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softwood flooring

Alsy | Posted in Construction Techniques on October 29, 2003 07:10am

The hardwood flooring in my post WWII San Francisco home is in sorry shape and needs to be replaced.  Unfortunately, part of the reason for the problem is a bad subfloor; non tongue and groove, 1×6, douglas fir , laid diagonally. The subfloor is of such poor grade that it will not hold the nails in the 5/16″ strip flooring and the whole floor squeaks.  My thoughts are to remove the hardwood and overlay the subfloor with 5/8″ plywood, glued and screwed (or nailed) to the existing subfloor and nailed into the joists.

On top of the new subfloor I plan to install a 1×6, flat grained, t&g, douglass fir floor, laid perpendicular to the joists.

I would like some feedback on;1. my proposed method of overlaying the subfloor, 2. what type of adhesive to use, 3. potential problems in installing a flat grained floor. 4. what type of stain and finish products to use on a softwood floor.

Thanks for your feedback.

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  1. TLJ | Oct 30, 2003 04:42pm | #1

    I'm willing to offer responses to 1 & 2.

    1. I think you're ok with screwing down 5/8 plywood into joists. Check your existing subfloor for proud nail heads, etc. first and screw down any spots that stubbornly stand up. Glue is unnecessary with screws (takes care of #2). If you experience heads popping off while screwing, go to a heavier gauge screw. You don't want that happening after you've finished your floor.

    You may have problems with edge seams that don't lay flush. Screwing into blocking will alleviate any future concerns here. Alternatively, use 3/4" T&G plywood.

  2. mathiasraulf | Oct 30, 2003 08:21pm | #2

    On # 2: Use any Bonding agent that is non-hardening (flexible) like SikaBond

    On #3: splintering - predrill, or staple into the tongue

    On#4: Regular stains (with or wo mineral thinners) will reverse the picture. theyll stain the softwood not zthe heartwood. looks awful. Try to get what we call a "positive" stain based on mineral thinner. This reverses the problem. Don´t know your expression for that. Work fast, brush on, take off with a rag. messy,messy. So cover the walls, baseboards. Try sample first. wear a coded respirator. ventilation.No smoking.

    I like wax-oil products. You could use any finish that will not cure up to hard and brittle. Softwoods will get a punched look after some gal runs over it with high-heels.http://www.osmo.de/osmocms/eng/produkte/...color/hartwachs-oel.php



    Edited 10/30/2003 1:23:52 PM ET by Matt

    1. johnharkins | Oct 30, 2003 09:58pm | #3

      good input here and some more to consider  clean up that subfloor  nails debris and make flat   then nail all w/ ringshank nails   clean again   - you'll probably get more and maybe better professional advice - but I would lay down some rosin or 15lb bldg felt here ( or on top of your plywood )   if your joists are 18" OC or better your 5/8 ply  /  if  24" centers I'd go to 3/4 subfloor material and lay your fir in any direction you like  glue not a necessity but hey  ringshank again thru ply long enough to purchase those joists    ** finish flooring **  I'd question your use of fir   the upstairs of our 1900 house has quarter sawn VG fir throughout and is exquisite when sanded and finished   but when our lab turns quickly or chases my son's errant ball there is evidence   many beautiful wood floor materials  not much difference in cost or difficulty of laying

      if you go fir I've had good success w/ a finish   I think it is a Varathane product Diamond Floor finish  water base  I've put down 4 coats in a day on two different jobs and the finish is great other than softwood marring  - other people have tradition of removing shoes and have no dog   looks brand new

      be very careful staining fir  will get muddy   what I did w/ DDiamond product is put  an initial coat down then mixed a white colorant ( made by same company ) app 1 / 6 w/ Diamond to cut any future kinda rose ing of the fir  holding on to that autumn gold kind of color

      hope that isn't too long & didactic   it amazes me what I get to glean from this site  thanks to all John

  3. dthodal | Oct 30, 2003 10:16pm | #4

    Generally speaking, your subfloor is pretty ideal for hardwood flooring. However if the grading of the fir was indeed poor, then you may be correct in blaming it as the source of your problems.

    Many houses built during the post war years were of poor quality as demand for housing skyrocketed with returning soldiers. Quality in both labour and materials. Squeaky floors can be attributed to poorly nailed flooring, no underfloor paper or subfloor nailing loosening up. Before I went to the expense and potential heigth problems associated with raising the floor I would check the following.

    1. Is the subfloor really such poor quality that it does not hold nails?

    2. Is the subfloor nailing loose?

    If the answer is no and yes, then I would suggest renailing the subfloor with 8d ringshanks and laying my new floor properly.

    If the answer to #1 is yes, then you have no choice, but to instail new subfloor. 5/8" cdx would be fine for that choice. I would suggest laying rosin paper first over the existing subfloor, then nailing as you suggest into the joists. Again an 8d ringshank will penetrate into the joist and hold both subfloors. Forget the glue.

