AlaskaAlaska LogLog BuildingBuilding ConstructionConstruction GuideGuide BuildingBuilding Energy-Efficient,Energy-Efficient, QualityQuality LogLog StructuresStructures inin AlaskaAlaska
by Michael Musick illustrated by Russell C. Mitchell
for Alaska Housing Finance Corporation Alaska Log Building Construction Guide
by Mike Musick additional text by Phil Loudon edited by Sue Mitchell graphics by Russell Mitchell photos by Mike Musick or as noted for
Alaska Housing Finance Corporation When we build, let us think that we build forever. Let it not be for present “delight nor for present use alone. Let it be such work as our descendants will thank us for; and let us think, as we lay stone upon stone, that a time is to come when those stones will be held sacred because our hands have touched them, and that people will say, as they look upon the labor and wrought substance of them, “See! This our parents did for us.” —John Ruskin ”
ii Acknowledgements
he authors would like to thank the many people who made this book Tpossible. Please know that your contribution is appreciated, even if we forgot to mention you here. Phil Loudon contributed a lot of time and text to the retrofit chapter. Sandy Jamieson, noted artist and master log builder, provided thoughtful comments and review. Phil Kaluza, energy specialist for Alaska Housing Finance Corporation (AHFC), contributed the sample energy ratings in Appendix C and other information on AkWarm. And particularly, this book would not have been possible without Bob Brean, director of the Research and Rural Development Division; Lucy Carlo, research and rural development specialist; and Mimi Burbage, energy specialist for AHFC. Thanks are due to Dan Fauske, executive director of AHFC, and Judith DeSpain, deputy executive director of AHFC, for their continued support.
iii Contents
Chapter 1: Introduction 1 Introduction ...... 1 Disclaimer ...... 1 Energy-efficient Log Homes...... 1 Big Logs ...... 2 Small Logs...... 3 Chapter 2: Problems and Solutions 5 Problems...... 5 From the Ground Up ...... 5 Good Soils ...... 6 Permafrost ...... 7 Design ...... 7 Shrinkage ...... 10 The Building as a System...... 13 If You Want to Borrow Money ...... 14 Top Ten Building Science Rules ...... 14 Chapter 3: Meeting the State of Alaska’s Building Energy Efficiency Standards 15 Statewide Regions ...... 15 Four Ways to Comply With the Building Energy Efficiency Standard...... 15 1. Prescriptive Method ...... 16 2. Building Budget Method ...... 16 3. Performance Method ...... 16 4. Energy Rated Method ...... 17 Chapter 4: Building the Log House 19 In the Woods ...... 19 Weathering...... 20 The Foundation ...... 22 Permafrost Foundations ...... 25 Log Working Tools...... 27 Half Logs ...... 28 Three-quarter Logs ...... 31 Compression-fit Saddle Notch...... 31 Round Notch ...... 32 Log Scriber ...... 32 The First Scribe ...... 33 Scribing the Notch ...... 34 Final Scribing ...... 36 Back on the Ground ...... 36 Cutting the Notch ...... 36 Cutting the Lateral Groove...... 40 v Contents (continued) The Log Walls ...... 41 Airtight Log Walls ...... 42 Finishing the Logs ...... 42 Chinking and Sealing ...... 43 Short Log Construction ...... 44 Making It Easier ...... 46 The Plate Log ...... 47 More Than Just Logs ...... 48 Windows and Doors ...... 48 Cutting the Splines ...... 49 Placement and Planning ...... 49 The Roof ...... 53 Sealing the Ceiling ...... 54 Hot Roof or Cold Roof? ...... 54 Chapter 5: Mechanical Systems 57 Chimneys and Vents...... 57 Combustion Air...... 58 Plumbing ...... 59 Arctic Utility Chase ...... 61 Electrical ...... 62 Ventilation...... 65 Chapter 6: Retrofit 67 Should You Retrofit or Rebuild? ...... 67 What is Payback? ...... 67 Retrofit Checklist ...... 67 So What Shape is Our House In?...... 70 Let’s Start at the Bottom...... 72 Exterior Wall Retrofit...... 75 Interior Wall Retrofit ...... 77 Roof Retrofit ...... 78 Chimney and Flue Penetrations ...... 81 Chapter 7: Maintenance 83 Log Homes Require Maintenance ...... 83 Washing and Finishing the Logs ...... 83 Find and Caulk the Leaks ...... 83 Carpenter Ants ...... 84 Conclusion 86 Appendix A: Alaska Building Energy Efficiency Standard A-1 Appendix B: Log Building Standards B-1 Appendix C: Sample Energy Ratings for Log Homes C-1 Appendix D: References and Bibliography D-1 Appendix E: Glossary E-1 vi Chapter 1 Introduction
Introduction Energy-efficient
he Alaska Log Building Construc- Log Homes Ttion Guide is written to help log From the south slope of the Brooks builders, owner-builders, contrac- Range, which more or less defines tors, architects, engineers, and the northern limit of the boreal building manufacturers build log forest, to the rain forests of the homes that meet the State of Alaska southern panhandle, Alaska is Building Energy Efficiency Stan- blessed with an abundance of trees dards (BEES) (see Appendix A). suitable for building log homes. The This book contains useful romantic image of a log cabin in the information for anyone interested woods is slowly being replaced in building or renovating energy- with log homes hand-crafted from efficient, quality log structures in massive logs up to two feet in Alaska. A number of basic proce- diameter and fitted so tightly that dures and techniques are described even after several