Recommended floor condition for radiant over heart pine plank

ethicalpaul

Hi all--

The radiant floor I put in my bathroom under tile using Uponor Quik Trak went so well and is so nice that I want to add radiant to my living room and adjacent dining room. This is not for primary heating, but just for comfort. I have a nice operational steam boiler providing primary heat (and the hot water loop) to this 1200sf two story house built in 1915.

My floors throughout the house are heart pine 2.5" tongue and groove nailed directly to the joists. They are .790" thick currently. No subfloor at all. See existing floor below:



If I were a single man I'd keep the original heart pine, refinish it, and use extruded plates underneath (the underside is readily accessible in the basement, wide open). But my wife wants new wood floors. (or you can help me to convince her otherwise)

So I think I should use Uponor Quik Trak (or should I?). I know it doesn't really provide much strength since each piece is small and cut in half but maybe I don't need much more strength. After all, the existing floor planks are quite hard (they don't make pine like this anymore) and have served admirably for over 100 years. But maybe the plywood will prevent some interaction between the old floor and the new?

And there is a strong possibility I'm not thinking of something. Here are the questions I can think to ask:

1. Should I install a layer of T&G plywood over the pine planks? If so, what thickness?
2. Should I run the new floor planks perpendicular to the pine ones?
3. Am I missing anything?

Thank you!

hot_rod

That would be a very pretty floor to sand and have a tough clear coat put over, keep angling for that option.

How is the framing below? Adding the quikTrac and another wood layer over that adds some weight. Any bounce to the floor now? A 1920 home should have some true dimensional framing lumber, maybe oak joists?

Adding the two layers on top will screw with door openings, base trim, stair rise, any slide in appliance clearance, those are other labor intensive details to consider.

LS123

Hello, not much experience with radiant floors. If I had the original wood floor like that I would keep it... perhaps get them reconditioned..... but its your house. Check with few local real estate agents how valuable the original floor, and what you might gain financially ( in terms of increase value of the house, etc, by putting radiant floors over 100+ year old, original wood floor) best!

ethicalpaul

hot_rod said:

That would be a very pretty floor to sand and have a tough clear coat put over, keep angling for that option.

How is the framing below? Adding the quikTrac and another wood layer over that adds some weight. Any bounce to the floor now? A 1920 home should have some true dimensional framing lumber, maybe oak joists?

Adding the two layers on top will screw with door openings, base trim, stair rise, any slide in appliance clearance, those are other labor intensive details to consider.

These are helpful points, thank you! I agree, I'll keep working on permission to sand the old pine.

The framing below is 9-1/4" x 1-3/4" actual dimension, seemingly pine, but really dense, on 16" centers. They don't bounce. There has been a little settling noticeable adjacent to the central beams.

The door openings are all fine because to get to these floors, I had to remove burber carpeting, pad, a 1/4" layer of MDF with a million nails (that's all the ugly nail holes you see in the photo) and a layer of tar felt (that's the black staining).

The appliances are only in the kitchen and that floor is a different condition and won't be touched by this project (that one comes later).

LS123 said:

Hello, not much experience with radiant floors. If I had the original wood floor like that I would keep it... perhaps get them reconditioned..... but its your house. Check with few local real estate agents how valuable the original floor, and what you might gain financially ( in terms of increase value of the house, etc, by putting radiant floors over 100+ year old, original wood floor) best!

I agree, I'd like to keep the pine floors, I love original elements of homes generally. I'm not going to contact any realtors...then they'd have my phone number!

LS123

the floor would probably be beautiful once you get sand and a finish it. How many people get to say i have the original 100+ year old floor. My last house after I removed the carpets, I discovered a floor like yours, but there were more tar and also some nails...I was able to remove tar by using a product I bought from HD. took little longer to get the broken nails out..

It would be wonderful if u can put the radiant lines under the original floor..

... Agreed about real estate agents... I heard Walmart has a special sale on very good socks to keep feet hot, .... LOL best @ethicalpaul !

ethicalpaul

Putting extruded plates under the floor would be a piece of cake, the hard part is convincing the wife!

Here is a closet I refinished last year to make into a laundry room to give you an idea of what they might look like:

I would endeavor to do better in these main rooms.

LS123

floor looks beautiful!... I forgot t mention, I had to work little harder to get the tar between the wood panels... I had my then wife pick few areal rugs, furniture, curtains etc and a diamond earnings convinced her and we had to compromise... wish you best with the project!

