Drying wood at home _ the wood database

Allowing lumber to passively sit at a given humidity level in order to obtain a desired EMC (air-drying) may be the simplest and least expensive method of seasoning wood, but it is also the very slowest. Perfect humidity level in house Drying times can vary significantly depending upon wood species, initial moisture level, lumber thickness, density, ambient conditions, and processing techniques. Proper home humidity level in winter Drying times and kilns

The traditional rule-of-thumb for air-drying lumber is to allow one year of drying time per inch of wood thickness; this adage obviously only takes a few of the aforementioned variables into account, but it’s at least a rough starting point in understanding the time investment required in order to properly air-dry lumber.


In situations where green wood is to be processed into usable boards, (especially in the case of thicker lumber), a kiln is frequently used to control the drying process. Proper house humidity level While there are various types of kilns used to dry lumber, the basic premise is usually the same: a large insulated chamber or room is used to balance and control humidity, temperature, and airflow to safely and efficiently bring wood down to an acceptable moisture content.

The main advantage of a kiln is that with the increased temperature and airflow—all while carefully maintaining and controlling the ambient humidity—the wood can be dried much more evenly, minimizing any sort of moisture gradient between the outer shell (which dries very quickly) and the inner core (which slowly equalizes moisture with the shell). Proper humidity level for a house Thus, a kiln is able to dry wood much more evenly, and it’s this uniformity in drying that allows it to also dry the wood quickly—simultaneously avoiding the drying defects usually associated with rapid, uneven drying. Proper humidity level for home Drying defects

But kiln drying may also introduce internal stresses into the wood—particularly if an improper kiln schedule is used, or if corrective measures are not employed—resulting in a condition known as case-hardening. Proper humidity level for house This defect is caused when the outer shell begins to dry faster than the core: the shell tries to shrink, but is inhibited by the still-wet core. Proper humidity level in a house If the moisture difference between the core and the shell is too great, the shell can dry in a stretched condition. Proper humidity level in home Later, as the core eventually begins to dry and shrink, the condition is reversed, and the stretched shell prohibits the core from completely shrinking. Proper humidity level in home for summer In extreme instances of case-hardening, the core can split and check in an irreversible condition called honeycombing.

This piece of Red Oak (Quercus rubra) exhibits honeycombing, which is among the worst of drying defects, both because it’s irreversible, and it usually can’t be detected by looking at the face of the lumber.

Kiln drying wood at elevated temperatures also has many other secondary effects as well, such as killing powderpost beetles (a destructive wood pest) in all stages of their development. Proper humidity level in home in winter However, it can also cause some woods—such as Black Walnut (Juglans nigra)—to lose the vibrancy of their heartwood colors, resulting in a more uniform and/or washed-out appearance.

For most woodworkers, running their own kiln to quickly dry lumber may be impractical or excessive. Proper humidity level in house In most instances, simply storing project lumber at a targeted humidity level is the best option to ensure it will be at the correct EMC when building time comes. Proper humidity level in house canada However, in some cases, such as when processing logs or other green wood into lumber, a more meticulous procedure will need to be followed. Proper humidity levels for a home Home air-drying tips

• Process logs in a timely fashion. Proper indoor humidity level in winter If a tree has just been cut down, or there has been recent storm damage, it’s best to process the logs into lumber as quickly as possible; doing so will help to open up the wood and aid in drying, which can prevent rot or stain from marring the wood. Recommended humidity level for home in winter Bark on whole logs can act as a natural moisture-barrier, and if left unsawn, can contribute to fungal decay and deterioration in some species. Recommended humidity level for home uk A hallmark of poorly processed, do-it-yourself lumber is the presence of spalted or partially rotted wood.

• Cut the wood slightly oversized. Recommended humidity level in a house Remember that wood shrinks as it dries. Recommended humidity level in home This, along with the material that will inevitably be lost when the boards need to be jointed/planed smooth, mean that green wood should always be cut larger than the desired finished size. Recommended humidity level in home canada (And you usually don’t need to bother jointing/planing the wood prior to drying, since it will no doubt distort at least slightly during the drying process, and the edges should be dressed after the wood has dried to EMC—an exception to this is that two surfaces of a log should be jointed level to facilitate getting even and predictable cuts on the bandsaw.)

