Thread: Kauri Pine flooring - advice needed

I'm not familiar with KP either. Weird effect, looks like someone spilt some bleach

Originally Posted by highlnader-7

Hoping someone out there can help. We have just had our 100 year old Kauri Pine floors sanded and finished in a 2 pac water based polyurethane. The sanding is fine and the finish is just as we hoped, however the timber itself appears quite ‘blotchy’ in places (aside from the natural timber variations) and we were told by the floor contractor that this is normal for Kauri Pine. We’ve had a number of floors sanded and finished in the past and never seen this before, admittedly haven’t had kauri floors before. Can someone confirm whether this blotchiness is normal or not, and if there is anything we can do about it?
kauri.JPG

I have seen a fair bit of K.Pine over the years,and never seen it 'blotchy'..it has fairly plain,consistent grain,which is one of the reasons it was once a very popular cabinet timber..i think something foreign may be responsible for the 'blotchiness',as opposed to it being there inherently..MM

Thanks guys, it certainly is weird. and its not contained to one spot either - the photo was just an illustration of the worst area.

mmm I think it's a bit of a stretch to say KP is typically blotchy, I have recycled/reused some well aged KP floor boards and didn't see any of the blotchiness you have there, more typical of most timbers is unevenness in finish where you have grain changes, if you are looking at an area around a knot for e.g. and this usually is most evident in the first few coats of finish, with subsequent coats the finish becomes more even, a similliar effect to what you have there is when you sand through a following coat in preparation for the next coat.
Just purely looking at the pic, it looks like something has been spilt on the original boards and is now showing it self or maybe it has reacted with the finish, hard to say definately.
Might be worth a phone call to the manufacture of the finish, they usually have a help line.



Pete

My 2 cents.... it looks to me like the light patchiness might be old varnish that wasn't sanded off completely. Was it previously varnished or raw? I've even seen residual shellac look like that.

Kauri pine flooring which has been finished properly will sand and finish very cleanly. However unsealed kauri will absorb any spillage. If the floor has been waxed or oiled rather than sealed with a flooring finish the oil will penetrate deeply and cannot be sanded out. Similarly if the original finish has worn through in places and then not resurfaced immediatelly it will colour unevenly if not sanded deeply. Looks like unevenly sanded previous varnish to me.

Originally Posted by Benmanang

Kauri pine flooring which has been finished properly will sand and finish very cleanly. However unsealed kauri will absorb any spillage. If the floor has been waxed or oiled rather than sealed with a flooring finish the oil will penetrate deeply and cannot be sanded out. Similarly if the original finish has worn through in places and then not resurfaced immediatelly it will colour unevenly if not sanded deeply. Looks like unevenly sanded previous varnish to me.

We have a very similar problem to the one in the attachment photo. We had two rooms sanded, sealed and given 2 polyurethane coats.The sander doesn't want to take responsibility for it, and says it can be a problem with kauri pine and baltic pine and he can't guarantee that an additional coat would solve the problem. He said that when they put the sealer on, it looked fine, the patches only emerged after the first coat of polyurethane. He is suggesting we add a coat of a wax-like product called Gemini - has anyone any thoughts on this? One of our rooms (hallway actually) had been previously sanded at least 10 years ago, and the other was raw and has probably been covered with carpet since the house was built in the 20's or 30's. Both areas are showing the problem, it seems to be randomly spread on different floor boards, so it doesn't seem like a single spill could account for the problem, and we are pretty sure that when the previously sanded floor was done 10 years ago it didn't show the problem. We have asked the sander to try giving an additional coat to a small test area in a corner, so we are waiting to see if that would make any difference. Very frustrating, as overall the effect is beautiful with a very warm colour, until the sun shines on it!

my two rooms don't look like that (both are about 90 ish years old)
but then we oiled ours with organoil


PS i suppose neither sander person advised of possible blotcheness prior to taking on the job?

That's interesting, the sander mentioned Gemini but not Organoil. I see on the Organoil website that they have a very limited number of approved flooring specialists. Oil sounds as though it would be less slippery than a wax-like covering. And no, the sander didn't warn us, though he noted that it was kauri pine when he came to do the quote-