Chipboard flooring for use in a damp situation? Can it work?

JustAnotherSaver

It's very likely our entire flooring (wooden) system is going to need replacing as it's rotten. We may well get X-years out of it, who knows. I have no knowledge on at what point it's time to say "this NEEDS replacing". I've been under the floor & the ends of the joists are visibly damp. They're mushy to touch in sections. Some joist ends are ok but many of the ones i've touched are mushy. Another i felt today felt & sounded quite bad.
Also the floorboards where they meet the wall - some of these are also mushy. Some lengths are fine.

KEY THING: The cause can not be solved. We have water under the flooring which is naturally occurring & cannot be stopped (trust me: we've looked into it). We're told that this level of water underneath is causing damp air which is just getting into the wood. Some of the floorboards are curved upwards (not like a banana, but curved all the same).




So with a replacement, i'd want it to stand the best chance possible against damp.
From what i've read & been told, i believe the joists should be tannalised & the ends wrapped in DPC (Visqueen?).


The question is the flooring itself.

I imagined it'd have to be floorboards (it'll be carpeted anyway), but a chap who is a customer where i work (who's doing someone elses flooring right now) said they would use moisture resistant 22mm chipboard flooring. It's quicker & cheaper.

I forget the readings now but i think when i read the flooring & joists the range was 25%-35%. Sticking it in the mushy sections i'm sure gave it the highest reading it can give on the reader (45% i think). I believe anything over 20% is when decay sets in.


So i emailed Kronospan, who are the manufacturers of the chipboard flooring that we stock. I did this because i imagined moisture resistant would be for a BIT of moisture, not permanent moisture.

Kronospan responded by saying they don't believe moisture resistant flooring would be suitable in this scenario & they struggle to think of what WOULD be suitable.


You'd think the manufacturer would know what they're talking about (although they don't always), but then if this guy has been working with this stuff for 30 years as he says, you'd think he knows what he's talking about (but they don't always), so i'm in the middle.

what do you guys reckon would be suitable? And would any extra treatment be required for it?

societys_child

Kronospan responded by saying they don't believe moisture resistant flooring would be suitable in this scenario & they struggle to think of what WOULD be suitable.

I agree with Kronospan, would'nt even consider chipboard. Do a bit of research into Stirling Board, you might find something more suitable, but I really don't know to be honest.

edit: Just found some info here to get you started

for use in load bearing humid conditions.

• Can perform even when wet

Ruski

Personally I wouldn't use ANY sheets materials - you'll get a better lifespan from floorboards of tanalised timber and will be both longer lasting and easier to replace if you get 'spot' areas to replace.

I'd also put dpc across the top of the joists.

All of this is going to be more time consuming and expensive than sheets, find yourself a builder whos isn't lazy.

HTH
Russ

Hintza

You have to get rid of the water somehow.

Dig the floor out? Tank it? Lay a slab?

I don't know but until you do that this will continue to be an issue.

DRP

Ruski wrote: »

Personally I wouldn't use ANY sheets materials - you'll get a better lifespan from floorboards of tanalised timber and will be both longer lasting and easier to replace if you get 'spot' areas to replace.

I'd also put dpc across the top of the joists.

All of this is going to be more time consuming and expensive than sheets, find yourself a builder whos isn't lazy.

HTH
Russ

I'd agree with this.

Having read your previous threads, there's no getting around the fact that your damp issue is long-standing / permanent (without spending a lot of ££).

On the other hand it is manageable and a new floor fitted in the correct way as you describe (tannalised, dpm etc) will be very resistant to damp - tannalised wood joists for garden decking in my old place lasted a decade with no rot.

I wouldn't bother with chipboard. Floorboards will last a long time are easy to replace individually if the need arises.

Have you considered ventilation under the floor to reduce ther humidity levels (ie. electric fan)?

zaax

Try to work out were is it coming from, but if it is unsolvable put in a sump pump.

A good piece about sump pumps

http://home.howstuffworks.com/home-improvement/plumbing/sump-pump1.htm

cyclonebri1

Only you can decide if you want to tackle the water issue, I did follow it but can't recall the details right now.

As others say, use T&G flooring. I'd lay roofing felt, slaters felt or similar over the joists prior to boarding, then hope for the best.:A:A:A

JustAnotherSaver

societys_child wrote: »

Do a bit of research into Stirling Board, you might find something more suitable, but I really don't know to be honest.

edit: Just found some info here to get you started

That's interesting. Thanks.