years of settle- in detail to help even the novice log ment and shrinking, you can’t builder get started building his or easily slide a knife blade between her first log project. Building an the logs. energy-efficient log home requires In the introduction to the eighth the highest level of craftsmanship edition of Building With Logs, author to meet modern standards of and noted Canadian log builder and airtightness, indoor air quality, teacher B. Allan Mackie invites the safety, comfort, and durability. reader to take a closer look at the physical properties of trees. He Disclaimer notes that “the body of the tree is Alaska Housing Finance Corpora- composed of hollow cells packed tion, its agents, and the authors of tightly together. Under a micro- this book assume no responsibility scope, they look like a honey- for the use of information in this comb. When the tree is book by anyone. All design details, felled and the vital methods of construction, and fluids have dried, structural systems should be these tiny air checked out by a professional to pockets seal, assure compliance with codes and becoming an regulations. This book is not in- almost perfectly tended to supersede either local or insulated build- national building codes. ing material. . .. The tree as it exists naturally is an almost perfect building material.” Cross section of a tree in magnification.
1 Big Logs eventually reach a lower limit to the diameter of logs that will meet the In the case of massive logs, R-value, prescriptive R-value requirements the resistance to heat flow, is not the of State of Alaska Building Energy only property relating to energy Efficiency Standards. For example, use. Logs with a good southern if the logs average less than 13" in exposure will store heat from the diameter in southeast Alaska, the sun during the day and slowly builder will have to increase the release that heat at night. The cycle efficiency levels of other compo- repeats until fall when you have to nents of the building system and start adding heat from your wood use the building budget method of stove or furnace. One or two short, compliance, which requires a HOT- hot firings a day of a good airtight 2000 or AkWarm computer energy wood stove during the winter use calculation, or the energy rated heating season will heat a well-built method to comply with BEES (See modern log home. The objective is Appendix A). to keep the mass of the logs from AkWarm is an energy analysis cooling to below a thermostat software program used by the setting for the fossil-fuel-fired Alaska Housing Finance Corpora- furnace or boiler. tion (AHFC) to perform energy As you travel north in Alaska, ratings on proposed house plans or the trees tend to get smaller and on old and new houses. Hot 2000 is
R-40 R-35 R-30 R-25 R-20 R-15 R-10 R-5 R-0 6" 8" 10" 12" 14" 16" 18" 20" DIAMETER OF WHITE SPRUCE LOGS
12% MOISTURE = APPROX. R-1.25 PER INCH 8% MOISTURE = APPROX. R-1.50 PER INCH * 4% MOISTURE = APPROX. R-2.00 PER INCH * * extrapolated from Carlson, Building a Log House in Alaska (see Appendix D, References and Bibliography)
2 an energy analysis software pro- Small Logs gram that was developed for the Canadian R-2000 Program and is As we noted above, small diameter also used by the Alaska Craftsman logs and 6-inch and 8-inch three- Home Program to qualify a home sided logs will not comply with the for meeting their standards of prescriptive standard unless they energy efficiency. are furred in (or out) and insulated Alaska white spruce has a and vapor barriered like a frame thermal resistance of about R-1.25 wall. Unless you are just building a per inch at 12% moisture content. simple cabin, 6 or 8-inch three-sided Oven dry white spruce has a logs usually just end up being very thermal resistance of 1.47 to 2.04 heavy and expensive siding. If you per inch. Log walls in the interior of are building a house to meet BEES, Alaska may have a higher R-value three-sided logs may be a poor because of the extreme dryness of choice of materials. It might be the air during prolonged subzero better to mill the trees into framing weather (Carlson, Building a Log materials or post and beam compo- House in Alaska—see Appendix D). nents and log siding or bevel siding. AkWarm assigns default It is, however, quite possible to R-values for logs that do not ex- use the building budget method or actly match the numbers listed the energy rated method to score above. The default R-value per inch enough points to qualify a 6-inch or in AkWarm steadily decreases as 8-inch log wall for four-star-plus the size of the logs increases. and five-star ratings. (See Appendix AkWarm assumes R-values as in C, Sample Energy Ratings for Log Table 1 below. Homes.) This can be accomplished Since the moisture content of with a thoughtful application of logs varies, AkWarm does not insulation to the foundation or floor consider moisture content in as- and a highly insulated roof, energy signing these default numbers. If efficient windows oriented to the your logs are especially dry, your sun, and efficient space heating. The energy rater might be able to logs must be especially air tight and override the default R-values and the ventilation system must comply input slightly higher R-values. with section 2.5 of BEES (Appen- dix A).