Jamie Hall

Keep that floor. I normally wouldn't advise trying to advise a wife about anything, but that floor is far too good to cover up. Honestly you will never, ever find a new floor which will come out as beautiful as that one will be, at any price.

You can easily put your radiant plates under it. That will work very well.

A word about finishing the floor, once you sand it. There are, indeed, a variety of nice new floor finishes out there -- polyurethanes of varying sorts. Very attractive. Very advertised. If you can get far enough with your mission to be able to keep that floor, don't use them. Use clear or yellow shellac. Clear will maintain the colour of the floor (well, a little darker);; yellow will make it a little darker and more gold in colour. ;You will need at least two coats (three will be better) and be sure to thin it (denatured alcohol). The fumes (alcohol, no more harmful than a couple of shots of Scotch) are powerful, but go away -- completely -- in a few hours. You can walk on it (light traffic) in 12 hours and recoat in 12 hours, and heavy traffic or rugs are fine after about two to four days, depending on humidity.

LS123

hi @ethicalpaul

Totally agree with Br. @Jamie Hall and others....

Just a little tip about getting the tar that may be stuck between the wood panels...

the room I had to clean the tar was directly above the boiler room. that house was about 60 years old. three sides of the basement was above ground, all bricks, no trees near by and sun all day. so the house & the basement would get really hot during summer... ( I had my hot water for the house come from the boiler in the basement) ...

I had clean the floor late fall ( I mean remove carpet, nails, remove tar, sand and put clear finish. )

Looked beautiful until following summer... boiler room was so hot, it started pushing tiny bit of the tar that was stuck between the wood panels.... I guess the heat and humidity (expand the wood panels.. so some sports had very small amount of tar squeezed up) the spots were few millimeters wide..

Reason I am bringing this to your attention, so you would not have to clean the wood floor twice...

If I were you, if you move forward with radiant floor under the original 100+ year wood floor....

(1) I would put the radiant floor connection first under the wood floor (... that will allow you to heat your old wood floor and push any tar stuck between the floor panels....

(2) once the tar is taken out, sanding and finishing be easier...

(3) hopefully when its humid too...so would panels be probably little bit more expanded...
** I used 80, 100, 120 grade sand paper....
Best!

WMno57

If those floors were mine, I would try to leave as much character as possible. Some scraping, little to no sanding. Dark wood pegs glued into the nail holes. I like the discoloration from the nails, wear patterns, and shadowing from long ago items that have left the building.

I had some new white oak floors installed in a previous house with the yellow shellac Jamie speaks of. The fumes chased us out of the house for the night, but it was worth it. It had a no sheen warmth that was great. Not a fan of glossy polyurethane.

I'm a car guy. There are full restorations, resto-mods, rat-rods, and survivor cars. To me the survivor cars are the most interesting. I also like old tools and furniture to show honest wear, care, and use. Everyone has different tastes. If old and survivor is not your wife's taste, perhaps you could remove the existing heart pine planks to use in another room or sell, install a new sub floor, and new wood flooring of her choosing. I have seen pre-finished wood that looks very nice. That saves you the trouble of sanding and finishing.

TAG

Are you on the east coast ... looks like what we called "bull pine" .. it was the everyman floor up to and around WWI. It gets like a rock ... it could be SYP .... but, my experience with SYP in and around DC from homes of the same period .. different. I could never match the bull with anything modern -- SYP was easier. Typically they used that "bull" everywhere including the kitchen/ bath and covered it with 10 layers of linoleum. They don't stain as easy -- that's why they often get a natural and some kind of clear. I agree about keeping it .. they do tend to the amber and you sort of have to embrace it. We seem to be stuck in this gray period .. most of it fake.

There is no problem adding plates -- you may find the best screw are the small sharp screws that are used for metal studs. They are sharp and will cut into the pine -- not too long.

Zman

In pitching the refinish idea, you might point out potential issues with building up the floors.
Exterior doors often need to be rehung, interior doors trimmed, toe stubbing potential at transitions, appliances like dishwashers will no longer fit under counter or become impossible to remove.
You might reach out to a local floor refinishing company and see if they have a similar refinished floor they could let your spouse take a look at.

ethicalpaul

Thank you @Jamie Hall and @LS123 ! I'll consider the shellac but I might go ahead and go with a clear satin Poly...these floors are quite yellow already.

