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Red Maple timber drying

Started by Hackermatack, November 16, 2017, 05:02:58 PM

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Hackermatack

Has anyone here ever tried making timbers from red maple? I am thinking about milling some into 6 x 6 to use as joists in my kitchen ceiling (loft over kitchen). I also have ash that I could use but I am pretty sure that would crack pretty bad, don't mind a little checking and cracking it adds character. In either case the logs will be in the 12-16" diameter range so most of the timbers would end up with a boxed heart. 
Jonsered 2230, 590, 70E. Kioti DK 35 /w fransguard winch. Hudson Oscar 236

Don P

Yes it'll work. Strengthwise it has good numbers. It moves a fair amount drying, it acts a lot like cherry.
Reminds me of the mason who said "mix it up like pancake batter"
"How stiff is pancake batter"
"Just like mortar"

Tends to open up worse on one face, one or a couple of major check rather than many smaller. I'm sure you could help direct that by plowing a kerf down the middle of the upper covered face of a square beam. weaken that face and let it relieve the checking stress there. Do you have time to let it dry at least some? If so I'd oversize it 1/2" and recut it when you're ready to use it, let some of the stress and movement happen. That's not much of a joist, what kind of span, joist spacing and load are you talking about?

Hackermatack

Load is minimal as it will just be a loft with low headroom at the eves, just a place for the grandchildren to sleep when they visit. The distance outside of studded wall to center of carrying timber will be 14' so the span will be 13' I will use 24" oc so only 18" between them I would guess a 6 x 6 maple timber ought to hold at least as much as a 2 x 12 spruce that is only  1 1/2" x 11 1/4". I am more concerned with my carrying timber as that will span will be 12-14' but I have a few big trees so that will be considerable bigger. The trees are very smooth without limbs on the butt logs to this will be nearly clear timber. Yes it will have a little drying time and I have in the past sawed pine oversize and skim cut it at assembly time. Works great sharp blade slow feed sands up quick. Good idea kerfing the top side, wonder if it would be better to mill it with the heart boxed dead center or try to keep it close to a face. I am only going to need 14-16 of these so I can mill 20 or so and take the best
Jonsered 2230, 590, 70E. Kioti DK 35 /w fransguard winch. Hudson Oscar 236

Don P

I'd center the heart to help keep them straight.
At 40 psf which is sleeping x 2' centers x 13' =1040 lbs load per joist.
I checked it on this calc;
https://forestryforum.com/members/donp/beamclc06b.htm
Total Load 1040
Dead load 347
Span 156
Width 6
Depth 6
#2 Red maple Beams and Stringers

Click "Show result" Looks good

From the last post I assume you have one end (520 lbs) of some number of these joists resting on a beam of some span. You should be able to adjust the inputs and check that one.

While you have the calc open I'll show you something. Leave everything the same as the joist above and play with the width and depth. Enter 5.5 x 5.5 a factory 6x6 , click show result and notice the section modulus and the deflection. Then enter a 1.5 x 11.25 notice the section modulus, used in figuring bending strength is higher than the 6x6. Notice the deflection is half, its twice as stiff. At 2/3 the board footage. "deeper is cheaper" when it fits!

Hackermatack

Thanks for the calculations, looks like 6 x 6 will be plenty strong for a sleeping loft. And yes they will have full bearing on the conventionally framed 2 x 6 exterior wall with each beam landing directly over a stud. Wile running them over the to of the center beam would be stronger it will not look as nice as mortised in, which of course weakens both beam and joist. I will oversize the carrier and tendons to compensate.  I am using 6 x 6 because they will be pleasing to the eye in a farmhouse style eat in kitchen with a antique wood burning range. The area will be 27' x 14' and will have a 12' wide opening into the vaulted ceiling living room which will be approx. 27 x 16.
Jonsered 2230, 590, 70E. Kioti DK 35 /w fransguard winch. Hudson Oscar 236

GeneWengert-WoodDoc

In the above calculations, the grade is the key.  The grade of No.2 is not the same as the grade of No.2 common for hardwood lumber.  I do believe that No.2 for timbers does not allow shake or unsound wood in the piece. There are also restrictions on knot size and frequency.  See para. 25 and 26 in
http://www.nelma.org/wp-content/uploads/2013/08/Section_6.pdf
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

Don P

This is a couple of ways to mortise in a joist. It removes the most wood from the "neutral axis" of the beam between the outer faces that carry most tension or compression, it bevels back up on the top compression face to restore as much wood as possible to that corner.


The first mortise would house the entire 6x6. The second removes less wood from the summer beam. The bottom of that joist has a long shallow cope removing not more than 25% of depth to distribute the stress better than a square cornered notch there. That is traditional and also recognized in the code.

