Wanna make upstairs floor sturdier...

builder007

Hello,

have concrete floor downstairs and suspended timber floor upstairs.

The timber floor is solid pine 20mm t&n over joists.

Would adding a layer of ply (say 18mm) add to the feeling of sturdiness or would it be waste of time/money?

Lightweight screed is not an option as it would need to be at least 40mm thick bringing the ceiling height below 2.4

thanks

BrokenArrows

builder007 wrote: »

Hello,

have concrete floor downstairs and suspended timber floor upstairs.

The timber floor is solid pine 20mm t&n over joists.

Would adding a layer of ply (say 18mm) add to the feeling of sturdiness or would it be waste of time/money?

Lightweight screed is not an option as it would need to be at least 40mm thick bringing the ceiling height below 2.4

thanks

I assume you mean under the pine

Sure it would help.

mickdw

What is the issue - is it noisy or is it movement that is the issue.

the_pen_turner

depends on the issue you have. it will help . glue and screw down the ply with proper flooring screws .

builder007

BrokenArrows wrote: »

I assume you mean under the pine

Sure it would help.

I actually meant to put ply over solid pine. Would that make any difference?

builder007

mickdw wrote: »

What is the issue - is it noisy or is it movement that is the issue.

It's not noisy but it's not silent... The main issue is the lack of sturdy feeling when compared to concrete floor

mickdw

Id be inclined to lift floor. Add as much bracing as possible between joists, then look at installing an isolated floor surface to help with noise transfer etc. There are a few systems available - it could involve screw fixing a ply floor direct to joists then using an isolating layer then floor board or there are systems to isolate the ply itself.

looksee

Has the floor just been put down? I think you will find you pretty quickly get used to the wooden floor feeling 'different', don't be in a rush to do anything. Putting ply over the timber can create its own problems, depending on the quality of the pine. Presumably you are going to cover the ply? what were you planning to use?

builder007

Hello. Thanks everyone
The plan is to put a layer of 10mm cork, then ply, then underlay, then laminate.

builder007

The pine is good quality... But still feels wobbly

the_pen_turner

builder007 wrote: »

The pine is good quality... But still feels wobbly

what do you mean by wobbly.
is the floor deflecting under you when your walking on it. is it really bouncy.

builder007

Not really bouncy but kinda bouncy if you know what I mean... I'm thinking to put down something rigid like 12 or even 18mm ply... But the fear is that it doesn't improve the bounciness much

mloc123

builder007 wrote: »

Not really bouncy but kinda bouncy if you know what I mean... I'm thinking to put down something rigid like 12 or even 18mm ply... But the fear is that it doesn't improve the bounciness much

If the floor feels bouncy an extra layer of ply will not help IMO. You probably need to double up the floor joists instead to take any bounce out of it.

the_pen_turner

i would add a few rows of noggings. another layer of ply will help a small bit but not a huge amount

builder007

Is agree but that's probably a much bigger job... Do you know how expensive would that be? I genuinely don't know...

Lumen

Bouncy floor is better for your back. It's a feature not a bug!

builder007

Very insightful comment

builder007

I spoke to a carpenter yesterday. He recommends 9mm plywood - or 12mm if the ceiling hight is not an issue. He did similar jobs in the past and he says he layed sound insulation (5mm rubber) between the floor boards and ply. This really sounds like a good idea.

What do you think guys?

builder007

I spoke to a carpenter yesterday. He recommends 9mm plywood - or 12mm if the ceiling hight is not an issue. He did similar jobs in the past and he says he layed sound insulation (5mm rubber) between the floor boards and ply. This really sounds like a good idea.

What do you think guys?

listermint

I think your username needs work

sydthebeat

builder007 wrote: »

I spoke to a carpenter yesterday. He recommends 9mm plywood - or 12mm if the ceiling hight is not an issue. He did similar jobs in the past and he says he layed sound insulation (5mm rubber) between the floor boards and ply. This really sounds like a good idea.

What do you think guys?

Not going to do anything for the bounciness.
Ok for some extra sound proofing.

Reducing the bounciness will require additional bracing as suggested previously.

the_pen_turner

9mm ply with rubber inbetween will probably make it feel softer rather than stronger

builder007

It's interesting what you are saying.

I would have though that adding a letter of 9mm ply would make the floor sturdier despite the fact that there is rubber underneath. It's is high density very heavy rubber that I'm talking about here.

the_pen_turner

builder007 wrote: »

It's interesting what you are saying.

I would have though that adding a letter of 9mm ply would make the floor sturdier despite the fact that there is rubber underneath. It's is high density very heavy rubber that I'm talking about here.

9mm ply is very weak and flexible. adding it directly to the pine would help a small bit . adding rubber in between will only allow it to bend.

i wouldnt go for anything less than 18mm . maybe 2 layers of 12mm layed 90 degrees from each other and fully glued to teh pin and to each other. then 90mm flooring screws into the joists. and 50mm floor screws in between intothe pine.

tabby aspreme

A few questions OP, how old is the house, how wide are the rooms, how deep are the joists, what spacing between the joists. Are the boards currently well fixed to the joists.

builder007

tabby aspreme wrote: »

A few questions OP, how old is the house, how wide are the rooms, how deep are the joists, what spacing between the joists. Are the boards currently well fixed to the joists.

The house was built in 2005. The rooms are quite large (the house is 3000sqft). 9 X 3 joists spaced every 40cm. The boards are nailed (not screwed).

5T3PH3N

builder007 wrote: »

The house was built in 2005. The rooms are quite large (the house is 3000sqft). 9 X 3 joists spaced every 40cm. The boards are nailed (not screwed).

