Need help with log cabin calculations

[getoverit]

I have a customer who has offered to pay me to saw all of the logs necessary to build a 2500 square foot log cabin. I have no idea on how to figure how many logs it will take or how much cutting it will take to build a building of that size. As of right now, I have no plans to work off of and the customer is requesting a rough estimate for labor and materials.

Right now, I am trying to price out the building based on SYP for the logs (since I can get them for free) and I am assuming that I will cut the logs three sides flat and one side natural. I am also assuming that they need to be 6" thick by 6" tall??

Can anyone help with the calculations or tell me where I can get the figures necessary to calculate this?

[srjones]

You should probably look at the plans to see how many linear feet of walls are required.  Without looks at the plans, there's no way to know.

For example, a 2500 sf cabin could be 25x100 or 50 x 50...

Whatever you bid, make sure to include a %factor over. 

[firecord]

To calculate your needs:

EXAMPLE  8' (96" WALL HEIGHT)x 24' x 30'  home:  (108' per course) 

Take the height of the wall in inches, divide by 6", which is the face of the material, multiply that number by the total feet of the wall or around the home.   
96 inches divided by 6" = 16 courses of logs
x 108 feet long = total of 1728 liner feet needed.

[getoverit]

Is there a "standard" amount to calculate for overage and waste?

would 20% be enough?

I have figured that based on a 32'X80' house with 10' high walls, it would take 280 logs 16' long. Should I figure the job on 350 logs just to be on the safe side?

also is a 6" thickness standard or would an 8" be better?

[Don P]

I've built mostly with milled logs. The most common sizes I've run into are 6x8 (8 tall)
8x6 (6 tall) and 8x8. Dont forget any log overhang in your lineal footage/row. Don't deduct for openings unless they are huge. Waste factor could be about anything. Variables there are quality of logs, lengths, owner fussiness, probably more I can't think of. Imagine I have a 26' wall length and you send 16'ers. Waste will probably be bad. I like having several length piles. The present job stacked to 18 rows main level, 35 rows in 2 gables and 52 rows in one gable. I don't like log gables. We have a small trailer load of leftovers, I guess we typically get about 5% over.

[getoverit]

Thanks Don!  That answers my questions. Guess I'll figure out a price now and see where it goes.

[isawlogs]

 I would never put out a price for sawing a job like you are about to do with so little info to go by . There are too many factors you dont know or are taking for granted . From what I read , alls you got to go by is that your customer is wanting s 2500 square foot building ...

   I would really like to know how it is you are going to give this person an estimate not knowing the type of building or the type of roof he is looking for .
  I sure dont want to imply that you cant do it , just very curious on how you plan on doing it .  ;)

   I have sawed and put up many , many log structures and there is no way for me to cut an estimate on the info you gave . the ball parc figure would need to be so big we could play all the league games at once  ;D

[getoverit]

The "customer" is a relative, and the trees are standing on his property, which adjoins my property on the farm.

At this point, All I am trying to do is to come up with a figure for turning about 6 acres of mature pine trees into logs suitable for log cabin building. One of my objectives here is to get a rough idea on how many logs it could take and then go from there.

The price I give him will include felling the trees, milling them into log cabin grade tongue and groove logs, debarking them and then removing the stumps.  As of right now, I am seeing that this job will most likely last me through the whole winter months and I am pricing out the job to him based on time ( 4 months) with a healthy profit included for me :D

Right now I have figured a minimum of 280 logs and then added to that figure to cover all of the possibilities, which brings me to around 400 logs that are 16' long. It will be up to him to find a builder who can work with 16' logs and design him a building using them.

[Stephen1]

Plan on 3\4" shrinkage in height for every foot of green logs. ie:  for a 96" ceiling you will need to build to 102-104" in height.

[UNCLEBUCK]

Also why wreck 6 acres of beautiful trees and send them through a t&g machine . You will be making a kit home , in log school those are called kits . You should have your relative go see a bunch of log cabins and see if he wants the kit look or the real cabin look .

[Stephen1]

Uncle Buck, I  to agree with that!
But, it sure would be a  lot less work, using a sawmill.

Also why wreck 6 acres of beautiful trees and send them through a t&g machine . You will be making a kit home , in log school those are called kits .

[getoverit]

I had considered making them the old traditional way, but knowing my relative, he doesnt have the time to take care of a traditional log cabin. One made in the "kit" style would more suit his lifestyle and time restrictions. This will be a second home to him, and at 2500 sqft will be much smaller than his primary home. He is wanting a rustic looking home for this one, and insists on calling it a "cabin"

Does the 3/4" per foot shrinkage rule apply to logs that have been air dried or kiln dried?  I am guessing he wants 10' ceilings in the house and I will need to figure the shrinkage into this. 

