The assembly of structural studwork is a straightforward procedure, with the most arduous part being the heavy lifting involved. With careful planning and adherence to the drawings, the installation of structural studwork forms a suitable foundation for further structural components. There are a couple of specific assembly styles suited for use in different applications, with a handful of varieties of each style. Here we shall look at the details and differences between the most common styles. It's important to note that there is no definitive style that can be used in every application, and that the specifications for studwork like this is typically calculated by the structural engineer to meet the requirements for an individual application. That being said, most often the drawings will specify some similar variation of the styles below.  

Before the installation of any structural partition, appropriate provisions should be implemented in order to support the wall. This ranges from solid concrete floors in internal scenarios, to RSJ’s or flitch beams involved in roof structures. With the appropriate provisions situated in the correct area, we can begin to set out the location for the studwork and calculate the lengths of our components. In scenarios where a subfloor system is present, marking out the location for the studwork can be easily achieved by snapping chalk lines on the floor surface to denote the location of the studwork. If the wall is sitting directly on top of timber joists or steels then the layout marks must be made directly onto these components. At this point the procedure varies depending on the scenario.

Internal structural studwork partitions are commonly found in modern residential buildings and are used as a replacement for traditional masonry walls for the reasons we’ve already discussed. These internal partitions are used to support joists either at their ends or to support the midpoint span of larger joist systems, providing stability to both floor joist and roof systems. Load bearing beams may also be supported through the use of structural studwork. The basic construction of these walls sees stacked horizontal plates supported by vertical timber studs. They may also be sheathed on one or both faces with structural sheet materials to provide rigidity and resistance to racking within the wall.

To begin the process of erecting one of these walls, some of the details about the component need to be acquired from the drawings and the immediate area around the location of installation. What material is the studwork to be made from? Does the drawing call for regular internal CLS or a specific dimension of treated timber? Is the wall sheathed with a structural sheet material? Is there room to assemble the studwork on the floor and then lift it into the desired location for installation? Note that due to the weight and difficulty associated with handling these types of partitions, structural studwork intended to be assembled within a room that already has a ceiling/ceiling joists installed should be built in situ. Structural studwork that is built in preparation to support joists or other components can be easily assembled on the floor and lifted into place, without the height restrictions imposed by installed joists.

In this example, the studwork will be assembled from treated 4”x2”, sheathed on both faces with 18mm structural plywood, before 12.5mm plasterboard is installed over the plywood on each side. This studwork is being implemented to support the span of new joists installed alongside existing joists as part of a loft conversion process, and as such will be assembled in situ. With the criteria assessed, the process can begin by marking out the area ready to receive the studwork.  

Cutting a single plate to the width of the room can help to set out the location of the wall, providing that the timber is straight. Using the plans and measurements provided, marks can be made on the floor using an existing reference point in order to denote the location of the new wall. The drawing displays an internal room measurement of 2.4m from wall to wall. By measuring in from each end of the room, reference marks can be established to line up the partition. It's important to remember to allow for the sheathing materials when marking out the location for the plates. In this case, the 2.4m marks on the floor denote the inside dimensions of the new room. From this point, an additional 33mm needs to be added to denote the position of the plate, as this measurement accounts for the total thickness of the 18mm sheathing plywood and the 15mm for plasterboard and plaster.

By aligning the cut plate with these marks, a square can be used to ensure that the layout of the new partition is square with the existing walls in the room. If necessary, slight adjustments can be made to bring the plate into square, though there is no guarantee that this is achievable in both corners - this is a factor dictated by the existing dimensions and layout of the building. A more critical check to make is to ensure that when installed at this location, the new partition will adequately support the intended components. It's not unheard of for the dimensions of a building to differ from those stated on the plans, and in these occasions, we need to use our discretion to ensure that the partition is providing appropriate support to the components above. Once layout of the partition is achieved on the floor, the lines can be marked vertically up the walls and connected across the ceiling surface. These reference marks will help to align the components of the studwork during installation.

