I was helping a friend refinish the hardwood flooring in an old rental house (built in 1915) and the oak strip flooring is very dry and brittle…would coating it with boiled linseed oil before we topcoat with Poly be a good idea?
Also, would Waterlox or some other tung oil based varnish be a good idea?
What about thinning the first coat about 30-40%?
I’m just concerned about sealing the wood well and trying to keep it from getting any more brittle. Any help would be appreciated.
Thanks!
Chris
Replies
Greetings E,
This post, in response to your question, will bump the thread through the 'recent discussion' listing again.
Perhaps it will catch someone's attention that can help you with advice.
Cheers
The bitterness of poor quality remains long after the sweetness of low price is forgotten.
Thanks!Chris
Chris:
I don't believe the type of finish you use will appreciably affect the moisture content of the wood itself. Wood's like a slow-to-respond sponge: it wants to reach equilibrium with the environment around it...
I'm guessing that fairly old flooring, particularly in a rental environment (which implies that maybe it hasn't been consistently cared for), may have experienced a bit of "trauma" over the years. My guess also is that the brittleness you're referring to is actually splits/cracks in the wood? If so, splits/cracks are aggravated by defective wood, improper or non-uniform drying, or by being subject to repeated wet/dry cycles...
Wood mostly soaks up (and releases) moisture through its' end grain, although I believe "open pore" types like oak can also exchange a fair amount through face grain. Applying a sealing-type finish on the top will effectively retard (or really slow) the exchange through this one face, but have little effect on any exchanges happening through other surfaces...
I'm afraid that if the stuff is brittle, cracking, etc.. and that this is unacceptable to you, you might have to replace it...
If it's not that bad, your optimal choice of topcoats would be more driven by the finish appearance you're after, and the amount of ongoing maintenance you wish to perform...
I've had very mixed luck topping mostly-oil finishes with poly - sometimes it turns into a gooey mess when the varnish won't "cure" properly. If you're considering this I'd strongly suggest experimenting first. Humidity, temperature, oil/varnish/thinner ratios, manufacturer compatabilities, and practically even the phase of the moon all seem to effect the results...
Mixing oils with varnishes can work, but can also yield variable results. In theory, the oil can give you the penetration while the varnish can give you the protection. In practice, your results can vary widely...
For an implied "rough and tumble" rental situation, I'd stick with a good quality (high solids content) polyurethane. I'd use an oil-based one, and I'd thin the heck out of the first coat or two. I'd then top coat it with the same stuff, only not thinned much if at all. Apply as many coats as you can afford, and that achieve the desired appearance (2 thinned, 2 non-thinned probably ought to do it). If you decide to use a water-soluble varnish, I'd be more careful about thinning it - I don't have any experience with this, but I've gathered that it can be problematic (you might want to surf some woodworking forums, particularly that discuss finishing techniques and methods)...
Messing with oil blends will give you a little bit of "yellowing" richness, and will give you a little bit of color penetration into the surface of the wood itself (scratches might not be quite so visible later on). But if you're topping it with poly anyways, and you're not after the "hand rubbed" or "close to the wood" sort of finish, then why bother?
I can't see how any of these considerations will appreciably affect it's moisture content, however. Now... Adding a humidifier? Ripping up the floor, putting down a moisture barrier and re-applying the floor? Dipping the ends of each oak board in wax? All of these might have a more significant effect...
ps., most of my comments are based upon woodworking/cabinetry experience, and I'm extrapolating this to a flooring situation. It's the thought process I'd apply if it were my floor, but I'd hope that others more experienced with your specific situation will weigh in additional inputs... Good luck with your project...
w-
great post.View Image
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John RuskinAndrew Clifford of Clifford Renovations, who serves as a steward of our history for future generationsWe can imagine something that only exists in our heads, in a form that has no measurable, tangible reality, and make it actually occur in the real world. Where there was nothing, now there is something.Forrest - makin' magic every day
I'm thinking the percieved "dryness of the oak flooring is from the release of the natural volatile oils in most woods. Some have more than others to start with. a polymerized oil that will cure slowly will have time to penetrat the pores and harden, strengthening the fibres. Red oak is very porous, and displays its brittleness in pold floors more than white and would benefit.Another possibility for some cases would be the Minwax wood hardener, but that would be prohibitively expensive for a rental, and dangerous to boot, both to breathe the vapours and in the event of a spark while the air is saturated with the VOCs
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white oak or red?
With white, I would not worry too much aboot it. With red oak, it will suk a lot of oil down into the pores.
Waaterlox good thing, linseed is a complication
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With todays eurethanes, specifically the prevelence of water-based, linseed oil is never recommended for a hardwood floor. Because of it's greasy nature, linseed oil never really dries but rather absorbs dust and dirt which gives it a dry look and feel; however it does not provide an adequate bonding surface for eurethane, especially water-based, and will result in peeling and chipping in a relatively short period of time, especially in high traffic areas.
that's why I aid it would be a complication
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Thanks to everyone for the reply...will try waterlox...THANKS!
