Creaking of new 1st floor

[PeterW]

@tanneja what is your spacing on the joists..?? 
 

18mm will bounce as it is very thin. You could add 12mm ply across the whole floor and glue to the deck and screw it to the joists to give you a very rigid 30mm floor. 

[tanneja]

@PeterW Fairly sure they are 400mm spacing.

 

Yes overlaying 12mm is possible, again that makes where the stairs emerge to teh 1st floor an interesting detail.  Also the door kits are in, so guessing that means taking off some of the door height to fit with a slightly raised floor (doors not purchased yet).  It certainly sounds like a better plan than taking up anything that is there already.

 

I was thinking of using some splice plates to go into the joists and floor above around mid span just to hold them relative to each other a little better, in case the glue and screws are allowing a bit of movement if the beams are suffering any deflection.

[Mr Punter]

2 hours ago, PeterW said:

18mm will bounce as it is very thin. You could add 12mm ply across the whole floor and glue to the deck and screw it to the joists to give you a very rigid 30mm floor. 

 

Agreed.  To all other readers, don't use 18mm chipboard onto joists.  22mm only please.  It is cheap enough anyway.

[tanneja]

Should I cut through the 18mm chipboard joins, to see if that works, or just overply?

[Mr Punter]

@tanneja do you have pictures of the floor from underneath?  Interested to see the ends of the joists and the mid spans.

[TonyT]

Is it the brandering under the ceiling as it’s not nailed on every joist, this may be the squeak

[epsilonGreedy]

5 hours ago, tanneja said:

Should I cut through the 18mm chipboard joins, to see if that works, or just overply?

 

 

Dedicated flooring sheets have a tongue & groove joint, my concern is that cutting through this will promote more flex.

 

In your position I would spend more time tracking down the source of the creaking, a teenager with acute hearing might help. Failing that I would consider gluing down a thicker fancy floor finish like bamboo veneer sheets, Jeremy Harris probably blogged about this step in his build.

[MJNewton]

Telescopic support rods like these could be useful to pinpoint the squeeky bits. Not only can they be used to brace different sections of joist/flooring to see if the noise goes, but can also be used to flex sections from below to see if you can trigger the offending parts. 

 

[tanneja]

I have use a support just now, applying pressure from underneath and it can have some localised reduction at that spot when stepping on the floor above, but it is very localised, rest of the floor has the same creakiness.  I have got up a ladder and pushed and pulled on the joists and the chipboard from underneath, even being a few centimetres away I can't discern if it is the joist to noggin interaction, the joist/noggin to chipboard interaction, the crew to timber / chipboard interaction, or the chipboard to chipboard interlocking interaction, I can't see how anyone can tell that as they are all basically next to each other.

 

It feels like I have no option but to strongly consider getting this chipboard up.  I'll take out some screws first to eliminate them as the issue, but as before, I would hope multi thread screws would avoid any movement allowing a tight fit.  Maybe where i put them back into the previous holes from the first set of screws could be problematic.  I don't think there is anything more than tiny deflection (if any) with the joists, my inexperienced gut says that the 18mm board is deflecting due to its lack of rigidity, and so the interlocking mechanism rubbing.  If grinding out some joins removed the creak, I would have my answer, but as stated above, will lose some floor rigidity.  Maybe I can claim some of that back with a 12mm ply overlay, rather than switching the whole thing out for 22 or 25mm.

 

If we did want to really go the whole hog, what is the most rigid, best quality flooring we could go with?  I don't think I would feel confident with standard 22mm chipboard given this headache.  It isn't a big area, so cost should be manageable, will be labour more than materials I would think.  Presumably cement board is too heavy.  Unsure if the foam backed board I have seen advertised is helpful if you plan to glue to the joists.

Edited February 25, 2021 by tanneja

[TonyT]

Nothing wrong with 22mm chipboard, pva glue and 63mm ring shanks. Standard for decades

 

so any modern improvements would be a positive, like foaming glue etc

[tanneja]

If there is any doubt about some miniscule joist deflection existing (seems unlikely and cannot detect), would we be better going with 22mm ply rather than 22mm chip board?  For what you lose with the interlocking, perhaps you end up with a firmer floor?  Material cost not a concern given the small surface area, it is just wanting a silent room experience.

[Russell griffiths]

3 hours ago, tanneja said:

If there is any doubt about some miniscule joist deflection existing (seems unlikely and cannot detect), would we be better going with 22mm ply rather than 22mm chip board?  For what you lose with the interlocking, perhaps you end up with a firmer floor?  Material cost not a concern given the small surface area, it is just wanting a silent room experience.

No it won’t make a hint of difference 

you can cover it in gold bars and it will still squeak if the joists are moving. 

You really need to locate the movement. 