Table 1 R-value Assumed Log Size R-value per inch by AkWarm 6-inch R-1.27 R-7.6 8-inch R-1.23 R-9.85 10-inch R-1.21 R-12.1 12-inch R-1.2 R-14.35 14-inch R-1.19 R-16.6 16-inch R-1.18 R-18.85 18-inch R-1.17 R-21.1 20-inch R-1.17 R-23.35
3 Chapter 2 Problems and Solutions
Problems From the Ground Up
he first mistake that many log The most important consideration Thome builders make is building for building a foundation for a log a “permanent” structure on a structure is the ground upon which temporary foundation. When the it sits. A log home may be two to foundation fails, the house will four times heavier than a compa- rapidly self-destruct. Differential rable frame house. The heavier and settlement caused by melting more expensive a structure is, the permafrost, seasonal frost heaving, more important it is to have good and flooding is the single most soil information upon which to base destructive problem in Alaska a foundation design. The best way buildings. to determine what kind of ground is A close second is poor moisture under your proposed log home is to control, which may take only a little core drill test holes under the longer to destroy a log house footprint of the foundation, to at through the natural decay process. least 40 feet deep if permafrost or Damp wood will be attacked by mass ice is possible. At the very rapidly growing colonies of mold, least, use whatever technology is at mildew, and mushrooms, pro- hand to dig a hole in the ground. grammed to return the logs to Drive a steel rod or dig a hole with compost on the forest floor. The a shovel or a backhoe or a cat. cardinal rule of log home longevity BARROW is to keep it dry. BEAUFO RT SEA
SEA CHI Permafrost UCK CH Continuous Permafrost In Alaska KOTZEBUE Discontinuous RUSSIA Permafrost UNITED STATES NOME Continuous FAIRBANKS Permafrost
B E R MCGRATH IN Discontinuous G S Permafrost ANCHORAGE E BETHEL A VALDEZ
Generally Free JUNEAU from Permafrost
GULF OF ALASKA
Source: Environmental Atlas of Alaska, 1978 Charles Hartman and Philip Johnson
5 About half of Alaska is underlain “The cardinal rule with permafrost. Approximately of log home one quarter of the state must con- longevity is to tend with discontinuous perma- frost, while the remaining quarter is keep it dry. generally free of permafrost (see map on previous page). The U.S. ” Natural Resources Conservation Service may be a good source of information on soils in your area. Good Soils
Good building soils in Alaska are generally non-frost-susceptible (NFS). By this we mean solid rock or free-draining sand and gravels that will not hold water and will not cause frost heaving when the Damage from rot ground temperature is below freezing. If you are building on good soils, just about any structur- ally sound foundation that complies with local building codes and accepted engineering principles can be used to support a log home. If you are building in an area Frost-susceptible soil where NFS material is not available, holds moisture like a ice forming you must be especially careful to sponge and swells as in soil the water turns to ice. control the flow of water off the roof with ample roof overhangs and rain gutters or roof troughs. The ground should be sloped away from the foundation in all directions, and surface runoff should be diverted around the site with swales, berms, or ditches or a combination of all three.
Non-frost susceptible soils are soils that drain well, so no water is left to freeze. This means sand or gravel.
6 Permafrost house in summer and drop their leaves in the fall, allowing the sun Think in terms of If you are building in the half of “ to penetrate deep into the house in growing old with Alaska with continuous permafrost, the winter. your new log you must design a foundation that South-facing clerestory or home. will maintain the below-freezing dormer windows are preferable to temperature of the soil beneath the skylights because of potential house. If you are in the transition glaciering and because a vertical ” zone of discontinuous permafrost, window will catch the low winter you must design and build as if sun more directly. Take care to you are building on frozen ground, avoid overheating with too much unless you know no ice is present unshaded west-facing glass. because you did a core drilling or Design the home to fit your other research. needs now and in the future. Think in terms of growing old along with Design your new log home. Your children Log house design should begin in may choose to live there with their the woods. You need to know what children. Some log homes in sort of trees are available. You Scandinavia have been lived in should know the average mid-log continuously by succeeding genera- diameters, how long, how straight, tions for over five hundred years. how dry, how old, what species. Design, construct, and maintain a It is equally important to know log home so that it will last at least the building site. When choosing as long as it took to grow the trees the best location for the house on that are used to build it. your property, make a drawing showing the location of the most beautiful natural features on the land. This may be an ancient grove of trees or an interesting rock formation or a meandering trout stream. Whatever it was that made you want to buy this land to build your home on should not be de- winter sun stroyed in the process of building that home. Move back from the stream, avoid getting close to the summer grove of trees, and don’t bulldoze sun that fascinating rock outcropping. The house must also work with the slope, solar aspect, vegetation, and other natural and man-made features of the landscape. Face the clerestory long side of the house directly at the midwinter sun for natural light shed dormer
E and passive solar heat. Don’t block N the winter sun with evergreen gable dormer S trees. Birch or aspen will shade the W
7 N
W
E
S
Birch or aspen will shade the house in summer and drop their leaves in the fall, allowing the sun to penetrate deep into the house in the winter.
