Library

Underscribing - Updated Chapter This is Chapter 8 from my full-color book, the Revised Log Construction Manual. The current edition was printed in 2021, and has extensive revisions. This file is the full chapter on Underscribing. All owners of my book (especially 2014 and before) should download this free upgrade because it includes important new information. Underscribing (invented by Del Radomske 35 years ago) is a super way to keep corner notches tighter over time. Proven and effective.

Dovetail Corners The first homes I built had dovetail corners. I did not learn dovetail construction when I attended the Mackie School of log building, so I had to figure out alot of it on my own. I wrote two articles for Joiner's Quarterly in 1991. You can search online for those articles, but that old information is not very useful and definitely not up to date. That is why I wrote a short book on DOVETAIL construction for my Log Cabin Secrets Series of books. My online shop (and Amazon and Apple Books) sell all my Log Cabin Secrets books. Available in paper, or as eBooks.

Selection Rules, Calculators, and Selection Maps

II developed a method to help you decide which diameter logs are best to use each time you prepare to add a new layer to a stacked log wall. I call this "LOG SELECTION". You will have an inventory of logs to use for the walls. Some logs are larger than average, and some are smaller. Eventually you will use all your logs, but which log to use next? Log selection rules help you decide whether to use a bigger log, or a smaller log, or an average log next. An entire chapter in my Revised Log Construction Manual explains why log selection is needed, and how to do it. Here you can download Excel calculators (metric or imperial). Download one of these files to figure the "Desired Shoulder Heights" for your set of logs. These are Microsoft Excel files, and you can open and use them if you own a copy of Excel software. If you do not have Excel on your computer, then they will NOT work. One file is for builders who use the metric system, and the other file is for imperial (inch) builders. Download just the one file that you will use. These files are copyrighted by Robert Chambers and they are free for you to download and use. You will need a copy of my book, the Log Construction Manual to understand how to use the numbers this spreadsheet produces. Contact me with questions, bugs, problems, compliments. Note that both spreadsheet files contain "Macros," and they are virus-free, if you download them from this link. To open the spreadsheet you must "allow Macros." You will need to make your own MAPS because the map must match YOUR floorplan. This PDF is an example of a 4-wall cabin.

Free Video Clips on You Tube

IMy how-to DVDs are tremendous at showing you how to use the tools to peel logs, scribe notches, cut notches and grooves. I have a YouTube channel with some free samples. Take a look: How to SCORE a notch with a mallet and chisel (to make a clean notch, without splintering). How to CUT a saddle notch with a chainsaw - includes the cutting and brushing techniques. CORNER ORDER- a video that helps you see the BBTT corner order of logs, and explains why sill logs are so important. ACCELERATED LOG BUILDING- a video that shows my ALB log-holding machines in action building a handcrafted, full-scribe-fit shell.

Mitered Log Joinery

I use a method of joining logs to each other (for roof trusses, post-and-beam timber frame, and more) that is sort of like timber framing. No scriber is used. I started with Ed Shure's method, and then, over years, developed it way beyond his techiques. I wrote two books in my Log Cabin Secrets series about mitered log joinery. You will need my two books to use and understand these downloads of a PDF of map angles (PDF), and an Excel spreadsheet of "adjusted angles". You must own Excel to open this file.



Parts list for Truss Jig. Sorry, it has not been kept updated, but this PDF will help you find some of the parts you need. Watch my YouTube video (see YouTube link above), and slow it down to identify parts that you see in the video. Please note that there is NO assembly manual for this jig, and NO user manual.



Log Cabin Secrets books are available on paper from my store (click links), or as eBooks from Amazon or Apple. These links take you to my webstore, where you can buy paper copies of my Log Cabin Secrets.

Maintenance and Preservation

A 14 -page PDF copyrighted by the Log Homes Council including information about PROTECTING against insects, decay, removing iron stains from wood, and more A 16-page PDF on FINISHES for log homes-- penetrating stains, water repellancy, mildew, and much more. A very valuable resource. How to protect log homes during construction, how good design helps protect logs, your choices for chemicals and finishes, wood cleaners. Produced by Forintek Canada, a top government research institute for everything about wood. PDF brochure that includes advice on preventing INSECT attack, avoiding bluestain and decay—advises use of deep roof overhangs, some chemicals (borates), and the like. Some very good color photos of bugs that attack wood. The emphasis here is on bugs--which makes sense, in Georgia. Written by the Georgia Forestry Commission. This large PDF is a training manual for Forest Service staff teaching how to preserve historic cabins. The title of the book says "dovetail," and there are some dovetail and lap-notch cabins, but many of the buildings are round log scribed and round log chinked. Information about how to assess condition and find hidden decay...and how to REPAIR. How to jack up foundations, and repair floors walls, and roofs. How to replace logs without taking walls apart. Lots of hands-on information about roofing (especially with cedar shingles and shakes). Doors and windows, chimneys. I learned a few things, and saw a tool I had never seen before: a "band clamp" (Figure 63).