    Flat grain wood floors can look nice with minimal problems; the biggest I have encountered specifically with fir is splintering. I would suggest you have your flooring end matched or do it yourself with a slotting bit and spline. 6" width is about maximum, I like to edge nail. I use a standard floor nailing gun, not staples. Set one every 12" and about 2" either side of your butt joint.

    I dislike staining wood in general, but especially flooring. The wear is uneven and eventually shows up and is hard to correct. Rather I use a penetrating oil finish to allow the natural colour to fully develope.

    Since most of my flooring customers like the durability of poly finish, I use DURASEAL oil-modified polyurethane. For soft wood floors like fir or pine, I will use DURASEAL 210 Neutral stain as my first coat. It is a heavy solids, clear stain that helps harden the wood prior to urethaning. It will also slightly darken the colour of the fir. 3 coats of polyurethane with a light screening between coats. Use gloss for the first two coats, then finish with satin for a low lustre appearance.

    walk good
  4. JohnSprung | Oct 31, 2003 02:56am | #5

    I have lots of that 5/16" t&g oak over diagonal one by doug fir in my 1926 house in LA.  Most of it holds nails just fine.  The exceptions are boards that the termites have eaten.  Do you have large areas stripped back to the subfloor?  Are you really sure that large amounts of the subfloor are bad, or is it just a few pieces?  If you are down to the subfloor, there should be big enough gaps between the boards that you can poke at the joists and see if you have any rot or termite damage there, too. 

    It's important to get the big picture of all that's really wrong before deciding what to do.  Can you post pictures?  That would help a lot more than a text description over the internet.

    -- J.S.

  5. AlanSenoj | Oct 31, 2003 04:50am | #6

    Hello, Alsnauer,

    Up in Vancouver, B.C. we have lots of fir flooring. In fact I'm looking at my fir living and dining room floors as I type this. It is beautiful.

    As to securing your subfloor, I would probably screw the loose boards and glue and nail/staple the plywood. I'm sure 5/8" is plenty. We have 3/4" solid wood (1x8) subfloor on diagonal under our t+g.

    I would think again about using flat sawn fir. Fir isn't the most stable wood in the world but vert. grain is pretty good. Flat sawn fir as wide as 6" would move like crazy with the seasons and humidity. I've never seen fir flooring wider than what we have:-1x4, and cracks have shown up between our boards.

    Even more important, fir is really soft. Even our old growth v/g (house was built 1917), ddamages easily. Drop a cup and find the dent easily. Flat sawn fir is softer and less wear resistant by many, many factors.

    I wouldn't use any kind of stain on fir. It has naturally a beautiful warm honey tone, that darkens a little with time.

    Good luck

    Alan

    Alan Jones
    1. Piffin | Oct 31, 2003 12:18pm | #7

      I second the idea of vertical grain fir instead of flat grain sawn. For finish, I would use an oil poly to bring out the amber colour of the wood naturally instead of beating stain into it.

      5'8" ply is fine and glueing may add to strength overall. If you decide to take other advice above, definitely renail the old boards in any case, and use tarpaper or rosin paper as a slip sheet between plys. One reason for squeeks in old or new floors is wood/wood rubbing so you not only need it fastened tight to prevent the wood/nail rubbiong but to keep from hearing the wood/wood/ movement too. Bostick wood flooring adhesive is a good choice..

      Excellence is its own reward!

      1. dthodal | Oct 31, 2003 03:54pm | #8

        Do you glue the underfloor paper to the subfloor or glue the plywood to the underfloor paper? Or do you glue them together?walk good

        1. Piffin | Nov 01, 2003 02:46am | #9

          Sorry if i wasn't clear enough in talking about all options.

          Either glue wood to wood or use a papre slip sheet.

          Excellence is its own reward!

      2. ANDYBUILD | Mar 24, 2004 11:02am | #13

        The new floor I "just" installed in my LR( approx. 350 sq ft) is old growth eastern white pine wide plank flooring (10-15") from Carlyle (sp?) Flooring.

        I glued it down over 2 1/2" strip flooring with PL Premium and face nailed the whole thing with handmade nails 32" OC.

        Stained it with a water based (I don't recommend water base by the way now that I used it....don't ask) stain and five coated that with tung oil. Looks totally awesome!!!! No squeeks at all.

        The water based stain is what I got from the company.thats what they sell little did I know when I ordered it.

        You can put a finish over it in half an hour.

        I waited over night though.

        When I went to put the tung oil down I noticed to my shock and surprise that the stain started coming up.ughhhhh.

        I could easily pull the stain from the floor but couldnt get it off my hands.go figure.

        I got the oil down fast enough so the stain stayed put. Why they sell water based stain is beyond me.

        Am I missing something here Piff?????

        I have about another 1500 or more sq ft to go in the near future.

        I thought it'd be the easiest floor I ever installed but to my surprise it was the most difficult one I ever did.

        By the way I ordered it with no T&G to keep it authentic looking.

        It really does look incredable after all is said and done.

