Creaking floor/joists

[Nozzle]

Hello all,

We've had the house extended, it's been a built a few years now, all decorated, carpet laid, bath in, floor tiled etc. At the time it was built I commented to the architect that the floor seemed springy but he remarked the joists were the correct size but the build was definitely to "a budget" without elaborating what was wrong or what could be better. He suggested noggins were added, so they were (you can see them in the later pictures).
View media item 84562View media item 84563View media item 84564
We have chipboard T&G which I initially unhappy about, In hindsight we should have gone for proper flooring boards. Though I think we'd still behaving the same problem, that is to say: the entire flooring in this room seems a little springy and because of this overall movement the T&G boarding is beginning to work loose and creaks every step of the way for half the room.

The joists run perpendicular to those in the original part of the house, as downstairs is the garage so there can be no internal supporting wall.
View media item 84544View media item 84545View media item 84546View media item 84547View media item 84548View media item 84549View media item 84550View media item 84551View media item 84552View media item 84553
What I want to do is pull up the T&G chipboard, somehow reinforce/strengthen the existing joist, then relay with proper wood flooring boards. That "somehow" is what I'm posting about really.

There are a number of snags I'll need to work through, or questions I'm seeking advice on:
Pulling up existing floor:
Large sheets, some of which have a stud wall nailed through them - how best to remove sheets with minimal damage to stud walls? Also to consider pipes and cables that are thread through chipboard - I must drill, cut or use some blunt pulling/stabbing instrument to remove the chipboard..
View media item 84557View media item 84558View media item 84559View media item 84560View media item 84561
Reinforcing the joists:
a) Add a/some steels?
b) Add some strapping?
View media item 84554c) Add more noggins?
d) Double up joist?
e) joist hangers?
f) best way to bed them on top of aircrete on one end, brick on the other.
g) Any solution needs to be suited for routing for existing cables/pipes.
h) Any other solutions? Concrete beams? Lifting tackles? Cable/pipe management?
View media item 84555
I'll be getting in a builder in for this reinforcing part of the project as I don't have the skills nor contacts, but I want to understand all the options out there so I can reject what isn't going to work or be inadequate.

Replacing floorboards
Best way to re-attach stud walls to the floorboards? (I think screw from the underside using a 90degree drill adaptor, whilst avoiding pipes & cables).
How best to make the transition from old flooring, across concrete "filler" above adjoining brick wall (photo xxxx.jpg) into the new boarding such that the hump doesn't show through the carpet as it currently does. May involve grinding/cutting back concrete with disc then bedding down some hardboard to the same level or having the new board extending over this to be affixed to the old joists (that run perpendicular)
View media item 84556
Some of the old boarding is currently supporting the bath and tiled bathroom, and this must stay undisturbed - I think it is the weight of this stuff and the shape of the partition is the reason why only half of the room creaks/bends rather than all of it.

Should I get an architect/architectural technician or structural engineer to size up the job or will that just add cost be no real benefit? What should I consider w.r.t building regs? The underside is already fire protected (i.e. garage ceiling is already fireline boarding one orientation, plasterboard the other)

I think this job is easier to manage "from above" as if I do it from the garage I have to take all the strips lights down, the ceiling (fireboard and plasterboard) the boxing-in of the soil pipe and take all the insulation out too). Though the advantage is I can see where all the cables and pipes are.

Nozzle

 

[loply]

Somebody once told me that running a bead of silicone or construction adhesive down the sides of noggins and joist intersections stops them squeeking.

No idea if it's true or not.

The T&G chipboard may simply be insufficiently screwed down (ie not enough screws)?

Don't use nails anywhere by the way, they're just asking for squeeking in my experience. Screws are a lot better. Big ones.

 

[catlad]

Doubling up the joists is a proven method of strengthening your floor.

 

[AronSearle]

Chipboard isnt the problem.

Joists shrink / things rub.

The joist may be structurally sound, but enough to flex a bit and cause things to rub.

Noggins don't do nowt to fix squeaky floors. If anything they can be the cause of squeaky floors, as the timber shrinks they become loose, or fixings around them become loose.

Anything loose = squeak.

'proper' floorboards can be just as prone to squeak as chipboard, more so even.


You could try using good quality T&G plywood, screwed and glued to the joists and glued in the tongue, make sure the joists are flat and even. Once it is all screwed and glued together, the plywood will strengthen and stiffen the whole floor.

As said above, doubling up joists will strengthen them, whether it is enough to just do the plywood screw and glue I cant say.

 

[Nozzle]

Thanks for taking the time to read my lengthy post. Prior to the carpet being fitted I already took a load up and re-screwed them down with longer screws. Pilot hole, then a clearance in the chipboard so the thread doesn't catch, then I think 3 1/2" screws to bring it up tight. What I didn't do though, was glue any of it down as that seems foolhardy if they even have to be bought up again??

If I were to double-up the joists, I think that would be better done from underneath as access would be trouble otherwise - at the moment there are no hangers, they just sit on aircrete/mortar. Is it best to re-do all this with hangars (new blocks as required) or to cut blocks away and have them both sat on the mortar? I'm sure there's a clever way to sort out the cables/pipes that thread through the existing joists - I'll have to duplicate those in the new joists then re-thread.

Do hangers exists for doubled-up joists? Or do you mean have a joist every 225mm instead of 450mm? How do these hangers attach to the wall, should it be done when the blocks are being layed, so now too late - or do they screw into the face of the block? (Aircrete being notoriously pants for any fixing, so I'd use the chemical injection stuff)

Nozzle

 

[AronSearle]

What I didn't do though, was glue any of it down as that seems foolhardy if they even have to be bought up again??

How often do floors need pulling up?

Most floors will be lifted once or twice in a hundred years, and that is mostly to install plumbing in old buildings.

If I were to double-up the joists, I think that would be better done from underneath as access would be trouble otherwise - at the moment there are no hangers, they just sit on aircrete/mortar.

Doubling up is hard to decide upon, it may be completely unecessary once T&G panels are firmly screwed and glued down. If you don't want to glue, then it is more likely necessary to eliminate flex.

You might get a feel for this by doing a small test area once you have lifted some existing chipboard.

Is it best to re-do all this with hangars (new blocks as required)

Nope, leave em as is. As they dry and shrink, you may find some joists are slightly proud of others, plane flat as necessary (if necessary).

Do hangers exists for doubled-up joists?

You can just attach a slightly shallower joist to the side of existing, or even just some plywood to one face.

 

[s60tsy]

is the existing flooring nailed or screwed? using nails for the chipboard can produce squeaks after time. also glue the joints with caberfix D4 glue, you could lift the problem areas of flooring and re lay with glue & screw method.

 

[Nozzle]

Should the glue be both on the tongue & groove or just on the top of the joists/underside of boards?

Will gluing (in addition to screwing) also prevent the springiness of the overall floor?

Nozzle

 

[garyo]

Did you use proper chipboard screws - the ones with a shank that's equal to the depth of the chipboard so that they're pulled tight down on to the joists, rather than 'floating' on the threads of the wood screws as everything dries out? It might be worth swapping the screws out if not - it could be an easy fix.