Author Topic: NHBC standards for chipboard floors on I-joists?  (Read 36855 times)

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New Home Expert

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Re: NHBC standards for chipboard floors on I-joists?
« Reply #15 on: January 24, 2014, 12:16:37 pm »
The edge of the old board that remains and the edge of the new board both sit on the same noggin.
The noggin provides a fixing and support for both board edges as they will not have a tongue and groove.
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Mugen

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Re: NHBC standards for chipboard floors on I-joists?
« Reply #16 on: January 24, 2014, 02:37:39 pm »
The edge of the old board that remains and the edge of the new board both sit on the same noggin.
The noggin provides a fixing and support for both board edges as they will not have a tongue and groove.

Right, I see what you mean.
I just wanted to make sure as I see a potential problem already.
I see from your picture of the proprietary clips and from what I recall when the floor was opened, the fixings to the joist is on each end of the 'fork'.  I cannot see how these can be fitted underneath the old board without removing this first. Meaning that the noggin and clips cannot sit between the old and new board.
That leads me to believe that they will use some other method that probably wouldn't be according to manufacturer's specification.   :-\

Tim Fee Snagging Inspector

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Re: NHBC standards for chipboard floors on I-joists?
« Reply #17 on: January 29, 2014, 09:03:02 am »
I wouldn't be too concerned about this.
As long as the existing floor is lifted so the clip can go under it should be alright. As for manufacturer's instructions check this out:  STEICO manufacturer's guide and details.
Unfortunately, noggin clips are not mandatory as the pdf says:
"Minimum 38 x 38 perimeter noggin skew nailed or fixed to joist using proprietary clip. Noggin to be fixed 25 - 75 mm from face of wall"

The clips do make it easier and give a better job so I expect given the trouble this is, Redrow wont be skimping on a few relatively inexpensive clips!
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Mugen

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Re: NHBC standards for chipboard floors on I-joists?
« Reply #18 on: January 30, 2014, 02:51:17 pm »
Fantastic thanks again!!

Since we are on the subject of floors and noises.  I've been told on a few occasions that the if the noises are deemed excessive then the builder must sort it out regardless if its installed to specification or not.

Is there a section on the NHBC standards that specifically mention excessive noise?



 

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Re: NHBC standards for chipboard floors on I-joists?
« Reply #19 on: January 31, 2014, 08:46:27 am »
Noise insulation standards are covered by the building regulations and concern noise transmittance, that is normally noise from the room/flat above. 

Creaking or cracking noises from the floor construction are always a result of NHBC standards and/or good practice not being followed somewhere.
Either that or the joist centres may be too wide for the joist and span involved, resulting in excessive deflection, often a source of floor creak.

It is also going to be difficult to determine what is "excessive" as it is a matter of opinon.
Generally, if you complain about this to the house builder within the first two years they should come out and, at the very least, 'try' to fix it.
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Mugen

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Re: NHBC standards for chipboard floors on I-joists?
« Reply #20 on: February 10, 2014, 09:47:32 am »
I took some photographs during the removal of the floors to capture some images of the joists.
From what I can see they appear to be damaged!!

When I questioned the carpenters they first said they would put some wood on the side of them but then claimed they are not damaged!!   So they just the laid new flooring over them! The photos are a couple of examples from one of my rooms but also this kind of thing happened on my other room as well. Now I am a bit wary of allowing them to start any work in the other remaining rooms (they are due to do more work on Thursday!)

Do you think the damage will cause any problems and have I the right here to stop works for the time being even or better, request to have someone else do it or at the least seek further advisory on the extent of the damage?
What I don't want is obviously stopping them and as a result the NHBC not helping me any further as Redrow will have an excuse to say that I stopped work progressing (this is also one of the reasons why I allowed work to continue on the day).

Grateful for any advice or suggestions (as always)

New Home Expert

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Re: NHBC standards for chipboard floors on I-joists?
« Reply #21 on: February 10, 2014, 10:14:24 am »
I am sorry to say that the damage to the joists could have severely weakened them.
All manufacturers of this type of joist forbid any removal, notching or drilling to the top or bottom timbers as these provide the integrity of the design.  Only the web (vertical middle area) can be drilled or cut and then only within strict guidelines.
 
You can check this on the Steico pdf here: STEICO Joist guide pdf

Any repairs must be done after the manufacturer has inspected the damage and any repair must be to manufacturer's recommendations.   All carpenters and site managers would know this!
 
My advice now would be to immediately e mail these pictures of the damage to both the NHBC and whoever you are dealing with at Redrow homes. 
In my opinion, some if not all of the affected joists may need to be replaced and by carrying on with the work they will only make a bad situation even worse. 
You may like to send the pictures to Steico and ask their opinion as well!

