(I use the Mini-Ligno MD/C from Lignomat, www.lignomatusa.com.) This allows for a more gentle kiln schedule to fully dry the timber. The fact is, most of my stacks of lumber air dry to 15% moisture content before entering the kiln. A lock ( To hang the baffles, simply attach hooks to the plywood frame. I had these custom cut and I air dried them outside under a tarp for 6 to 18 months (depending on which load they came in on) and then I kiln dried them in a Nyle dehumidification kiln for 3 months. My question focuses on the initial relative humidity featured in the Safe Drying Rate table. On this order alone, I saved over $1,300 by drying the lumber myself. 6 0 obj Reweigh and obtain the oven dry weight. endstream endobj startxref The problems with solar kilns include limited control over temperature and limited solar exposure, depending on your region and site location. %PDF-1.6 % 0000002827 00000 n Would adding humidity at the start, bringing the initial relative humidity rate to 87% as suggested in the table, result in better product or faster drying? Both restrained and control boards were dried to approximately 9 percent moisture content, representative of final in-service condi- tions. Another common sticker size is 1" x 2", and these work fine as well. I recently picked up a back issue of American Woodworker, #94 June 2002, that has a good article on constructing a simple DH kiln. Such temperatures are high enough to kill insectsanother advantage of kiln drying over air drying. Operates at a temperature range from 80F - 160F (26 - 71C). These kilns will typically hold several thousand board foot of lumber. Wood-Mizer dehumidification and solar wood kilns range from 300 to 35,000 board feet capacity for drying lumber. trailer << /Size 918 /Info 891 0 R /Root 907 0 R /Prev 482770 /ID[<67858f68421814977b05bc7913f6cc23><4073af979fbabe8f1c016146fd1c21ef>] >> startxref 0 %%EOF 907 0 obj << /Pages 902 0 R /Type /Catalog /DefaultGray 903 0 R /DefaultRGB 904 0 R /Metadata 905 0 R >> endobj 916 0 obj << /S 499 /Filter /FlateDecode /Length 917 0 R >> stream Adjust the baffles or fan direction to achieve good airflow. Once the flooring deck is constructed, think about sealing the shed framing at every opportunity. building the dehumidification dry kiln. A typical kiln schedule is a series of temperatures and relative humidities, which are applied at various stages of drying as can be seen in Table 1. . Willie Sandry is a furniture maker and a lumber kiln operator in Camas, Washington. Minus the drying equipment, a shed kiln is just an insulated storage space, with a host of possible uses. The order was 540 board feet (BF) of 5/4 white oak. The delicate blue and white color scheme c The velocity through the load is assumed to be between 275 and 350 fpm, except for the white woods (including maple, ash, basswood, hackberry) where higher velocities (up to 600 fpm) are desired and acceptable. I then manually rotate the fan boxes halfway through the drying cycle. With a 130 F kiln temperature, sterilization will take 10 to 12 hours (Dry Kiln Operators Manual, 1991). The cost associated with shed construction was similar to buying a prefabricated kit. For end baffles, I use 2-thick rigid foam insulation screwed to the main baffles. The baffles do not need insulating properties, and plywood would work just as well. My baffles hang from T-bar assemblies mounted to the ceiling. But kiln drying may also introduce internal stresses into the woodparticularly if an improper kiln schedule is used, . Perhaps the best part: you wont need to calculate your lumber needs down to the board foot. Kiln Drying . << The baffles do not need insulating properties, and plywood would work just as well. Low Temperature Kiln Drying Systems (120F), High Temperature Kiln Drying Systems (160F), Very High Temperature Kiln Drying Systems (220F), Website Content Copyright 2023 Nyle Systems |, Affordable and easy method to accomplish top quality lumber drying, Designed specifically for any sized operation, Modular based systems for unlimited capacity, No boiler or steam required with gas furnace, Can be installed along side existing kilns, Chambers are sized with our DH systems to meet your lumber drying requirements. Each layer of lumber is separated from the next by a series of stickers or spacer sticks. Dehumidification kilns from Nyle Systems in Brewer, Maine. This gives me a secondary method of tracking the drying process, using both water volume and moisture content (MC) readings. In exchange for building the shed myself, I wound up with a shed of higher quality, with more features. Not bragging or anything! Created and Presented by: Henco Viljoen and Elijah McCarty with Nyle Dry Kilns. Case hardening is a defect caused by the outer portion of a board drying quickly, while the inner portion dries more slowly. Soon the DH won't show much water collected in the tray. Although I can maintain the 90 degree temperature, I could not start at the recommended