Building Stud Wall Partitions

Many of the internal walls in houses are made from a framework of timber members covered with some sort of building board—often plasterboard. In brick-built houses, such timber-framed walls are usually used only for non-loadbearing purposes. In timber-framed houses, internal timber-framed walls are of course used for both loadbearing and non-loadbearing purposes.

Building a non-loadbearing partition wall is relatively straightforward, and is a good introduction to the techniques involved in building any sort of timber-framed construction. The skills needed are not complicated and can be quickly and easily acquired.

Stud wall applications

One of the main uses for a stud partition is to provide an additional room by sub-dividing one large room into two units with independent access. This avoids the expense associated with a new rear, or roof, extension. And, although you must consult the local authority before proceeding to ensure that your project complies with building, fire and public health requirements, the additional loading imposed by stud partitions can always be carried by existing joists—providing that no load-bearing walls are demolished to accommodate the new stud wall.

Other common uses for stud partitions include the closing off of unwanted alcoves like those on either side of a chimney breast; the provision of built-in cupboards, which can also be incorporated in a full-width partition dividing one room into two, and the creation of a dining or work area within a larger room, sheltered by a divider extending into the room.

Other popular uses include the straight division of one room into two spaces where no independent access to the second room is required, as, for example, an extra bathroom leading off the bedroom.

Planning a stud wall

Stud partitions are straightforward to construct and can easily accommodate doors, hatches, decorative arches or borrowed lights.

The main design problem when planning a partition is the need to provide access if each new room must be a self-contained unit. The normal solution is a small lobby with two doors , entered by the existing door and lit by borrowed lights above each new door. This, of course, requires two partitions.

In most cases, the room you create must have its own windows. The only exceptions to this rule are ‘non-habitable’ rooms—what this means differs from country to country, but it usually includes bathrooms and small kitchens. In such rooms, you will have to provide adequate mechanical ventilation instead.

If you are lucky, you may be able to arrange for one existing window to serve both rooms, by building the partition so that it runs through the middle of the window—but this solution almost always looks like a poor job, and in any case, the amount of light received by each room might not be enough to satisfy regulations.

In some circumstances, you may feel that large, borrowed lights in the partition give adequate natural lighting, but again you must comply with building regulations and codes.

The anatomy of a stud wall

The main elements of a stud partition are two full-width horizontal timber members ; and vertical members between the top and bottom plate. In the UK, it is customary to further strengthen the framework by nailing short cross-members between the studs. The usual size timbers used for the main framework, especially in Canada, is 50mm X 100mm sawn timber, but for small partitions—the framework of a built-in cupboard for example—this can be reduced to 50mm X 75mm.

Additional cross-members are used above doors , and above and below openings such as hatchways. These provide a rough framework in which a finished frame or lining can be fitted.

At this stage, thought should be given to any fittings which you may want to hang on the wall—toilet cisterns, radiators for a wet central heating system and so on. Heavy items like these will have to be fixed to the frame members, not to the wall covering, so additional supporting timbers may be necessary. Electrical fittings may need supports, too.

To reduce heat loss, and to some extent to provide some noise insulation, you may want to fill the cavity between the cladding with some insulating material such as glass fibre.

Wiring and plumbing should be installed in the wall, and then the framework can be covered. The covering may be gypsum board laths, or larger sheets of plasterboard covered with a skim coat of plaster, or plasterboard used as ‘drywall’ where only the joints are covered with filling plaster. Or you may prefer to use one of the other many decorative wallboards which need little or no finishing off. Or you might want to use fibre or insulation boards. Skirting boards and architraves round doors and so on complete the j ob.

Setting out the frame

The first practical consideration is to find the direction of the existing ceiling joists. If the proposed partition runs parallel to the joists, the head must be positioned beneath a joist for easy fixing. If this is not possible, bridging pieces must be run between the appropriate joists to take the head. Access for this work may be obtained by lifting floorboards in the room above. First establish the line of the chosen joist and then mark its run; this will determine the position of the head.

When the partition runs across the joists it may be positioned anywhere. Find the centre of one joist by poking a bradawl in the ceiling and, using that as a guide, establish and mark the position of every second joist along the partition line—the joists should be at about 400 or 460mm centres.

Having marked the position of the head on the ceiling, mark the walls vertically with a plumb line, and draw a line across the floor to indicate the position of the plate.

Once the basic job is marked, plan the stud arrangement in detail on the basis of the size of the cladding material. The aim is to ensure that the vertical edges of adjacent cladding sheets fall over the middle of a stud and that there are sufficient studs between the edges of the boards to support the boards properly so that they do not flex.

