Creaky upstairs floors

5starpool

My house is less than 18 months old, and some of the floors upstairs creak badly in spots. The flooring under the carpet is sections of what I presume to be chipboard. I broadly know what has to be done, long screws into the timber beneath the joins. I'd like to do it myself but I am wary for a number of reasons and would like to ask a few questions to see if I can get any answers here:

1. There are carpets in the affected bedrooms. Is it something I should attempt myself to pull up the carpet and put it back afterwards? I'd probably need to pull up about 2 feet of the carpet. The carpets were laid by Des Kelly staff, and I'd assume they have tack strips by the wall, but I don't know. I have never pulled up or put down carpet before and this is the bit I'd be most nervous about doing.
2. Once the carpet it up, is it reasonable to assume that where the boards join is where I'd put in screws, either side of the join (in multiple places to be sure)?
3. What screws would be best for this purpose.

I need to do this in 2 rooms, and the floors creak loudly either side of a partition wall.

Thanks.

Lumen

Carpet fitting is hard.

5starpool

So that's a firm 'get someone in to do it' then?

Lumen

Not necessarily. You could try taking up a small section of carpet at a time, screwing the OSB down into the joists, and fixing it back again. That way it won't need to be stretched back on. Worst case is you end up with a saggy carpet and then have to call in the carpet people to fix it (trivial job).

Just make sure you don't hit any electrics or pipes.

In terms of which screws, I'd get proper flooring screws, like this:

https://www.topline.ie/tools-hardware/nails-screws-fixings/screws/wood-screws/spax/flooring-screw-500-pack

kadman

Screwing down floors when you dont know what you are at is a recipe for an expensive disaster.

Lots of plumbing and electrics below floor surfaces between the joists.

5starpool

What's the trick to not hitting pipes or electrics when you can't see what's under the boards? Should where the pieces of flooring meet always be over other timber? I'd imagine it should be, but just because it makes sense to me doesn't make it so.

GreeBo

5starpool wrote: »

What's the trick to not hitting pipes or electrics when you can't see what's under the boards? Should where the pieces of flooring meet always be over other timber? I'd imagine it should be, but just because it makes sense to me doesn't make it so.

The trick is to take up the boards first...

You would be amazed how some floors are layed, in my previous house some genius plumber had notched the underside of the floorboard to run a pipe....the floorboard for godsake!

My perfectly set circular saw didnt matter a damn when there was 5mm of pipe inside the floorboards... :rolleyes:

kadman

5starpool wrote: »

What's the trick to not hitting pipes or electrics when you can't see what's under the boards? Should where the pieces of flooring meet always be over other timber? I'd imagine it should be, but just because it makes sense to me doesn't make it so.

Electrics and pipework will just as easily be located through holes bored in joists.
So just because you find timber bearers below where flooring meets, it means nothing.

And electrical stud finders that locate timberwork and pipework mean they find all manner of metal, but what it is , is another thing.

As the previous poster says lifting the flooring is the only way.

kadman

And long screws is the last thing you need.

5starpool

Thanks for the replies all.

Calahonda52

I agree withe risks here when u don't lift the floor, so here is an idea.
Lift the carpet and see how the floor is fixed down.
Assuming it is nails, you could remove the nails and replace with screws off the same length in the same hole.
I would use a 6mm screw, pre drill the board only with a 5mm hole and counter sink it, this will give max pull on the board down to the joist

Lumen

Having just put 400 or so 4.5 x 70mm torx-headed decking screws through 30sqm of OSB without pre-drilling, these would be my first choice.

It does seem stupid to use decking screws internally, but I haven't found a builders providers that has self-drilling screws specifically advertised for flooring, and they're all posidrive which in my amateurish experience is worse than torx. I tried regular woodscrews with enough shank to pull the board cleanly without pre-drilling, but they didn't seem to have the same pulling power.

I'm probably doing it wrong.

(I also have a squeaky flooring problem which will get done sooner or later, but those are 30 year old nailed floorboards)

Ted Plain

I'm in the same situation as you.


The house is about four years old and is floored out with tongue-and-groove OSB. Not only are they held down with nails which have worked loose, but the joints are in no man's land out between the joists. This gives a dual quality to the creaking.



Anyway, I'm doing up the main bedroom soon and the floor creaking is so bad that I'm actually skilsawing the whole lot out and putting down a new one. There are even two areas where the board ends do not meet and are sagging.


I've done this before in my first house, replacing the wretched, old chipboard with plywood. I used full-size 8 x 4 boards and ensured that all joints met over wooden joists or noggins that I put in. I also used non-T&G and left a tiny gap between the panels so that they would never rub off each other and cause creaking. I screwed them down solidly with the cordless screwdriver and normal 40mm wood screws.