Windows and Gaskets - Tech Sheets

Windows and Doors in Log Openings 1 a PDF on the choice between flanged and non-flanged window styles for log homes, the difference between Carpentry Rough Opening (CRO) and Log Rough Opening (LRO), and how to frame bucks into openings. Photos and drawings as well as helpful words of advice. Download and print and use this information. Windows and Doors in Log Openings 2 a PDF including detailed head, sill, and jamb drawings of installing doors and windows, how to flash the opening, how to air seal it, and using settling boards and settling space a safe way. Photo and drawings as well as a description. Architects and designers may find the drawings useful--and carpenters and DIYers definitely will. Gasket Material, Design, and Installation a PDF about the gasket (rubber seal), that Natural Log Homes uses inside their grooves and notches. NLH uses a rubber seal that I designed, tested, and that they have made just for them -- it is not an off-the-shelf item available anywhere else. Good close up photos of how it is installed in logs.

Fire Resistance Log Walls

Written by Dalibor Houdek, PhD, and first published in Log Building News #35 (September 2001), this is a reprint of a 3-page article about scientific lab-testing done on scribe-fitted log walls and their resistance to fire. (Log walls come out great, by the way.) This download is courtesy of the International Log Builders Association. Tech sheet on fire resistance of logs walls, from the Log Homes Council.

Rigging and Lifting (US Army Field Manuals)

Chapter 5 from the army field engineer's manual, this PDF chapter shows you how to build and rig lifting devices like GIN POLES, derricks, A-frames, and more. Simple, practical information. There is not much about gin poles that is in print, and this is some of the best information I have found. (Please note that the ILBA's Log Building News also had an article about a gin pole .. please email the ILBA for a copy of that back issue, it is not available on this, or any other, web site.) These US Army chapters are excellent, hands-on information about lifting safely, and low-tech. Chapter 4 from the field manual on how to build ANCHORS (stakes, deadmen, tree wraps) and how to guy them to support a gin pole, derrick, etc. Also, how much you can expect each sort of anchor to hold. Chapter 3 from the field manual on how to rig for LIFTING, hoisting and pulling. Includes block & tackles, mechanical advantages, and more. Chapter 2 from the field manual on KNOTS, spicing ropes, and more.

R-Value and Thermal Efficiency

ENERGY PERFORMANCE of log walls— 2013 research by the BC Log & Timber Building Industry trade association. Several important reports and downloads for free from their website. This button is a link to their website. Research paper PDF on laboratory testing of logs walls for AIR AND WATER INFILTRATION, and modeling log wall energy performance. Also blower door tests of entire houses. Lots of photos (also infrared photos, and pressurized tests with smoke), and charts. Good information on non-log leaks in log homes (windows and doors, tongue and groove). Very useful information. 29-page PDF booklet that has information on the THERMAL EFFICIENCY of log walls. The Log Homes Council is an organization of companies that build milled or manufactured log home kits, but much of this information also can be applied to handcrafted log homes. A short PDF from Forintek Canada that reviews various home ENERGY CODES, and includes some excellent recommendations for designing and building energy-efficient log homes. Considers Rescheck and EnerGuide software. A 3-page article PDF by Dalibor Houdek of Forintek Canada, that first appeared in Log Building News #38, about the R-VALUE of LOG WALLS 2005 study PDF by two engineers that used a BLOWER DOOR combined with INFRARED thermal imaging cameras to study air and heat leakage of log homes. The blower door is used to reduce the air pressure inside the house, this makes cold air leak into the house quickly, and the camera "sees" the cold air, and identifies where air is leaking. 24 log homes were tested for ENERGY PERFORMANCE by the Minnesota Department of Energy, PDF written by Stephen Klossner. Most of the air leakage was found to come through the ceiling (conventional framing) and under the log sill. A chart of the U-value of log walls by thickness and specific gravity.

European Thermal Efficiency and Codes

Norway log home construction guidelines. European Union ETAG 012 document - a giudeline for technical approval of log home kits. Log home guidelines in Finland. Switzerland (in German) Czech Republic (in Czech)

Best Practices Construction Book

The International Log Builders Association (ILBA) publishes a 'best practices' booklet that is a must-have for all pro builders and do-it-yourself builders. EFFECTIVE PRACTICES & METHODS (EP&M) Available to buy as a PDF from the ILBA, or as a paper book from Amazon. Loads of valuable information. Written by the builder-members of the ILBA, and revised once every 5 years. The current version is 2025.