humidity level unless I added humidity. Dehumidifier suggestion: http://amzn.to/2iYZqVZThis is the first in a series of videos showing how I built a kiln for drying lumber. This will allow the DH to drain automatically without you needing to enter the kiln. A kiln schedule is a set of temperatures and humidities that are used during kiln operation. Typical dehumidification kiln (FPL 1999 p. 12-10). An official website of the United States government. To condition the lumber, I introduce steam into the kiln for about two hours. Sears Canada 70 Pint Dehumidifier. Dehumidification drying system. Dehumidification Kiln. Add up the amp draw on all the equipment you plan to use in the kiln, including a heater, dehumidifier, fans and steam generator. Instead of using expensive electrically reversible fans designed for commercial kilns, I came up with a simple hardware solution. They are based on different air flow rates, etc. This can create internal stress in the lumber that is released when sawing. Official websites use .gov Share. Remote operation and networking is optional. There are two ways to remove water from the DH unit, and they both work well. Sticker spacing can be increased to 24" apart for 5/4 or thicker hardwood. A lazy Susan with 180 detents mounts the fan box to the ceiling. Your order will come with a return form with convenient instructions, or you may send your returns directly to Returns Department, Rockler Woodworking and Hardware, 4365 Willow Drive, Medina, MN 55340. The water tray can be removed and emptied manually, or a hole can be drilled through the wall of the shed to pass a drain tube. 4. Wood drying (also seasoning lumber or wood seasoning) reduces the moisture content of wood before its use. In-service replacement of warped 2 by 4's as wall studs or truss members is costly. Figure 3-4 Drying Schedules Normal Schedule Alternate Schedule Moisture Content Dry Bulb Wet Bulb Dry Bulb Wet Bulb Group 2 Above 45% 90F 85F 100F 97F . As the MC drops and I crank the DH on more and more, the temp tends to rise up too high just from the heat the DH throws off, even though the light bulb heaters are not on at that point. In vacuum kiln trials, logs were heated to 56C at 70 percent log radius depth and the temperature maintained for . If you intend to kiln dry lumber from a green state, right off the sawmill, you will need to be well-versed in airflow rates and follow a detailed drying schedule. 0000004213 00000 n Additionally, a 12 air plenum is required between the walls and stacks of lumber. The baffles direct airflow over and through the stack and prevent the top layers from drying too quickly. A free BASIC program to convert the designations into actual temperatures and humidities is available from the author. Bring your moisture meter to confirm. 0000000710 00000 n For all kiln drying schedules, a heater should be used to sterilize the lumber and kill any insects that may be present. Ciencia y Tecnologia, Duygu Kocaefe, Ayhan Aytin, The Bolivian secondary forest products industry has experienced substantial growth during the last 10 years. A variety of wood drying kiln technologies exist today: conventional, dehumidification, solar, vacuum and radio frequency. I'd like to know for my own curiosity, as well as to be able to generate SDR schedules for other species not given in the American Woodworker article, like the 6 foot long 24" wide slabs of 8/4 madrone I got this summer. This will allow the heater to cycle on and off automatically, according to the kiln operators setting. This prevents "dead spots" inside the chamber that experience limited airflow. Schedules. Enter the email address you signed up with and we'll email you a reset link. The lumber was then measured for crook, bow, and twist. %PDF-1.4 % Manufacturer guarantees/warranties for power tools, CNC and laser products will supersede the Rockler Guarantee if these items are damaged or defective. Hardwood lumber kiln drying schedules typically keep the dry bulb temperature below 180 F (82 C). A dehumidification kiln continuously recycles the heat throughout the chamber, rather than . Small, complete dehumidification dry kilns under 5,000 board-foot capacity are not available for sale. I opted not to install a true vapor barrier between the framing and sheetrock, because of potential condensation and mold issues with sheds constructed this way. Also, today, we are often kiln drying No.2 Common lumber which requires a milder schedule than upper grades; in the 1950s, seldom was this lower grade lumber kiln dried.) On the last load of lumber I purchased, I saved $2.50 per board foot compared to retail prices for kiln-dried lumber. H6`2}s=n:l)CR>/"\ kiln/. Place a 1x6 board on the floor behind the stack, tilted to a 45 angle. They are normally mounted in the gable of household attics, and they are designed to be used in high temperature environments. The air flow rate through your stacks should be about 350FPM. In the third column, write down the