GeneWengert-WoodDoc

In most design numbers, the bend-ability (or better, the deflection) determines the size and span. We do not like bouncy floors and roofs, so we make them stiff, which means that we have excess strength. 
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

Hackermatack

40 + years of experience and the good advice given here tells me my design is plenty strong enough for a loft with a couple spare beds for company (easier to get them to leave without a proper bedroom). If the floor happens to spring a tad we will know what they are up to. The timbers will not even be part of the roof structure as that will be supported by a engineered scissor truss.  My original post was more about the aesthetics drying qualities of red maple. I also have some good white ash that I could harvest for the project. I have never tried to dry red maple as a timber, I have dried some ash 4x4 & 6x6 and found that it cracks more than some. I like Don P's suggestion of making a cut on the top side of the timber I don't know why it never occurred to me to do this before as I have been doing it for years on wide board shelving. 
Jonsered 2230, 590, 70E. Kioti DK 35 /w fransguard winch. Hudson Oscar 236

mike_belben

Fwiw, red maple is often pretty wormy and makes a really nice farmhouse floor planking with all the worm character.  Its got that old charm. 

If it aint wormy just roll it in the mud a few weeks and it will be. 
Praise The Lord

Hackermatack

We apparently do not have the same bugs up here in VT. I have burned many cords of red maple and rarely encounter worm wood. Powder post beetles will get into milled lumber some but not nearly as bad as ash. I would love to put a natural wood floor in the kitchen but most of my house will be slab on grade construction with radiant heat. My building site is pretty much solid ledge so a basement under all but a little of it is out of the question. I guess I am stuck with tile or if I want wood engineered snap together wood.
Jonsered 2230, 590, 70E. Kioti DK 35 /w fransguard winch. Hudson Oscar 236

mike_belben

Im doing radiant slab as well, someday. 

Id think you could put a tongue and groove plank floor over slab.. No?
Praise The Lord

Hackermatack

I suppose it is possible but my research and experience indicates it is not a good idea. Radiant slabs dry the crap out of wood flooring and our humid summers make the wood go the other way. If you start with bone dry wood it swells and buckles in the summer or if you start with 7% or so wood you get cracks in the winter. As the kitchen will have a antique wood burning cook stove tile over concrete should be a good option at least under the stove.
Jonsered 2230, 590, 70E. Kioti DK 35 /w fransguard winch. Hudson Oscar 236

Don P

Aside from the moisture swings in the wood, putting wood over a radiant slab is sort of like putting a quilt over a woodstove. I'm not saying I love walking on concrete but with a radiant slab, the slab is also part of the heating equipment.

Hackermatack

One can put a padded thick shag carpet over a radiant slab floor and although not the best choice the heating system will still function. It is common now to put 4" of ridged foam under slabs and tempering valves for each zone to adjust the water temperature. The heat would rather go up than down anyway and by adjusting the water temp higher the room will still heat. Engineered wood floors conduct heat pretty well and would not stand up to high temperatures. It might take 150* to make a carpeted floor do its job and low 70's may work fine under tile, laminate, or engineered HW. At least the master BR will likely have a basement under it and I will take a chance on real wood flooring there and run the water temp. just high enough so it does not feel cold and if need be I will install a Euro style radiant wall heater to take up the slack. 
Jonsered 2230, 590, 70E. Kioti DK 35 /w fransguard winch. Hudson Oscar 236

mike_belben

The humidity issue is a good reason not to.  But something to know about radiant heat.  You are heating a mass, not an air space.   This is a very slow, gradual temperature rise.  Radiant slabs water is around 80f or less.  Hotter will crack a slab. 

Again you are heating mass.  The more mass, the more stable the temperature because the BTU's are stored in it and radiated to the room air as that room air temp gets lower, creating a temperature differential for the transfer to occur across.  2" plank over a 4" slab.. 2" stone over a 4" slab, 2" tile over a slab..  Its all mass. 

Hippies build rocket stoves with sidedraft piping through sand and masonry benches before the flue pipe exits their yurt, teepee or igloo or whatever the new thing is today.  The point is if the fire temp peaks at 800f and exits the flue at 200f then you know the btu went somewhere.  Putting temp into mass or water is a vastly better storage mechanism than heating air.  Water is 800x more dense.  Thermal mass is why "russian stoves" made of huge fieldstone columns work so good.  Thermal mass.


Sorry for the OT.  Im passionate about cheap, efficient construction and cozy living with minimal utility expense.  Warm house, cheap heating bill = the good life.
Praise The Lord

Hackermatack

Did a lot of reading about the Russian masonry stoves or fireplaces years ago, good idea but I'm only going to burn wood in one old cook stove for nostalgia sake. Looking pretty hard at geothermal heat pumps. Probably crazy not to burn much wood given that I could never burn the cull hardwood I have as fast as it grows. I guess I must have cut and burned better than 200 cords in the past 40 years but I'm opting to cut and sell as long as I am able and burn something else. Wood prices tend to follow fossil fuel prices and I have never had a problem marketing a few cords of dry wood in midwinter at top dollar.
Jonsered 2230, 590, 70E. Kioti DK 35 /w fransguard winch. Hudson Oscar 236

Don P

Insulation is mass. Pile a massive stack between you and the woodstove. Or for that matter pile a huge mass of wood on the radiant floor. You will freeze. The rate of heat transfer is too low. Not enough btu's will get out our side of that pile to offset the losses. That is the reason the radiant would have to be run warmer to heat the house if an insulating material like carpet or a wood floor covers the slab. The rest of that increased heat required to push enough btu's through the wood floor to maintain the same temperature as a bare slab doesn't disappear, it is escaping the higher delta T across the other insulated faces and edges. That system is less efficient, mass is not the only quality, the rate of heat flow through the mass material is also a big factor.

mike_belben

The stove with wood blocking it is an example of heating the air, not mass heating.  Naturally an air barrier is going to well.. Act as an air barrier.  Radiant is a direct contact thermal transfer.