8 roof ventilation air space 2-by-4 nailer over purlin ridge pole
king post
log truss
purlin
3/4-by-6-inch tongue and groove chimney flashing perpendicular to purlin gable end
continuous vapor retarder king post tongue-and-groove rigid foam between truss ceiling boards 2-by-4 nailers plate log le e po ridg
post purlin
g te lo pla eave slip joint for log settling tie log vapor retarder on warm side
pins (wooden dowel, chinking rebar, spikes, etc.) window air/vapor seal spline partition wall wainscot
oist subflooring (plywood typical) rim j lateral groove flo rim or jo closed cell joist ists sill seal floor
foundation and footing
steel plates for seismic anchor
The parts of a log house
9 Shrinkage inches or more. All partitions and walls incorporating vertical posts Designing for log construction is and stairways must allow for not the same as designing for frame settlement, and log floor systems construction. You have to allow for must account for five or six inches settlement of the horizontal wall of settlement. 1 logs and gable logs of between /2 All window and door framing 3 and /4 inch per round of logs, de- and vertical support posts and pending on species and water con- interior frame walls must allow the tent. A green 8-foot-tall log wall logs to settle down without hanging may shrink about four to six inches up and causing gaps to occur in height, while a 12-foot-high log between log courses. Air leakage gable wall may shrink six to eight through poorly fit logs is not only one of the greatest sources of heat loss, it is also the major moisture transport mechanism in a leaky house. Moisture carried by air leaking through cracks between the logs or holes in the ceiling vapor retarder
This ridge pole, which rests on a horizontal log gable, shrank and settled more than 6 inches and is now crushing the Sheetrock.
Unpainted Sheetrock exposed as logs settle. The space above the partition, which was more than 6 inches when built, is now 1.5 inches after 12 years The gap left for settling here is covered with scribe-fit trim. of settling.
10 A slip joint for a partition wall that is perpendicular to the ridgepole
A 2-by-4 stud wall partition slip-joint to keep walls straight and allow the ceiling iling of ce to settle. A wooden dowel is used to slope wooden dowel align the partition wall with the top plate, which is attached only at the top. The dowel is run down through snug- fitting holes and braced with additional blocking.
blocking for dowel
A slip joint for a partition wall that is parallel to the ridgepole
beveled 2-by-6 nailed to the ceiling ceiling crown molding
top plate
dowel
blocking Sheetrock
The dowel is only nailed or glued at the top, and slides down through snug- fitting holes in the plate and 1 blocking as the building settles. A 2-by-6 with both sides beveled at ceiling slope and 1 /2 inches wider than wall frame is nailed or bolted to the ceiling to attach wide crown molding.The crown molding is only nailed at the top and slides down over the Sheetrock.
11 Two ways to attach frame partitions to log walls and still allow for the settling of the logs
1 /2 " plywood spacers Before the partition walls are built, the logs are slotted a few inches for the square Sheetrock edge to slide in as the logs settle.
2
1
Option 2: Two studs, edge against the wall, spaced apart with small plywood scraps and bolts through the slot to the Option 1: A stud laid flat against the logs. This method can be faster to wall with bolt run through slots long build. enough to allow for settling. This method uses less wood.
12 will condense into liquid water when it reaches a cool surface. This could lead to rotting logs and mildew glaciers forming on the roof. In order for a log structure to frost meet the airtightness requirements of the energy standard, it should be built to the highest possible stan- dards of craftsmanship as outlined in the Log Building Standards of the Canadian and American Log Builders Association (Appendix B).
Frost buildup and mildew at a leak around the ridgepole.
The Building as a System
Log buildings must be designed to work as a system and must control the flow of heat, air, and moisture in and out of the structure. The build- ing system includes the foundation, floor, log walls, windows, doors, washer ceiling, heating appliance, ventila- steel plates tion system, energy-efficient light- ing, the occupants, and the outside environment. A change in any part lag bolts of the system will affect the perfor- mance of the rest of the system. For example: you build a well- crafted home that is so air tight that the air inside becomes stale and unheathy, and the wood stove An adjustable vertical support post. won’t draw very well. You must ventilate the house, so you put in a powerful exhaust fan. Then the wood stove belches smoke back into the house. Finally, you cut an “A change in any opening in the wall to provide air part of the sys- for the wood stove. So now you tem will affect have a system and you are in control of the fresh air in your house. the performance of the rest of the system.