appropriate dry-bulb temperatures. Dont even think of powering your kiln with an extension cord. Always avoid conditions that add moisture back to the lumber, especially during start-up. The conversion method described in the Dry Kiln Operator's Manual is not really accurate, but it is safe. endstream endobj 283 0 obj <>/Metadata 40 0 R/OCProperties<>/OCGs[294 0 R]>>/Outlines 53 0 R/PageLayout/SinglePage/Pages 280 0 R/StructTreeRoot 72 0 R/Type/Catalog>> endobj 284 0 obj <>/Font<>/Properties<>/XObject<>>>/Rotate 0/StructParents 0/Tabs/S/Type/Page>> endobj 285 0 obj <>stream In larger kilns, the heater may be needed in the latter part of the drying cycle. Basically the idea seems to be to maintain a constant temperature, and . If required, look-up and write down the RH (sixth column) and EMC (seventh column) for each schedule step. The DH is not needed at this time, as the lumber is already bone-dry. Kiln schedules are completely assembled and written out for easy use. Table 1 shows a typical drying schedule for sugar maple. Its a nice use of technology and adds a measure of safety as well.) This is because it needs to be dried to a lower moisture content than wood will air dry to outdoors. I modified one of the Radio Shack combo units so it could measure the RH remotely as well as the temp. /Name /ImagePart_0 When that is the case, I know Ill have usable lumber in just a few weeks. Warp in dimension lumber is a significant cause for loss in grade and value. Page 30 Wood-Mizer Figure 3-4 Drying Schedules Normal Schedule Alternate Schedule Moisture Content Dry Bulb Wet Bulb Dry Bulb Wet Bulb Group 2 Above 45% 90F 85F 100F 97F . Changing the position of the doorway in various kiln setups helps provide the best access to the stacks of lumber. The schedules can also be formulated manually as follows. Please refer to Appendix A which shows the Lumber Dry Kiln Bill of Materials. This will allow the DH to drain automatically without you needing to enter the kiln. Check your local building codes for regionally specific requirements and electrical permits. As a result, the kiln schedules were too severe. Apply foil tape to the edges of the main baffles to help protect the Styrofoam. For international returns, please click here. Download Table of Contents. Schedules for several thicknesses and specialty products (e.g. So, with that lengthy introduction, here is my question. Vote. Thicker lumber like 5/4 or quartersawn lumber is naturally more stable. Question 1998. by Dr. Eugene Wengert. Determine the correct designation, such as T3-D2 for 4/4 red oak. 2. 1. a furnace or oven for burning, baking, or drying, especially one for calcining lime or firing pottery. Dehumidification drying equipment is available, but an enclosure must be built to house the equipment and dry the lumber. Wood-Mizer dehumidification and solar wood kilns range from 300 to 35,000 board feet capacity for drying lumber. A bead of silicone caulking between the subfloor and sill plate will prevent air infiltration. If the interior volume of a kiln becomes too large, basic heaters and home dehumidifiers may be inadequate to control the kiln environment. If you cannot find exact match, look at SG of same family species. After four days, I decrease the RH setting on the DH to 30% and continue to run the fans. (A major source was Dry Kiln Schedules for Commercial Woods which is available from the Forest Products Society in Madison, WI.) The Bolivian wood products industry was surveyed to determine lumber drying capacity, technology and. This report contains suggested dry kiln schedules for over 500 commercial woods, both temperate and tropical. 158 p. Dry kiln schedules for commercial woods : temperate and tropical. The column on the right I added part way through is the kiln's internal RH. A kiln schedule is a set of temperatures and humidities that are used during kiln operation. A 1.5-kW dehumidifier was installed in the solar dryer to determine the performance of a combined solar-dehumidification dryer. This helps keep the lumber straight during the drying cycle; in fact, improper placement of stickers can permanently deform lumber. When the drying is done in a kiln, the product is known as kiln-dried timber or lumber, whereas air drying is the more traditional method.. I chose double wall construction with 1/2 sheathing, and 1/2 T1-11 siding. 73. For the sterilization phase, air temperature needs to be around 140 F, for three to five hours. 