Cupped pumpkin pine floors

[Melanie Rys]

Hey everyone!

My husband and I have purchased a beautiful 1780 house and need some assistance. We have completed the major items (all new electric, roof, structural, septic and plumbing) and are now moving on to cosmetics.

The pumpkin pine floors are gorgeous but areas have heavy damage from the previous owners pets. Just scratches, not waste products thank goodness. The majority of the floor is beautiful and shiny with the classical orange patina. Other areas are down to the bare wood, large areas that can't be hidden.

Here's the rub. I had the local guy who specializes in these floors out and he said because of the cupping he will have to take "quite a bit" off the floors. The boards are random width but up to 15" wide and a little over 1" thick with cupping up to .5 inches. That's a lot more than I want to take off, as the floors have quite a bit of bounce already and it would take them millimeters away from the T&G.

I'm willing to live with the cups, They don't really bother me. I'm looking for options to fix the wrecked areas without taking up to a half inch off the entire floor. I understand that a traditional floor sander won't be possible. I'm willing to do it myself by hand or by any other method that will save the majority of the wood. This is where I need suggestions, I'm not sure where to start.

Thank you so much for reading this extremely long post!! Any tips or suggestions would be greatly appreciated.

[peter gagliardi]

First, it sounds like you need to control the humidity levels. One in the house, and a bigger one in the basement will go a long way towards remedying this.
After that, you could sand out the areas with a small but agressive sander like the Festool Rotex 150 on the agressive setting. You will need/want it hooked to their vac, this will ensure virtually dust free working inside the house.
I regularly use mine when patching in a floor, or adding a small area in an existing house.
It works very well, and the people are amazed they don't have to dust the whole house, or rewash all the dishes.
I can't recommend this system enough for exactly your needs and wants.
I have even sanded entire floors when laying hardwood in small bedrooms etc.

[ed morini]

One of the biggest mistakes is to put a conventional floor sander on one of these floors. Its asking for trouble. The cupping in the floors is, I believe, due to the natural condition of the wood during the humid summer months. I do agree that dehumidifying the area under the flooring goes along way to control the cupping. I have wide oak floors and can tell the humidity level by the gap in the seams. Having said that, the winter dry air should help the situation.
There is no practical reason to try and flatten the floor through sanding in this case and I would venture a guess that the cupping will reappear the following humid season.
Best practice is to scrape the surface to new wood and refinish, although not many are interested in doing this anymore. Second would be sanding as directed above with a sander that will remove the finish but not re-contour the floor. You may find, depending on the age of the finish, that the disks will fill rapidly, usually indicating a varnish finish. The urethane finishes can be quite problematic. I find, a well sharpened scraper does a good job of getting the finish off the wood without sacrificing its thickness. I f a floor finisher is recommending a floor sander on these floors I would pass.
Agree or disagree with the above, but I would not recommend a floor sanding machine on those floors. JMO

[Melanie Rys]

Thank you both so much. So you think the floors will cup less once we are dry?

We tore out the slab in the basement and are pouring a new one with proper underlayment as soon as the under slab plumbing is inspected (next week). This and finishing the pointing of the exterior will drop humidity levels in the basement a ton I hope. If the floors go back to flat-ish that would be great.

[ed morini]

Those improvements will certainly help with the moisture issue. I would add a plastic layer over the dirt that is going to be concreted. The concrete will take longer to set up but the plastic will inhibit the moisture from coming through the floor. Depending on the size of your basement, you might need two dehumidifiers to accomplish a real moisture control situation. Because mortar is not waterproof, each joint in the stone foundation will allow moisture intrusion. In effect you'll be drying the area outside the house also. You may also experience more cupping in the floors when you pour the concrete, as it will add a serious amount of moisture to the house while the concrete sets up.
It's getting later in the year now and the humidity levels will begin to drop, causing a drop in the moisture content of the wood in your home. The floors should start to dry, and reach their equilibrium moisture content ( that level where the wood and the surrounding atmosphere are the same)consistent with the surrounding atmosphere, and the cupping should start to diminish. It hard to say how much, but in mid winter around here in Massachusetts you might hit a moisture content of 8% maybe a little lower depending on your heating system (forced hot air is drier unless equipped with a humidifier), at this point I think you'll see how much of the cupping is eliminated.

[Nike Nihiser]

To keep moisture levels down in the basement make sure your gutters have good drainage sloping away from the house. It's a good idea to extend the gutter drainage tube at ground level at least 4 to 5 feet away from the house also.

[John TenEyck]

I would add to those who said to essentially do nothing until the basement moisture is well controlled. You won't really know the natural shape of the floor boards until you establish equilibrium relative humidity in both the basement and upstairs. You don't just want to lower the RH in the basement; you want it to be the same as upstairs, within reason of course. Put RH gauges upstairs and down, and try to get it within 10%. The actual value is not nearly as important as both being the same. After you accomplish that, it will likely take weeks/months for the floors to come to their equilibrium with that. Then you can determine what actions to take with the floor.

John

[Thomas L Carpenter]

Wouldn't sanding remove the pumpkin pine patina as I believe it happens on the surface and not throughout the entire thickness of the wood?

