Joinery, what is a mortise and tenon?

The mortise and tenon joint has been used for thousands of years by woodworkers around the world to join pieces of wood, mainly when the adjoining pieces connect at an angle of 90°. In its basic form it is both simple and strong. Although there are many joint variations, the basic mortise and tenon comprises two components: the mortise hole and the tenon tongue. The tenon, formed on the end of a member generally referred to as a rail, is inserted into a square or rectangular hole cut into the corresponding member. The tenon is cut to fit the mortise hole exactly and usually has shoulders that seat when the joint fully enters the mortise hole. The joint may be glued, pinned, or wedged to lock it in place.

This joint is also used with other materials. For example, it is a traditional method for stonemasons and blacksmiths.

Mortise and Tenon joinery technique

Mortise and Tenon joinery technique

Types

A mortise is a cavity cut into a timber to receive a tenon. There are several kinds of mortise:

Open mortise: a mortise that has only three sides (usually open on top of the wood)

Stub mortise: a shallow mortise, the depth of which depends on the size of the timber; also a mortise that does not go through the workpiece (as opposed to a "through mortise").

Through mortise: a mortise that passes entirely through a piece.

Wedged half-dovetail : a mortise in which the back is wider, or taller, than the front, or opening. The space for the wedge initially allows room for the tenon to be inserted; the presence of the wedge, after the tenon has been engaged, prevents its withdrawal.

Through-wedged half-dovetail: a wedged half-dovetail mortise that passes entirely through the piece.

A tenon is a projection on the end of a timber for insertion into a mortise. Usually the tenon is taller than it is wide. There are several kinds of tenon:

Stub tenon: short, the depth of which depends on the size of the timber; also a tenon that is shorter than the width of the mortised piece so the tenon does not show (as opposed to a "through tenon").

Through tenon: a tenon that passes entirely through the piece of wood it is inserted into, being clearly visible on the back side.

Loose tenon: a tenon that is a separate part of the joint, as opposed to a fixed tenon that is an integral part of one of the pieces to be joined.

Biscuit tenon: a thin oval piece of wood, shaped like a biscuit.

Pegged (or pinned) tenon: the joint is strengthened by driving a peg or dowel pin through one or more holes drilled through mortise side wall and tenon. This is common in timber framing joints

Tusk tenon: a kind of mortise and tenon joint that uses a wedge-shaped key to hold the joint together.

There are other types of mortises and tenon, feel free to add in the comments and/or share pictures.

Generally the size of the mortise and tenon is related to the thickness of the timbers. It is considered good practice to proportion the tenon as one third the thickness of the rail, or as close to this as is practical.

History

This is an ancient joint dating back 7,000 years. The first examples, tusked joints, were found in a well near Leipzig - the world's oldest intact wooden architecture. It has also been found joining the wooden planks of the "Khufu ship",a 43.6 m long vessel sealed into a pit in the Giza pyramid complex of the Fourth Dynasty around 2500 BC. The oldest known use dates from the Early Neolithic Linear Pottery culture, where it was used in the constructing of the wooden lining of water wells.

It has also been found in ancient furniture from archaeological sites in the Middle East, Europe and Asia. Many instances are found, for example, in ruins of houses in the Silk Road kingdom of Cadota, dating from the first to the fourth century BC. In traditional Chinese architecture, wood components, such as beams, brackets, roof frames and struts, were made to interlock with perfect fit, without using fasteners or glues, enabling the wood to expand and contract according to humidity. Archaeological evidence from Chinese sites shows that, by the end of the Neolithic, mortise-and-tenon joinery was employed in Chinese construction.

The thirty sarsen stones of Stonehenge were dressed and fashioned with mortise-and-tenon joints before they were erected between 2600 and 2400 BC.