Put an oak burl in the oven to 150f. Take it out, climb into bed with it.  Is it not warm?  Is it not saturated in BTU energy that is now being dissipated into your blankies?  Does it matter if its a piece of brick, tile, stone or concrete?   Not really.   

I wont argue that different materials may require different water temps to emit BTU at the same rate as some other, thats reasonable.  If youre saying that wood doesnt work over radiant, id have to disagree.  There are many many homes out there with wood over radiant.  Google it if you like.  Many products available
Praise The Lord

Hackermatack

Guess we are getting a long way from drying red maple but anyhow. I until this year owned a rental house that I built myself, it had radiant heat in the finished walkout basement. The floor covering was standard carpet with pad, the slab was 6" thick with 3 inches of foam board under it to which the pex tubing was stapled. The tubes were spaced 12" apart, I ran the water temp around 130 although the warm up was slower than baseboard it was never a issue. The various tenants over 15 years all were very satisfied with the heat once the learned not to mess around too much with the thermostat. The finished area of the house was 1500 sq ft and it does get cold in NE VT. A oil fired boiler heated the house and hot water winter and summer and the oil was included in the rent so the tenants had no reason to skimp. The most oil that I used in one year was just under 500 gallons. Most heating contractors around here have pretty much stopped worrying about whether the heat will get thru the floor covering. The big concern is what the heat will do to the covering. The R value of most wood is a tad under 1 per inch so 3/4" wood floor will not block the heat. I have been involved quite a few radiant installations over the years and have never seen one of them fail to heat the house. I did see one done by another builder that the engineered hardwood flooring failed, the company made good on the materials but the contractor got stuck for the labor.
Jonsered 2230, 590, 70E. Kioti DK 35 /w fransguard winch. Hudson Oscar 236

mike_belben

Praise The Lord

Don P

If it works better use the analogy of a very thick wood floor that is in direct contact with the radiant slab. The low thermal conductivity of the wood will choke the ability to transfer enough heat from the radiant slab through that floor to keep the building warm.

I'm not saying it can't be done, or that you cannot heat the home, I've done it. I'm saying it is inefficient. It requires higher water temps and more energy to heat the house than if the wood was not there. As soon as you have to turn up the water temp to maintain the same comfort level, that excess heat energy isn't in the house, it is outside.

Try this;
http://timbertoolbox.com/Calcs/conductivity.htm
Enter this, Lets look at 1 square foot, you have the tubes 2" down in the concrete and at that level it is uniformly 80°F, the room above is 65°F, click enter, 62.46 btu's per hour are flowing from the 80 degree slab to the 65 degree surface. Now leave the temp delta the same, change to wood and .75" thickness, 18.04 btu's/hr can get across that material at that temp spread.

How are you going to get the needed number of btu's across the wood? Turn up the water temp. turn up T1 to 117°, and presto we can get the needed btu's through the wood floor. In order to get the same number of BTU's inside the building we've had to turn up the water temp 37° due to the wood floor. Can you do it? Sure. It doesn't come free  :).

By turning up the slab temp we have increased the delta between slab bottom and earth and slab edge and outside air... you can play with the calc and see the increase in btu flow across those materials.

Now put a bunch of wood mass on the radiant slab, enter 4" thick wood floor, 80 degree slab temp, I've got 3.38 btu's leaking through. The room is still losing temp at a rate that requires our 62 btu's/square foot/hour, can you get there?

Hackermatack

Quote from: mike_belben on November 26, 2017, 09:27:05 PM
Sorry for the sidetrack

I consider myself a expert at hijacking threads. You sir are the master, job well done  :D
Jonsered 2230, 590, 70E. Kioti DK 35 /w fransguard winch. Hudson Oscar 236

mike_belben

:takes bow:

Thanks for the clarification Don.  I agree with what youre saying now, i initially took you to mean "it wont work"
Praise The Lord

Hackermatack

I have see radiant under all sorts of floors most of them seem to work quite well. I like it because I seem to feels warmer at a lower thermostat setting and in the case of a radiant slab very little fluctuation in temperature. My son has a 45 x 66 shop with 17' ceilings and 3 overhead doors heated with radiant in the slab and a outdoor boiler. We had heat loss calculations done before the build and the experts said that the slab would not produce enough BTU's to do the job so we plumed in provisions for some Modine heaters. That was 8 years ago and to date we have not installed them. It is not uncommon on a below zero winter night to have 4 plow trucks covered with frozen slop and loaded with half frozen sand parked inside. It does take a while for the temperature to recover when all three doors are opened and the trucks are put in but come morning everything is thawed and ready to go. 
Jonsered 2230, 590, 70E. Kioti DK 35 /w fransguard winch. Hudson Oscar 236

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