Solar Kiln Dried Silver Maple as framing lumber?

[etd66ss]

Wasn't sure what forum to put this in, chose this one as I am hoping some familiar with wood species may also have engineering expertise on where they can be used in construction.

Long story short, I have been designing my home for years, thought I finally saved up enough to build it, paid an architect to generate plans for me, then got some post COVID build estimates, more than double what I was expecting, cannot afford to build.

I hear lumber prices are expected to skyrocket again this spring, couple that with construction companies can't seem to hire & retain labor, and it equals it may be too expensive for me to build for years to come...

I am in WNY, and my local building inspector informs me that I can use sawn lumber for home construction, but it has to be graded and stamped. I looked into this, and it is doable.

I am tempted to buy a sawmill to couple with the solar kiln I am building to generate my own construction lumber.  Here in NYS, I can use sawn air-dried lumber for building any non-residential structure, but for residential I will need the lumber stamped.

The question after all that is, if I plan to do this, what species should I choose? I plan to harvest from my own property.

I will list the species I have starting with least desirable to most desirable tree to leave standing, meaning the large mature trees I am most willing to cut down for lumber:

1) Silver Maple - I hate these trees and would be my first choice to part with. Average dry weight is 33 lbs/ft^3, .53 Specific Gravity at 12%MC, 700 lbf Janka Hardness, 8900 lbf/in^2 Modulus of Rupture.

2) Eastern Cottonwood - Also not a fan of these. Average dry weight is 28 lbs/ft^3, .45 Specific Gravity at 12%MC, 430 lbf Janka Hardness, 8500 lbf/in^2 Modulus of Rupture.

3) Scots Pine - These trees are dying like crazy, I have 100's left, but have lost 100's of mature ~70-80ft tall trees the last ~15 years. Average dry weight is 34 lbs/ft^3, Specific Gravity .55 at 12%MC, 540 lbf Janka Hardness, 12,080 lbf/in^2 Modulus of Rupture.

4) Norway Spruce - I would rather not harvest these. Average dry weight is 25 lbs/ft^3, .41 Specific Gravity at 12%MC, 380 lbf Janka Hardness, 9130 lbf/in^2 Modulus of Rupture.

5) Red Oak - No way I want to harvest these. I only have about 1-2 dozen trees, 30-60 years old. Average dry weight is 44 lbs/ft^3, .70 Specific Gravity at 12%MC, 1220 lbf Janka Hardness, 14380 lbf/in^2 Modulus of Rupture.

The trees I am most willing to part with are similar in dried weight to typical SPF construction lumber, but not as strong when looking at the Modulus of Rupture.

The Scots Pine probably makes the most sense but I think the knotty nature of the wood decreases its strength for dimensional lumber?

I don't think I could use any of this wood for floor joists or roof rafters?

Also, the Cottonwood and Maple are listed as "perishable" in terms of rot resistance. I also assume they are not very insect resistant. Though I don't think lumber yard SPF dimensional lumber is any more insect resistant.  I would still need to buy some lumber for ground/foundation contact etc.

[Don P]

Grading lumber for residential in NY. What you have done sounds like a fine plan. Your state laws do allow a small mill to self stamp for residential IIRC, ultimately it is the inspector's call and it looks like you have a plan.

Species. Look at the plans. What do they call for, There should be callouts for minimum species and grade of spanning members.

Without getting out of everyone's happy place for species/ grade/ grading/inspecting/engineering and the potential rabbit holes using "different" species can lead a poor bureacrat down. Go over to awc.org and download a copy of the Supplement to the NDS. In the first few pages are the species and species combinations that are documented in that code referenced book in your hands... these are the real, allowable design numbers rather than the Lab average ultimate strength numbers in the OP. They were breaking clear 2x2's in a lab, we have knots and don't want to break, or even bend much. The numbers are related. You posted the raw data, the Supplement cooked that into my "Allowable Design Values" for various species and grades.

Then, look up the design values for whatever the plans call for. Look up your desired replacement, is it as strong or stronger?

Mills, good luck, they are backordered too.