Building Code for Log Homes

The International Code Council (USA) writes a building code that covers milled (machined) and handcrafted (scribe fit) log homes. It's called ICC-400 Standard for Design and Construction of Log Structures. You can browse the entire 2022 edition for free at this link to the ICC.

The Wood Handbook

The Forest Products Lab in Madison, Wisconsin was at one time the premier headquarters for research about using wood for construction. Budget cuts have gutted the agency, but they produce a book called the Wood Handbook that has a huge amount of useful information. It is like an encyclopedia of wood. The whole book is available free online as a large PDF (you can do the search to find it). Here are a few chapters you can download.



Interior Humidity, Mold

The buffering effect of heavy timber constructions on the indoor moisture dynamic, article by Stéphane Hameury. "Mold, Housing and Wood" is an article by Robbins and Morrell (226 Kb pdf) is a good introduction to mold, health, wood, and homes. Includes some very basic tips for cleaning and killing mold. More mold links are available on the Western Wood Products Association website. But there are tens of thousands of links to information on mold in homes on the Internet, and this is by no means complete! It's a place to start.

Alaska Log Construction Guide

Written by Mike Musick for the Alaska Housing Finance Corporation in 1999, this book is not copyighted. Mike has good chapters on foundations, energy standards, scribing and cutting notches, plumbing, venting, insulation, and more. The focus is on Alaska's need for energy-efficient homes, but there is plenty of material here about other log building topics. The entire book can be downloaded here as a PDF for free.

Equilibrium Moisture Content

Equlilbrium Moisture Content, also known as EMC, is the moisture content of wood in your area when air drying has come to an end; in other words, the wood has come to equlibrium with the local climate. This PDF article from the USDA Forest Products Laboratory lists EMC for many USA cities, and many locations outside North American as well. Essential for figuring out how much your logs will shrink. Note that my book, the Revised Log Construction Manual has an entire chapter on log shrinkage, moisture, and settling. EMC worldwide. USDA Forest Products Lab PDF that giives EMC for many places around the world. Wood Shrinkage Calculator - an Excel file that you can use to calculate shrinkage for wood. You must know your species and your local EMC. The Excel file has Macros, and you must ALLOW Macros for this to work.

Spiral Grain in Logs

"Spiral Grain the Inside Story" is 3-page PDF article from Log Building News 63 (July 2007) about what spiral grain is, where it comes from, and how it affects logs in log walls. Lefthand spiral is one of the leading causes of badly fitting corner notches and grooves in log homes. This article, written by Robert W. Chambers, is a good introduction to the problems caused by left-hand spiral building logs. You will find a lot more information on spiral grain, other log defects, and where to find good log building logs, in my book the Revised Log Construction Manual Spiral grain causes power poles to twist. Article by Wellner and Lowery. The authors put green (not dry) power poles into the ground and measured how crossarms twisted over time as the poles dried to local EMC (see above). A Classic study that proves that round logs with spiral grain will twist as they dry. The Forest Products Lab in Madison, Wisconsin published this article about spiral grain in Ponderosa Pine. An interesting article from Sweden about spiral grain in logs. Eye-opening photos of their research into reducing twisting during drying.