0000003109 00000 n These well-known dehumidification kiln packages have been among our bestselling products for the past 30 years. Choosing a Kiln Schedule Corrosion resistant epoxy coated aluminum cabinets and specially coated dehumidification coils for an extra long life. I usually see a large volume of water in the DH each night when I check the kiln. Kiln dried wood typically sells for a third more than green lumber and eliminates the need for . If severe enough, the lumber can develop honeycomb cracks throughout. End baffles are also a good idea to prevent airflow from bypassing the stack entirely. In Fig. Phytosanitary heat treatments of Ceratocystis lukuohia and Ceratocystis huliohia-colonized Metrosideros polymorpha wood were evaluated using kilns. Select a heater with an adjustable thermostat and a tip-over shutoff. However, because wood from If you intend to kiln dry lumber from a green state, right off the sawmill, you will need to be well-versed in airflow rates and follow a detailed drying schedule. Contractors work on a tight schedule, and that may not allow much time for curing and drying concrete. In larger kilns, the heater may be needed in the latter part of the drying cycle. A small electric heater supplies auxiliary heat to maintain adequate kiln temperature. Delete from my manuals. Any small building could work, as long as it has a minimum of 2 x 4 framing, and will seal out unwanted air. Loading the kiln begins by rousing my sons and letting them know Ive planned a day of work. These well-known dehumidification kiln packages have been among our bestselling products for the past 30 years. After a short period of grumbling, they join me to lay down wood blocks for the first layer of lumber. An anemometer confirms that your effort constructing baffles was worthwhile. By setting the relative humidity (RH) on the dehumidifier, you can control how often it runs. After four days, I decrease the RH setting on the DH to 30% and continue to run the fans. Apply foil tape to the edges of the main baffles to help protect the Styrofoam. Heat comes primarily from an integral dehumidification unit that also removes . There may be more depression values than required; ignore the extra depression values in this table. hTn8>_l7h.&E:Bem=C9n\8]lMPc. For a single-stack kiln I recommend a minimum shed size of 8 x 12. This air space is absolutely critical for even airflow, so count on the extra floor space right from the design phase. Windows and doors are also sealed, as well as any holes cut for electrical service. Appendix B . A pre-hung steel exterior door is ideal in this situation, because it offers weatherstripping and is fully insulated. A household dehumidifier (DH) removes moisture from the kiln chamber. Sign In Upload. Drying lumber too quickly can lead to deep end checking, warping and case hardening. I like these "starter blocks" to raise the lumber a few inches off the floor. I then manually rotate the fan boxes halfway through the drying cycle. 0 Q,kjifT33P[! The moisture loss, drying time and drying defects were determined. I usually see a large volume of water in the DH each night when I check the kiln. For these items, please call the store where you purchased them or our customer service department at 1-800-376-7856 so we can assist you. I'm thinking I could vent it manually, but with the RH so high externally I am not sure if that is the right thing to do. noun: kiln; plural noun: kilns. If we revisit the example of a $1,300 gross savings from a load of 540 BF of white oak lumber, and we subtract the estimated cost of $62 to kiln dry the lumber, we arrive at a net savings of $1,238 less than retail. In addition, weight on top of the stack can be helpful, but nothing replaces baffles for the best lumber yield. Another great option is to convert an existing shed or outbuilding to a lumber kiln. Consider not only the space for the lumber stacks, but extra floor space to easily load and monitor the charge of lumber. This kicker board will help distribute the airflow more evenly through all layers of lumber. Using a Kiln Schedule Can also be used on any mobile device! Difficult-to-dry species might not exceed 60 C (140 F). %3.3 The following tables show some examples of oak schedules for steam dry kilns and dehumidification dryers. Hardwood kiln drying schedules typically keep the dry bulb temperature below 80 C (176 F). Once the lumber is sterilized, it is ready for the conditioning phase. Academia.edu no longer supports Internet Explorer. Different species should not be loaded simultaneously into the kiln due to often differing kiln schedules. Reply. By setting the relative humidity (RH) on the dehumidifier, you can control how often it runs. MC values in the kiln schedules are based on the wettest half of the kiln samples. I find that unplugging the DH is helpful during the sterilization phase so I can add a second heater, without overwhelming my electrical circuit. Soon the DH wont show much water collected in the tray. Custom Doors, Drawers & Glass Accessories, Using a Small Scale Dehumidification Kiln, Learn Woodworking Tips & Tricks with Rockler, High-quality brands and products you can trust, Expert advice and free post-purchase support, Exclusive, innovative products that help you Create with Confidence, Detailed instructions, technical specs and guides to make the most of your purchases. Projects included design, construction, installation and commissioning of heat-pump based dehumidification equipment for seafood