 

 

 

 

Source Wikipedia

 

Why you should listen

tree forest life

A professor of forest ecology at the University of British Columbia's Department of Forest and Conservation Sciences in Vancouver, Suzanne Simard studies the surprising and delicate complexity in nature. Her main focus is on the below-ground fungal networks that connect trees and facilitate underground inter-tree communication and interaction. Her team's analysis revealed that the fungi networks move water, carbon and nutrients such as nitrogen between and among trees as well as across species. The research has demonstrated that these complex, symbiotic networks in our forests -- at the hub of which stand what she calls the "mother trees" -- mimic our own neural and social networks. This groundbreaking work on symbiotic plant communication has far-reaching implications in both the forestry and agricultural industries, in particular concerning sustainable stewardship of forests and the plant’s resistance to pathogens. She works primarily in forests, but also grasslands, wetlands, tundra and alpine ecosystems.

 

https://www.ted.com/talks/suzanne_simard_how_trees_talk_to_each_other

Wooden nail

Hardwood nails

Hardwood nails

There haven’t always been iron and steel nails to use in construction. Long before nails and screws were widely available, most construction – whether it was furniture, ships or building construction – made use of wooden nails and pegs. Even now, construction using wooden nails, dowels and pegs is a hallmark of quality.

Wooden joins like those that use wooden nails are preferable to metal nails and screws in construction that will be exposed to the elements. The reason is a simple one – a rusted nail contributes to rotting wood, weakening the construction. A securely fastened join using wooden nails is stronger and lasts longer than most metal and wood construction.

There are a number of construction firms that specialize in timber frame construction of cabins and cottages, using all wood joins, including wooden peg and wooden nails as fasteners.

The idea of fastening wood together using wood may seem strange to anyone that’s not a woodworker or cabinet maker. After all, what else is a hammer and nails for? Or a screwdriver and drill and screws? Any fine furniture maker can tell you different, though. The use of mortise and tenon, dovetail and wooden nails joining methods are all common methods that go back far into history – and are still used NOT for historical accuracy, but because they are simply the better way to hold wood together.

Wooden nails are made from dowels, generally a hardwood. They’re often pre-shaped with a rounded or tapered tip to make insertion easier. They may be smooth or grooved to hold glue better, and they are available in many different lengths. The finished quality of your furniture can’t help but be affected by the quality of the wooden nails used in its construction.

Keeping the Natural Equilibrium

DusunBambu

In areas where nature is the key selling point, the design is often made not only to copy nature but is done in such a way as to respect it. This kind of approach can be seen in many ecotourism establishments in Indonesia. Bandung, where the mountainous landscape is one of its greatest attractions, has seen a significant growth in ecotourism. The DusunBambu Family Leisure Park located in the outskirt of Bandung is a great example of where nature and design can live in perfect harmony.

Leisure Park – DusunBambu

According to Lindberg and McKercher, a great ecotourism concept should recognize its responsibility towards the nature and culture of the surrounding areas. It should not only conserve the environment but also sustain the well-being of local people. DusunBambu Family Leisure Park that was founded in late 2013 by CEO Ronny Lukito understands this definition and it reflects all across their 15-hectare establishment.

Out of their entire land, DusunBambu actually only uses around 5,100 square meters, about 3%, for their needs, leaving the rest of the natural space untouched. In this 3% area, they have built a range of interesting facilities such as villas, a restaurant and café, a food court, a childrens’ playground, and a camping ground with a design approach that pays tribute to the traditional Sundanese culture. DusunBambu, which means ‘the bamboo village’,makes wide use of different types of bamboo in its design elements.

We saw the use of bamboo for making furniture and as part of the broader design concept at KampungLayung, which is the villa area of DusunBambu. Offering an au naturel concept, KampungLayung really has that Sundanese village charm where the villas are built in the traditional Sundanese semi-permanent house style, mixing wood and rattan with a roof that is partially covered by dried palm leaves. There are 5 villas in this village, having either one or two bedrooms, and each villa is accompanied with a nice terrace to unwind. At the end of the village lies the open and communal fire place overlooking the rice paddy fields. It is interesting how the landscape design has incorporated the indigenous vegetation from that area such as the giant fern trees and the bird’s nest ferns to create that authentic village feel.