 

[SimonD]

Sorry if I missed this already but what depth are your joists? Am I correct in reading that the span is 3m? I guess you've checked you haven't got any twisted joists throughout the installation? And the other question is whether the original joists were installed when wet? (this is one of my pet hates about some builder/timber merchants storing carcassing timber exposed to the weather and then installing them that way. With framing timber, for example, there's a maximum allowable moisture content above which you don't frame with the timber).

 

You'll always have some timber joist deflection, it's just a question of whether it's within the correct tolerances.

 

I personally prefer TG4 OSB floor boards to chipboard, and plywood of course is very good, but more expensive. At 18mm thickness the OSB is fine for up to 600mm joist centres so at 400 cc you've got a good margin. OSB glued and sufficiently nailed should give you a creek free subfloor, but that does depend on the joist installation.

[SimonD]

On 24/09/2020 at 23:48, Mr Punter said:

 

I have always been a bit suspicious about the rules on using the really annoying short twist nails in joist hangers.  They seem quite insistent on it but with some hangers where there are loads of holes and no excessive loads I am sure that even dry lining screws would work fine.  The fat twist nails are really easy to remove, so I think they could and probably do work loose but that is perhaps not included in the must stick to rules.

 Screws don't have the required shear strength so should never be used for joist hangers. Also, the nailing pattern for joist hangers varies according the installation so you don't always have to nail all holes. I use metal connector nails using a positive placement nailer, makes life a whole load easier for joist hangers.If joists are installed correctly, the nails won't experience forces that pull out the nails.

[SimonD]

Just one more question. I guess you've checked the installed lengths of the joists?

[Onoff]

15 minutes ago, SimonD said:

Just one more question. I guess you've checked the installed lengths of the joists?

 

Saying that the joist depth as well maybe?

[TerryE]

We've got some bad creaking spots in our 1st floor. Nothing to do with the anchoring of the flooring to the EcoJoists, and everything to do with the cross-joist brace only being nailed across the joists and not properly screwed in.  Missed this until after we moved in and by then post second fit, so screwing the cross-brace to the EcoJoists would have been a total PITA.  Workaround: avoid stepping on the small ~ 1m² area which creeks .  20-20 hindsight, and I wish that I'd fixed that cross joist properly ?.

Edited February 26, 2021 by TerryE

[Dave Jones]

what thickness and make of boards was used (egger ?), what glue was used ? What spacing of screws was used ?

 

Done properly using decent board it wont squeek at all.

[tanneja]

The joists should be as however specified, they appear to be 170x50mm joists with 400 centres.

 

I expect the existing 18mm TG chipboard used came with glue but perhaps it was separate. screws have been done every 200mmish around boards.  I have instructed the builder to have a think about how we could instead do the floor in 22mm ply. I like the idea of its rigidity, with everything else in the house being the highest standard we can afford, these creaking floors would be a disappointment. I dont see any deflection in the joists myself, I feel it has to be some failure of the TG product or installation.

[Matt60]

On 24/09/2020 at 16:28, PeterW said:

Not enough screws. Find the joists, go along with 60mm screws every 150mm. If they haven’t glued the joists to the boards, it will squeak ..!

 

 

 

I suspect this is spot-on. My last house had very noisy floorboards, when all the carpets were replaced I put loads of screws in and it improved massively.

[tanneja]

I can see how that is a logical conclusion, however I feel the screws we have are overkill.  Maybe the gluing of the joists to the board (where locally in some places it may have more glue thickness than others) has meant for an inconsistent level with the boards, and so walking on them creates flex in areas, which manifests as noise on the board joins, this despite screwing them all down within an inch of thier life.  I don't think we can try anything else at this point, seems more cost effective to get them up and see if 22mm ply solves things.  Wondering whether to glue them to the joists/noggins or not.  Maybe just the multi-thread screws first and see if they alone do the job.

[markc]

where is the small area that squeaks? mid span? near a wall? service void? etc. i reckon it could well be a joist hanger/connection noise depending on location

[tanneja]

@markc the squeaks are mainly centre of room, but so also happen a little further away too, for one room it happens immediately as you enter the room.  The noise is coming from the area very close to the footstep (when listened to from underneath), not from the hangar location.

 

Of course that doesn't mean they the aren't perhaps responsible for the noise in some way, maybe we can inspect everything critically when the chipboard comes up.

[PeterW]

29 minutes ago, tanneja said:

The noise is coming from the area very close to the footstep (when listened to from underneath), not from the hangar location.

OK that could be the floor and the sole plate of the wall immediately around the area. Do the walls run perpendicular or parallel to the joists and were they built off the deck or the joists ..??

[tanneja]

@PeterW it is a small room, so one stud runs parallel on a triple joist, the perpendicular wall sits on the joists too, not on the chipboard.  The other two walls are external masonary.  I feel like I would be surprised if it were the studs given where I identify the sound coming from.  The chipboard is well clear of the perimeter of the door opening and walls (10mm),