Drying. Construction lumber is 19% max. I can air dry to 12-14% under shelter pretty easily.

Saw to 1-3/4", dry, plane to 1-1/2", rip to final width after dry. Doing that nails, hangers, etc work, if you run short you can run to the store. Yup you can build with roughsawn, I think it creates more work in the overall and is usually poorly connected, wrong nails. I planed around 2,000bf of 20' 2x12's this week. Took 3 days, I can only do so much of that kind of fun at a stretch. Oh, and framing has come down enough between when we decided to roll our own and now, this wood is now no bargain. I'm having to decide what is fair, when this started I was a hero now I could be a zero, life's funny like that  :D.

[stavebuyer]

By the time you figure all the extra labor and costs involved in producing the framing lumber I don't think the savings will be all that much. I also think we may see some market corrections at least in framing lumber. Some of the other inflation influenced price increases like copper and appliances probably are permanently increased.

[etd66ss]

By the time you figure all the extra labor and costs involved in producing the framing lumber I don't think the savings will be all that much. I also think we may see some market corrections at least in framing lumber. Some of the other inflation influenced price increases like copper and appliances probably are permanently increased.

I would be the one logging, milling & drying, I never count my labor, because what else am I going to do with my free time lol?  Associated costs would be the cost of the sawmill (which I want one anyways, not just for this task), sawmill and other equipment maintenance, and of course the cost to get the lumber graded and stamped.

My house design is only ~1250 sq-ft single story, and it is an ICF design. The walls are concrete from the basement footer to the roof. The one estimate I did receive (waited 4 months for only one estimate, most GC's didn't bother to give me one) the framing was extremely high.

~$87,500 for the roof, floor & interior walls lumber. Only the roof has sheathing, the floors use Warmboard plywood for radiant heat and that was not priced out separately, so could be a large part of the cost. And that price tag is materials + labor,

I can't imagine if this was a fully stick frame design what the estimate for framing would have been... My brother built a 2500 sq-ft house back in 2014, one of those McMansions with many corners and crazy roof lines, his framing lumber budget (materials + labor) was ~$28k.
Overall the estimate was $560,000 for a single story 1250 sq-ft house, ~$450/sq-ft.  Not doable for me, I have to find some other way...


 


 


 

[Don P]

 It looks like the only framing you would be milling is the floor and roof in the main building, which those look very long and likely need to be higher grade stock, some interior studs. It looks like the wing is trussed and slab. You'll probably regret that water table around the house, that is tough to effectively flash and look good over time. Can you make the wall thicker and eliminate that detail? The mill will make you more money when it gets to interior fit and finish.

[etd66ss]

So looking at the NDS supplement, Maple vs. Douglas Fir:



 


 


 


 

It looks like on ave, the Modulus of Elasticity of Maple is about 69% of Douglas Fir. Lower than I expected tbh.

The architect did not call out any species for my roof rafters or the 2x10 floor joists for the living room. The rest of the roof and the main floor diaphragm use trusses.  My assumption is trusses do not need to use Fir, but rafters and joists do.

The roof rafters are pitched at 12/24, so maybe at that pitch I could use non-Fir rafters...

[etd66ss]

It looks like the only framing you would be milling is the floor and roof in the main building, which those look very long and likely need to be higher grade stock, some interior studs. It looks like the wing is trussed and slab. You'll probably regret that water table around the house, that is tough to effectively flash and look good over time. Can you make the wall thicker and eliminate that detail? The mill will make you more money when it gets to interior fit and finish.

I guess I am not sure what you are referring to as the "wing"? The garage? My architect never mentioned any issues with my design.


 
Any way I can make these images full width of the browser? I attached a pdf of the floor plan so it's easier to read, I think...
Do you mean this roof intersection?


 

[Don P]

I'm not seeing any framing info in that.

Yes, what I could see in the section cut over the garage and BR/WIC looked like manufactured trusses, I couldn't tell what was over the office/bath bumpout for roof framing but those are bought goods.