and fish gelatin products, hardwood lumber kilns and laboratory testing. Although dehumidification kilns are slower than conventional kilns for drying, the lower drying temperature has the reported advantage of less degrade and less shrinkage. . /Filter /JBIG2Decode Place a 16 board on the floor behind the stack, tilted to a 45 angle. Sticker spacing can be increased to 24 apart for 5/4 or thicker hardwood. A.gov website belongs to an official government Nyle Systems dehumidification kiln packages are our best known product with nearly unlimited drying capabilities. In this research, a drying restraint system was evaluated as a means of warp reduction in 8- and 16-foot-long SYP lumber. Kiln drying is the process of drying wood in a controlled environment, where temperature, air circulation and humidity are monitored and stabilized. /Subtype /Image of this publication is to make available to dry kiln operators and others interested in kiln-drying wood, kiln schedules that are completely assembled and written out for ready reference and easy use. I often buy from sawyers or homeowners at 40% to 50% of retail price. If MC readings still arent at the desired range, the heat may need to be increased for the remainder of the drying cycle. This shed will be essentially unheated for much of the year and very hot during the kiln-drying cycles. An anemometer confirms that your effort constructing baffles was worthwhile. Unfortunately, little information is available regarding lumber drying technology and practices used, which is essential for the formulation of improvement strategies. Moisture content step schedules can be converted to schedules based on time once a kiln operator develops a data record from at least 6 different kiln runs with lumber of the same thickness and species. In this paper, the effective schedules were further investigated for longer culm parts treated with boron. There are two ways to remove water from the DH unit, and they both work well. Made in China, it exudes the classic style of Asian and Chinese cultures, featuring a unique shape that sets it apart from traditional jars. Select a heater with an adjustable thermostat and a tip-over shutoff. 0000006297 00000 n Initially, I set the DH to 40% RH, because I dont want to remove moisture too quickly. The approach described in the article where you try to keep the water leaving at a steady rate is fine. Dehumidification dry kilns operate at lower drying temperatures (typically below 150F) than do conventional kilns, which results in longer drying schedules. /Width 1628 The four charges of lumber ranged from 600 to 700 board feet (bf), and a woodworker with no dry-kiln experience operated the kiln. There are two main reasons for drying wood: Woodworking When wood is used as a construction material, whether as a structural support in a building . Inexpensive Dehumidification KilnIn this video we'll build and load a 14' long 4' by 4' wood kiln that dries wood by heat and dehumidification.We had quite a. My kiln uses four ceiling-mounted fans, each rated for 1,600 CFM. A low temperature heat treatment chamber and/or dehumidification kiln is identified as operating between approximately 43C (110F) and 56C (133F) for an extended period during the kiln drying cycle. You can download the paper by clicking the button above. Saving money by drying your lumber may not be the answer for every woodworker, but the basics shown here demonstrate that it is within the reach and skills of the average person. The schedules are all moisture content based, using the moisture content of the wettest half of the kiln samples. The first load was started with 60% and this load was started with 78%. (In the original Dry Kiln Operators Manual written in the early 1950s, some species were not used in high quality products. After seven to 10 days, I reverse the fan direction to make sure all stacks of lumber dry evenly. For more capacity, consider a two stack kiln (12 x 12), or a three-stack kiln (12 x 16). I was hoping someone could point me in the right direction or share experience. Most species of hardwood lumber can be safely dried this way, once the moisture content is 20% to 25% or less. Sorry, preview is currently unavailable. Go to the second number designation (the wet-bulb depression designation) and find the corresponding depressions in the table below. At the planer mill, warped 2 by 4's represent a significant loss in value. Measure airflow over the stacks of lumber in various locations. Each layer adds approximately .81 R value. Should a Moulding Mill Bring Sawmill Operations In-House? The kiln operator sets the kiln controls based on the initial moisture of the lumber as it is loaded into the kiln. There might be a problem with that if the chamber overheats and has to be vented because some water will leave that way. Subtract the wet-bulb depression from the dry-bulb temperatures for each schedule step and enter the value in the fifth column. My aim was to develop