Structural Engineering with Logs

New Zealand Earthquake -- This PDF is a survey of damage to log homes caused by the 2016 New Zealand earthquake. "Must" reading for structural engineers, and for people building in an earthquake zone. I believe that one of the major causes of damage to some of these log homes was that the owners did NOT keep the throughbolts ("hurricane rods") tight as the log wall settled. I have been in contact with the authors of this article about this. Many of the rods in these houses were loose (some by 3" to 6" , 75mm to 150mm), and when the vertical waves of the earthquake hit the houses, there was a tremendous mass (the walls) moving upward. This could have easily snapped some of the steel rods. Two big lessons to be learned: keep the throughbolts tight, and use large, thick washers! Lateral Loads on Log Walls An article by Tom Hahney from Log Building News #32 (ILBA) of interest to structural engineers and to anyone building a log home in an earthquake or high-wind zone. NOTE that the ILBA has a special reprint of several articles about structural engineering for log homes - - please contact the ILBA by email: info@logassociation.org Lateral Resistance of Handcrafted Log Walls A 33-page report of research published by Forintek Canada. Technical, and probably of interest only to structural engineers. Very hard to find a copy of this, but if you need to calculate wind or earthquake loads on notched log walls, then this is what you're going to want! This research was done at the request of the ILBA. They built log walls and log corners and tested them to the point of destruction in the laboratory. Ground-breaking stuff. Very large file. Lateral Resistance of Log Walls, an article by Leichti, Scott, Miller and Sharpe, from Structure Magazine, March 2006. 5-pages (305 Kb PDF file) Good stuff. Every engineer should have a copy in their library—technical work with finite element analysis for seismic resistance, and more. The Response Seismic Modification Factor for Shear Log Walls. A 113-page Master's thesis (2010) in Civil Engineering from Kansas State University by Samantha Kessler. Technical, and probably of interest only to structural engineers. The result of her research a proposed R factor (response modification factor) of 6.0. Strength Values of Softwoods -- "Allowable Property Values" (500 Kb) A 30-page report of many softwood trees, and the values allowed for bending (MOR, F-sub-B) and stiffness (MOE), shear, compression, and more. Published by the West Coast Lumber Inspection Bureau, File APV-2 (website has more free downloads). This download includes many species from Europe that are tough to find information about, but has many of the common softwoods, too. Meant for engineers—it is a booklet full of tables of numbers that are used when designing structures. Here's another web-link for similar info, though not nearly as detailed: http://www.hobbywoods.com Also, the "Wood Handbook" (see on this page) has design values for a large number of hardwood species from around the world, and a few of the more common softwoods. Bending Strength of Log Stringers for bridges. One of the few research projects I have found that tested the bending strength of whole round logs. USDA publication. FPL Research Paper 341, Studied Sitka Spruce and Western Hemlock, but still very valuable knowledge. There has been almost no testing of full round logs for design values like bending strength (Fb) and shear, etc, so this is a valuable article. 3D Model of Strength Predictions of Round Logs (Poles), by Franco and Pellicane ASCE. 60-foot (18 meter) poles were tested to failure. American Wood Council -- This website has many useful downloads including "National Design Specification for Wood Construction" which give the engineering Fb, E, Fv, and etc for most North American log home species -- make sure you use the "large timber" tables called 4D (pages 44-50). And one of my favorites, the "Wood Structural Design Data" (a book of 264 pages) has easy-to-follow formulas for all sorts of wood beams, but the BEST part are the span tables. The tables are written for rectangular timbers (so you use the "inscribed timber" method when using these tables for round logs) but it is very fast and easy way to figure out about what diameter log will work for your ridge, purlins, joists and other beams. A goldmine, and it's free. All the free downloads are on this library page. Scroll down to "NDS" (highlighted in green on the webpage); and to "Span Tables" "Wood Structural Design Data." It's a bit hard to find these, but they are there. You'll also find free design info for lag screw connections, fire resistance, wind and seismic loads on wood structures, plank flooring design and loads, and more.

User Manuals for ChambersScribers

Owner's Manual for the Chambers Classic Scriber Owner's Manual for the V.2 Scriber Owner's Manual for the V.2 ARC Scriber

Don't know which scriber you own? The model is engraved into the body of the scriber.

A How-to Book from 1945

PDF of a wonderful old 1945 US Forest Service booklet called "Building With Logs," by Clyde Fickes and Ellis Groben. A classic. A few of the highlights are: some floorplans for simple cabins. Measured drawings for log furniture. Instructions for how to build a log cabin without a chainsaw. And probably the first-ever drawing of a log scriber with a bubble level attached to it (on page 5). It is interesting that they used the bubble scriber only for the corner notches. They used a scratch-scriber for the long grooves. This booklet is rare and out of print.

This and That

Ink durability on logs. An article I wrote for Log Building News about tests I performed on various pencils and pens to see how their lines faded over time outdoors. A chart that compares various machines for lifting logs in a log building yard. Helps the pro and do-it-yourselfer compare and contrast a variety of 'crane' options including telehandlers, tractors, boom trucks and more.

Sound transmission through log walls. Tech note from Log Homes Council.

Accelerated Log Building

I invented and patented a new way to building handcrafted log home shells, called Accelerated Log Building (ALB). A simple machine in each corner holds 3 layers of logs so they can be scribed. Once the top layer notches and grooves have been scribed, then the bottommost layer of logs is removed, the stack with two layers is lowered by the machines, and a new top layer of logs is added, and scribed. This means that a building never gets taller than 3 layers tall while it is being stacked and scribed. Even a full two-story log shell is never taller than 3 layers (less than 6-feet) while it is being scribed and cut. This PDF tells the story of how I invented and tested my original Accelerated methods. Later I made improvements (like the machines to hold logs at the corners). My YouTube channel has a video showing Accelerated Log Building using the corner machines. There are several interesting outcomes to ALB— it showed me the proper way to apply Underscribing amounts (see free chapter at top of this page), and it showed me an unexpected relationship of corner notch settings which can be expressed as a formula seen here. This means that a two-notch log in an ALB stack can have different scribe setting amounts for its two notches. Also, it is the groove scribe settings (G) that determine the notch settings (N) for every layer of logs (X). Totally unexpected!