The ledge that concerns me is the one formed by the stone (gray areas) and the tan wall above. Water running down the wall hits the ledge and has a choice. Better to keep that driving water rolling off as quick as possible. I've run into that one with siding above a brick veneered ledge. We rebuilt every gable wall. Not sure I'm understanding it all just grist for the mill.

[etd66ss]

Oh, that ledge is natural stone veneer. Due to cost that is probably going away.

And if I were to get a mill, I would likely change the design to stick frame, so all the concrete walls above grade go away.

The estimate for all the concrete work was over $160k. So it looks like ICF compared to todays lumber prices is still not a bargain due to the labor involved.

Also, here is a link to the full plans which have been redacted of personal info.

https://drive.google.com/file/d/1VRGt_b-swdtlpe71_AwHgMGbZ-K6qMOp/view?usp=sharing

Originally, the decorative beams was all I planned to mill for the build, but now I might want to do more.

[farmfromkansas]

Cottonwood is a interesting wood.  When Kansas was opened up to settle, the only big trees here were cottonwood.  So most of the barns are built from cottonwood.  Thing about cottonwood, is if you cut down a green tree and saw it, air dry it off the ground, it seems to gain some rot resistance.  Have a neighbor who has a couple old cottonwood sheds, everything, framing,flooring, siding, nailers on the roof, all but the shingles were cottonwood, and those buildings are 100 years old or plus. Still usable buildings.

[Don P]

I just noticed the plans link. Check pg1 under masonry, steel and wood notes, start around item 15 and read to the end. Before starting just about everything on those pages needs to be in your head, top of mind. It looks like standard #2 or better SPF is the callout, everything on that page looked like stock boilerplate, but I didn't study it. Then look at the following pages for exceptions. we just hit shop warmable temp, yaay!

[etd66ss]

I just noticed the plans link. Check pg1 under masonry, steel and wood notes, start around item 15 and read to the end. Before starting just about everything on those pages needs to be in your head, top of mind. It looks like standard #2 or better SPF is the callout, everything on that page looked like stock boilerplate, but I didn't study it. Then look at the following pages for exceptions. we just hit shop warmable temp, yaay!

Yeah, I think those are Architect Copy/Paste notes for every set of plans.  I would need the architect to denote exceptions if I were to use something other than #2 SPF.  On the current plans the only exceptions should be for the LVL's etc.
I'd have to do all my milling & drying, then see where the grading comes in before I'd even pay the architect to make those changes. I'd probably mill Silver Maple, Cottonwood and Scots pine to see where the grading falls.
However, if I were to do all this, it puts off my home build for probably ~2 years. However, I guess I can't afford to build in these COVID times anyways...

[Don P]

Whew, that took about 2 seconds, the shop is 12° but the stove is dancing  :D.

His callout is #2 SPF or better, he's already provided for an exchange. I haven't looked, check your desired species and see if it meets equal or better, if so you're golden. If not check the joist and rafter span tables or the calc on the awc website. If they will get you there that is prescriptive, your call but no archie or engineer required.

I built in lean times, I tend to buy high and sell low, it makes twice as many people happy. The equation favors sweat equity if you can maintain while putting in the hours.

[GeneWengert-WoodDoc]

The building inspector is adhering to the letter of the law.  However you night be able to point out that sometimes it says "or equivalent..

So, getting it graded is tough, as you need someone certified for hardwoods.  Then, once you have the grade, which is very strict on knots, sideways warp, and good nailing edges, there will be span tables that must be used.  Some uses, like a beam in a basement or over a garage door, plus other locations, require high quality pieces that you should buy.

Much silver maple is quite knotty, so you might get low grade pieces that you cannot use. Also, store bought 2x lumber is finished at 1-1/2" after drying.  With maple, you need to dry it to get the same size, or else you will have wavy floor, roof and walls.

Also, for floor joists, the limited span means extra work. Eventually, you reach the point where "store bought" is cheaper and easier to handle.  Saw the silver maple into 4/4  lumber and sell it.

[etd66ss]

The building inspector is adhering to the letter of the law.  However you night be able to point out that sometimes it says "or equivalent..