        Be floored though on the water base stain part of the process

                      andy

        "My life is my practice"

        Edited 3/24/2004 4:03 am ET by ANDY CLIFFORD(andybuildz)

        1. MikeFitz | Mar 24, 2004 03:31pm | #14

          Andy-

          Any chance you could post a picture of the finished product?  I'm thinking about doing the same thing myself in the near future, and I'd like to see what a real install (not the company's portfolio) looks like.

          Mike Fitz

          1. ANDYBUILD | Mar 24, 2004 03:52pm | #15

            Mike,

                  I'm trying to totally finish that room off this week. I have red rosin paper and drop clothes on the floor right now so pictures will have to wait till next week end.

            I'll post em in the photo gallery.

            To tell you the truth it looks "exactly" like the floor in their ad in FHB.

            I'm gonna do the entire house with it I love it so much.

            In my opinion from experiance is to stain all the planks before you put them down along with a couple of coats of tung oil. Thats got to be the best and easiest way to do it.

            When the ordered arrived here via Yellow Truck Co they were packed beautifully in a large covered crate. Therefore before you get em dirty finish them.

            BE floored

                             andy"My life is my practice"

        2. Piffin | Mar 24, 2004 07:14pm | #16

          Here would be my thoughts ;

          I learned the hard way a long time ago that some stains and finishes don't befriend one another.

          and we all know that oil and water don't mix.

          and all the finishing instructions I ever read were to try a sample spot before barging ahead.

          and I'll add that my understanding of Tung oil is that it penetrates the wood to harden it up, making me suspect that the layer of stain might interfere with that. I would have probably used a tinted tung oil.

          Now for my own curiosity - Pure tung oil takes a day for every caot at least to cure up. Polymerized and mix downs with oher varnishes go off faster. Since you got five coats quick, I have to ask if you had a pure tung or if it was a polymerized version for quicker dry time. I will be doing something similar soon enough so what brand was it and are you happy with the tung itself? 

           

          Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

          1. ANDYBUILD | Mar 24, 2004 07:46pm | #17

            Piff

                 The stain was made by Carlisle as was the tung oil so I went with what they told me.

            Sorry if I made it sound like I put five coats on in a day.

            I did one coat each day for five days although the directions said you can do it after eight hours.

            The tung oil has mineral spirits, specially processed tung oil, ester gum, oletin gum resin in it

            Also says its ok to use over varnish, shellac, lacquer or filler.

            I think you answered my question with out knowing it.

            They probably use a water stain so in can in fact penetrate the stain into the wood.

            I figured out while not being able to sleep cause of worrying over it how to do it easier and more efficient.

            Stain the boards "before" I put them down.

            Then take a lambs wool applicator .......pour the oil into a paint tray......and with "one" quick pass lay down the oil. Its the first coat thats the most difficult.

            The minute you "work" the oil on the stain it comes up. You can't work it AT ALL!!!!

            I'm going to use that stain again because of your unrealizing explantion.....lol.

            MAkes sense to me now.

            I've used tung oil over shellac before and of course there wasn't  a problem but from what you said I think the water stain is probably a better idea now.

            Going to a big home show here this weekend.

            I'm on a contractors guest list curtisy of Timberknee flooring.

            I think I may use them next time. Their prices were a whole lot better than Carlisle's especially the shipping costs.

            I'll speak to them about all f this cause I'm going to have a real lot more to do.

            I'll let you know what they say and how their product looks.

            My guess is that most all the wide plank companies have very similar pine.

            They don't grow the trees.they just have their own mills so...........

            Anyway.back down to that room again to try and finish up.

            By the way.it looks unbelieveably great.

            PS....I used a 220 grit sandpaper in my vibrating sander on the fourth coat. MAde a hugeeeeeee differance. Came out smooth as glass.

            Be floored

                              andy"My life is my practice"

          2. Piffin | Mar 24, 2004 09:50pm | #18

            It will be interesting to hear what more they have to say. Since it was same brand both stain and finish, I would expect them to be compatable. You probably didn't have enough set time for the stain.

            BTW, did you sand before stain too to remove the mill glaze and soften the wood or use a preconditioner? Either of those helps stain settle in and take more evenly. 

             

            Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

          3. ANDYBUILD | Mar 24, 2004 10:13pm | #19

            Actually they told me I didnt have to sand but I did anyway.

            The directions for the stain said eight hours.

            I let it dry for 24 hours.

            "My life is my practice"

  6. jakesmom | Mar 22, 2004 12:38am | #10

    Hi,

    I am curious if you did your floor and how it came out. I have 2200 sqft. of T&G CVG fir to lay in the next few weeks and am still unsure about what to use as finish.

    Bing

    1. ed2 | Mar 24, 2004 02:37am | #11

      bing- oilbase poly looks the best on fir, gives it the depth you're used to seeing. occasionally use water borne poly on fir or pine, don't care for the superficial look, no depth to the grain.

  7. Floorman | Mar 24, 2004 04:55am | #12

    If the 1 x 6 is as bad as you say, I would just take it out. Sawzall the walls and the cabinets as close as you can and install 3/4 t & g plywood as a new subfloor. Trying to save something that ragged is not the way to go. My builders tear it out all the time on remodels.  GW

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