The NHBC are providing a structural warranty for ten years and this damage is likely to result in a claim under the warranty, so I expect they will be eager to ensure Redrow do a proper job this time and not 'bodge' an unauthorised  repair as the carpenters suggested to you!
 
By removing old floor boards that had been glued to the top of the joist, the damage was foreseeable. 
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TaylorWimpeyDidThis

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Re: NHBC standards for chipboard floors on I-joists?
« Reply #22 on: September 24, 2014, 08:25:33 am »
....just reading this

Taylor Wimpey's solution was to insert screws through the plasterboard ceiling across every ceiling on the ground floor. In one area they removed the flooring and it was clear that the noggins had shrunk and were poorly cut to size. Their excuse was that the house was built in very wet weather and everything has since shrunk.

On one floor the tradesmen were amazed at the amount of movement in the floor. One of them upstairs walking around with two downstairs underneath....open mouthed.

They pulled up the carpet upstairs and screwed down / glued the boards  - there are still popping and creaking sounds but it is markedly improved.

Makes you wonder what state the rest of the noggins are in though!

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Re: NHBC standards for chipboard floors on I-joists?
« Reply #23 on: September 25, 2014, 10:51:43 am »
Adding yet more screws to the plasterboard will make no difference to the stiffening of the floor and deflection. 
All it will do is make it less likely to crack and "pop" the finish at the fixings.
These floor joists should not overly deflect.  In fact it is one of the selling features of this type of joist.
Over deflection is evidence that the manufacturer's design and detailing has not been strictly followed.
There are many details that must be adhered to and deflection is evidence of a failing in this respect.
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gerryb

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Re: NHBC standards for chipboard floors on I-joists?
« Reply #24 on: October 23, 2014, 01:37:03 pm »
I'm a happy owner of a new 4 bed Charles Church home but had a similar issue with very creaky floors.

The builder's explanation was that the upstairs floor must have got wet before the house was watertight and as a result there has been excessive shrinkage between the I-Joists and the ceiling. There were nail pops to suggest that the ceiling was coming away from the I-Joists.

Walking upstairs caused very loud creaks that seemed to originate from the walls where the horizontal plaster board in the ceilings met the vertical plasterboard that was blobbed to the downstairs walls.

I thought this was going to be a major pain to fix but apparently it's quite common and resolved by screwing the ceiling plasterboard to the I-Joist from underneath. A few hundred screws later and a repainted ceiling and it's vastly better.

I mentioned this to my neighbour and he's having every ceiling downstairs done.


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Re: NHBC standards for chipboard floors on I-joists?
« Reply #25 on: October 27, 2014, 06:54:29 am »
Considering its a Persimmon new home I am not surprised they said the flooring had got wet during construction!  Both the chipboard floor and especially the I joists should not get wet. Moisture resistant chipboard is not waterproof!

Nail pops (most house builders use screws these days to help stop "pops") are caused by the floor deflecting causing the filler over the nails to fall out.  This would not be the cause of the floor squeaking!
What you have is the chipboard moving up and down on he nails causing a squeak. The cure, providing the I joists have been properly installed, is to screw the chipboard down to the joist and remove the nails.
Any chipboard that is deformed or mis shapen should be replaced as it will be weaker having got wet.

Adding more screws to the plasterboard ceiling will be unlikely to stop the floor squeaking.

I am amazed new home buyers are prepared to put up with this amount of work in their new home!
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Re: NHBC standards for chipboard floors on I-joists?
« Reply #26 on: September 09, 2016, 07:23:26 am »
There has now been an investigation by the University of Salford Acoustics Research Centre and it would appear the cause or origin of the cracking noises is at the junction of the wall drylining and underside of the floor structure. If a gap is made between the wall board and any dabs and the floor joists and ceiling boards the cracking noises are eliminated.

In a Joint statement   by the NHBC, GPDA and the Engineered Wood Product manufacturer’s in the UKTFA based on the research commissioned by the 3 organisations to find the location and root cause of the noise. The investigation was carried out by the University of Salford Acoustics Research Centre.

So Resilient Bar was not the answer after all.
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mkfc1981

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Re: NHBC standards for chipboard floors on I-joists?
« Reply #27 on: April 27, 2018, 01:29:29 pm »
....just reading this

Taylor Wimpey's solution was to insert screws through the plasterboard ceiling across every ceiling on the ground floor. In one area they removed the flooring and it was clear that the noggins had shrunk and were poorly cut to size. Their excuse was that the house was built in very wet weather and everything has since shrunk.

On one floor the tradesmen were amazed at the amount of movement in the floor. One of them upstairs walking around with two downstairs underneath....open mouthed.

They pulled up the carpet upstairs and screwed down / glued the boards  - there are still popping and creaking sounds but it is markedly improved.

Makes you wonder what state the rest of the noggins are in though!


I think I have this issue, but can't get them to look at it properly, who did you use for inspection?