I'll have to email the manufacturer to see what they say. We get OSB board in as special order & my experience of it when it get wet it's useless. Now i know we're talking about damp AIR and not WET here but i wonder if it's going to be about as useful as the chipboard.

With all that said, assuming the floorboards are 1930s original, it's only the ends that touch the wall that have suffered. The rest are fine. So maybe a +1 vote for floorboards again.

Ruski wrote: »

Personally I wouldn't use ANY sheets materials - you'll get a better lifespan from floorboards of tanalised timber and will be both longer lasting and easier to replace if you get 'spot' areas to replace.

I'd also put dpc across the top of the joists.

All of this is going to be more time consuming and expensive than sheets, find yourself a builder whos isn't lazy.

HTH
Russ

Thanks. I think i would perhaps go floorboards actually based on my last point in the quote above.

RGEARDS TANALISED TIMBER::::: I was talking to a chap who's a keen DIYer who said that tannalised wood is still wet wood as it's been treated under pressure. It's still not bone dry. He said this will shrink as it dried which isn't what i want & that i'd be better with & i quote what he said - "seasoned wood".

Now, you're all infinitely more knowledgeable than I so it all makes sense to me when you put it to me. Then when someone comes to counter that statement, that makes sense also. So, what's your take on what he says about tannalised timber?

JustAnotherSaver

Hintza wrote: »

You have to get rid of the water somehow.

Dig the floor out? Tank it? Lay a slab?

I don't know but until you do that this will continue to be an issue.

We can get rid of it....temporarily. It just returns. We have a sump pump in place.

I was speaking to a builders merchant & the materials required to fill the void, we're talking many thousands - which we simply don't have.
The void is a metre deep. While not unique, from talking to builders this seems deeper than 'the norm'. The living room alone is 7mtr-x-3.5mtr, then there's the hallway which would be about 1.5mtr-x-2mtr/3mtr.

And this is before we get onto the topic of whether the workmen do a proper job & don't cut corners with my £thousands+thousands as that water has to go somewhere. From googling different articles, this can end up coming up your walls. From research, it seems better to try & manage it.

DRP wrote: »

I'd agree with this.

Having read your previous threads, there's no getting around the fact that your damp issue is long-standing / permanent (without spending a lot of ££).

Agreed. This is simply money we do not have as i say. I know we've been here before & i appreciate not everyone is familiar with my 'story'. I'm just looking into managing it now as i've spoken to many builders & everyone has a new & different opinion. I can only select one.

On the other hand it is manageable and a new floor fitted in the correct way as you describe (tannalised, dpm etc) will be very resistant to damp - tannalised wood joists for garden decking in my old place lasted a decade with no rot.

I wasn't sure if the floor would need replacing but i stood on the ends of the floorboards tonight & i could see them flexing quite an amount. Not sure if this is normal, but i think for the sake of it, we'd just rather get it right.
And while the floor is out, a new sump pump would be going in.

Have you considered ventilation under the floor to reduce ther humidity levels (ie. electric fan)?

There are 2 airbricks to the front of the living room.
There are 2 to the rear but it's a square pipe that runs through the centre of the brick through the solid floored (floating floor) diner at the rear(.
There is one to the front of the hall which is to the right of the living room & one to the side of the hall.

When we moved in, all were blocked. I've cleared them out. I'm going to cut air ducts to fit so that the insulation cannot drop down to block it again.

It's been put to me - fit MORE air bricks.
It's also been put to me - it doesn't matter how many air bricks you fit, it wont sort the problem.

Obviously only one of those sets of people can be right. Perhaps when we get round to it (as we've decided this is now a long term project & the short term is to sort upstairs & move in) we'll just get a builder to insert 2-3 more air bricks at the front as it can't harm anything (he says!). Unfortunately no air bricks can go to the rear to help out the other 2 as it's solid floored.

martinthebandit

http://www.cemex.co.uk/beam-and-block-floor-systems.aspx

If your laying carpets etc why are you looking for a wood floor?

andyhop

Tanalised timber and wrap the lot in DPC, not just the ends

The floor could be done in 22/25mm marine plywood , even apply a coat of yacht varnish to underside and all cut edges