”13 If You Want to you to design and build to meet Building your “ Borrow Money these codes and standards. house with an Building your house with an eye eye toward com- All construction should comply toward complying with the Ameri- plying with the with local building codes and the cans with Disabilities Act makes the Uniform Building Code, the Uni- house easier for you and your Americans with form Mechanical Code, the Uni- visitors to live in as well as making Disabilities Act form Plumbing Code, the National it easier to eventually sell. You makes the house Electrical Code, and the State of never know when you might be- Alaska Building Energy Efficiency come permanently or temporarily easier for you Standards. If you wish to borrow disabled, and it’s a lot cheaper to and your visitors money from the Alaska Housing incorporate handicap-accessible to live in, as well Finance Corporation and take features now, when you’re building, as making it advantage of their many interest than to retrofit later. Features like rate reduction programs, or if you lever handles on doors and faucets easier to eventu- want to refinance or sell your make life easier even if you're not ally sell. ” home, most loan programs require disabled. Top Ten Building Science Rules
1. Heat flows from hot to cold. 2. Heat does not rise—warm air rises. 3. Heat is transfered by conduction, convection, and radiation. 4. Heat flow through insulation is slowed by air or other gases. 5. Airtightness prevents major loss of heat. 6. Air flows from higher pressure to lower pressure. 7. Air leakage is the primary moisture transport mechanism. 8. Diffusion is a secondary moisture transport mechanism. 9. Dew point is the temperature at which airborne water vapor condenses into liquid water. Water vapor is not a problem—liquid water is. 10. The vapor retarder should be placed on the warm side of the thermal enve- lope.
14 Chapter 3 Meeting the State of Alaska’s Building Energy Efficiency Standards
Statewide Regions The Arctic Slope does not have any suitable trees from which to or the purpose of creating build log homes. Therefore, this Fstatewide building energy manual will not include a discus- efficiency standards, Alaska is sion of building with logs in Region divided into five geographic and 5, the North Slope. climatic areas (see map below) with minimum standards for each Four Ways to Comply region. With the Building Energy This chapter explains the different ways to meet these stan- Efficiency Standard dards. The standards themselves There are four methods of compli- are found in Appendix A. ance with the State of Alaska Build- The traditional sod homes of ing Energy Efficiency Standard: the north and west coasts were 1. The prescriptive method constructed of driftwood, whale 2. The performance method bones, and sod. These structures 3. The building budget method often had a below-grade entry 4. The energy rating method tunnel, with an animal skin door to All of the methods require regulate the flow of ventilation air minimum standards of balanced through a hole in the roof. These structures were often heated with a BARROW BEAUFO seal or whale oil lamp and body RT SEA heat. EA* Region 5 HI S CKC CHU Region 4 KOTZEBUE Region 3 RUSSIA UNITED STATES NOME FAIRBANKS
B E R MCGRATH IN G
S E A ANCHORAGE BETHEL
Region 2 JUNEAU
GULF OF ALASKA Region 1
Statewide Regions
15 mechanical ventilation. (See BEES 2. Building Budget Ventilation Requirements in Ap- Method pendix A.) The building budget method sets 1. Prescriptive Method limits on the total amount of space heating energy used by a building. The prescriptive method requires Your house is allowed to lose only a minimum R-values for the ceiling, calculated amount of heat per floor, and walls including windows square foot per hour. This requires a and doors (Table 2). This method computer energy use analysis using requires the least amount of calcu- either the HOT-2000 or AkWarm lation. You just have to meet or software programs. These software exceed the R-value requirements programs are available through for all of these building compo- AHFC. nents, comply with all the state- wide mandatory measures outlined 3. Performance Method in chapter two of BEES, and meet the ventilation requirements. The performance method allows the However, meeting the R-value trade-off of insulation requirements requirements for an above-ground between elements of a particular wall will be difficult with smaller thermal envelope assembly, such as logs. increasing wall insulation values to
Table 12 Prescriptive Standards Thermal Envelope R-value Requirements Above- Below- Slab Floor Region Heating Ceiling Grade Floor Grade Base- On Window Door* Fuel Wall Wall ment Grade
Region 1 Southeast All Fuels R-38 R-21 R-30 R-15 R-10 R-15 R-3 R-2.5, 7 Region 2G Natural Southcentral Gas R-38 R-18 R-19 R-10 R-10 R-10 R-3 R-2.5, 7 Region 2A All Southcentral, Fuels R-38 R-25 R-30 R-15 R-10 R-15 R-3 R-2.5, 7 Aleutian Other Than Kodiak Natural Gas Region 3 Interior & All Fuels R-38 R-25 R-38 R-19 R-10 R-15 R-3 R-7 Southwest Region 4 Northwest All Fuels R-38 R-30 R-38 R-19 R-10 R-15 R-3 R-7 Region 5 Arctic Slope All Fuels R-52 R-35 R-43 N/A N/A N/A R-3 R-7
* Not more than one exterior door in a residential building in Region 1 or 2 may have an R-value less than 7 but not less than 2.5.