So, getting it graded is tough, as you need someone certified for hardwoods.  Then, once you have the grade, which is very strict on knots, sideways warp, and good nailing edges, there will be span tables that must be used.  Some uses, like a beam in a basement or over a garage door, plus other locations, require high quality pieces that you should buy.

Much silver maple is quite knotty, so you might get low grade pieces that you cannot use. Also, store bought 2x lumber is finished at 1-1/2" after drying.  With maple, you need to dry it to get the same size, or else you will have wavy floor, roof and walls.

Also, for floor joists, the limited span means extra work. Eventually, you reach the point where "store bought" is cheaper and easier to handle.  Saw the silver maple into 4/4  lumber and sell it.

It's been a while since I have sawn Silver Maple, but found some pictures of the last time. I could not recall from memory, but in these pics the boards do have some knots, but not excessive.


 


 

 
I haven't harvested any trees yet. The above lumber was from Silver Maple that was logged to clear land (many years ago), most of the Maple trees were processed into firewood, the above lumber went into constructing some shelving (a lot of it went to waste however due to insect damage because it was not kiln dried). I was not selecting clear stem canopy trees to minimize knots. I was just clearcutting mostly multi-stem/branchy maple. I do however have a lot of canopy Silver Maple to choose from that might deliver rather clear grain.

I do have other species to choose from, but I am also thinking about what I'd want to leave in my forest. I'd not want to part with the Spruce trees. The Scots Pine trees are dropping like flies and I need to harvest them before I lose them, however they would be a lot more knotty than the Silver Maple I imagine.

According to the AWC sawn lumber species table, Maple falls under the NELMA grading agency rules, closest authorized agency to me on the AWC agency listing is in Cumberland Center Maine. I have yet to contact any grading agency to discuss the grading process. Only thing I have learned to this point is that it's a hourly charge for the service, so you need to have an efficient setup. And likely mill and process way more lumber than you would need to hopefully ensure you end up with enough graded lumber for the project. I have no idea on cost, if I'm looking at $100's, $1000's or $10,000's. I would assume $1000's.

But before all that, I need to look at the species span tables to get an idea if there indeed is a lot of extra work.
One other question I have for my building inspector is, if it is allowable to have trusses designed for my project utilizing sawn lumber. I'm pretty sure this is allowed for non-residential construction, but need to find out if I can used lumber that I have graded to build trusses for a residential structure.

[Don P]

Let's start at the horse's mouth. This is the NY building code.
I'm opening to the first cite, index is on the left sidebar to other chapters;
CHAPTER 3 BUILDING PLANNING, 2020 Residential Code of New York State | ICC Digital Codes (iccsafe.org)

Check R301.1.3
As long as you have a sealed design for your trusses, you may build them yourself. The engineer's truss instructions/requirements are in R802.10

R301.8 says the code speaks in nominal dimension lumber (2x is 1-1/2, etc)

R317- where treated lumber is required.

Here's the meat and taters...
R502.1.1 NYS native lumber law written into the state building code, now you can hand the inspector a citation if he asks for grading. If it is unclear turn to,
R602.1.1, same language
R802.1.1, and again. Grading is fine, and encouraged, but that is your choice.
Those are the headings of the structural framing chapters, the intent is very clear.

BUT! You have a problem. The architect specified #2SPF or equivalent. Look at the Fb and modulus of elasticity of silver maple compared to SPF. Graded or not, it is not "or equivalent". 

You have plans and a weaker species than called for. You'll need to resize the members. The awc span calc should be able to help there. This would be a plan change.

[etd66ss]

Let's start at the horse's mouth. This is the NY building code.
I'm opening to the first cite, index is on the left sidebar to other chapters;
CHAPTER 3 BUILDING PLANNING, 2020 Residential Code of New York State | ICC Digital Codes (iccsafe.org)

Check R301.1.3
As long as you have a sealed design for your trusses, you may build them yourself. The engineer's truss instructions/requirements are in R802.10

R301.8 says the code speaks in nominal dimension lumber (2x is 1-1/2, etc)

R317- where treated lumber is required.