Another design highlight at DusunBambu is the artificial lake called Purbasari that is surrounded by 12 little and long wooden houses. Functioning as a family restaurant that serves great traditional Sundanese cuisine, all these long wooden houses only have one area inside with a long table in the middle. Here they apply the traditional Sundanese eating concept known as ‘lesehan’, where we sat on the floor and the food was served on a low long table made of local wood. All these houses have a trapezium shape with a little porch and a wooden staircase that leads to a small wooden deck. You can reach these houses either along a nice walking path or with one of their colourful canoe boats via the lake.

In the main public area of DusunBambu lie two more interesting restaurants : the two floor Burangrang café and restaurant overlooking the Purbasari lake and the LutungKasarung restaurant which is situated on the raised skywalk and has been made to look like a bird’s nest with each ‘nest’ covered by living tree branches. Still in the same area there is the PasarKhatulistiwa food court that has various renowned food vendors from Bandung as well as mini souvenir stores located in a two floor building. On the left side of the food court is a large open air childrens’ playground that is covered with artificial grass rugs and comes with mini playhouses as well as a petite ‘Labyrinth’ garden maze and where the children can play with cute rabbits or just run around with their friends.

Another special feature of DusunBambu is the fact that they also have a beautiful camping site known as the Eagle Camping Ground. They have around 10 camping pitches with some having room for two family size tents. Each tent has a nice view of the hill, an open barbeque grill for alfresco dining and a semi-permanent bathroom that is situated below the tent site. The tents themselves are made by Eiger – a well known outdoor supplies company from Bandung that already has a worldwide reputation. The tents have a 6 meter wide space separated into a sleeping area (with two separate sleeping bags) and a living area. Following the current ‘glamping’ trend aka glamourous camping, this Eagle Camping Ground is definitely perfect for such an experience.

DusunBambu really has all the right elements to be the leader of ecotourism establishments in Bandung. This is definitely the place where nature and design have achieved a great equilibrium.

Joinery, what is a shiplap?

 

Shiplap is a type of wooden board used commonly as exterior siding in the construction of residences, barns, sheds, and outbuildings. It is either rough-sawn or milled wood. The rabbet allows the boards to overlap in this area. The profile of each board partially overlaps that of the board next to it creating a channel that gives shadow line effects, provides excellent weather protection and allows for dimensional movement.

Useful for its strength as a supporting member, and its ability to form a relatively tight seal when lapped, shiplap is usually used as a type of siding for buildings that must withstand cold and aggressive climates. Rough-sawn shiplap is attached vertically in post and beam construction, while milled versions providing a tighter seal are more commonly placed horizontally.

Small doors and shutters such as those found in barns and sheds are often constructed of shiplap cut directly from the walls, with only thin members framing or crossing the back for support. Shiplap is also used indoors for the rough or rustic look that it creates when used as paneling or a covering for a wall or ceiling. Shiplap is often used to describe any rabbeted siding material that overlaps in a similar fashion.

Shiplap joint for cladding and paneling

Shiplap joint for cladding and paneling

Problems: Cupping and Crowning

cupping and crowning

Cupping and crowning are two terms used in the hardwood flooring industry to describe the reaction wood floors experience when there are problems with moisture levels in the home. It should be noted that very slight cupping or crowning can take place within normal humidity changes such as with those of the changing seasons and periodically should be expected. Solid wood flooring tends to be more susceptible to these problems as the wood planks are made of solid wood the entire way through, whereas engineered wood experiences less issues because only the top layers of the wood are made from the wood species in question. Both cupping and crowning can be experienced regardless of the wood species or width of the planks.

Cupping: Cupping happens when both side edges of the plank seem to rise up out of the floor and cause a “dip” to appear in the middle of the plank. It looks like a cup, a misshaped “U”. Cupping can be slight or very noticeable. When excess moisture is absorbed into the plank it causes the edges of the plank to expand with such force that they crowd the planks on either side of it, forcing the edges of the wood to rise up causing the dip in the middle. Usually this is because moisture remains underneath the planks.

Crowning:  Crowning takes place when the edges of the wood shrink in towards the bottom while the middle or the top of the plank swells up past the rest of the regular level of the floor. It looks like a small roll sticking out above the rest of the flooring. This can either also be barely or very noticeable based on the situation. This happens when moisture is left sitting on top of the plank rather than the edges.

