Working With Timber
Before we take a deep dive into the nuances and procedures of the tasks involved in carpentry, we will look briefly at the general principles and good practices involved with handling and working with timber. Most of these principles are in relation to the cellular construction of timber, the defects and natural properties of the timber, and the basic construction criteria that we aim for.
Storing timber
When timber arrives on site, it's important to store it properly prior to installation. Often, the moisture content of the timber is high, with the lengths sometimes sopping wet, due to outside storage at the merchants. When wet timber is rapidly dried, natural tension in the timber can be amplified, distorting the lengths. During hot weather, timber that is stored outside should be covered to keep the beating sun from unevenly drying the timber and creating warpage. In the same vein, timber should be covered or kept inside during wet periods of the year, in an attempt to keep it dry before installation. Excessively wet timber that is installed before an appropriate level of moisture is achieved can lead to damp problems in the building, also occasionally leading to mould or rot occurring.
Lengths of timber should be stored on bearers to allow for air to circulate the pile, in an effort to lower the moisture content on site and prevent mould. The bearers should evenly support the timber along their lengths to ensure bows and other defects are not introduced into the drying lengths. Heavy timbers that are unsupported in the middle can develop a bow during their storage, making them less ideal to work with.
In some instances, timbers that possess defects such as twists or bows can be partially straightened by placing blocks or other heavy weights on them during storage. For all intents and purposes though, the time between straight timbers being purchased and installed should be as slim as possible to prevent the eventual distortion of the lengths during storage on site.
Observing and selecting timber
When carrying out carpentry operations involving the timber that we have stored somewhere on site, we need to carefully select the lengths that we use for our intended applications. As a rule of thumb, the straightest lengths should be used for the longest components, taking advantage of the natural straightness of the lengths. Lengths that are badly twisted or bowed should be left until last and cut up into smaller components if possible. Cutting these lengths up for smaller parts can help to significantly reduce the noticeable defect, making the timber easier to work with.
Timbers that feature extreme defects such as shakes, splits, or excessive knots in small clusters should be cast aside, as these timbers are not structurally sound. When selecting the timbers, the direction of the crown should be noted, ensuring that they are all facing the same way.
Transporting timber
When moving timber around site, or installing components, there are methods and procedures that we can abide by to make the overall task easier. Lifting lengths at their centre point is the easiest in terms of managing the weight, as even portions of the timbers are present in front of and behind our hands. For heavy lengths, timbers may have to be carried with our hands down by our sides to more safely manage the weight. For less heavy lengths, timber is typically carried on the shoulder, allowing our core muscles to support the weight of the timber instead of hanging from our arms. For wide lengths, single timbers may have to be managed one at a time to reduce the risk of injury. To get these lengths onto our shoulder we must first get them to waist height off of the floor using our arms. With our hands gripped either side of the board, straddling the centre of the length, a quick twisting motion will place the timber centrally on our shoulder. By thrusting our shoulders upwards in conjunction with our arms, we can readjust the position of the timber if required. If the timber isn't centralised, our core has to work harder to stabilise the timber from tipping instead of being able to simply support it.
For smaller lengths such as 4”x2”, we opt for carrying multiple lengths to maximise efficiency when transporting the timber. Typically, 4-5 lengths of smaller timber is the comfortable limit without risking injury. Carrying multiple lengths at once comes with its own challenges and can be tricky to get a hold of as a new tradesperson. Here are some tips for carrying multiple lengths successfully. Getting the lengths onto the shoulder can be difficult directly off of the ground, and so it's easier to stand them up first. By leaning them against each other on a wall or hard surface, they can be much more easily lifted. To do so, bend the knees with a straight back and grab the lower portion of the timber at a height where the centre of the lengths is rested on the shoulder. By standing upwards into the timber whilst pulling it away from the wall, gravity will naturally bring the back end downwards, laying the lengths effortlessly across our shoulder. The downwards force of our hands on the front of the timber stops the momentum from pulling us over. Once the timber is stable and happily centralised, the stack can be easily carried on the shoulder and supported with 1 or both hands. If the timbers aren't very straight, they can sometimes tend to spin around during transport. This occurs when the bow of two timbers is sitting atop one another. The lack of friction between the lengths makes keeping the timbers together awkward. To avoid this, stack all of the timbers with the bows in the same direction.
Regardless of the weight of the timber, most lengths are at least 2.4m in length, sometimes more than double that, and as such it's important to know where both ends are in relation to oneself in the middle. Swinging lengths of timber around in an area carelessly without being aware of one's surroundings can lead to harm or damage coming to other operatives, people in the area, or surrounding components. Visualising the timber whilst carrying it can help to prevent the timber from damaging anything. If the lengths are kept in line with our body and the direction of travel, then the front and tail end of the lengths will follow our path. It's important to focus on the front end of the timber and where we’re going and worry less about what's going on behind us. For long lengths, if we can see that the timber is straight ahead of us, the back portion must be straight behind us. The same is true for the horizontal position of the timber. If the front end is straight out in front of us, then the back must be too, and is at no risk of lifting in the air and hitting something.
When taking lengths up onto a scaffold, the principles of leverage can be applied to aid us. When heavy lengths are lent against the scaffold, we can use the handrails to lever the timber up and over onto the scaffold. Once at a decent height, downward force that is applied to the top edge of the timber will lever the length over the rail, allowing us to bring timber up.
Working characteristics of timber
Here are some notable points about the working properties of standard timber lengths. This information will be useful during the practical aspect of carrying out carpentry tasks.
As discussed earlier in the book, lengths of timber possess a grain that runs more or less parallel to the length of the timber. When working with timber, the majority of the cuts that we make are “cross grain” - cuts that are made perpendicular to the grain of the length. The fibres are most resistant to load in this orientation and must be severed to cut the length of timber. This is in contrast to the strength of timber down its grain, with a tendency to split apart under excessive force. This can be used to our advantage when notching timbers or cutting half laps and tenons. By severing the grain at specific points, we can use a chisel to split the short grain and remove the majority of the waste material.
All lengths of timber, as is the case with all building materials, will flex under load. Being able to physically bend lengths of timber can help us to bring lengths that arent straight into alignment with one another. Just because lengths possess defects such as bows or twists, it doesn't make them completely unusable - just more difficult to work with. Small amounts of bow and twist can be undone using force and proper bracing after the fact.
Under high pressure the surface fibres of the timber can compress, with common structural softwoods being particularly impressionable. Whilst this doesn't affect the stability of the timber, it can be unsightly in certain aspects. For example, the pressure exerted onto timber through missed hammer strikes will leave impressions in the surface of the timber that can be unsightly and make the overall project look sloppy. If the pressure is too great or exerted over a relatively sharp edge then the surface fibres may be severed, permanently damaging the face of the timber.
In finished timber components, grain that is compressed but not severed can in some cases be raised again through the use of heat and moisture to restore the surface of the timber.
Whilst the majority of the timber that comes from the merchant is successfully shaped using modern milling machines, sometimes timber arrives that falls outside the expected quality. For example, machine snipe, splintered edges, non-dimensional cuts, and other defects may be present. In addition to this, the ends of the lengths are not necessarily square in relation to the length. These factors are important to consider and notice when handling and installing timber components.
When actually working with timber, we want to establish a familiar direction of work in relation to the timber so as to ensure that all of the components are installed in the same orientation. In most applications, this includes “rounding the timbers” on a bench before starting the task, checking the direction of the crown and stacking them all in the same orientation.