Joiner input please - chipboard floor cracking/squeaky

Furts

pawlala wrote: »

Update. Hatches were cut in the flooring so joiner could inspect.

Straps were loose, so they fixed them down. No joy.

Extra noggins were fitted across the joists in some areas. No joy.

Cracking noises appeared to be coming from joists themselves, the I-Joist type. No excessive movement, just noise when they're stood on. Exacerbated when the flooring in in place. The noise is horrendous.

Completely stumped. Problem now in the hands of management. Nothing more the joiner could do this week.

Was the noise from the joist (suggests a damaged joist - quite easy to occur) or from the contact with any other chipboard sheets still bearing on the joist?

Or to put another way, had all the chipboard sheets been removed from contact with that joist?

pawlala

they didn't remove the whole floor, just the hatch sections, so it may still be the chipboard. but it was making a heck of a noise on the joist itself. sadly I couldn't supervise all of the time, and I don't think they wanted to remove the whole floor, just to see if the straps were the cause. But I'll save your question for the next time they come.

Furts

Hi pawlala

I think I mentioned earlier, and apologies if I did not, but the straps explanation was almost dead cert BS to me.

Keep everyone posted and rest assured, perhaps unlike your builders, there are mse users who know a little about building!

pawlala

thankyou I will!

cyclonebri1

Furts wrote: »

Hi pawlala

I think I mentioned earlier, and apologies if I did not, but the straps explanation was almost dead cert BS to me.

Keep everyone posted and rest assured, perhaps unlike your builders, there are mse users who know a little about building!

And some that know very little ;)


The has a real problem if the composite joists have lost their integrity, the strength of those things lies in the fact that every layer is bonded to the next correctly.
Sounds like at a minimum the whole floor comes up and the joist are drilled and screwed together to prevent movement within the joist itself.

Interesting though if this is the case, never heard of it happening???

Furts

cyclonebri1 wrote: »

And some that know very little ;)


The has a real problem if the composite joists have lost their integrity, the strength of those things lies in the fact that every layer is bonded to the next correctly.
Sounds like at a minimum the whole floor comes up and the joist are drilled and screwed together to prevent movement within the joist itself.

Interesting though if this is the case, never heard of it happening???

Yes if they have been mis-handled the top or bottom web, or both,can be loosened from the stiffener, IMMHO they are flimsy, cheap items to be avoided.

If someone starts drilling and repairing them there is then a question of design, warranty and liability. Hence the original manufacturers need to be involved, or a specialist engineer design input.

That said the bearing at the wall is probably a more suspect area.

pawlala

that's interesting, walking along both the walls where the joists are connected is solid, probably the first foot and a half or so away from the walls and then it starts to become noisy. Whereby the centre square of the room is the "crackiest". sorry for the terms, im not a technical joiner person! but I agree, I had never seen these I-Joists before, I would have felt much happier with huge beams of wood!!

Furts

pawlala wrote: »

that's interesting, walking along both the walls where the joists are connected is solid, probably the first foot and a half or so away from the walls and then it starts to become noisy. Whereby the centre square of the room is the "crackiest". sorry for the terms, im not a technical joiner person! but I agree, I had never seen these I-Joists before, I would have felt much happier with huge beams of wood!!

Hi pawlala

Apologies for being technical. Two points;

Along the wall is the area where the joists could shear but this is OK. This suggests the bearings are OK.

At mid span there is maximum bending moment and this is the noise area. This suggests a damaged, undersized, or over centred joist.

Or bad fixing of the floor as previously mentioned.

cyclonebri1

pawlala wrote: »

that's interesting, walking along both the walls where the joists are connected is solid, probably the first foot and a half or so away from the walls and then it starts to become noisy. Whereby the centre square of the room is the "crackiest". sorry for the terms, im not a technical joiner person! but I agree, I had never seen these I-Joists before, I would have felt much happier with huge beams of wood!!

Weight for weight they are supposedly stronger, and probably are, but they are a composite and as such if any part of the make up is flawed the whole beam is compromised. This is why if they where "huge chunks of wood", they would have been graded, no weakening knots etc, and passed as fit for purpose.

But the I beams will never shear in spite of what furts thinks.
They will always fail at the centre in a domestic loading, but it would never happen, they could be half the size at each end andf still remain stiff..

You stand near the edge and you are putting nothing but point load on the end of the beams, only thing that can give there is the brickwork foundation, so it won't.

Treading the floor away from the edge does 2 things, it imparts a bending moment within the beam and actually a lift about the centre point of the support, so now the beam is actually trying to lift the boards at the beam end.

Furts

Think physics and mechanics. The bearing end is where shear occurs, the middle is a bending moment.

I did not say the joists would shear - I am referring to the forces acting on them.