• Seal the ends. Recommended humidity level in home during summer In addition to processing logs in a timely manner to prevent stain and decay due to excessive moisture, the opposite is also to be avoided: allowing the wood to dry out too quickly will result in splits and endgrain checking. Recommended humidity level in home during winter It is important to remember that moisture escapes from wood about 10 to 12 times faster on the ends than through other surfaces. Recommended humidity level in home during winter canada Sealing the endgrain forces the moisture to exit in a slower, more uniform manner. Recommended humidity level in home in winter If this is neglected, the ends will tend to shrink faster than the rest of the wood, creating tremendous stresses on the piece that’s ultimately only relieved with endgrain checks—a very common drying defect. (Although there are specially formulated endgrain sealers on the market, just about anything will do in a pinch: paraffin wax, polyurethane, shellac, or even latex paint can be used to seal the endgrain surface. Recommended humidity level in home summer The key is to build up a thick, obstructing film that will inhibit moisture from escaping at the ends of the board. Recommended humidity level in home winter In order to minimize the risk of checking, it is best practice to coat lumber ends within minutes—not hours or days—after coming off the saw.

• Stack and sticker. Recommended humidity level in house Having lumber of uniform lengths and thicknesses greatly aids and simplifies the stacking process; once a log is sawn up into planks of satisfactory dimensions, it’s crucial to stack them in such a way that they will be exposed to air on all sides—stickers are typically used for such a task. Recommended humidity level in house during winter Stickers are small pieces of wood (usually about 3/4” x 11/2”) that are used to add space between sawn planks, which increases ventilation and aids in a more uniform drying process. Recommended humidity levels for home summer Sticker spacing varies depending on the species and thickness of the lumber being dried; a conservative spacing scheme would be every 12”, though usually 16” or 24” spacing can be safely used on thicker pieces.

• Add weight. Relative humidity in a home Once the stack of wood is stacked and stickered properly, it’s helpful to add weight to the stack. Relative humidity in the home uk The lumber at the bottom of the stack is probably weighed down sufficiently by the wood on top of it, but boards near the top greatly benefit from added weight. Relative humidity levels in a home Weighing the stack of wood down helps to prevent warping or distortion, which is especially important during the initial drying phase when going from green to an ambient EMC. Suggested humidity level in house Neatly and properly stacking, stickering, and weighing wood will go a long way towards ensuring that the drying process will result in flat, stable, and usable lumber.

This small stack of Buckthorn (Rhamnus cathartica) half-logs has just been cut, stacked, stickered, and sealed with a water-based wax emulsion coating.

• Add heat once EMC is reached. What are normal humidity levels in a home It’s important not to rush the drying process too quickly, but once a wood pile has safely reached EMC, it may be necessary (especially during humid summer months) to bring the MC down even further for a specific project. What can cause high humidity in a house This can be as simple as moving the lumber stack from a garage or shed into a heated basement indoors. What causes high humidity levels in a house In cases where shorter pieces are used, a drying cabinet can be used to gradually reduce the MC down to 12% mc, 6% mc, or any other level that an application may call for.

A drying cabinet can be nothing more than a simple wood cabinet with an incandescent lightbulb on a dimmer to finely control the light output—which in turn dictates both internal temperature and consequently relative humidity. What humidity level should my house be in summer Many thermometers (both traditional and digital) sold by big-box retailers also feature a hygrometer with a somewhat accurate readout of the relative humidity; the ability to know the rh of both the drying cabinet and the wood shop proves to be a helpful and prudent investment. What is a comfortable humidity level in a home Warp and distortion

When a wood species has a high T/R ratio, it will tend to shrink in one dimension more than another while drying, causing distortion or warp. What is a comfortable humidity level in a house A good way to visualize the tendencies of wood during drying and shrinking is to picture the arc of the growth rings trying to flatten themselves out. What is a comfortable humidity level in your home (This of course is not actually the cause of the shrinkage, but it serves as a good memory tool to help visualize dimensional changes.)