C
I'd plan on moving out for a couple days. Love Waterlox Tung Oil finish on my Reclaimed yellow pine floors but that stuff reaks- be sure to get a proper respirator and vent well.
it does take time to cure, but there are those of us who like the smell!
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So now we know why you have CRS.
seeyou invented CRS
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John Ruskin Laminate is just a picture of hardwood printed on countertop for your floor.We can imagine something that only exists in our heads, in a form that has no measurable, tangible reality, and make it actually occur in the real world. Where there was nothing, now there is something.Forrest - makin' magic every day
Yes- you and Claude Monet. I believe I saw on Discovery the origins of Impressionist painting go back to those fumes!
Around here our first coat of a poly floor finish is a sanding sealer, not thinned. Our wood moisture content stabilizes around 6%-7%, so we're as dry as most of Arizona and thinning wouldn't improve over the results out of the can. If it's doug fir we'd definitely thin the first coat, but oak doesn't seem to matter. All flooring guys we've been in contact with have said the same.
For a rental I don't think any of our flooring guys would use anything other than an oil-based polyurethane. It's a simple system with a proven track record.
most sanding sealers I have used have a label that recommeneds - "Do not use polyurethene over this product" and many polyurethenes in their dat sheet say not to apply over a sanding sealer.I investigated this, having already applied it to some work that was going to get poly.Apparantly, theere is wax in the SS that prevents good bonding between coats. They recommend that you wait a minimum of 30 days for the SS to fully cure and/or sand it enough to create a mechanical bond between coats. We normally sand between coats anyways, and this was some woprk that had already been a good three weeks since the SS.We used to use it on floors as soon as laid, to prevent staining from dirt, spills etc. and to keep it from absorbing moiisture. My floor finishing guys asked if I would refrain from that practrice, as they always noticed that SS will clog their belts and discs of sandpaper more quickly.Now, we normally copat all four sides of flooring with dewaxed shellac before instalation. It really helps with keeping the wood stable.
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Now, we normally copat all four sides of flooring with dewaxed shellac before instalation. It really helps with keeping the wood stable.
Piffen - Waz a "copat"?
Don K.
I can't believe somebody pee-ed in the middle of my wonderful posting
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Shellac on four sides would probably also help if anything was spilled on the floor and somehow managed to get under the poly between cracks...I've often thought about sealing the back and edges if I ever install wide floor boards.However, I've also heard that shellac will cause problems if installed under an oil based poly because the poly is harder and the shellac will flex more on a floor. I used to work in a paint store about a million years ago and it seems to me that we had some floors fail when they were done with shellac under poly.Ever had any delamination problems?C
We do a lot of wide board work. The shellac goes on before installation. So the floor finisher sands it back off the top before using the poly, stain, Waterlox or whatever is going on.
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Just watch using shellac under Waterlox. I did this and had a much longer dry time for the Waterlox than expected, and also didn't get the penetration that Waterlox really needs for best performance.
Hi, thanks for that mention. Help me learn more from it...Are you sure it was from the shellac?
How long did the shellac cure first?
Was it dewaxed shellac?
Had you used waterlox before or since to compare?
What waas the basis of "what I expected"?waterlox does take much longer to cure than any other floor finish I know of and it is very much ifluenced by humidity and temperature, as well as air flow.
It needs oxygen to cure. Without a ready supply, it will take longer to cure well.
For instance a small place with the windows all closed up in a chilly humid location might take a week for a coat to cure...
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Are you sure it was from the shellac? How long did the shellac cure first? Was it dewaxed shellac?Had you used waterlox before or since to compare?What waas the basis of "what I expected"?
What else could it have been?
Zinser Bulls Eye dewaxed
cured for at least two weeks
Hadn't used before, but took at least 3X to dry as what it said on can...also Waterlox tech support guy said NO sealers recommended under Waterlox. But I had already sealed all sides with shellac and went ahead anyway with the Waterlox....it wasn't really disasterous, but the results were not up to what I expected from advertisements and what I read about on this BB. I can only blame the shellac.
Thanks for the reply and infor.
What else?
I did make some suggestions.
But if their tech support said so, I'll listen.It may have been my recommendations in part that led you to this methodology, but Mayeb I was not clear that I seal with the shellace before installation and then the floor finisher sands it off the surface before finishing. Sorry if I failed to be clear.
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Oh that's quite alright.
Incidently, FWIW< and this may have something to do with it as well, I used the rather unorthodox tehnique of cutting oak veneer plywood into 2X2 squares, champfering the edges, coating with shellac, installing over Advantech (Piffen screws and plugs), scuff sanding with an ROS, and then laying on the Waterlox.
MeThinks that the plywood veneer may have soaked up MORE shellac than a solid hardwood...and I couldn't sand very aggresivly, of course, with that thin oak veneer.
Anyway, I had done another floor the same way except used poly over the shellac and it worked great.
Everyone that sees these floor loves them and the technique, by the way. Kind of like Old Navy or Chipotle's kind of effect.
I've never been in either kind of store, so I can only imagine the efect it has on people.I am absolutely sure that using this method on veneer plywood had much to do with your results. You see, the surface veneer is very thin and immediately behind it is a layer of glue that is practically a moisture barrier. The only wood to treat with Waterlox was the thin veneer which was encased between partial shelac and glue. That is afar cry from the solid wood antique and new wide pine flooring I have used it on.