16 make up for north-facing windows. house and accurately measure the You are not allowed to trade off air loss from leakage. This test also insulation values with different helps a builder find those leaks. thermal envelope assemblies. In Several tight log homes have quali- other words, you could not use this fied for a four-star plus energy compliance method to reach a heat rating, and a few log homes have loss target by increasing the R- made a five-star rating, scoring 88 value of the roof insulation to make points on an energy rating. A new up for low wall or floor insulation log home in Fairbanks was recently values. Therefore you cannot use rated five-star plus. the performance method to make up for the lack of R-value in a log wall. 4. Energy Rated Method
The energy rated method requires that the building shall achieve at least four-star plus (83 points) on an energy rating performed by a trained and certified energy rater. This is the method most often used by builders to comply with BEES. An energy rater records the R-values of all the elements of the thermal envelope and notes the efficiency of the heating appliances, lighting, solar aspect, and other energy use considerations. The most crucial aspect of the energy rating for the log builder is photo by Phil Loudon the blower door test, which uses a Using a blower door to test the airtight- powerful fan to depressurize your ness of a log home in Arctic Village.
17 Chapter 4 Building the Log House
In the Woods
rees are a renewable resource if Tlogged on a sustainable time schedule of a hundred or more years between harvests. The way to ensure a perpetual source of house logs is selective logging. House logs are best cut in winter, when the sap is down and the logs can be skidded over the snow with minimum damage to the logs and the environment. Bark beetles are dormant in winter, and a long winter drying season may dry the logs enough to keep the beetle Saw safety: use hearing protection and eye population down in the spring. protection when using Bark beetles will not invade dry a chain saw. Never cut logs. with the top part of the Choose trees that are of the tip of the blade. If you do, the saw could kick length and diameter that will suit back into your face. your needs. Think in terms of cutting a matched set of logs with A modern equivalent to horse- the same mid-point diameter. logging is a four wheeler fitted with Leave the remaining trees un- an arched log-carrying frame damaged by traveling lightly on the equipped with a 2,000-pound land as you skid the logs out of the capacity electric winch powered by forest. The trees left behind will the 12-volt battery system of the off- benefit from having more light and road vehicle (see drawing below). space to grow in.
An arched log-carrying frame that is pulled by a four-wheeler style all-terrain vehicle.
19 Whether you are clearing your Sawmill Island own land or logging a timber sale, (As told by Robert Charlie, director of the Cultural Heritage keep waste to a minimum. Maxi- and Education Institute.) mize the use of local wood products whenever possible. Birch makes Sawmill Island is located directly across from Old Minto, which is about 30 miles downriver from Nenana. Old Minto was good cabinet building material and originally settled in 1912 by a group of Athabascans from the flooring or window and door trim. Minto Flats area. Today, Old Minto is the site of a cultural Aspen and poplar or spruce make heritage camp. One of the reasons that Chief Charlie originally good paneling, wainscoting, and settled in Old Minto in 1912 was the abundance of timber trim. Douglas fir, hemlock, and found at Old Minto and across the river on Sawmill Island. Sawmill Island is about 1.7 miles long. The timber served many white spruce can be made into purposes, but it was primarily used for fuel by the community framing lumber or timbers for post members and later for contracts with the United States and beam construction. government. White spruce trees are likely to be the logs of choice for building in In the early 1920s, Robert Charlie’s uncle, Arthur Wright, who was one of the first Native ministers for the Episcopal Church interior or southcentral Alaska. in Alaska, used timbers from Sawmill Island to build Old Large, straight aspen or white Minto’s first school. The two-story structure was about 60 by poplar can also be used. In southern 80 feet. Arthur Wright had a small portable sawmill located on Alaska, yellow cedar and western the island. Also built of timbers from Sawmill Island was the Episcopal Church that stills stands today. The Cultural Heritage red cedar, Sitka spruce, Douglas fir, and Education Institute is working to preserve it as a historical and western hemlock all are excel- site. lent log building materials if they are straight and of the size required Years ago, there were four or five winter trails to the island for your building. Alaska yellow that led to dry timber areas. Everyone in the village used the island to get wood. Also, you could walk into the woods in cedar is very strong and very the summer, and pick gallons of cranberries. durable and suitable for cabinetry and furniture, power poles and During World War II, the federal government was busy building pilings, decking, bridges, and Galena Air Force Base. About that time, Robert Charlie’s dad was the first contractor with the Alaska Railroad (federal housing. government) to sign for cord wood. The first year he signed Don’t peel too far ahead of the for 50 cords of wood, the second year for 100 cords of actual placement of the logs on the wood, and the third year for 150 cords. Most of that wood wall, since the bark protects the came from Sawmill Island. wood from mechanical damage, Later on, Robert’s dad signed a contract with the federal mold, and mildew. government to produce 1,000 cords of wood. People from his village produced the 1,000 cords of wood. Robert’s brothers Weathering and dad cut about 360 cords. People would stack the cords along the river and the steamboats would use them to power Logs may have to be treated with a the boats up and down the Tanana and Yukon rivers. During dilute solution of mildewcide after the war, the federal government leased steamers from Canada peeling to keep them from turning and had another three steamers that traveled these rivers, hauling materials to the Galena base. green or black with mold. Some builders prefer to use a solution of Today, Neil Charlie’s allotment is partly located on Sawmill borate crystals dissolved in water Island. Robert Charlie says that his family used to have their fish and sprayed on the logs to retard camp on the island. He remembers as a child seeing old slabs mold growth. Borate is less toxic to of wood and sawdust where Wright had his portable sawmill. the environment and to the log workers than some other chemicals used to protect logs from mold.