Most boards are made in sizes that allow studs to be set at 406mm centres or 400mm centres; some boards require studs to be set at 457mm or 460mm. So decide on the boards you intend to use, and the way round you intend to fix them, and check their exact measurements before setting out the studs. Of course, it is unlikely that the partition width will divide exactly into your chosen stud spacing—so the spacing at one end of the wall, or at one side of a doorway will probably be less than the standard.

There are then two methods of constructing the frame—prefabricating it, or building in situ.

Prefabricated assembly

This is the easier method, particularly with two people. But it does rely on the walls, floor and ceiling being perfectly straight and at right angles to each other for best results. Small variations from the rectangular, or slopes that you can accurately measure, are allowable—but if the walls, floor or ceiling are very irregular, use the in situ method.

To prefabricate a frame, you need a space on the floor the width of the partition, and a bit longer than the partition is to be high. Lay out the framework on the floor, with the bottom plate lying on the floor, more or less along the line where it is finally to go, but resting on its short edge. Lay the studs at right angles to this plate, again on their short edges, and finally lay the top plate in place.

Before you do this, of course, you will have to cut the studs to the correct length. This is the height of the room, less the thickness of the top and bottom plates , less a further amount equal to just under Ihe thickness of the bottom plate again—a total, usually, of just under 150mm. Make sure you cut the studs accurately square: there are no housing joints in this sort of framework to help rigidity. The top and bottom plates will normally be the width of the room, but you can make them a little smaller if you have to allow for any irregularities.

It is probably easier to leave out studs round doorways and other openings, so that you can get them accurately positioned after you have raised the framework.

Now nail straight through the top and bottom plates, into the ends of the studs. Use round wire nails about 90mm long; two into each end of each stud. It is easiest if two of you do this simultaneously, working one on the top and one on the bottom of each stud in turn. If you synchronize your hammer blows then the framework should not move out of position. If you cannot manage this, or if there is only one of you working, then you will need to fix some sort of stop to the floor to hold the plates in position and stop the framework jumping apart as you nail.

Stand the assembled framework up— you will need more than one helper if the wall is large—and drive an extra length of bottom plate under the entire length of the wall. If you have cut your studs accurately the framework should now be wedged quite firmly in place, and you can adjust positioning with light mallet blows until it stands plumb and square in the correct place.

The next stage is to skew-nail the lowest bottom plate to the floor. Then nail the upper bottom plate to the lower one. Finally, fix the top plate to the joists. Nailing it should be fine, but if you find that you are starting to damage the surround ceiling plaster badly then switch to screwing.

Building in situ

In many cases, prefabricating will just not be possible and you will have to build the framework vertically, directly in its final position.

The position of the top plate is probably the most critical, especially if it has to lie along the line of a joist rather than at right angles to them. So fix this in position first.

Using plumb lines, mark out the position of the bottom plate on the floor, directly under the top plate. Fix this plate in place. Then mark off the stud positions on both top and bottom plates, taking into account any door- ways or other openings.

Cut the studs to length—all at once if the ceiling-to-floor height is regular; one by one if the distance varies. These studs have to be skew-nailed into place and you will find that, as you start hammering, they will shift out of place. Prevent this by fastening a G-cramp or temporarily nailing a small wooden stop to the plate on the opposite side of the stud to which you are nailing. Or get a helper to hold the stud as you nail.

Doorways and openings

Door frames hatchways and window frames and so on all need fixing to a solid sub-frame. For a non-loadbearing wall these are easy to make.

The vertical sides of the subframe or rough frame are simply studs running the full height of the wall. Nail these in place if they are not already there. The lintel or header forming the horizontal top of the opening is usually formed of two 50mm X 100mm timbers nailed together to form a beam 100mm square. Face-nail this to the studs at the correct height, making sure it is level and positioning it so that the timbers are edge-on—that is, with the 50mm dimensions of the two timbers lying horizontally. At least one short stud will have to be fixed above the header. skew-nailed in place.

If the opening does not go right down to floor level, then you will need a rough sill—the horizontal bottom member. This can be a length of 50mm X 100mm timber, laid broad side horizontally. Fix it by face-nailing—nail horizontally through the studs into the ends of the sill. Fix dwarf studs under the sill, skew-nailed to the bottom plate, and face-nailed to the sill.

Fit all the aperture linings with countersunk screws disguised with wooden plugs or oval nails punched beneath the surface which are subsequently filled, ensuring that linings protrude by an equal distance on each side of the studwork to ensure a flush finish with the thickness of the cladding.

Cladding the partition

Before you hang the sheet material you must run any electrical cables through specially drilled 12mm holes in each stud. If necessary, you must add a special noggin to hold the new box in the desired position.

Any plumbing pipes should also be run through the framework. If you have to cut notches in the studs for these, strengthen them with metal plates, nailed over the notch.

