Thread: What's happening to my floorboards ?

Andy

Certainly looks like continued drying down to a different moisture content. How wide are the boards? In times past high quality boards were narrow (less than 75mm) but modern trends have reverted to wide boards. Shrinkage after laying becomes more noticeable.

It does look as if the moisture content may not have been right for your area and extensive use of air-conditioning will have exacerbated that problem. Looking more closely at your pix it looks as though the boards are only about 100mm (nominally).

If further drying is the issue maybe some form of humidifier might assist, but I don't know how this is practically applied.

Regards
Paul

I'll preface this post with the statement that " I have no particular skills or qualifications to back up what I say". That seems to be the standard not my fault clause that people use these days.

However, I would agree with Paul. The installation of air con may well have changed the average weather dynamic in the house. Resulting in dryer than expected conditions and hence the splits in the boards. Humidification MAY resolve the issue over time, just as the air-conditioning created the problem, over time.

Cheers

I haven't looked up the "book" (Keith Bootle, Wood in Australia) but I don't need to (you may wish to do so, it has great information on most Australian timbers). We had a Jarrah 19mm parquetry floor installed in Brisbane in 2000. it looked absolutely superb. But, in a wet year it swelled so much that i pushed the walls of the house outwards. In a dry year(s) (drought) it cracked up and split off the base. Jarrah seems to have considerable expansion/shrinkage across the grain.

Jarrah is a great timber for furniture and is relatively soft (for a eucalypt) so kind to tools. But, although beautiful, it needs lots of expansion/contraction room.

It looks like your boards are edge-glued (maybe by the finish) so they are splitting rather than opening the joints.

I don't know about Sydney but here in Brisbane it has been exceptionally dry (only 1 mm rain in September) so, if similar in Sydney, that would certainly contribute.

Can you humidify below the boards? The bare timber will absorb moisture much better than the sealed upper surface.

Good luck,

David

Agreed with all stated above about expansion and contraction.

I had returned from the Sunshine Coast QLD about 5 weeks ago with a piece of Myrtle for a platter (thank you Frank). It had been dried for quite sometime, and was/is very beautiful.

Fast forward to today in VIC, and it has cracked substantially at both ends and on another of the sides. EMC is to blame here.

Hi Andy, we've had the driest few months in decades, so everything is contracting. The A/C is likely exacerbating the situation. I have double front doors, and the gap between them is wider than I've ever seen. We need some rain!

cheers,

Allan

I had Jarrah floor boards on my front veranda for over 20 years. Heavy rain wet them thoroughly and they got the full afternoon sun. They were layed with a credit card gap between them. Never had any problems with cupping or splitting but a factor may have been that they were never coated, so the underneath and the top were exposed somewhat equally to the conditions.
Only had to replace them because the outer edges fell apart.

Originally Posted by ajw

Hi Andy, we've had the driest few months in decades, so everything is contracting. The A/C is likely exacerbating the situation. I have double front doors, and the gap between them is wider than I've ever seen. We need some rain!

Agreed. We've had virtually nil rain here for about 4 months or something? The AC on top of that is the cause for sure.

I have a "Dry weather" gauge here - the back of the house will drop after a certain amount of dry weather, and the indicator is that the back door starts sticking. It was sticking after the dry Blue Mountains winter of 2016, and is now doing the same again (for about the last 4 weeks, maybe longer).

Just looking at rainfall records for Springwood:
July 0.6mm and the average is 54mm
Aug 18mm and average is 50.8mm
Sept 2mm and average is 54mm

So you've had 21.6mm out of an average of ~160mm in the last three months. No doubt of the cause of timber splitting.

Originally Posted by groeneaj

Over the past 4 months my floorboards (solid Jarrah) have started to crack. I've been in the house for just over 4 years now and this is the first time it's happened.

The only thing I can think of is that we got ducted air conditioning installed about 12 months ago, and with the wife and baby being home most of the time, it got a fair bit of use this winter. Could this be the reason?

yep that will do it.

here most houses have ducted central heating teamed with humidifiers -- I'm still coming to grips with how the humidifier works (in winter it needs to be cranked up to around 40%) so unfortunately I can't help you with a solution for your floor.

Dry air is a floor killer. Be it air con or open fire. Add to this the fact that few floor layers leave the flooring to stabilize before fixing. These days they rock up to the job in the morning when the flooring is delivered, dock it all to room lengths and got to rat with a nail gun. Come knockoff time all finished. Next day floor is sanded and a poly finish is applied before you can blink. Efficiency, you may say. But there is a cost. And you are looking at it.
Our current dry spell will not be helping either.
Best practice for flooring is to cut and lay in the boards upside down as soon as possible after the house is weather proof. This allows the timber to recondition to suit the environment. This will be compromised by air con or a fire to some extent but not as drastically as a rush job floor.
Who knows what the moisture content was when the floor was put down, but it is obvious that it is much less now. Cracking of boards will be caused by edge glueing caused by the polish. A good argument for oil. Jarrah moves a lot so narrow boards are preferable. Mind you, if the boards edge glue, it matters not what width the boards are they will crack when dry stressed.
You will probably find that with rain all will return pretty much to normal, unless the boards were too wet when laid. If this is the case nothing will change.
What to do now? Increase room humidity. Particularly when air con is running. Easy way to do this is a small container of water in front of the air con outlet.
Hope this helps.

Thanks all for the replies.

It doesn't surprise me at all that the air con is the reason for the cracks. In addition, the past few months have been ridiculously dry as Brett & Allan mentioned.

So I need to get more moisture in the air? With summer approaching will the humidity in the air suffice even if there is minimal rain? Alternatively I can look at getting a humidifier, which seems necessary especially when winter comes around next year. This is something I'll need to look into.

Originally Posted by groeneaj

With summer approaching will the humidity in the air suffice even if there is minimal rain?

That depends, but probably not. If the air feels dry to you then it'll be dry to the timber. If it's sweaty weather then you're probably ok.

Maybe install one of these, or make a wooden display thingy.

We live in Brisbane and don't have air conditioning yet recently we have been woken by the sound of our 4 year old Blackbutt floor boards making a cracking sound early in the morning. We used whittle wax to finish the floor rather than the common polyurethane finishes that are "harder" and thus more like glue. The cracking therefore is only the finish hidden between the tongue and groove joins. The only issue we are seeing is some small gaps are now seen between the boards. I am not sure if this helps at all.


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Continued shrinkage is not just a phenomenon of floor boards but also fine furniture. When I think back we used to always sit a bowl of water on top of the slow combustion heater when it was lit during winter. This was to add moisture to the air. We have not done this in recent times for various reasons: Not much in the way of fine furniture and floorboards that you can fall down between (actually not quite that bad, but you get the picture) so increasing gaps are barely noticeable.

In the first instance I would suggest a container of water placed strategically in front of the air conditioner so the air flow passes across it could get you out of further trouble until a more sophisticated solution is found. It might also help you to evaluate that this is indeed the problem. I appreciate that ACs mounted high on the wall might present some challenges to achieving this. Improvise.

Regards
Paul