Here's the meat and taters...
R502.1.1 NYS native lumber law written into the state building code, now you can hand the inspector a citation if he asks for grading. If it is unclear turn to,
R602.1.1, same language
R802.1.1, and again. Grading is fine, and encouraged, but that is your choice.
Those are the headings of the structural framing chapters, the intent is very clear.

BUT! You have a problem. The architect specified #2SPF or equivalent. Look at the Fb and modulus of elasticity of silver maple compared to SPF. Graded or not, it is not "or equivalent".

You have plans and a weaker species than called for. You'll need to resize the members. The awc span calc should be able to help there. This would be a plan change.

Thank you for the codes. I will re-investigate. However, if I am remembering correctly, the last time I talked to my building inspector about this, he mentioned townships have the authority to add on top of the state-wide codes. So in my township, sawn lumber for residential use needs to be graded, if I don't like it I can buy property in a town in NYS that doesn't require grading, etc. So instead of trying to fight it, I figured I'd look into the grading services.

As far as the architect, yeah, those are his copy-paste notes that I'd have to have him change.

I went ahead and performed some analyses for the first floor diaphragm.
The span is 23" 1-1/2" between the ICF basement walls.



 
The current design incorporates floor trusses, but I am going to look at joists for now, just so I can more easily compare SPF to Silver Maple.


 
The above free software did not allow me to choose NDS species, so I found another online software that had a 14 day free trial.



 

I chose to use the beam analysis in this software instead of trying to setup a floor diaphragm like the first software. This doesn't allow direct comparison to the first calculation, but it allows me to import materials right from NDS, so I can bring in the Silver Maple.

I started with a No1/No2 SPF joist @16% MC:


 


 
The above plot shows the SPF No1/No2 2X12 deflection meets the L240 criteria of course.

I went ahead and performed the same analysis for a Silver Maple (NDS Mixed Maple) 2X12 @19% MC. I chose No3 grade, assuming that my trees aren't going to produce No2 grade. (Though I think I could get some...):


 


 
So, comparing the deflection of the SPF joist to that of the Silver Maple joist, there is about a 14.5% increase in deflection. The joist still meets the L/240 deflection criteria. Therefore, I'm not seeing where there would be any extra work involved in terms of bracing to use Maple in place of SPF.

I then looked at milling the Maple to an LVL size to utilize store bought top mount hangars on the ledger bolted to the concrete walls. I changed the section of the Maple beam to 1-3/4 X 14, using these hangars on ledgers of the same 14" depth, but 1-1/2" wide:


 


 


 
So, compared to the 2x12 SPF joist, the milled 1-3/4 x 14 LVL-sized Maple deflects about 49% less. It might be overkill to use these as it is more load on the beam and columns carrying the joists to the basement walls and footers. I'd have to do some calculations for that. I am 6ft tall and I don't want a beam anywhere near my head when I am in the basement. One of the reasons I initially went with floor trusses in my design was to remove the beam and posts. However, those trusses in today's market are not feasible.

As far as drying and processing the Silver Maple. I'd likely try some test pieces to arrive at shrinkage factors to get me close enough to the desired finished size so I'm not wasting too much when ripping & planning.

As I said, I have sawn and used maple in the past, but it seemed very susceptible to insects. I do plan to finish my solar kiln next summer, and hoping that drying the Maple would make it more insect resistant? The kiln would likely get the lumber lower than 19%. At what MC would I need the Maple to be to deter insects?

Also, I do recall that a fair amount of the Maple I sawed in the past crooked quite a bit when it was air-dried...

I'm going to perform this same analysis on other species I have available for harvest.

[Don P]

Those calcs, or the one's in the toolbox here are fine for prelim design but not for the inspector. You can check chapter 3 but I think min floor deflection is L/360 but generally try to be stiffer if possible. Same thing with the center girder, beyond code, get girders up around L/600+ for a nicer feeling floor.