It is not necessary to scribe insulation board to butt tightly against uneven walls or ceilings because a scribed timber fillet should cover the join. Likewise, time is saved by hanging unscribed plasterboard, then filling any irregularities with bonding plaster before the finish plaster is applied.

To scribe the timber fillets, or plasterboard, if a perfect fit is desired, hold the work upright and as close to the wall as possible. To keep it firm, plasterboard may be lightly tacked to the studs, with the timber fillets braced with a couple of packing pieces against the wall. Set a pair of compasses at 10mm and run the point down the wall from top to bottom. The pencil will mark the work to the exact contour of the wall, and you can then either saw or plane it to shape.

Now hang the cladding, working outwards from the door lining to the walls. Plasterboard should always be hung with the grey side outwards if it is to receive a skim coat of plaster, and it is wise to tack each sheet lightly to permit realignment in the event of subsequent errors. Use 40mm galvanised or sheradized plasterboard nails to secure the sheets. You may leave a gap of 2-3mm between the sheets, and a 12mm gap at the bottom. This aids easy positioning and will be covered by the skirting board.

To cut plasterboard use a trimming knife. Score the board along the desired line, then snap it open and cut the paper on the other side for a clean break. Alternatively, use a fine-toothed saw. Insulating board may be cut to size in a similar fashion. The last sheet, which finishes against the wall, may be sized by turning it over and overlapping the previous sheet with the opposite edge against the wall. Mark the sheet top and bottom against the previous sheet, then cut and turn the right side out again. The sheet will then slot neatly-into place.

If you do not wish to use insulating board because of the visible fillets, but cannot tackle the finish coat on plasterboard, it is possible to build a 12mm plasterboard partition that can be decorated direct. To do this, use linings that finish 25mm wider than the studwork, as for insulating board. Hang the plasterboard ivory side out, fill and tape the joins and coat the partition with special sealant so it can take wallpaper paste. You can then wallpaper the plasterboard.

Once all the cladding is positioned, cut the holes for electrical boxes with a trimming knife and run the cables through them. Now fix the cladding firmly in place. Nail plasterboard at 150mm intervals along the studs and noggins, and nail insulating board at 100mm intervals along the edges and at 200mm intervals elsewhere. Avoid the line of the cables when nailing the board, and cover the nail heads with filler. Fill the gaps between the plasterboard sheets with special joint filler and cover them with linen sealing tape to prevent possible cracking of finish plaster along the join lines. You may apply the skim coat of finish plaster as soon as the filler has set.

If you are drylining,’then you fill the gap much as above, but of course, do not then skim with plaster..

Finishing off

The partition is finished by completing the aperture detail. Hang the door and add a door stop. Glaze the borrowed lights—set the glass in putty between glazing beads to avoid rattling. Add sliding or hinged doors to the apertures, if desired, and fit all the apertures with architrave. Then nail a skirting board that matches the rest of the room in place.

In the case of insulating board partitions you must add the timber fillets that cover the joins. After scribing the fillets to the walls and ceiling, nail the ceiling then the vertical fillets in position using 40mm oval nails. Finally punch the nail heads beneath the surface and fill the holes.

Using a preformed arch

The best method of creating a decorative arch is to purchase a preformed arch fabricated in heavily galvanized light steel mesh. There is a good range of sizes and designs available. Select the desired arch and construct the studwork as for a door. However, no lining is required; the two vertical studs and door head suffice for plastering over.

After hanging the plasterboard, fasten the two halves of the arch in position with galvanized clout nails. Then nail a strip of expanded metal lathing down each side of the aperture from the preformed arch to the floor. Finish with a plasterboard bead—a right-angled metal lath that overlaps a plasterboard and expanded metal lathing to provide a sharp edge for the finish plaster. Apply a thin coat of metal lathing plaster to the galvanized surfaces before the finish plaster is applied.

Felt covered stud wall

You can use prefabricated felt panels as an attractive alternative to plasterboard for cladding a stud wall. This technique can also be used as a cladding for masonry walls, where it is useful for covering deteriorating plasterwork.

The idea is not complicated. Use standard 12mm chipboard, and cut the boards into lengths which will fit from floor to ceiling leaving a 140mm gap. Rip saw the boards into two lengthways to give you 610mm wide panels. Tack the panels temporarily to the studding to ensure a good fit, scribing to walls and ceiling as necessary. Cut smaller panels to fit round doors into corners.

Remove the panels and cover each with felt as shown. Fit a 150mm plain skirting to lie flush with the back of the fitted boards.

Screw the panels in place using mirror screws with a decorative caps. For a neat flush, ensure that these are set level and at regular intervals on each panel. Add linings to door or window openings.

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