Update, my wife agreed we can keep the floor! All your opinions helped her understand the rarity and preciousness of it. It helped that I told her "we can revisit the issue in the future" which is actually true and not just "husband BS" because, obviously, we can! Whereas if I put it under Uponor and new hardwood, it will never see light again

@WMno57 I love what you said about the "survivor cars", I agree completely. I love old things that were used and show it a little bit. This floor qualifies. I don't think I'll be cutting dowels for all the nail holes however...there are hundreds!

@TAG Yes I'm in northern NJ. I am not sure if they are "heart pine" (a non-species-specific term), "yellow pine" or some other pine. I hadn't heard of "bull pine" before. I'm just sure they are pine Here are a couple pictures of it from below with the joists, and you can see the stained fingerprints of the dead guys who installed it!




Thanks for the tips about the plates and screws. I think I'll shoot for 1/2" which will give a bit less bite than that due to the plate thickness of course.

@Zman thanks for that additional ammo In this case, it would actually be easier to build up more layers because before I re-exposed these floors after decades, they were below carpeting and an annoying MDF layer, so all the doors are already high.

Now the topic is: what to do to them. @WMno57 already put in his vote for scraping, something I have no experience with. I was considering using a floor orbital sander (rather than drum) to gently remove the ancient varnish (or whatever it is) and tar stains (they aren't deep like wet tar, they are just smudges from the felt paper that was there).

I was thinking starting with a 60 grit then going to 80, then 120, something like that. I'm going to have to rent one of those "pods" to put my furniture in I think...the house doesn't have enough spare space to jam things elsewhere.

LS123

@ethicalpaul , the floor as is nice. i do agree with all. try too google what some people do with old original wood floors... yes, remove the whatever tar sports carefully. I mentioned the sand paper grade I used, perhaps, after u remove glue sports, try just the lightest grade of sanding like 100 or 120, but dont remove too much ( this will leave some original look.) take a look and see how it would look like... you and your wife might like light sand look.

If you dont like that and then you always have the option to remove more by using 60 or 80 grade.
I have used a sander that move side to side... hated it... then rented a commercial grade belt sander, it was easy to use... but dont keep it running at one spot too long... it will sand too much that spot...and make the floor look like was not done professionally....

I have seen once that one restaurant that had a fire, part of the wood floor got burned, they liked the patterns and color differences, so the carefully burned the rest of the floors to match the burned floor.... ( i am not suggesting you should burn your floor.

I think googling with your wife what to do with the floor would be the best!

Ttry this on google, take a look at them with your wife.

search was "how to restore old hardwood floors" look at the image tab

https://www.google.com/search?q=how+to+restore+old+hardwood+floors&client=firefox-b-1-d&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiv-oW4_bnvAhWIl-AKHRsDCncQ_AUoAXoECAoQAw&biw=1366&bih=654

there are lots of potions if u continue to google and find what you both like..

Please thank your wife for saving the beautiful wood floor you have on behalf of all the members who contribute for two of you to make a decision...

Best!

TAG

Your location answered my question -- they are not SYP.

While they are "hard" ... it's due to the pitch and 100 years of drying. They are not hard when it comes to sanding .... the professional type drum (Clarke) can do a lot of damage in short order in the hands of an experienced user. The consumer units from the big box stores will take more time -- but, are a better bet for a first timer on a soft wood.

You don't want to hurry -- it's better to start with a higher grit sand paper and waste $10 of paper and some time getting used to the machine. See how it works and feels --

Years ago: Up to 60's into the 70's shellac was used everywhere. It was easy to apply -- fast dry and since it softened the previous coat ... no issues re-coating. Remember helping my grandparents coat the sun porch in Maine every spring -- must have had 60 coats. It's soft and there are much better things available.

When I was doing rehabs back in the 80's -- most of them had a heavy coat around the room. It was common to pull back the rug and only coat the visible floor area.

ethicalpaul

TAG said:

Your location answered my question -- they are not SYP.

While they are "hard" ... it's due to the pitch and 100 years of drying. They are not hard when it comes to sanding .... the professional type drum (Clarke) can do a lot of damage in short order in the hands of an experienced user. The consumer units from the big box stores will take more time -- but, are a better bet for a first timer on a soft wood.

You don't want to hurry -- it's better to start with a higher grit sand paper and waste $10 of paper and some time getting used to the machine. See how it works and feels --

Years ago: Up to 60's into the 70's shellac was used everywhere. It was easy to apply -- fast dry and since it softened the previous coat ... no issues re-coating. Remember helping my grandparents coat the sun porch in Maine every spring -- must have had 60 coats. It's soft and there are much better things available.