For this, go to the code referenced joist and rafter tables.
I'm going to take you in through the main publications index... go here first for wood (sawn lumber) structural design stuff, this is generally the source recognized in the code.
Publications (awc.org)
Scroll down kind of paying attention to what's there until you get to the 2021 span tables for joists and rafters, and download that.

*apawood.org is the referenced source for engineered wood stuff.

With your grading report in hand,
look in the Supplement for the design values for the species and grade described.
Look in the span tables are set up by design values rather than species and grade.
This is the code documentation path for prescriptive work.


The quick calculator is here, hit the span calc, should give the same answers;
Calculators and Software (awc.org)
Looks to me like 2x10 in #2 mixed maple passes.

With it and the toolbox here #2 mixed maple 2x10's on 16's play out around 13'6"-13'9".  I find it difficult to incorporate a true #2 into anything other than sheathing or woodstove. I suspect most sawyers are the same. Keep your eyes and brain in gear and #2 values are fine.


edit, girder design, you pass by WSDD on the way down the page to the span tables, grab that as well. The scotch tape is failing on the '92 here at my elbow  :D.

[etd66ss]

Those calcs, or the one's in the toolbox here are fine for prelim design but not for the inspector. You can check chapter 3 but I think min floor deflection is L/360 but generally try to be stiffer if possible. Same thing with the center girder, beyond code, get girders up around L/600+ for a nicer feeling floor.

For this, go to the code referenced joist and rafter tables.
I'm going to take you in through the main publications index... go here first for wood (sawn lumber) structural design stuff, this is generally the source recognized in the code.
Publications (awc.org)
Scroll down kind of paying attention to what's there until you get to the 2021 span tables for joists and rafters, and download that.

*apawood.org is the referenced source for engineered wood stuff.

With your grading report in hand,
look in the Supplement for the design values for the species and grade described.
Look in the span tables are set up by design values rather than species and grade.
This is the code documentation path for prescriptive work.


The quick calculator is here, hit the span calc, should give the same answers;
Calculators and Software (awc.org)
Looks to me like 2x10 in #2 mixed maple passes.

With it and the toolbox here #2 mixed maple 2x10's on 16's play out around 13'6"-13'9".  I find it difficult to incorporate a true #2 into anything other than sheathing or woodstove. I suspect most sawyers are the same. Keep your eyes and brain in gear and #2 values are fine.


edit, girder design, you pass by WSDD on the way down the page to the span tables, grab that as well. The scotch tape is failing on the '92 here at my elbow  :D.

I did download all that stuff previously, but somehow missed the online calculator. That would have been way easier than what I did this morning...
Looks like a #2 2X10 Mixed Maple does indeed pass, but a #3 2X12 Mixed Maple fails. So the beam calc's I did on the SkyCiv website are not correct. Must be something to do with analyzing the member separately as opposed to in a floor system.

I think the big challenge with the Maple would be getting decently straight lumber. From my little experience with it, it moves a lot when drying.

[Don P]

I borate most wood like that green, right off the mill. If there is a spectator, put em to work  ;D. I usually saw to 1-3/4", dry, plane to 1-1/2 which generally cleans up in 2 passes up to 2x12 wide. Then rip to nominal width, removing drying crook. That is called SDR, Saw-Dry-Rip and helps with species that move a fair amount.

Grading, Be flexible on timing if possible, if a grader can check you while on his rounds it can cut the windshield fee. They need to see all sides of every stick, its cheaper to turn for him. Have a saw ready to dock lumber, it can make something useable that wouldn't be otherwise. Needless to say you don't want to do that much. Grade as you process at some or every step upstream of him and catch all you can, reprocess smaller and replace if needed.
NELMA On-Demand Lumber & Timbers Grading Program

Edit; I think I saw mention of something above to maybe clear up. When you see a grading agency listed in the Supplement beside a species, that means that is the "rules writing agency" for that species or group. They "adopt" and create any special grading rules, if needed, for that species. Any accredited agency can grade that species, the grader will review any special rules, if needed. It does not mean that only a grader from the rules writing agency can grade that species. There are a number of "Non Rules Writing Agencies", more than rules writing really.