It did a fine job and the floor never creaked again.


My house has the open web eco joists and so I'm thinking that joist notching or hitting cables or piping should not be an issue.



If you don't want to go to that extent there are screws that you can put in through the carpet.

Lumen

Ted Plain wrote: »

The house is about four years old and is floored out with tongue-and-groove OSB. Not only are they held down with nails which have worked loose, but the joints are in no man's land out between the joists. This gives a dual quality to the creaking.

I have been told that T&G joints don't need to be located over joists. I've also been told that T&G joints should be glued. And that they relieve the need to leave expansion gaps because the expansion can happen within the T&G joint.

It seems improbable that all these things can be true, since a glued joint strong enough to stop flex in between joists is unlikely to also allow expansion within itself, but there you go.

It is probably faster to glue a joint than it is to cut the board.

listermint

Cant beat a bungalow

This sort of noisey stuff would drive me bananas

Calahonda52

listermint wrote: »

Cant beat a bungalow

This sort of noisey stuff would drive me bananas

until you convert it!

listermint

Calahonda52 wrote: »

until you convert it!

Dont start.

The boss is at me for that :eek:

Ted Plain

Lumen wrote: »

I have been told that T&G joints don't need to be located over joists. I've also been told that T&G joints should be glued. And that they relieve the need to leave expansion gaps because the expansion can happen within the T&G joint.

It seems improbable that all these things can be true, since a glued joint strong enough to stop flex in between joists is unlikely to also allow expansion within itself, but there you go.

It is probably faster to glue a joint than it is to cut the board.

I'd say they're not glued at all, just lashed in as fast as possible. There are even two areas that are sagging when you walk over them. Maybe where some of the tongue was broken before laying.


The whole floor is just cheap, nasty, very shoddily installed and is now destined to land in a container in Ballymount.

Calahonda52

kadman wrote: »

And long screws is the last thing you need.

Context dependent:D

Wheety

Do not use a drill to just screw down the floorboards where you think it should be fine without checking. Believe me.

Lumen

The advantage of slightly longer screws is that it's easier to hit the joist under the edge of the boards by skewing the screw in from a bit further out.

Particularly if you're being a bit half-arsed about it.

Well that's my experience anyway. I'm probably doing it wrong.

chicorytip

Wheety wrote:

Do not use a drill to just screw down the floorboards where you think it should be fine without checking. Believe me.

The objective is to drill directly into the joist to create a screwhole. Is this correct? Is it possible to locate the exact position of a joist without lifting the board, say by tapping a hammer along it's length and listening out for a duller type of noise which might indicate this?

Wheety

chicorytip wrote: »

The objective is to drill directly into the joist to create a screwhole. Is this correct? Is it possible to locate the exact position of a joist without lifting the board, say by tapping a hammer along it's length and listening out for a duller type of noise which might indicate this?

I could see through a small gap in the floorboards where the joist was. I thought I was great screwing a screw into the middle of the floorboard into the joist. Then I heard the pump in the attic kick in and a hissing sound under the floorboard. I've never moved so quick to get into the attic and turn the water off.

The plumbers who put in the heating had the water pipes just below the floorboards, running through notches in the top of the joists.

Managed to fix it after leaving the floorboard up for a week to dry out. Will never do that again without checking.

GreeBo

chicorytip wrote: »

The objective is to drill directly into the joist to create a screwhole. Is this correct? Is it possible to locate the exact position of a joist without lifting the board, say by tapping a hammer along it's length and listening out for a duller type of noise which might indicate this?

Hitting the joist isn't the problem, it's missing everything else!

colette dunne

just want to ask, as I am having major problems with all the floors upstairs in my house. can nails or screws just be put in directly in front of the ones already in the floors or not. when even the dog walking upstairs sounds as if the ceiling is about to cave in, the cracking and snapping is too much to bear, and all the floors upstairs move when walked on, some pop up. I  think the flooring is called yellow tongue. any suggestions on how to deal with the problem would be appreciated.

Ted Plain

I'm just about to start into my job of replacing the floor in one of the upstairs rooms.

I'm going to put in some Rookwool slabs and am considering putting down some sound insulation strip for joists like this stuff here:

Acoustic Impact Strip

Has anyone used this before? is it any good?

One thing that strikes me is that it is 5mm thick. Not a problem in itself, but I am taking up the existing OSB with a skilsaw and will only be able to get within 10cm or so of the edges.This would leave the new floor 5mm proud of the old, remaining outline. I'm putting down underlay and carpet and so the 5mm difference might result in a crease mark when things settle down.

Does the strip compress down somewhat with the weight of the flooring?

Lumen

Ted, I just did exactly that over the last couple of weeks.