When I was doing rehabs back in the 80's -- most of them had a heavy coat around the room. It was common to pull back the rug and only coat the visible floor area.

Thanks for all that information, I am agreeable to it! That's another reason I didn't want to put in a new floor. I told my wife "90 percent of the floor is covered by the rug and couch anyway "

I will take a bit of issue with the question of hardness...these are pretty damn hard

LS123

just a look of the finished softwood floor

ethicalpaul

Those are a little too shiny for me

LS123

pine is generally considered as soft wood, you are so lucky it 100+ year old pine and had just enough time to be hard over the years... yes, same with me, areal rugs, furniture, plants, and other decorative items covered most floor, just more than enough spots of finish wood floor for people to be wondering about and even be a conversation starter....

LS123

agreed... its probably too shiny... I was trying to point out trying to keep as much of the original floor look... but not suggesting you should... check out the google links. best

Jamie Hall

Is there any possibility at all, @ethicalpaul , that you and your wife could take a drive to northwestern Connecticut? First place, I'd love to meet you -- and second place, I have a few thousand square feet of very very similar pine flooring which I have restored and shellaced to show you...

And I will make a real pitch here for shellac. Yes, in comparison with the modern polyurethanes, it is soft. However, it is absolutely trivial to repair a bit of damage if necessary -- say a dog, or someone in cleats, or shoving furniture around. A bit of alcohol on a rag (denatured is best, but vodka works) and you can rub almost any damage out. For more damage or more wear, just give it a bit of a rub and recoat; the patch will never show. If it really gets worn -- in a couple of decades -- go over the whole thing with the alcohol and clean it up and recoat. No problem at all.

Whereas with the polyurethane, if it gets damaged or worn you have to sand it all off and do it again. There is no satisfactory way to patch poly. Really?

And there is the shine... who wants a living room that looks like a basketball court?

Now sanding. My thing as you know is restoration, so I tend to go the least invasive route I can, even if it means more work. I would never go coarser than 80 grit, and in most cases 120 will be just fine. A little more work, a lot less potential for gouges and damage. Also, use at most an orbital with a flexible pad. The big drum sanders are just dandy (it's what you need for the polyurethanes...) but they take things down much faster than needed, even when used with caution, and it's very very hard to get an even job along any edges. ;On the floors I mentioned above, I used an initial alcohol rub (more like a wash!) (they had been shellaced previously), then in a few obstinate cases a hand belt sander very carefully, followed with a hand orbital sander, 120 grit. You cannot get the deeper staining out, but from the photos I'd say it wasn't too bad. Be aware of the possibility of the occasional splinter. Not usually a problem, but they can be -- and they either need to be glued down or cut out.

ethicalpaul

Thank you Jamie! We would love to have a look and have family up that way too. Your passion has me intrigued in shellac, which I am almost completely ignorant about, but I do love the period-appropriateness of it, and I do dislike the "plastic-ness" of poly.

Is this a reasonable example that I could do some testing with?

https://www.amazon.com/Rust-Oleum-Zinsser-304H-1-Quart-Shellac/dp/B000BZTIZW/ref=sr_1_2?dchild=1&keywords=shellac+wood+finish&qid=1616081391&sr=8-2#

And I appreciate your advice re: sanding. It fits with my fear of hurting these floors. I am very happy to stay away from drum sanders. My little laundry room I did completely with hand sanders and it was nice to err on the side of "extra elbow grease required" vs "oops!!"

LS123

Br. @Jamie Hall and @ethicalpaul .... Am I included in the invite?
not for few more weeks though... just got my dangling arm (RC fixed)

Jamie Hall

Yes, that's exactly the shellac I use, @ethicalpaul . I cut it somewhere between 1:1 and 2 parts alcohol and 1 part shellac for most work.

And @LS123 -- of course!

PC7060

Definitely recommend keeping and restoring old floors. We had our old maple floor sanded and refinished using oil based polyurethane (satin) . Boss Wife was very happy. These floor were on second level of house with no subfloor. 1st level has oak flooring over diagonal plank subfloor. Strange the things the old builders would cut corners on.

hot_rod

I had a pro do this floor in our barn, it was the hay loft. Light sanding, even left the hay particles in the seams when he finished it, 17 years ago. They call this long-leaf pine, looks like yellow pine to me It does have transfer plates under some areas, this is a 3/4 T&G.

TAG

I'm old school -- still use shellac and good old spray lacquer. My go to floor finish years ago was Waterlox as it was a nice low sheen and easy to fix. The new low VOC formulations are not as good.

