Floor bounce - PosiJoist Floor Vibration checks

[readiescards]

Can this thread remain on the subject 'Floor bounce - PosiJoist Floor Vibration checks' please ? 

Many thanks

Paul

 

PS My floors seem worse as time passes or it is cold outside (not sure which)

[readiescards]

On 09/02/2021 at 11:37, Dave Jones said:

 

egger is brilliant stuff. the amount of abuse it will take is unreal.

 

Odd my builder and the posi-joist manufacturer both are blaming the abuse the egger boards took from 6 months of bad weather as being the source of the floor movement/bounce.  While Egger themselves remain adamant their product would be fine.  (It did swell a tiny bit on a couple of exposed edges but that was about all)

[Adsibob]

So what is better egger or caber?

Edited February 13, 2021 by Adsibob

[TonyT]

Egger instructions are about 60 days without protection from memory, so would agree this would void the manufacturers warranty as the install instructions haven’t been followed.

[TonyT]

I agree with lots that have posted that the minimum spec and poor installation practices will generally result in poor outcomes.  Majority of trades  need supervision or will take the path of least resistance.

 

personally I over engineer critical parts of the build that would give me grief, but then I’ve worked in the game for 30 years so have seen the failings before.

[readiescards]

On 13/02/2021 at 09:22, TonyT said:

Egger instructions are about 60 days without protection from memory, so would agree this would void the manufacturers warranty as the install instructions haven’t been followed.

 

While it certainly gives Egger a get out, they seem unfazed and suggested their product will still be fine.

 

Have to agree as three of the rooms where not exposed to extreme weather and yet still are suffering floor bounce/flex.

[TonyT]

Combination of poor installation practices equalling non satisfactory outcome.

 

It happens in every trade

 

[Dave Jones]

On 13/02/2021 at 08:51, readiescards said:

 

Odd my builder and the posi-joist manufacturer both are blaming the abuse the egger boards took from 6 months of bad weather as being the source of the floor movement/bounce.  While Egger themselves remain adamant their product would be fine.  (It did swell a tiny bit on a couple of exposed edges but that was about all)

 

6 months is a bit of a joke though. I think from memory egger warranty 45 days exposed to weather.   All exposed edges should have been brushed with the same foaming glue as well.

 

If you know you wont be getting watertight in that time don't put the floor down. With your builder on that one.

 

As for bounce, who specified the joists ? Struct eng  ? Was the egger fitted correctly and noggins used where ends not hitting joists etc ? Was it screwed every 150mm ?

Edited February 21, 2021 by Dave Jones

[trialuser]

Egger specifically don't want it screwed every 150mm.

Used to be first row only, now seems it can be first row only or optionally a few other fixings at 1200mm

[Dave Jones]

8 minutes ago, trialuser said:

Egger specifically don't want it screwed every 150mm.

Used to be first row only, now seems it can be first row only or optionally a few other fixings at 1200mm

 

they also say to screw the leading edge when installing which makes it very hard to butt the next one up if there is any deviation at all in the trusses.

 

150centres and not a squeek or bounce out of mine. All ends landed on a truss or noggin.

[Nickfromwales]

5 minutes ago, Dave Jones said:

 

they also say to screw the leading edge when installing which makes it very hard to butt the next one up if there is any deviation at all in the trusses.

You tuck the next board into the previous and THEN screw the leading edge of the previous board, not before. To be done with the glue wet, not left an then 'come back to it'. 

[Dave Jones]

15 minutes ago, Nickfromwales said:

You tuck the next board into the previous and THEN screw the leading edge of the previous board, not before. To be done with the glue wet, not left an then 'come back to it'. 

 

bit difficult as the next board hasnt been layed yet as the row has to be completed before the next one joins. 

 

neverthless we ignored that part and screwed them down as the next wow was fitted.

 

[Nickfromwales]

8 minutes ago, Dave Jones said:

 

bit difficult as the next board hasnt been layed yet as the row has to be completed before the next one joins. 

 

neverthless we ignored that part and screwed them down as the next wow was fitted.

