Splitting Floor Boards

[droberts]

We had our Brushbox T&G floor sanded and polished by a professional about 12 months ago. Over the last couple of months a number of the boards are starting to spit. Some of them are getting quite long (>1m) and in places pose a risk to getting splinters in the feet. It seems to run along the grain and is particularly bad on the groove side of the board. I guess this is the weekest point. Is it the polyurethane gripping the adjacent board and ripping the thinner wedge of the groove of the board. Is there anything that can be done to arrest this problem from getting worse?
Dave

[behindblueeyes]

This is a problem called edge bonding.

It occurs when a super strong floor finish (such as a two pack) is used.

It is most prone to environments where the timber is subject to movement (ie humidity, and rapid changes in climate). It is also more common with new flooring timbers than old.

Because the floor finish is so strong, it bonds the timber together removing any chance of the timber being able to move. If the timber is unable to move, then the timber is put under stress, and the weakest parts of the timber give way.

My advice would be to get this professional to return and remove the finish.

Replace the cracked timber and recoat it with a tung oil type product that will allow the timber to move.

However, because it is not as stong as a 2 pack, it will require some maintenance in the form of polishing or recoating with tung oil down the track.

Find out what product was used, and confirm with that particular companies customer service line before taking any action.

All the best.

[droberts]

Thanks for your feedback. I was certainly shocked to hear your suggestion to remove the finish and reapply a new one. Is this the only solution. Is it possible to apply some sort of oil eg. Linseed from underside of the floor (highset house) to try and reduce the seasonal swell and shrinking?
David

[behindblueeyes]

It certainly is drastic action that I suggested. And to be avoided if at all possible - obviously due to the time and cost associated.

Hopefully someone with a bit more experience than I can teach us both a thing or two.

[Theva]

Droberts,

Need more info:

1) Is the flooring new or old?

2) If new, was it installed by flooring mobs or DIY? How is it attached to the joists?

3) How is the sub-floor ventilation? Is the house in tropics, subtropics or in colder area?

These will help in making informed comments.

Edge bonding happens in new boards if they are not cramped properly. Even if you remove the surface coating, the bonds between the boards along the T&G will remain.

More comments later.

Regards,

Theva

[KevM]

Dave,
Might be a bit late now but have a look at this link. http://www.tastimber.tas.gov.au/species/pdfs/4pgdoc.pdf

It will explain what might has gone wrong when the floor was laid or finished.

Kev

[droberts]

Theva,
In response to your earlier questions, these are some of the details.
The floor was the original done when house was built approx 30 years old. As far as i am aware this would have been done by a builder.
As for how are they attached to joist, they are nailed with one nail approx in the centre of the board at every joist.
The house is highset with a garage underneath. We are in South East Qld (sub-tropcial).

Thanks for your interest. I spoke with the profeesional that did the sanding / finish and he explained this problem was unavoidable as we have been experiancing a long hot year. His only suggestion was to try to increase humudity under the house (enclosed under) by putting buckets of water around the place. Until it rains he said this was the only option?
David

[Theva]

David,

Edge bonding is more likely in new flooring. If your boards were installed thirty years ago, then there will be sufficient muck in the T&G to stop two pack poly getting in and cause edge bonding.

Most comprehensive information on flooring can be found at the following website:

timber.org.au and look up flooring.

There is a 1.8 meg pdf file on flooring.

At present, controlling moisture in the boards is seems to be the only option.

One option is to give it a water spray from underside.

If you want to try this, then add some pesticide to take care of timber are other pests (one gram of premethrin per lit of water) and boron to prevent,fix rot, fungi etc (boracol-400, diluted to 25% strength).

These chemicals are used in pest control and termite treatment applications. Finish it with warping the underside with house warp type foils ( eg-Sisalation 438 with reflective foil facing downwards) tagged to joists & boards.

This will also improve the thermal insulation.

Applying linseed oil is not advisable because, this provide food for fungi and other pests.

Hope this is of some use.


Regards,
Theva

[droberts]

Thanks for your feedback Theva. There are a few points there. Are chemicals for termite treatment available. I had done a bit if internet searching but didn't come up with anything. I thought these chemicals were restricted from the public, explaining why pest controllers charge so much. I was looking to try and set up some bait stations to try and nock out the nest. There are various suppliers of these bait stations but again they charge a fortune to check these things every month and then extra yto treat the termits if they get in the bait tube.
David

[Theva]

David,

If you are using bait stations then I presume that you have or had termite problems. If these buggers are around then they are best handled by the pros.

The chemicals used in bait stations are highly toxic (arsenic trioxide) and only available to pest controllers; you wouldn’t want to mess with them anyway.

If you are after preventative treatment and installing a perimeter chemical barrier, then the required chemicals can be obtained from pest control suppliers. BCA covers guidelines for termite management in & around existing buildings(Australian Standard 3660-part 2).

Recommended termiticide for sub-terrain termite barrier is bifenthrin. This last for years or more (if soil is not sandy or not subjected to water run off). Dosage is 1g to 1.5g /l it of water, 2.5 to 5 lit of solution injected / mixed into sq m of soil. The barrier area should be min 6" wide, and to a minimum depth of 2" below the top of concrete foundation. This barrier (or other barriers) should cover every possible access. Pro quantities- 5 lit of 100g/l cost $300 + GST.

For dry wood termites - premethrin, 1g/l to 5g/l. It is also a multi purpose pesticide. Chemspray brand permethrin 100g/l 500ml is available at Bunny's gardening section for app $35. Pro quantities -5 lit of 500g/l cost around $350 from pest control suppliers.

Suppliers- try Globe Aust-07 55373688 in SEQLD

useful links on termite treatment method (in schools):http://www.eduweb.vic.gov.au/hrweb/ohs/pdfs/Termites.pdf


Some research info on termite behaviour & treatment: http://www.build.qld.gov.au/research/BrDocs/termiticides/termiticides_section01.pdf

Pros & cons of traps - termite baiting (http://www.forests.qld.gov.au/library/tn43.pdf)

Regards,

Theva

[Spike]

If you are thinking of some termite traps take a look at

http://www.termitetrap.com.au/index.html

I have'nt used them, I found this link in ABC Gardening magazine some time ago.

Cheers
Spike

[katric]

Hi DROBERTS,
I'm new to this site too and have been taking a while to read all the posts. Have only just read about your flooring experience. It's (frustratingly!) surprising how much wood can contract and expand with changes in humidity ... even very aged timber. I imagine that removing old floor coverings might have caused your floors to dry out more than usual. I'm in the process now of trying to find a suitable finish for our old timber floor and would prefer not to use the 'hard' products for the reason you've described. But I don't know how difficult the oiled finishes are to maintain. We get a LOT of dust here. I imagine you've probably sorted out your problem by now but was wondering if it would be worth getting the guy back who did the floors in the first place. Being the 'expert', he may have some advice, even if it's just to sand back again and refinish ... filling the splits with the finish as well. Just a thought. Lets know what you decide to do, anyway.
Good luck.
K