20 Safe tree felling One-third of the way through the tree
First cut a wedge-shaped chunk about one third of the way through the tree in the direction you want it to fall.
Leave wood in the middle for a “hinge” so the tree falls in the right direction. plastic felling wedge Then make the second cut on the other side of the tree, slightly above the first cut. Use a felling wedge if needed to start the tree falling.
Use the lean of the tree to start the fall.
wind
Stop felling completely in high winds.
Plan ahead for your escape route (watch the Check the landing area for hidden butt: it kicks). stumps or rocks that can damage your valuable tree. Don’t damage the other trees.
21 After a couple of years lying There is an ongoing debate of around with the bark on, logs will whether to place the first logs start to rot and may become bark directly on top of the treated foun- beetle habitat. At this point, it may dation sill plate or on top of a be best to peel the logs and treat timber of the same height as the them with a water-repellent wood floor joists. If you use a timber for a preservative to keep them sound rim joist, it is a relatively easy until you can begin to build. matter to attach the first round of Spring is the worst time to fell logs, using whatever pinning and peel a log. However, if you system you use for the rest of the must use wet, green logs, place log wall. Some log builders prefer to them on the wall as soon as pos- build on top of the plywood sible so that they take a set in line subfloor, which has been framed to with the shape of the building. the outside of the sill plate. In either If the logs begin to turn green case, the logs or timbers must be with mold, wash them with a securely attached to the foundation solution of household bleach and with long anchor bolts or with detergent, rinse thoroughly, and coupling nuts connecting all-thread allow to dry completely. Protect rods to the anchor bolts. Some 1 them with a water-repellent wood builders extend /2-inch rebar 18 preservative and allow them to inches to 2 feet out of the founda- season before applying the final tion, drill the log accordingly, and finish. bend the rebar tightly against the first logs with a sledge hammer. If The Foundation the logs sit on top of a floor, addi- tional blocking should be installed As we noted earlier, the configura- where the joists are parallel to the tion of a foundation for a log house lay of the logs. is the same as a good foundation for any structure of comparable size and weight. The difference comes in the weight of the walls, and the means of attaching the first round of logs to the foundation.
rim joist
fiberglass floor joist untreated wood must foam be at least 6 inches insulation above ground
pressure-treated or naturally decay-resistant wood sill plate, with closed-cell sill sealer underneath
Add blocking (crush blocks) under the wall where the logs run parallel to the floor joists.
22 countersink
hardwood dowels, steel pins, rebar or bolts
6-by-10 timber closed cell sill sealer and caulk flashing closed cell rigid foam caulked on four sides with Tremco sill sealer 2-inch ledger for floor joists to rest on protection board or coating required treated lumber or naturally decay-resistant wood sill plate
R-value varies with region and design
vapor retarder damp proofing Sheetrock
exterior foam insulation heated basement R-value varies with region and design
seal all cracks, penetrations, and joints with approved sealer
4-inch concrete slab radon/moisture retarder rigid foam insulation
gravel base radon sub-slab suction system compacted earth non-frost-susceptible materials
23 Options for attaching the half log to the foundation
countersink 1"
Plan ahead and decide on the method of anchoring before you pour concrete or install piers.
Rebar set in the concrete and left protruding high enough to come through the first round and then bent A long J-bolt anchor left over parallel with the log. This method high enough for a large will also work with a standard rim joist timber to be bolted and crush blocks (see illustration on down and wooden page 22). dowels or rebar used to anchor the logs to this timber.
