Monthly Archives: November 2009

– Coating icky contaminated floors

Here’s a sneak peek of our forthcoming useful tip in our December newsletter HUMMINGS- (Issue 17).

We do harp on a bit about some topics but they’re worth repeating. In this case,  the oily timber problem seems to be making an epic comeback.

Now, before anyone writes in to complain that we are saying nasty things about nice products which they happen to sell, like Brush Box, or Spotted Gum, let’s be clear: We love timbers like Brush Box and Spotted Gum. They are beautiful timbers and we love to see them on floors.

And this, folks,  is exactly why we like to help our contractor customers face the cold, hard reality that certain species are chock full of natural oils and saps which wreak havoc with conventional and popular coatings such as single pack, solvent-based polyurethane.

We like to know that they are being finished to the best standard in order to promote their beauty in the homes of the consumer. Because they are beautiful timbers, did we mention?

The fact is, modern exotics are chopped down younger than in previous generations and they retain more immature saps as a result. These oils and saps like to reject solvent-based, single pack polyurethanes as well as some two-packs .

When the contractor’s customer (builder or home-owner) announces they have installed Queensland Spotted Gum (or whatever)  you have two choices. You can either run away screaming, or be prepared.

Firstly, DON’T finish on too fine a grit.  A 120g screen is as fine as you’d want to go. No 150 or 180 paper. Finishing too fine literally draws the oils to the surface with all the heat and activity. It “burnishes” the oil across the face of the timber, spreading it around like a glaze. Also, the more closed the grain, the less adhesion the coating will have. Will all those contaminants around, the last thing you should be doing is limiting the scope for adhesion.

The conventional wisdom of washing the floor with solvents, thinners or metho seems to be less effective these days. Firstly, on bare timber, you have the same problem as above; drawing the oils to the surface. This is fine if you can then disperse them. But solvent/thinners/metho wipes on a first coat will be just as disastrous. The key here is to a) disperse whatever contaminants are on the surface and b) make sure the first coat is nicely cured to lock in whatever contaminants are under the surface. Too much solvent will reactivate the coating.

Which means the floor will be better off with a hot soapy bath (who isn’t?). A quick warm mop with a water-based floor cleaning solution specifically for timber floors (such as Arboritec Floor Clean). Then a wash with cold water is needed.

The soapy wash gets rid of the contaminants. The cold water wash “snaps” the moisture curing coating and ensures a clean, powdery cut back. The last thing you want is a tacky, reactivated coating which will fail to prevent the rise of more contaminants.

We these tips in mind you should be able to approach both the pre-coating phase and each coating phase with enough preparedness to avoid a disaster. There is never too much preparation for this.

Don’t forget to compliment the homeowner on such a fine choice of timber :).

Comment with your experiences or ideas.