Replies

1. 
   StanleyNiemiec | Sep 11, 2002 02:15am | #1

   Equilibrium Moisture Content (EMC) is dependent not only on humidity but also temperature.  During a rain storm outside humidity is likely close to 100% but wood inside will not change rapidly enough during a rain to create huge amounts of swelling.  It would be better to understand that day to night changes need to be averaged to obtain a more accurate daily value.  Seasonal variation will be greater than daily variation.

   If you are truly concerned about the possible EMC range, I would contact the nearest weather station to see what type of data they can provide.  A US Coast Guard Station will probably have that data and it will be likely applicable because their information will be also close to the lake.  If you are between two, you might wish to obtain both and compare.  IF you have that data then you will be able to better predict your extreme values; but these will be outside information and will have to be adjusted for inside temperatures and the amount of humidity you add with showers, washing dishes or clothes.

   I suppose that if you wanted to collect your own data, you could establish a sample set of 8 to 10 wood pieces and a good accurate scale.  If you weighed the samples weekly, you could get more exacting information regarding conditions within your house.

   The choice of finish is also a factor.  Various finishes have differing Moisture Excluding Effectiveness (MEE).  Some are much more effective than others though given a long enough, they will all approach a MEE value of 0%.  Coating the ends of the strips before installing will also be beneficial.

   Finally, rate of change in EMC will vary between species.  For example Red oak is considerably more porous than White oak.  The more porous the wood, the more quickly it will change dimension.  Sawing pattern will make a difference as well  --  quartersawn stock is more stable than flatsawn but if you are considering oak, it will also be considerably more expensive.   Another species like Black cherry, will have less dimensional movement than say hard maple. 

   The reality is that wood changes dimension and if you expect a perfect floor that never develops any openings, you will never get it; unless you completely control ambient temperature and humidity (climate control).   

1. 
   booch | Sep 11, 2002 04:42am | #2

   I am with you Niemiec1,

   The matching of species is sport in our world, as is matching construction to the movement. I don't expect perfection nor desire it, whorls & waves are what makes real wood interesting. If I wanted the continuous smooth finish that schlocky plywood prefinished would be the choice. Per Hoadley's book the variation in my environment is 6-7 percent RH in the winter and +12 percent RH in the summer.

   My focus is compatability in the materials. Consider, I want to put down a Marquetry Compass point in the middle of my floor that is 3 foot in diameter. Built with venier on some 7 ply birch. Humidity & temperature Movement with a 3 foot diameter circle of plywood on the floor I'll get minimal movement. Minimal estimate is 1/8 inch movement in this circle of plywood. Each edge will move 1/16 to and from the center. Solid KD oak expands about 1/8' per foot radially. (Rough numbers for sure, but it illustrates the problem.) I'll have a circle of strip floor around the plywood in the summer and an oval in the winter with the slightly smaller circle of plywood in the center. The gap will be fairly large 1/4 on each side is my guess. Sounds like an ugly job asking for a throw rug.

   I can't see putting plywood with dimensional strip hardwood flooring. Certainly the plywood with the venier on top is easier to make, but I don't think it will last.

   Cutting full thickness flooring to make the image is a bit daunting. At least they are all straight cuts rather than curves. That part is do-able

   Beyond the cutting I wonder about the quality of the glue joint. Flat cut end grain to the same flat cut end grain. I fear I'll be walking around the image on the floor afraid to step on it.

   It doesn't feel like a good solution yet.

   Edited 9/10/2002 9:47:55 PM ET by Booch

1. 
   StanleyNiemiec | Sep 11, 2002 07:15am | #4

   Hopefully this will be an "AH HA" moment for you. 

   If you have stability in the medallion (because of its plywood construction) and allow the strip flooring to float as it normally would do, the dimensional change (expansion and contraction) could be evenly distributed among the strip flooring pieces over that 3 foot range. 

    

   Thus instead of having one very large gap, you will have many small gaps.  The key to construction is to make sure you allow this to happen.  One method that might be successful would be to create a groove all the way around the medallion and insert a spline.  If you cut a groove in the strip flooring after you cut the arc of curvature to fit the medallion spline, then the individual strips will not raise and, without adhesive in the groove, will be allowed to float.  If you keep the flooring nails a reasonable distance from the medallion (say 6 or 7 inches) the flooring at the medallion interface will not be critcally restrained.   

   Further if you create a round form that will allow you to use a router pattern bit with a guide bearing, that form could be attached to the floor and each piece of flooring trimmed to fit the curvature in its appropriate position.  The other option would be to create a routing compass to generate a smmoth even cut of the proper curvature.  You could permanently nail the first half of the flooring in place but leave the last half only spot nailed until the complete contour is attained. 

   Then the medallion could be inserted and secured, and the remaining flooring nailed down. 

   If you are creative with the design of the medallion, you could screw it to the subfloor and then plug the holes with a contrasting wood that becomes part of the actual design!!! 

   Thin veneer is probably not a good idea.  "Veneer" that is 0.25, 0.3125, 0.375 or even 0.4375" will however work.  Get the appropraite thickness of baltic birch, create your pattern and as a last step, imbed the pieces into a thin layer of flooring mastic with some fasteners coming up from the bottom.  Make sure the pieces are thick enough so that the medallion can be sanded with the rest of the floor.

1. 
   booch | Sep 11, 2002 04:43pm | #5

   Niemiec, you wrote:

   you could screw it to the subfloor and then plug the holes

    "Veneer" that is 0.25, 0.3125, 0.375 or even 0.4375" will however work.  as a last step, imbed the pieces into a thin layer of flooring mastic with some fasteners coming up from the bottom. 