18mm OSB over those joist strips over 150mm acoustic rockwool between 9 inch joists.

I was concerned that they were just crappy foam. I'd be happier with some sort of solid rubber, there's a risk that they degrade over time, but I was in a hurry and couldn't be bothered to do any further research.

Anyway, they seem to have done the job, the difference is unreal.

If you want to space your flooring to even out those differences you might consider Gutex Happy Step, a 4mm woodfibre board. I put it between layers of OSB in my shed project. It is the most fragile building material I've ever dealt with but does the job of spacing nicely. You'd use it over the OSB and under the finished floor, like underlay.

However, are you sure you can't get that last 10cm out with a pry bar? What's stopping you exactly?

Ted Plain

Thanks, Lumen.

Well, I'll be using a skilsaw and the base plate on it will get me to about 10cm of the walls. Internally, there are plasterboard walls and wardrobes sitting on the floor, so I can't get it all out. Anyway, I want to lash into it and get it done and not spend all day with a hand saw or jigsaw or whatever!

The strip stuff is PE foam, so does it compress under pressure? If t did then 2-3mm of a difference would probably not make any difference.

Lumen

Ted Plain wrote: »

Thanks, Lumen.

Well, I'll be using a skilsaw and the base plate on it will get me to about 10cm of the walls. Internally, there are plasterboard walls and wardrobes sitting on the floor, so I can't get it all out. Anyway, I want to lash into it and get it done and not spend all day with a hand saw or jigsaw or whatever!

The strip stuff is PE foam, so does it compress under pressure? If t did then 2-3mm of a difference would probably not make any difference.

You might be better off just putting acoustic underlay (like the Happy Step I mentioned) over the OSB layer. Then you can run it over both old and new.

https://gutex.de/en/product-range/products/product/gutex-happy-step/

"can improve the impact sound insulation by up to 30 dB"

I'm sure there are other similar products.

You'd want to be sure that the new OSB is screwed down properly to avoid squeaks (consider Spax flooring screws which I think Screwfix do, haven't found them in any shops).

Ted Plain

Got the job finished last week!

Ended up doing the ensuite; retiled floor and shower area, new slate-style shower tray, 30cm shower head, vanity sink unit, towel radiator with chrome valves and chromed copper piping and a sensationally good Manrose in-line extractor fan. Really happy with the results.

I cannot stress enough how good the fan is in comparison to the absolutely and utterly useless junk that had been installed.

Also fully redecorated the bedroom, ripping out the old floor and putting in Rockwool. I used the foam impact strip on the joists too. It squashed down to ~2mm, so there were no problems with it being higher than around the edges.

The difference is huge. The floor feels really solid underfoot and there is not a sound to be heard! A big job, but well worth it.

Lumen

Ted Plain wrote: »

a sensationally good Manrose in-line extractor fan. Really happy with the results.

Does that sit in the hole in the wall or are you venting out through the attic?

padthebull

Hi Ted,

Just came across this thread as I am thinking of doing a similar job on my floors upstairs. The house is approx. 25 years old and the entire upstairs area creaks non stop when walked on. I've tried screwing the boards to the joists and put down new underlay and carpets in one or two rooms to see if that would help but still pretty much the same. I'd say the floorboards are connected straight to the joists with no subfloor. At this stage I think I will just rip them out altogether with a skilsaw like you mentioned and put in insulation between the joists with 18mm OSB and relay the underlay and carpets.

Jut wondering what acoustic insulation you used? Presumably a loft insulation would provide a level of acoustic as well as thermal insulation as opposed to a specific acoustic insulation? Did you go with T&G OSB board in the end?

WildCardDoW

padthebull wrote: »

Hi Ted,

Just came across this thread as I am thinking of doing a similar job on my floors upstairs. The house is approx. 25 years old and the entire upstairs area creaks non stop when walked on. I've tried screwing the boards to the joists and put down new underlay and carpets in one or two rooms to see if that would help but still pretty much the same. I'd say the floorboards are connected straight to the joists with no subfloor. At this stage I think I will just rip them out altogether with a skilsaw like you mentioned and put in insulation between the joists with 18mm OSB and relay the underlay and carpets.

Jut wondering what acoustic insulation you used? Presumably a loft insulation would provide a level of acoustic as well as thermal insulation as opposed to a specific acoustic insulation? Did you go with T&G OSB board in the end?

You usually don't put proper thermal insulation between floors as you'll be happy for the heat to rise up the house.

Isover Acoustic has some thermal properties so if acoustic is a concern, either from above to below or vice versa, so should be good.

T and G OSB is you're only bet if replacing old floorboards (cost wise). Then it's just minimising the cuts where you can and linking the tongue and Grove as much as possible!