Probable Causes:

    • Outside of normal changes in the humidity levels during seasonal changes, moisture can remain underneath the floor or on top of the planks without the homeowner necessarily being aware that it’s happening.
    • A big spill could have taken place on the floor that was left unattended or not cleaned up after in a proper manner.
    • Moisture could be leaking up through subflooring.
    • A leaky pipe in the walls could be dripping down onto support beams that in turn lead to subflooring materials.
    • Dryer vents can become clogged and then different moisture levels unknowingly get pumped back into the house. (It’s common for homeowners to be unaware this has been happening especially if the homeowner often turns the dryer on but then leaves the home and comes back several hours later.)
    • Condensation near the bottom of uninsulated patio doors may accumulate near the edges of the floor.
    • There may be a leaky faucet or pipe under the sink.
    • A refrigerator or freezer may be not be working properly and leaking fluids slowly where the homeowner cannot see it.
    • In locations that receive a lot of rain, rain run off may not be properly diverted away from the exterior of the home allowing moisture to seep in underneath the home and therefore potentially into subflooring.
    • Slow leaks could exist in roofing or in overhead sprinkler systems. 

Solutions:

Install a humidifier or dehumidifier in your home to help keep the humidity at constant levels. Be diligent about hardwood flooring installation preparation and make sure your home remains at a constant humidity level while the wood is being acclimated in your home before installation. Dryers can help speed up drying spots in the floor if need be. Once relatively constant humidity levels have been achieved in the home, have your flooring moisture tested to determine if any further action is necessary. Depending on the age or condition of the hardwood floor, the planks may need to be resanded and or recoated.

What is a tongue and groove?

Tongue and groove

Tongue and groove is a method of fitting similar objects together, edge to edge, used mainly with wood, in flooring, parquetry, panelling, and similar constructions. Tongue and groove joints allow two flat pieces to be joined strongly together to make a single flat surface.

A strong joint, the tongue and groove joint is widely used for re-entrant angles. The effect of wood shrinkage is concealed when the joint is beaded or otherwise moulded.

Each piece has a slot (the groove) cut all along one edge, and a thin, deep ridge (the tongue) on the opposite edge. The tongue projects a little less than the depth of the groove. Two or more pieces thus fit together closely. The joint is not normally glued, as shrinkage would then pull the tongue off.

In another assembly method, the pieces are end-matched. This method eliminates the need for mitre joints in furnitures and face nailing on floors.

For many uses, tongue and groove boards have been rendered obsolete by the introduction of plywood and later composite wood boards, but the method is still used in higher-quality boards. Plywood may also be tongued all round to fit it flush into a framed structure, and plywood for sub-floors used in platform framing is often supplied with tongue and groove edges.

When joining thicker materials, several tongue and groove joints may be used one above the other.

One of the following woodworking tools may be used to produce the tongue and groove:

  • A four- or six-head moulder (for large quantities)
  • A wood shaper (spindle moulder)
  • A circular saw bench
  • Suitable hand planes: a plough plane for the groove and a tongue plane for the tongue, or a combination plane
  • A spindle router

Don’t mistake it with tongue-in-groove !

 

 

 

 

Source Wikipedia.

 

Your floor and its reactions to greenhouse effect.

I have a vacation home and when we left our floors were fine. Now they are weird shapes and or are making noise when we walk across it. Why is this happening?

greenhouse and wood floor

This is known as the “greenhouse effect”. Your hardwood flooring will still react to moisture and humidity changes within the home even if you are not there for extended periods of time. Most of the time, a house has been closed off, its central air units and other humidity control devices, if any, have also been shut off during your absence. This causes the heat that is trapped by the house during the day to stay in the house. When the house cools at night, condensation will form in various places of the home and over time this constant “up and down” effect wreaks havoc on your hardwood flooring. Once you’ve entered the home and caused constant humidity levels to re-balance in the home, you’ll need to take measures on repairing cupping, crowning or even buckling if it has occurred.

When you leave the home again, leave some of the windows a bit open to allow for proper ventilation of the home. Use window blocking bars, sticks in the window sills or other security devices to prevent the windows from opening fully in your absence.

 

 

 

 

 

Text extract from woodmonsters.com