The answer to ‘how long’ would still depend on the many other factors: How warm does it get inside the cabinet? What species or density of wood? How big is the piece of wood? What is the humidity outside the cabinet (thus how humid the air coming into the cabinet)?

I have had success taking wood down to 6% in mere minutes by microwaving very small pieces of oak in the kitchen microwave a few pieces at a time (a lot of trial and error getting the timing/settings just right for my wattage of oven [of course the microwave heats the water on the inside and you then set the wood outside the oven to dry while you heat the next batch; test and repeat until you get it]).

If your cabinet is air-tight, you will never lose any moisture, so if you utilize a cabinet originally designed for food storage, be sure to cut a hole in the top and bottom to allow air to pass through. What is a comfortable humidity level inside a house Make slider doors over the holes to allow you to adjust or damp the amount of air flow. What is a comfortable indoor humidity level You could use a micro-controller with temp and humidity sensors to control the heat and the air flow. What is a good home humidity level I think the core temperature of the piece being dried has a lot to do with how fast it dries. What is a good house humidity level Get your cabinet temp up to 120F and it will dry quickly, in a matter of days. What is a good humidity level for a home It’s like an easy bake oven.

Maybe this is a dumb question, but I plan on building an addition next year, so I have about 12 months between now and when I will be doing the framing. What is a good humidity level for my house If I were to buy the lumber (2×6’s etc) from the yard now and stack it and sticker it and leave it under cover (in my barn) for that year, will it prevent some of the problems with warping you typically get from typical Home Depot (or wherever) lumber? I’m in Ontario, so humid summers and cold winters, which the stack would experience. What is a good humidity level in a home I know lumber quality seems to be lower these days, so I was hoping to mitigate that through some prevention, if possible.

I am making a reclaimed pine rustic table top for a client. What is a good humidity level in a house I bough the pine from a reclaimed timber yard and the wood was left outside so the planks were wet. What is a good humidity level in your home They were 31 mm x 250 mm wide and 2 metre’s long. What is a good humidity level in your house I have over the course of a week left the wood in my house to dry enough so it is damp and not wet. What is a good humidity level indoors I have plained the wood to 25mm thick over 4 days to allow movement. What is a good humidity level inside a house My problem is that the wood is still slightly damp but a lot better. What is a good humidity level inside during summer As I am making the table top for a client, they will want it back in a few week. What is a good humidity level inside during winter My big question is how dry does the wood need to be and how long is a short but suitable time to dry enough to put a finish on it and give it to the client. What is a good humidity level outside I need help with this please.

As you hopefully found out before now, the answer to the question of how dry wood should be depends on the humidity of the air in which it will stay, but generally under 7%. What is a good indoor humidity level in summer If you coat only one side and then put the table in a dry home, the uncoated underside will dry out before the coated top side and this can result in warping and cracking.

If the wood feels damp, then I consider it too wet to coat, but it really depends on what you are coating it with. What is a good indoor humidity level in the winter If you get the water content down to some percentage as measured by a probe and it feels dry to the touch, you can seal it on all sides and then it shouldn’t matter how much water is in the wood since it will be sealed in. What is a good inside humidity level You also want to avoid over drying or drying too fast. What is a good level of humidity in a house The way to determine water content is usually by jamming an electronic probe into the side of the board on an inconspicuous surface, but if you know how much your wood should weigh dry versus wet then you can determine water content by weighing it. What is a good level of humidity indoors I suppose that tip is more useful for people using very small pieces of wood who don’t want any surface marred by test probes.

I was wondering, can I use interior paint to seal the ends of split logs? I have a large walnut tree that fell in a storm and after around a year took a firewood sized log, split it, let it sit for a few days and finally coated the ends with interior white paint. What is a healthy humidity level for a home Just what I had in the house. What is a healthy humidity level in a home There are some cracks already up to an inch in that appeared after painting. What is a healthy humidity level in a house Is it cracking simply because I did not get it painted right after cutting? The cracks only appear to be in the sapwood. What is a healthy humidity level in your home Also, there is a vein type line going all the way down the halves in the center. What is a healthy humidity level indoors There are perpendicular cells all the way up it, and in between those, it is hollow. What is a healthy indoor humidity level It is only about 3/16 at widest… Not to worried about it but was just wondering.