a small dehumidification kiln for better control of the three key components of lumber drying: temperature, airflow and humidity. Align the stickers over the starter blocks on the first course. This gives me a secondary method of tracking the drying process, using both water volume and moisture content (MC) readings. Air speed of 350 feet per minute is appropriate for common hardwoods such as oak and maple. A discussion of how to apply "safe drying rate" calibrations with a home-built dehumidifying kiln. Dehumidification Opportunities for Dehumidification Drying Of Hardwood Lumber Dimension Kiln Drying Hardwood Dimension Parts Discoloration Preventing Discolorations in Hardwood and Softwood Logs . My kiln schedule starts with running all fans and the dehumidifier for two days, measuring and removing water as it accumulates. However, you may need more cycles depending on the species, moisture content, and size of the timber. Over 40 years experience building kilns. Thus, a drying program can be adapted according to the characteristics of the kiln load, e.g., species, dimensions, and moisture content. /Type /XObject My number one priority was to build a kiln that was easy to load and easy to monitor. Lay down the bead of caulking before raising the walls. I cannot stress the importance of baffles enough. T8-C3 or similar for hard maple), the article instead provided a table showing the "safe drying rates" (SDR) for a number of species. The last step requires a short period of high humidity to relieve the drying stresses in the boards. Select 3/4 conduit brackets for hanging baffles on 1/2 galvanized pipe. Also, for that approach to work, the chamber needs to be air tight. A typical home center sheds floors are underbuilt for the weight of a load of lumber. This returns some moisture to the very dry exterior of the lumber, while not affecting the core moisture level. This lets the operator sort stacks by lumber species, so they will be easy to retrieve when the drying cycle is complete. If your lumber stack is built on starter blocks, you will need to limit airflow there as well. This kicker board will help distribute the airflow more evenly through all layers of lumber. Our next kiln charge is scheduled to begin around February 6, 2023. I dont think the same could be said for an old reefer truck converted into a kiln (no matter how well it dries lumber). Another common sticker size is 1 x 2, and these work fine as well. Heres a classic project that both steps up and provides overflow seating. Once the core readings are 6% to 8% on a fresh cut, the lumber is dry and ready for sterilization. Remove samples from the stack, and cut an inch or two off one end. 44. Without baffles, the top layers of lumber experience potato chipping with cupping, twisting or warping. This can be done by heating above 133F for 4 hours (measured at the core of the wood), or at 120F for about 7 - 10 days. The MC ranges are chosen so that the loss of the first one-third of moisture, and the highest risk of checking and staining, will occur in the first step listed.). Evaluation of kiln-drying schedules for wild cherry wood (Cerasus avium), Model to assess energy consumption in industrial lumber kilns, Mathematical modelling and experimental investigation of dehumidifier drying of radiata pine timber, A survey of Bolivian lumber drying operations, Warp reduction of SYP lumber by restrained drying, Western Juniper Drying Project Summaries, 1993-96, Vacuum contact drying kinetics of Jack pine wood and its influence on mechanical properties: industrial applications, Kiln drying behavior of lumber from ten fast-growth plantation species in Costa Rica, Effect of fire-retardant treatment and redrying on the mechanical properties of Douglas-fir and aspen plywood, Properties of Douglas-Fir and Aspen Plywood, A numerical study on the influence of the bond-line diffusivity on moisture-related stresses and deformations of three-layered spruce cross-laminates, Error in Estimates of the Moisture Content of White Oak Kiln Sample Boards, Green Kerfing Treatment for Improving Softwood Lumber Drying: A Review, A comparison of kiln-drying schedules and quality outcomes for 4/4-thickness black cherry lumber sawn from small-diameter logs, A comparison of kiln-drying schedules and quality outcomes in 4/4-thickness black cherry lumber sawn from small-diameter logs, Data bank for short-length red oak lumber, Hardwood lumber widths and grades used by the furniture and cabinet industries: Results of a 14-mill survey, Lumber and veneer recovery from intensively managed young-growth Douglas-fir, WOOD-FRAME HOUSE CONSTRUCTION U.S. DEPARTMENT OF AGRICULTURE FOREST SERVICBAGRICULTURE HANDBOOK NO. Staff. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. Remove samples from the stack, and cut an inch or two off one end. The DH is not needed at this time, as the lumber is already bone-dry. When properly loaded, this kiln can dry approximately 600 board feet of 4/4" lumber.