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That "style" expressed in stores like Old Navy and Chipotle's is kind of minimulist, with counter tops of galvinized steel, lots of birch plywood with laminations exposed and finished, display racks of theaded steel pipe and fittings, stained and sealed concrete floors, etc.
I've noticed that some of the clear coat finishes explicitly say to not use over shellac.And if you are going to seal with shellac, why not just go for a shellac finish? It was common for years.
It was, but it does not weaar well undser foot traffic.
Whih is why waxing floors twice a year was also ommon for years
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The problem with that idea is that shellac is harder than poly. The problem with shellac and poly is the issue of whether the shellac contains wax. Poly should have no problems adhering to dewaxed shellac.
That said, for true floor finishes, including oil based poly, why improvise. The finish manufacturer probably makes its own version of a sanding sealer designed to be compatible with its own finishes. READ the manufacturers technical instructions and follow them. Floors are too tough to correct if there problems develop to go off based on the advice of an internet forum.
Sounds like you don't have too much confidence in Breaktime.But you make a good point, one I repeat dozens of times every year. Too many builders read the instructions only to try to figure out what went wrong after the fact.
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The sanding sealers that I've used on floors are almost always from the same manufacturer and designed to be used together with the polyurethane.
Essentially the only benefits are it doesn't need to be thinned to soak in well and it dries quickly. I can't imagine there's anything wrong with using thinned down poly or another product for the first coat as long as the poly bonds to it well.
There was an interesting quirk about sanding sealers that we wouldn't have thought much about. After running out of a certain lot # of SS we finished the house with a slightly newer can from the same manufacturer. The color imparted by the two SS were completly different and the floors with the slightly older SS had to be stripped to fix the problem. We must have hit a slight reflormulation since the consistancy for a number of years prior and since have been quite good.
Beer was created so carpenters wouldn't rule the world.
Yep, one thing about SS is that it is cheaper and easy to use, but inconsistant since it's primary purpose is not fopr coloration, but for sealing.BTWE, I have not used SS in 5-6 years now and all finishes are getting to be low VOC. Are the newer SS that you use a water based or the old wicked smelling stuff that can give you a headache times ten?
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Are the newer SS that you use a water based or the old wicked smelling stuff that can give you a headache times ten?
We're using the older solvent based stuff, although the older and wiser we get the first step has become getting the resparators on.
I have been impressed with the water based finishes and it sure seems like that's going to be the way to go as the formulas get better all the time. We're stuck in the past, but the older system is reliable, economical and produces good results with the few sporatic floors we do (maybe two a year).
Beer was created so carpenters wouldn't rule the world.
" Our wood moisture content stabilizes around 6%-7%, so we're as dry as most of Arizona "Not exactly.IIRC 6-7% if the equalized moisture content of wood in most of the US. It willonly get up to 8-9% in the most hummid climate.It is not the same as the RH of the air.
It is not the same as the RH of the air.So true. I am amazed at how many people cannot grasp that "relative Humidity" is way diff from actual moisture content
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IIRC 6-7% if the equalized moisture content of wood in most of the US. It willonly get up to 8-9% in the most hummid climate.
If anyone were to take monthly moisture content readings of the interior framing of their house and average it out, few locations outside the southwest would produce 6%. The banana belt strip that goes a bit north of boise is the farthest north that 6% is common. Anything north of that is at least 7% as is most of Wyoming. Northern Colorado is mostly 7% from what I've seen.
At least to a finish carpenter in the rocky mountain region 8-9% is miles away from what we have here. I take that back, we had a flooded hardwood floor completely buckel and pull off the floor at 9%. :-)
Beer was created so carpenters wouldn't rule the world.
9-10% is more normal here
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We did order in some high mc southern yellow pine flooring from the southern coast for a big mountain home where the owner wanted a rustic floor with big gaps full of black dirt and debris. The 6" flooring ended up with something like 1/8" gaps. The client was thrilled. Go figure. :-)
Beer was created so carpenters wouldn't rule the world.
Yeah, I was building one in '99 while next lot over had a bigger one going in. I walked over one day at lunch to visit the lead carp there. They were laying floors that were rough cut from old hemlock. Looked just like an old barn floor or a subfloor from fifty years ago. Asked him, "So, when you gonna lay the finished floor?"He made a face and said, "Yer walkin' on it"
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I'd think a floor that rough would catch a lot of dirt...but maybe that is the idea...
Chris
In another house,I just replaced one last winter. They could not use a mop or walk on it in stocking feet.. The only way to clean was with a vacumn.
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Quick question, I am going to be installing prefinished Bruce/Armstrong 3 x3/4 plank in my living, dining and kitchen area. In the kitchen area am wondering if I should seal the bottom/sides/ends with shellac to reduce the chances of damage from water spills? Or is there a thin sealer that could be applied over the finished floor to prevent liquids from reaching the bare wood between the boards that will not react with the factory finish.
Thanks in advance
Jim