With the layout completed the rest of the components are ready to be cut and installed. The overall construction of this studwork features doubled up sole and top plates, as well as double end studs, with single studs at regular 16” centres through the rest of the wall to accommodate the 8’ sheathing material. These doubled components are layered during assembly for additional stability. The uppermost top plate is cut to the total width of the room - the same length as the sole plate in a perfect world. Existing deviations in the verticality of the surrounding walls may cause the top plate to be larger or smaller than the bottom plate. Using appropriate fixings the top and bottom plate can be secured in relation to the layout marks. Coach screws or gun nails can be used to securely and quickly fasten the top plate to the ceiling through the existing joists. The sole plate can be fastened using plugs and screws into the masonry subfloor. Care should be taken when drilling into the subfloor, as pipes or underfloor heating may be present.  

By taking vertical measurements between the two fixed plates, the end studs can be marked and cut. If an accurate measurement is hard to achieve due to the height, an approximate measurement plus an inch can be marked and cut. By resting this long stud on the edge of the bottom plate, a pencil can be used to mark a line on the stud against the underside of the top plate. By then cutting to this mark, an accurate length for each end stud is achieved. This principle can be used to cut the remainder of the studs later on in the process. Once the two end studs are cut, they can be installed via nails through both of the plates, as well as fixings into the wall using some form of mechanical anchor.  

At this point a secondary check needs to be made to ensure that the fixed frame is correctly located within the room in accordance with the desired layout on the drawings, and all of the components meet the basic carpentry requirements. Once this has been confirmed, the remainder of the timber components can be installed. For this style of structural studwork, a secondary frame is created within the initial frame to increase the load bearing capacity of the partition. Another sole and top plate measured, cut and installed, with another set of studs supporting the top plate at each end of the partition. As the wall is being sheathed in standard 4’x8’ structural plywood, the stud layout needs to suit 16” centres. To achieve this, a mark should be made at 16” in from either of the walls surrounding the partition. This mark is the centre of the first regular stud. By measuring backwards from this mark ⅞”, or half the thickness of the stud, and making a small kerf with the saw at this point, an accurate notch is created to pull the rest of 16” measurements from. By offsetting this first mark, all of the sequential marks will display the outside of the studs, which makes lining things up easier during installation. This layout is continued along the bottom plate to the other end of the wall, ensuring the location for the stud in reference to the layout marks is clarified to avoid confusion during installation. This 16” layout will accommodate the sheathing in either a vertical or horizontal arrangement, with the joins between the sheets always landing halfway on a stud. 

As the partition is being built in situ within an existing structure, it is possible that each stud may vary in length due to discrepancies in the level of the floor or ceiling surfaces, and so the appropriate number of studs should be cut with around an inch allowance and marked in the same way as before. Each stud should be cut and installed in sequence, to avoid any mix ups. All of the studs should be crowned in the same direction to achieve a more uniform surface on both sides of the finished partition. It's important to note that these studs within a structural partition cannot be straightened through methods we look at later in relation to non-load bearing studs. This means that it’s imperative to use suitable straight timber from the start. Each stud should be fixed in place using nails skewed diagonally into the bottom plate in reference to the layout marks. The studs should be plumbed up in both directions and flushed with the top and bottom plates to create perfect intersections. With the first stud installed plumb, additional layout marks can be made on the top plate to increase the speed of installation.

Once all of the studs installed, the next step is to install the solid blocking. In structural applications, this solid blocking can be installed in a variety of ways, with the exact type being specified on the plans. In this instance, a single row at the midpoint height of the studs is required. A common height for the installation of solid blocking in studwork partitions is 4’ off of the floor, with the full height of the room being 8’. Marking this height at each end of the partition and snapping a chalk line between them is the fastest method of layout here. The blocking will be staggered either side of this line throughout the wall. To effectively cut the blocking, offcuts of timber can be registered against one side of each stud and marked against the next. After cutting to this line, the blocking should slide snugly into place. Using nails, the blocking should be fixed in place through the back face of each stud. Continue this practice throughout the whole wall between every stud. The very last piece of blocking should be cut slightly oversize by a few millimetres, to ensure that the entire row is tightly installed.  

With the blocking installed the sheathing is ready to be measured and cut. If the sheets of plywood are being installed vertically, simply cut them to length the height of the room from the ceiling to the floor, with a slight allowance in order to get the sheet into place without it binding. The sheet does not have to be cut tight, as it primary purpose is to provide stability to the structural load bearing studs. If the sheets are being installed horizontally, the first row should be installed around 5mm from the floor, with the top row being ripped to width to fill the remaining gap. The sheathing should be installed with appropriate screws or nails, typically 60mm nail gun nails. One side of the partition can be freely sheathed, with steps being taken before the installation of the other side. Between the studs, appropriate insulation needs to be installed. In most applications, this insulation is 100mm of fibreglass quilt, though the exact style and thickness will be stated within the specification. Additionally, if the wall has any services such as pipes or cables running within it, then the appropriate trades need to carry out their work before the sheathing on the other side of the partition can be installed. This may require the sheathing to be left off for a while. Once any services are installed, the sheathing can be installed and the partition is ready to be faced with plasterboard.