By the way, I gave him a "rough-ball park" price today (thanks to the advice I got from you guys  _grin) and he seemed happy with what I gave him. He will be seeing a builder and engineer in the near future and  will have some plans drawn with more precise log requirements.  I gave him a price based on 16' logs, and calculated by the linear foot. I found sites on the net that price out logs this way, so I assume it is a valid way to calculate costs? I also priced it out based on 400 logs 16' long.  If his requirements need more logs, then my price is by the log, so he understands the price will go up if there are more logs needed.

I will also be milling the flooring for the home and most likely the wood needed for the cabinets also. Should be profitable for me and cost saving to him because all of the wood is already on site (in log form) and doesnt have to be bought.

[Stephen1]

the 3\4" is what the wall will shrink over about 5 years.

[firecord]

Does the 3/4" per foot shrinkage rule apply to logs that have been air dried or kiln dried?  I am guessing he wants 10' ceilings in the house and I will need to figure the shrinkage into this.

Not to hijack this thread but I'm learning, I have a  DUMB QUESTION!!!

If using Southern Yellow Pine how much drying would be required before building can begin?  I will be cutting 7"X 10" SYP cant's to build mine and have only planned for 1 year of air drying.  Is that enough? 

[Jim_Rogers]

Which way are you stacking the 7x10s? 7 tall or 10 tall?
It will take years for these to air dry to the core.....

Jim Rogers

[firecord]

10" tall 

Yea, I figured they would be drying for a long time.  But I assumed you just wanted to get the drying process started before you started staking them.  Is it really even necessary to let them dry some or just a good idea.  I read all this timberframe stuff and some of yawl start with fresh cut and others use dried.  I would figure that if you cut the dovetail joints in while it is still drying and shrinking, it would be tighter. 

[getoverit]

As a part of my pricing, I calculated in the cost of treating the log with THIS STUFF to help with the drying and curing process. I'm hoping that it will drive out the water quicker and give a log that will last much longer and be bug resistant too.

[Stephen1]

10" tall 

I would figure that if you cut the dovetail joints in while it is still drying and shrinking, it would be tighter. 

As the wood drys because it shrinks in circunfrence not length. With dovetail the joints will probably shrink smaller ,I would think as you do your research you will find that there is a formula used for dovetail joints. Scribefitting round logs have got to where sadlle notches are used because as the log shrinks in circumfrence the log above slides down the saddle.

[isawlogs]

  Sure glad you got that all figured out and got yourself a winter job out of it ...  :D :D
I have one more little question for ya  ;D ;D   Whats the difference between taking care of a" kit " and a traditional ...  ???  As far as I can see both will have wood exposed to the elements to a surten extent ... non .
  Have you concidered a sawed dovetailed log with chinking .  ;D ;) It would take a lot less logs to get to the height you plan on going .

Firecord
You will find that as the wood dries , the dovetails will shrink less then the logs , this being that they are cut in the heart wood .
What have you thought of as insulation to go between your logs .  ???

[getoverit]

I had figured it would be a more constant chinking problem with a traditional log cabin vs the tongue and groove on the "kit" form. I may be way out in left field though.

I'll admit I know absolutely nothing about log cabins. I'm just a sawyer trying to fill a need for my customer and a need in my pocket for me :D

I'm always looking for ways to make money with what I have available though. Seems like a good way to do it to me

[firecord]

Drawing is crude but here is what I have in my mind at the moment.


Cant's will be stacked with a 4 X 6 milled infill to create a gap for chinking.
Logs will be cut to accept the infill log as a barrier in the chinking space.
Kinda toung and groove but not really

[beenthere]

Just a comment on a thought I had when looking at your drawing, that the infill should not be so thick (in height). If it could be thinner, then it wouldn't have a tendancy to 'roll' over, which with warping of the 10" timbers, might happen. I'm not sure just why you are using the wood infill, but something more like 2x6 seems would be better than the 4". I can visually see pushing on the wall and having it buckle. That may not be a problem, only my perception.

[getoverit]

What I have in mind right now is something along the order of this:




Milling a channel in the top and bottom of each log and then inserting a 2x4 or a 2x6 should prove to be steady enough to hold things together??

[firecord]

Ok  howbout this?

OR

Adding all-thread from slab to top headder to reduce buckle?

Also do I have to let the logs dry any or can I start building as soon as I get enough cut?

[Stephen1]

Firecord, why bother with the 2x4 spline if you are going to use threaded rod. I would set up a jig and router a tounge & groove, then place a product like emseal between the logs. if the logs are not dried completely, you might as well start building right away.