With the advent of crystal clear water and 2part finishes the trend away from any amber/ orange has moves most people to them. My new project is using very wide white oak -- it's been aged a bit and I don't want any amber. So the color you want will determine the finish.

ethicalpaul

Long Leaf Pine is one of the varieties of Yellow Pine, from wiki:

In the Southeastern United States, yellow pine refers to longleaf pine, shortleaf pine, slash pine, or loblolly pine.[3]

neilc

a purist would not sand, but drag knife it,
a super sharp steel at a hard angle, shave it smooth,
brother Jamie ?

Jamie Hall

neilc said:

a purist would not sand, but drag knife it,
a super sharp steel at a hard angle, shave it smooth,
brother Jamie ?

I'm not sure; I can research that. Problem is that to get it smooth you would really be looking at essentially planing it -- and having done a fair bit with draw knives I can assure you that it's not all that easy to be really steady with them -- and if they aren't shave your face sharp it's pretty close to impossible. And even with a really sharp jack plane it would be slow, as you couldn't take much without risking grooves at the edges of the strokes. Let me think about it.

Very early floors of that sort -- tongue and groove pine, or sometimes without the tongue and groove -- weren't finished at all. Rather, from time to time sand -- quite literally -- would be spread on the floor and worked about using a very slightly convex harder ;piece of wood and then swept up. Ship's decks are maintained in a slightly different way, rubbing a "holystone" -- a piece of soft sandstone or sometimes pumice -- across the ;deck. A bit tedious, but it works.

WMno57

Good article here on how to hand scrape vintage wood floors:

https://www.oldhouseonline.com/repairs-and-how-to/hand-scrape-wood-floors

Jamie Hall

Fair enough, thank you, @WMno57 . But... if the old finish is shellac, which it often is, I think I'll stick with the technique of getting the old shellac up with alcohol and then lightly sanding.

I can see, though, if someone has vandalized the floor with urethane that that might work well enough. The two tricks would be to keep the blade extraordinarily sharp and have it in a really rigid mounting (that two handed affair, which is really a narrow blade draw knife, but with a rest for extra control of the depth of the cut, looks good) and take very very small bites.

JUGHNE

So Paul, have you been shopping for the diamond earrings yet?

ethicalpaul

The radiant in the living room is all the payment she wants 😅

TAG

It's common to use a scraper in the tight spots .... production floor guys use the orbital and it always leaves scratches. Trying to do a whole floor ... that's a lot of work and unless you are trying to match something special ..don't think narrow pine warrants the work.

The key is to go slow. I have done a bunch of floors -- not enough that I would not have to practice a bit.

Boon

@ethicalpaul I'm late to the party but wanted to add that we chose to refinish our no-subfloor, 1920s heart pine, too. Clear coat. Absolutely beautiful, 5 out of 5 stars, but we will have to revisit ours in, I'd guess, 5+/- years [7-10 years post-refinishing].

By looking at the floor boards where they meet the baseboards, we knew that previous refinishing removed quite a bit of wood and that there was a chance that our refinish attempt might not go so well. Our floors are pretty thin, probably too thin, now.

It isn't uncommon for us to hear a tongue & groove joint snapping loudly now & then, and we get some splintering at the t&g joints. The snapping/splintering, I think, is mostly due to expanding/contracting of either the wood flooring or the joists, from which the radiant piping (going to radiators, not flooring) is secured on unistrut. We don't get the snapping/splintering through summer.

Hopefully your floors still have a lot of meat on the bone.

Jamie Hall

@Boon 's comment on thickness is one reason why I don't advocate sanding any more than is absolutely necessary. And his comment on finish life is quite correct -- for poly. It is not correct for shellac, which, depending on how fussy one is, can go decades without wholesale restoration.

LS123

ethicalpaul said:

The radiant in the living room is all the payment she wants 😅

@JUGHNE .... I think @ethicalpaul is in sales... he is a good salesman, just get his wife to settle for a old 100+ plus floor with radiant heat without any bling bling LOL

Boon

we will have to revisit ours in, I'd guess, 5+/- years [7-10 years post-refinishing]

Finish, yes, we did use poly, but I should clarify, Jaime .... I meant revisit, as in, my foot will probably go through the floor in another 5+/- years

ethicalpaul

Thanks Boon! Unless I’m mistaken mine are still on the original finish. 

TAG

FYI -- You can refresh poly. Gets cleaned and screened