co.uk/torfloor2/#:~:text=The original and market leading,fixing the panels to joists.
 

The OMNIE TorFloor 2® Underfloor Heating system can be used on joist centres up to 600mm with no compromise on the integrity of the floor deck. 

 

  On 18/03/2024 at 19:34, Dave Jones said:

would never use 4x2 unless its a very short span, 2m max.

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However

  On 18/03/2024 at 17:38, Lesley72 said:

Install 200 x 50mm C16 floor joists at 400mm centres.

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So not 4x2 🤷‍♂️

[Lesley72]

@Dave Jones I’ve found this photo.. not sure what use it will be 

[saveasteading]

Joists are designed for collapse and acceptable deflection ( 1 in 360 I think).

Deflection is always the critical factor in domestic use.

 

If the joists are the right size, and noggined, then they won't be budging. It must be the boards deflecting between joists. Have you tried bouncing on them at different positions, ie on or between joists?

Near the wall the joists won't budge at all.

[Dave Jones]

did they  use hangers ?

 

They notched out to sit on that wall. wonder how level it was ?

 

Was the chipboard foam glued down ?

 

Should be rock solid if it was ?

[saveasteading]

Photos are great. The noggins need to be more central or another row of them. But i suspect that isn't the main issue.

[saveasteading]

  On 18/03/2024 at 19:47, Dave Jones said:

They notched out to sit on that wall.

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Sorry i don't know what that means.

 

I can't see hangers. Are these just nailed into the wall plate?

[Lesley72]

Really sorry I don’t know the answer to the questions. When I asked my builder he said he built the joists as per the architect spec 🤷🏻‍♀️  

 

Am I right in assuming lvt would also crack

and resin flooring would crack with the deflection?
 

so that leaves me with carpet or lino?   neither I would want in my very expensive extension /kitchen diner 😭 

 

can anyone advise on the best flooring option is we can’t now have tiles? 

[joe90]

  On 18/03/2024 at 17:38, Lesley72 said:

Joists are not to be built into walling but are to be supported on restraint type joist hangers.

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However, it just may be the floor has too much flex for large format tiles.

  On 18/03/2024 at 20:02, Lesley72 said:

can anyone advise on the best flooring option is we can’t now have tiles? 

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What about wood flooring, I used oak faced engineered flooring in my lounge glued down and it looked great.

[Dave Jones]

  On 18/03/2024 at 19:54, saveasteading said:

Sorry i don't know what that means.

 

I can't see hangers. Are these just nailed into the wall plate?

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[Lesley72]

  On 18/03/2024 at 20:08, joe90 said:

 

What about wood flooring, I used oak faced engineered flooring in my lounge glued down and it looked great.

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Thanks will have a look. 

[Adsibob]

  On 18/03/2024 at 20:02, Lesley72 said:

can anyone advise on the best flooring option is we can’t now have tiles? 

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I think tiles might be ok if you go smaller. The ones you laid were quite big.

 Alternatively, can you raise the floor level by 28mm? If so, you could lay a 24mm screed with steel mesh in it for reinforcement, then cover that with 3.5mm microcement, including the 0.5mm “upgraded” plastic mesh for additional reinforcement. Will look amazing, particularly if you pick one of the cement like greys or greens.

[Lesley72]

  On 18/03/2024 at 21:17, Adsibob said:

I think tiles might be ok if you go smaller. The ones you laid were quite big.

 Alternatively, can you raise the floor level by 28mm? If so, you could lay a 24mm screed with steel mesh in it for reinforcement, then cover that with 3.5mm microcement, including the 0.5mm “upgraded” plastic mesh for additional reinforcement. Will look amazing, particularly if you pick one of the cement like greys or greens.

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@Adsibob thank you.  Can you recommend any companies I could approach for a quote?  I live in the north east. South Shields 

[bassanclan]

How is this timber fixed to the blockwork?

There doesn't seem to be a joist hanger.

I suspect the timbers are resting on a concrete block on its side. A noggin against the wall hides a lot!

 

Have you got much insulation under there? Doesn't look much space for insulation and ventilation.

 

If you are having to rip up the tiles then the chances are that the subfloor is going to be damaged, so worth spending the time getting that right first.

 

If the builder hasn't fitted hangers as he should then all these remedial costs are on him!