 

Not difficult at all, done it on every floor I've ever laid. You just need to get a wiggle on, and lay each row into each other with the glue still wet. Most rooms are leas than 7m so less than 4 boards long.

Many ways to skin a cat though. Poor cats  

[Dave Jones]

3 minutes ago, Nickfromwales said:

Not difficult at all, done it on every floor I've ever laid. You just need to get a wiggle on, and lay each row into each other with the glue still wet. Most rooms are leas than 7m so less than 4 boards long.

Many ways to skin a cat though. Poor cats  

 

i dont think you understand......

 

We floored the house at one time not rooms ....

[Nickfromwales]

Length of longest run? On a long run, eg 7 or 8 boards long ( @2.4m per board x8 would allow for a 19m run ) needs at least two people on it. Still easy to lay wet on wet.

I understand just fine, and have been laying these types of floors for a 1/4 century. If the job needs more hands to the pump to execute it correctly, then that is what I applied. Never had a single squeak from a single floor, ever.

Glad that your method worked, also.

[Stephen Aitch]

SURVEYOR RECOMMENDATION NEEDED 

 

We had joists installed at 600mm centres and the result is significant discomfort and bounce.  The issue was made worse by use of acoustic flooring, so floor was nailed not glued.  Inevitably it has worked loose.

 

Not sure who we ask (sue if necessary) to cover remedial cost?

 

- Builder - chose to install at 600mm centres instead of 400mm shown on drawings

- Accoustic flooring supplier - for supplying a floor unsuitable for use with posi-joists

- Architect - for specifying acoustic (Hush) flooring with posi joists

 

In terms of remedy, it sounds like the floor needs to come up and be replaced with thick ply.  Which means new skirting/remedial plastering etc.  May also go for ply side bracing on the posi joists...

 

Many thanks for any advice

 

 

 

[joe90]

48 minutes ago, Stephen Aitch said:

- Builder - chose to install at 600mm centres instead of 400mm shown on drawings

Is my go to.🤷‍♂️ my drawings showed 600mm centres but as my builder knew (and agreed with me) that I hate bouncy floors he installed at 400mm centres. 

[ProDave]

56 minutes ago, Stephen Aitch said:

 

- Builder - chose to install at 600mm centres instead of 400mm shown on drawings

Why did you let him do that?   I am surprised building control did not pick this up?

[saveasteading]

3 years later.

 

should this be a new discussion?

 

It  must be rebuilt. The bounce is an indication, but the whole floor is understrength.

Did the builder save on joist cost or are they sitting around?

 

It isn't just your comfort, but may make the house unsaleable.

[Stephen Aitch]

Can anyone recommend a surveyor experienced in posi-joist design issues/rectification pls?

[ToughButterCup]

I really feel for you. 

 

I have no experience of rectifying the issue, but it occurs to me that if you use double threaded screws (that is a secondary thread at the screw head as well as the normal shank), then that might go someway to alleviating the problem in the meantime.

 

Good luck with your search.

[saveasteading]

On 24/10/2024 at 17:58, Stephen Aitch said:

surveyor experienced in posi-joist design issues/rectification pls?

It isn't a surveyor, but a Structural Engineer. Look for a local practice and phone them.

[ToughButterCup]

On 13/10/2024 at 10:44, saveasteading said:

...

It isn't just your comfort, but may make the house unsaleable.

Because?

[saveasteading]

2 hours ago, ToughButterCup said:

Because?

Because bounce is noticeable and should show up in thorough surveys. 

 

The solution may not be too drastic.. select from...

1. Insert additional joists.

2. Screw timbers to the sides

3. Screw plywood to the sides

4. Build floor and/or ceiling in plywood.

 

I did 4, where I had very limited depth to match an ancient skinny, bouncy floor. Plywood on top with lots of fixings satisfied bco and performed well.

(it transforms the joists into T beams with very strong top flanges.)

[ToughButterCup]

35 minutes ago, saveasteading said:

... should show up in thorough surveys. 

...

 

in which case the price of the house becomes more flexible too 😉