Seismic zones in Alaska
Possible Magnitude 2 max. damage (Richter) of largest Zone to structures earthquake
0 none less than 3.0 NOME 3 FAIRBANKS 1 minor 3.0–4.5 2 2 moderate 4.5–6.0 ANCHORAGE BETHEL 4 3 major greater than 6.0 potential damage is greater than 4 zone 3 due to geologic and tectonic 3 features
Source: Environmental Atlas of Alaska, 1978 Charles Hartman and Philip Johnson
24 Most of the engineered ply- wood I-beam systems have compat- ible laminated rim joists, which may eliminate the need for extra crush blocking along the ends of wood beam the joists. Follow manufacturer’s plywood plate directions. In any case, build it strong so that the connections of the logs to the foundation, the 8 inches connections between logs, and the connection of the roof to the logs polyethylene or are all designed to meet the engi- asphalt paper neering requirements of your wrapped around piling specific earthquake zone, wind active freeze-thaw layer load, and snow load design levels (at least 40 inches; (see seismic zones map, previous sand slurry may be much more) page). Permafrost Foundations timber piling
One way to support a log structure on permafrost is to build it on pilings that are drilled, driven, or dug to below the active seasonal frost layer and deep enough to provide lateral sway bracing. It should be drilled deep enough into 12 inches dia. the permanently frozen ground to freeze the piling in place. The floor must be well insulated and situated
wood beam Examples of foundations for permafrost
wedges 3'-0"
U-bolts
three layers of pressure-treated lumber
25 about three feet above grade to allow outside air to flow under the house in winter to keep the ground frozen and to shade the surface in summer from the heat of the sun. Avoid disturbing the organic ground cover that insulates the soil. (See Building in the North by Eb Rice for an in-depth discussion. See Appendix D.) Another permafrost foundation is post and pad, where a bed of gravel is placed on the undisturbed vegetation mat and treated wood timbers are embedded in the gravel and tightly stacked in alternating layers to support either posts or A nice-looking post and pad foundation installed near Fairbanks. beams to support the building. Some builders are building a treated timber system of railroad ties and horizontal beams to support a home on a gravel pad. A promising new-high tech permafrost foundation called Triodetic has been used extensively in the Canadian north and has been used in arctic Alaska in the last few years with apparent success. The Triodetic foundation system incor- porates a series of interconnected triangles of steel tubes to form a bridge over unstable soils.
The Triodetic brand space frame is one option for building on permafrost.
26 Log Working Tools cant hook A log builder’s tool kit can range in cost and complexity from an ax and Peavey a cross-cut saw to an array of chain saws, electric planers, routers, grinders, and drills. The main tool Swede hook in a modern log worker’s kit is a (log carrier) powerful, lightweight chain saw with a 16-to-20-inch bar. Rubber anti-vibration dampers should log dogs (24 to 36 connect the handlebar to the saw to inches long, 4 to 6 chalk box/ protect the operator from problems inches high) plumb bob with his or her hands. Other essential tools include a good sharp ax; a draw knife; a chisel sharp pocket knife; a log scribe fitted with level bubbles; pencils, marking pens, and lumber crayons; curved slick a chalk-box string line; a two-foot gouge carpenter’s level; heavy-duty electric drill and auger bits; chisels; wooden mallet; claw hammer; and log scribe sledge hammers. For moving logs you will need Peaveys and a me- chanical winch or a block and tackle system. For big logs you will need a crane or a high lift system of 2-pound some sort. For sources of log work- sledge ing tools, see Appendix D, page D-8.
adz drawknife
chain saw guide electric chain saw sharpener scorp
gouge knife or scorp
27 Half Logs Once the log is sawn in half, secure both halves in a horizontal The first round begins with a pair position and brush the surface of half logs. These are usually run straight and smooth with the edge the shortest length of the building. of your chain saw. This is an ac- When supported at each end, either quired skill and will come with a on the wall or on a pair of skids, a little practice. log will usually come to rest with Snap a center line on the bottom the bow down and the straight of both half logs and snap another edges to the sides. Roll the log back parallel line near the outer edge just and forth with a Peavey to locate outside the foundation (see #4, next 1 the very straightest lie and hold it page). Cut a /4-inch-deep kerf at the in place with a log dog or with outer line with a circular saw to wedges with the straight edges of hold a metal drip edge flashing. If the log to the sides (see illustration you do not have metal flashing 1 #1, next page). available, cut a /4-inch deep groove Use a chalk line to snap a line with a chain saw to serve as a drip down the center of the mass of the break and to prevent water from log. Use a level to mark vertical flowing under the first round of lines on each end of the log at the logs. centerline just established (see #2, Transfer the center line to the next page). top of each half log, using a level to Then roll the log over until the extend a line on each end of the log. end marks are horizontal. Dog The half logs are then placed on the securely and snap a line down the foundation with the center marks length of the log on the other side. lined up with the wall centerlines If you have an attachment to marked on the foundation or floor. turn your chain saw into a two- Place any bow to the outside. Butt man saw, then sawing the half logs ends should run the same direction is relatively straightforward since so that when you reach the top of each of you have a line to guide the the wall, the top round will end up saw. If you are cutting single with the butts facing the same way handedly, you may want to place to support a long roof overhang at an observer on the far side to signal the gable ends if desired, and the up or down. top round will be easier to finish in If you cut the half log from a any case. Some builders choose to vertical position, with the log lying alternate the butt-tip lie of the half with the centerline on top, it is best logs and subsequent plate logs. to have only one sawyer cut the Use closed-cell sill seal or EPDM entire length of the log from one gaskets to provide a weather-tight end to the next without changing seal between the half logs and the direction. That way, if one person’s floor or foundation. Caulk the first sense of vertical is a little bit out, at logs to the floor with a bead of least it will be consistent and won’t sealant along each side of the sill compound any error. seal.
28 Cutting the half log
wooden wedge to or cut saddle on top 1 hold log in place of support logs
log dog
2
3
4 cutting the kerf for flashing
29 sill sealer side B side flashing A groove or kerf
bead of sealant (caulk)
side flashing A side B