   Great information,

   A couple of questions come to mind. In the above selections from your response I got a bit turned.

   Using the flooring and a template sounds great. I just need to find a router bit to cut the slot in the flooring. It may be simple but I don't have many bits that don't have a nut or some other projection below the cutting edge. I just need to browse thru some cat's to find the bit. I already have the bearing guided bit for the template follower. Possibly using a power floor casing saw could cut the groove in a couple of passes. It would be worth the rental.

   Flooring mastic? Is that the adhesive you use to adhere the veneer (thanks for the spelling correction) to the baltic birch plywood base? Do you use that same adhesive for the high detail border work I saw in "LANDG's" visuals?

   The border visual details look great, but I wonder how to fasten them to the surface. Nails appear to need longer boards to hold a nail without splitting the tongue. It is hard to imagine drilling and plugging each piece of the basket weave in the first image LANDG provided.

   My final room flooring detail will be simple. Center 3' medallion of a compass point, then a brass-ebony-brass border attached to the outer edge of a 4" wide border of wood around the fireplace hearth.  That area is so small that I don't fret over movement.

   There are a pair of 8 foot transitions from flooring to tile flooring. I'm expecting a short taper of screwed & plugged hardwood to the tile edge. Subfloors and materials come within 1/8" in height. Last concern is the gap between the tile & this short taper. (RTV ?, RTV modified grout?) I suspect there will be constant change at this joint. The good news is that the transition is at the ends of the flooring not the side. Movement should be minimal.

   The room would be confusing with an overall border. The living room contains a spiral staircase and a curved section of wall plus the above details. Just making a spiral staircase opening with flat stock should be a challenge. Visually the additional detail would be overwhelming, plus I'm at my limit.  I still have to construct the fireplace & chimney 40 feet above the floor in question.

   I think you have me past the how's-that-gonna-work stage. Time to get some materials and make some trial balloons in my shop.

2. 
   IanDG | Sep 11, 2002 06:34am | #3

   What sort of inlay/borders are you considering?
   I would make them from the same thickness timber as the strip floor and the installation would be nail and glue down and I wouldn't expect any problems -- subject to the finish you want to use and construction of the sub-floor.

   This, for example would work well

   View Image

   and so would this

   View Image

   the chain border is another which suits strip flooring

   View Image

   
   

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   Edited 9/10/2002 11:49:19 PM ET by IanDG

1. 
   booch | Sep 11, 2002 05:03pm | #6

   Beautiful work IanDG,

   As I wrote in response to NIEMIEC1, there are many tasks ahead of me and I think those examples may push my envelope. Although, it is tempting. I need to work past the medallion construction and then I'll consider the border work.I suspect the first foot of border installation is a bear then it becomes a regular activity. As I asked of Niemiec1, what is the fastener schedule on the first image? Nails? Probably on the banding at the edge, but the field must be glued somehow otherwise the material would split. What kind of glue, floor mastic, PL400? Where would you glue it, edge to edge or to the substrate? If to the substrate, (subfloor), then do you eliminate the paper barrier?

   I do promise pictures when this is completed.

   Edited 9/11/2002 1:43:22 PM ET by Booch

1. 
   IanDG | Sep 12, 2002 12:35am | #7

   Bear in mind that my method of fixing strip flooring is to secret nail AND glue (no paper barrier) so my fixing details for the typical border to strip flooring would beFirst strip nailed and glued to the cut edge of the strip flooring and glued to the floor. The remainder of the border pattern is glued straight to the sub-floor (no nails). The first board of the margin (between border and wall) is glued to the last border strip.(no paper barrier) The paper is a damp-proof membrane -- far better IMO that the membrane is below the floor structure over the crawl space and a pervious finish is used on the floor.View ImageIf you are using a brass/timber/brass edging like this aluminium/walnut/aluminium one shown then a couple of things you might find useful.Because of the difference in hardness of the metal/timber it is difficult to sand the area flat. An ROS with a stick-on pad -- a hook and loop has too much give -- is best.I found it always better to make the border 'off floor' as a unit and cut to length/mitre as required. That way the metal strip could be screwed to each side of the timber strip.

   Edited 9/11/2002 5:37:15 PM ET by IanDG

1. 
   booch | Sep 12, 2002 06:17am | #9

   That ROS tip sounds good. I find the same problem with sap wood and heart wood in glue ups for furniture. Damn, you gotta watch what you are doing.

   As for the metal timber setup I think it ought to be easy enough if it is done on the side like you mention. scraping your knuckles on the floor doesn't make the work go faster.

   You mentioned glue with the hidden nails. Generally speaking are you into construction adhesive like was used on the subfloor to Joist? Possibly the mastic adhesive used for wall tile, or are you using  the polyurethane or Aliphatic resin (wood-furniture glue)

   Gotta go, 21st anniversary tomorrow.  I have to get back in training.

1. 
   IanDG | Sep 12, 2002 06:23am | #10

   For the field and the margin I secret nail each board at about 14" centers with a bead of construction adhesive at the same centers.For the border I would use a good parquetry adhesive like Bostik's polyurethane one.

3. 
   floman47 | Sep 12, 2002 06:14am | #8

   Here’s a link to a thread about an inlay I made, also how I made it.  You are thinking too much about movement.  Just do it!  I install everything little loose so I have expansion all over.  I’ve installed allot of inlays over the last 20 years and I haven’t had any problems, and all of my work is by the ocean.

    You can get a flat bottom-grooving bit at local flooring wholesaler. There not cheap $50 to $60

   http://forums.taunton.com/tp-knots/messages/?msg=6739.1

    

   Jeff in so cal 

    

    

   
   

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   Edited 9/11/2002 11:15:51 PM ET by FLOMAN47