[Jim Becker]

To preserve the majority of the patina, the damaged areas will have to be fixed by hand...Trust me, you do NOT want to sand the life out of those floors. The previous owner of our property did that and my foot went through a board a few years ago, prompting me to have to completely replace that room's floor with new white pine that I then had to hand finish to more or less match the rest of the wide-pine in our home.

For the repair finish work on our floors, I used my Festool Rotex 150 and Festool 150/3 sanders to do what's necessary...down on hands and knees.

[Sam Beagle]

I'm a floor guy too. I'm in pa where I'm constantly doing old pumpkin pine. (Which if anyone is wondering) is actually a gorgeous old white pine that takes on awesome color. Black, red, brown, even some silver sometimes.
When I encounter these floors, which was last week for me. I always use a 10" belt machine. Basically all your doing is flattening what wants to be flat and allowing the concave areas to keep the old finish. Just keep right going like a standard restoration. After your final sand. Whatever is left, you get a good scraper and file and handscrape all the remaining content. Lastly you hit those areas w 80-120 grit paper and buff the whole floor off using a square buff. Do not use a rotary buffer. It will tear the floor apart. Use a square buff. Any questions PM me.

[Melanie Rys]

Wouldn't sanding remove the pumpkin pine patina as I believe it happens on the surface and not throughout the entire thickness of the wood?

Yes, but huge areas of the floor in high traffic areas are already missing the patina and down to the bare wood unfortunately thanks to the previous owner's big dogs with long claws. 😣

[Michelle Rich]

If the floors do not stop cupping, would it be possible to remove the cupped boards, rip them and replace. This takes cupping out of boards so one can use for
furniture..why not floors?

[Jim Becker]

If the floors do not stop cupping, would it be possible to remove the cupped boards, rip them and replace. This takes cupping out of boards so one can use for
furniture..why not floors?

Simple answer...the primary visual attribute of these floors is "wide pine". Ripping them would completely destroy that. Wide pine floors, common in this area of SE PA, date back to the 1700s sometimes...

[Mike Cutler]

Melanie

Old houses have "charm", but that charm can sometimes cause problems. My house was built in 1919, with a dry stone piled basement. not anywhere near as old as yours, but even it has it quirks.

I agree with the others, that before you do anything, get your humidity under control and see what you have when that is done. Put some inexpensive throw rugs and runners over the damaged areas.

If the floors are original, you have moved away from a traditional flooring business. You're looking for "that guy/gal", and they do exist, that isn't as interested in getting your floors flat as quickly as possible, but rather working with what they have to preserve the historical charm. It may take a couple of seasons to "tighten it back up", but if you're patient, it will be worth it.

If you're willing to do the work yourself, start with a random orbital sander and work the most damaged ares first. Use a higher grit, say 120 and above, and just go slow. To abrasive a grit, will remove material too fast for your experience level. Avoid the siren song of the hand held belt sander. If you're not really experienced with one, you can really muck up the floors worse than what you already have to deal with.
Make sure you have the sander hooked up to a vacuum,( There are many systems available) and wear a dust mask. The finish by itself, and years of grime, dirt, animal dander, bacterias, and who knows what else that will come up, are much, much, worse than just wood dust. Protect your lungs.
,
Contact a professional finisher to reapply the floor finish when you're done. Start small and teach yourself as you go and you'd be amazed at what you can accomplish. Just go slow!

BTW
If you were to ever choose to replace that floor, you have no idea how much money those boards are worth. Cupped, damaged, and all.

[Marc Jeske]

These are my thoughts, factually based but still subjective..best way I can explain it.

To save the most floor wood, and best end result refinish, it will take about 1 year..as follows......


Pick about 5 - 10 representative spots on the floor where the cupping is severe.

Mark them semi permanently so that foot traffic will not obliterate your locations, then lay straightedge across the board at the mark.

ACCURATELY measure cup depth, and document.

Do this in about 5 - 10 places.


Now redo the concrete, w at least 6 mil poly under.


After placement, let the concrete "flash off" (my choice of words) for about 18 hours, THEN --- Gently FORCE VENT for 20 - 30 days so the moisture leaving the fresh concrete does not hang around in your basement.

Now, some may say that for quality of hydration of the new concrete, the venting I suggest may possibly be deleterious.

That is true, and I'm not a concrete curing expert,but I don't know how else to keep the floor above from gaining moisture from the concrete.

My venting may prevent the concrete from reaching total max strength, but for a basement floor, not a rocket launch pad, I think totally fine.

I would do as I'm saying and feel comfortable.


An even better option, would be to like staple a 4 mil poly barrier under floor temporarily, and WAIT to vent for about 1 week, thereby giving concrete more time to hydrate.

Pull down the poly after maybe 2 weeks of venting.


Once a month after concrete is done, re measure those 5 - 10 cups, and document to see if you are returning toward "flat"

After a few months, I would expect to see progress, albeit very slow... Accurate measuring is mandatory to avoid "doubts" of what is happening or not.

May take (SWAG) up to like 9 + months to return to YOUR ambient equilibrium IE maximum flatness in your installation and specific situation.


You are probably in the US NE ? Heating the basement within reason the warmer the more accelerated your anti cupping progress.

Once you have a FEW months w NO change of cup depth, THEN, NOT before, refinish your floor.

So, it will be a solid year + till you can redo the floor.

You can only somewhat accelerate the process w the air venting, then the heat, but it will still take time.


Anyone w improvements to my post please feel free to add / correct it. Marc