In modern loft conversions, external vertical walls as part of dormers and gable ends are typically assembled from structural studwork. These walls are often made from wider timber such as treated 6”x2” and sheathed externally with plywood for rigidity and partial weathering purposes. A common finish on the outside of these walls as part of the roof assembly is cladding or lead. This type of wall when used in these applications is beneficial to the overall speed and efficiency of the job, as it eliminates the need for bricklayers, especially in reference to gable ends. The overall construction of these walls is very similar to the other type of structural walls, with an emphasis of doubled up top plates and sheathing. In most cases in these roofing applications, the wall is only sheathed with structural plywood on the outside face of the wall in order to receive the felt and finish. The inside face of these walls is often simply plaster boarded and skimmed, with appropriate insulation installed between the studs beforehand. In these external applications, this insulation is commonly rigid foam insulation. Additionally, in terms of fire regulations, an additional layer of fire rated cement board sheathing may be installed over the face of the external plywood sheathing, before the installation of the battens and cladding. If there is suitable working space, these partitions can be assembled on the subfloor and lifted into place. When these walls are erected, the roof structure is supported and mechanically fastened to these timber components. We look more at how these structural partitions play a part in roof assemblies in the roofing section.

In many modern roofing applications, timber framed dormers feature windows or french doors with juliet balconies. Additionally, internal structural studwork may occasionally feature walkways through them. In these instances, engineered beams/headers must be installed to distribute the load above the opening to the supports that frame the opening. Here is the process of creating openings within structural studwork.

The opening itself must be of the correct size without disturbing any important components within the wall. The outside frame of the wall including the doubled plates and end studs must be maintained at all times. A header must be installed to span the distance above the opening and distribute any of the load applied above it. This header must be adequately supported with additional studs known as jacks. The header must be assembled from an appropriate width of timber in accordance with the engineer's calculations. Where necessary, cripple studs must be installed between the header and the top plates to maintain correct load distribution. Where applicable, a sill must be installed atop cripple studs to form the bottom of the opening, at an appropriate height in accordance with local regulations.

Within modern roof assemblies, timber framed dormers and gable ends commonly feature windows. As such, an opening must be formed within the exterior structural studwork in order to receive the window. The process is as follows. This assembly can be carried out either in situ after the erection of the wall, or during the creation of the partition on the floor and lifted into place. With the initial outer frame of the wall assembled, featuring the double top plate, the layout of the opening and surrounding studs can begin. The rough opening width and subsequent jack stud locations are marked on the bottom plate - this size is typically found on the drawing, as well as the exact location of the opening in relation to other components on the drawings. These marks denote the inside faces of the jack studs.

Depending on the exact assembly requirement the window opening may be formed in a handful of different styles. In this instance we shall focus on a typical opening and window size. The internal width of this opening is 800mm. From these two inside marks the thickness of two timbers, one each for the jack and king studs respectively, can be marked. The king studs are located on the very outside of the opening and are full height studs that span from the top to the bottom plate. Cut and install these two components. By referencing the drawings, the height for the top and bottom of the rough opening can be ascertained, and their locations can be marked vertically on the king studs. At this point, a header piece should be made, formed as either a double or triple timber in accordance with the procedure for assembling these components. Alternatively, an engineered timber beam can be used as the header in these scenarios if the engineer's specifications allow. The length of the header should span the distance between the two king studs. This header can be installed between the two king studs in line with the registration marks already made. Another single timber the same width as the studs should be cut at the length of the header and installed in the correct location to form the sill piece. At this point, the cripple jack studs can be installed to support the sill and header. After this, regular cripple studs can be installed between the bottom plate and the sill, and the top of the header and the underside of the top plate. These cripple studs should be installed O/C in reference to the original layout of the wall. From here, the procedure of assembling the wall carries on as normal. The drawings display some variations of the assembly of a structural window opening.

Doorway openings