Surely they're not all 9x3 joists? If they are they should be super sturdy, provided there are adequate noggins.

the_pen_turner

9x3 would be excesive. what is the span

builder007

Might be the case. I only lifted one floor board in the landing.

the_pen_turner

have you a pic.

5T3PH3N

builder007 wrote: »

Might be the case. I only lifted one floor board in the landing.

That's probably just a trimmer for the stairs ope, the rest of the joists are more than likely 9x2.

builder007

Not sure but the house is quite large. There is a brick wall in the middle of the house and joists are supported by the external wall on one side and the brick wall on the other side.

builder007

It might be that the floor boards are of poor quality (solid pine) and thats causing the bounce... I don't know.

I'm thinking of adding 12mm ply to basically connect the floor boards into one big panel structure and help distribute the downward force more evenly across joists...

Do you think the logic is sound?

the_pen_turner

builder007 wrote: »

It might be that the floor boards are of poor quality (solid pine) and thats causing the bounce... I don't know.

I'm thinking of adding 12mm ply to basically connect the floor boards into one big panel structure and help distribute the downward force more evenly across joists...

Do you think the logic is sound?

its a bit like hitting your head in the dark and putting a plaster on without checking if your bleeding or if you need a stitch. it might work , it might not.


you could take up a floor board or 2 and fit some more noggins and then do the ply

Odelay

builder007 wrote: »

The house was built in 2005. The rooms are quite large (the house is 3000sqft). 9 X 3 joists spaced every 40cm. The boards are nailed (not screwed).

Probably a 9x2. You shouldn't be able to bend then spaced at 400mm by walking on them unless spaced at a ridiculous span.
Something else is wrong.

builder007

Was talking to a friend now. He said OSB is much stronger then plywood and he shared this link:

https://youtu.be/RLpAEundEro

I find it hard to believe but the video clearly shows that OSB is less flexible...

builder007

And then I found this

https://youtu.be/zCPlL9UQGT4

the_pen_turner

builder007 wrote: »

Was talking to a friend now. He said OSB is much stronger then plywood and he shared this link:

https://youtu.be/RLpAEundEro

I find it hard to believe but the video clearly shows that OSB is less flexible...

thats a terrible test. the ply wood is the cheapest nasiest suff they could find. try that with proper gread wbp or marine ply. there looks to be only 3 ply layers int he test they used and looks to be only shuttering grade at best.

the_pen_turner

builder007 wrote: »

And then I found this

https://youtu.be/zCPlL9UQGT4

if in doubt , get a cannon.

builder007

I'm going nowhere near OSB.... Ply all the way.

Marine ply is too pricey... The standard one will probably do!

the_pen_turner

marine is over kill for you but it would wipe the floor in those tests

builder007

Yeah. I'd say so.

12mm ply then some good rubbery underlay then 12mm laminate...

Hopefully that'll do the trick

mickdw

4.5m approx is typically the max span for 9 X 2 so if longer than that, it's possible that you have 9 X 3 in some areas.
I'd not go ahead with any floor works without looking at what is going on in the floor. If you have large spans, it's possible you have have under sized steel beam in floor allowing bounce. Anything is possible until you investigate.

bloodless_coup

builder007 wrote: »

Yeah. I'd say so.

12mm ply then some good rubbery underlay then 12mm laminate...

Hopefully that'll do the trick

You seem to have your mind made up all along and are not listening to any of the feedback so best of luck to you!

How rubber is going help in any way, and not make it even worse, I've no idea.

builder007

I'll definitely lift a few more boards to see what's the story... Haven't decided yet..

Rubber thing was recommended to me to deal with impact noise stuff... But you are right... I was also sceptical when I heard the guy talking about rubber...

mloc123

Wood flexes... even if you double up the joists and put ply down... wood will still flex (somewhat). My upstairs is 9x2s with pine t&g on top, max spans of 3.5m.. there is some flex in that.. like every house I have lived in before. Most people will not even notice this, I would imagine this has become an obsession for you now.

builder007

Might be the case


I was thinking last night whether there is a good/clever way of measuring the flex...

A tool... or some kind of a setup/contraption that will give me the extend to which the floor is not solid...

mloc123

builder007 wrote: »

Might be the case


I was thinking last night whether there is a good/clever way of measuring the flex...

A tool... or some kind of a setup/contraption that will give me the extend to which the floor is not solid...

Have you lived in a two storey house before this one?

builder007

I have. It was an old Georgian house

sbsquarepants

How bouncy exactly are we talking? A light spring or a full on trampoline?:D

As stated already, wood flexes - it will move to some extent no matter what you do, are you just being over fussy?

I recently moved home, typical joists + floorboards upstairs. The bloody noise when you walked on it was unreal, squeaking and creaking. I spent 2 solid days screwing every board down to quieten it. Worked a charm, not a squeak....for about 3 weeks. Not quite back to square one now 8 months later, but not a million miles off it either! I'm sorry I ever bothered.

You could spend days fixing this "problem" only to find your floor is still bouncy in 6 months time - timber floors bounce, that's just what they do!

unhappyBB

My upstairs floors are driving me mad with the amount of noise they make. It was seriously like walking on a bunch of screaming cats :pac:. I decided not to just screw them down because I didn't think that would work (delighted now after reading the last post).
I'm now ripping up the laminate, underlay and 18mm T&G chipboard that was there and replacing it with:

insulation between joists (for a little soundproofing)
3mm rubber underlay strips along joists
18mm ply wood
foam underlay & laminate

I'll probably throw in more noggins now too based on this thread. One question though, do noggins have to be the full 9" height or can I just use the 3"x1.5" that I have on hand?