Building and designing interior walls
A home's interior is defined as much by the style and position of walls as by their colour and design. Walls are important not only as a structural feature but also for controlling heat and providing privacy. Regardless of their purpose or design, interior walls require a strong interior framework and adequate sheathing for the finished surface. This could be drywall, wood panelling and even stone or brickwork. Whether the framing is built with wood, metal or even plastic, wall construction involves different techniques. This article provides smart advice on how to quickly complete your project.
Tips & Tricks
To help latex paint adhere better to drywall joints, when you mix the drywall compound, replace a small amount of the water with latex or latex paint. Your primer will then penetrate the compound more effectively.
Most interior walls are built with 2" x 4" wood studs which are inexpensive, easy to cut and can be fastened with screws or nails. Wood studs can also be purchased in shorter lengths to fit the space within the floor and ceiling plates of homes with 8' ceilings, and this saves cutting. Metal studs are popular because they are strong, light, easy to fasten with screws and have portals stamped out for electrical wiring and plumbing. For sheathing, drywall is the most popular but light, wood-filled panels are also used, as well as decorative wood such as pine.
Drywall is a practical and inexpensive way to cover studs and provides a smooth surface for decorating. As not all rooms have the same design and function, drywall panels are manufactured in different types and thicknesses. For fire resistance, 5/8" drywall is preferable to ½" drywall, whereas ¼" panels are ideal for archways and corners where flexibility is required. Another type of drywall contains additives to make it mould-resistant. This type, generally called “green board”, while not actually waterproof, will withstand the high moisture levels in bathrooms and kitchens. In bathrooms, fibro-cement panels are often used as a base sheathing against the studs before green board is installed. “Blue board” is drywall panel with a thin vinyl surface. This type of panel is used for veneer plastering, where a skim of plaster is applied on the whole wall to make an even surface. Sometimes the plaster itself is coloured, so no painting is required.
Drywall panels can be either nailed or screwed to wood studs. Drywall nails have a cupped head and a ringed shank, designed to grab the stud better than a smooth nail. The most common lengths of drywall nails are 1 3/8" and 1 ½", and the most common thickness is 13 gauge. If the drywall panel is being fastened with screws, use no. 6, rough-threaded, 1 ¼" or 1 ½" drywall screws. To fasten drywall to metal studs, use fine-threaded drywall screws. Panelling can be attached to wood studs with small finishing nails or coloured panelling nails.
Drywall or panelling cannot be put on walls that are not level. This is not just for aesthetic reasons but also because the weight of the panel could cause the entire sheet to pull through the nail or screw heads. To check that a wall is squared up, place a level across the wall studs. If the wall is not level, tap a long nail into the stud at each end of the wall and run a string across the studs, tying each end to the nails. Now pull the string knot out at each end and this will give you the line at which the wall is level. Now you can either move the top or bottom plate to line up with the strings or insert shims to reinforce the wall sheathing. Bowed studs can also be planed until square.
To soundproof a room against loud noises from the street or other rooms nearby, it should have a Sound Transmission Class (STC) rating of 60 or higher. This can be achieved by installing special, pre-built wall dividers or by filling the spaces between regular wall studs with an STC-rated insulation batt. These batts are manufactured from fibreglass, foam, cellulose or rock wool and are made to fit studs 16" on centre. However, since studs themselves (wood or metal) are good sound conductors, the edges where they meet the panels should be coated with acoustic sealant or foam strips to dampen sound vibrations.
For cutting large sheets of drywall, make sure you have a long, straight-edge rule. Use a light, plastic clamp to hold the ends and keep the straight-edge from slipping when cutting. Place the drywall panels rough side down on two saw horses and cut through the paper on the good side, to around 1/16" deep. Raise the board under the cut so that it breaks cleanly. Now use the fold to guide your knife and cut the rough paper on the underside. For vertical cuts, lean the board against the wall and snap the board toward you. To cut out holes for electrical boxes and light switches, coat the edges of the boxes with coloured latex paint or chalk powder. This will transfer to the back of the drywall panel when it is put into place and thus provide a template to cut out with a keyhole saw.
Making neat corners is the crowning touch in a drywall project, and there are various ways to do this. The standard way to finish a corner is with 90° metal corner bead. But in some cases a different angle may be required, which metal corners cannot provide. For rounded or “bullnose” corners there are vinyl products in a variety of configurations, from simple right-angled corners all the way up to crown mouldings and intricate archway decorations. Not only do they readily accept drywall compound but they are also paintable.
The most convenient way to buy drywall compound is premixed, because it is easy to use and what you don't use can be stored for another day. However, this type of compound cannot be applied too thickly, and it may take up to 24 hours to dry. It may also be harder to sand than the dry, bagged variety. Dry-mix or “setting-type” compound has to be mixed on site but the drying time is much shorter – usually about 90 minutes but as little as 20 minutes. This is great for taping and joint work because you can finish the joints and move on to the decorating in the same day.
To square any structure, particularly when it is large, always remember the 3-4-5 rule. Mark one side of the right angle at a multiple of 3 (3 ft, 3 m, 6 ft …) and the other at a multiple of 4 (4 ft, 4 m, 8 ft …). Measure the distance between the two points. If this diagonal line measures 5, or a multiple of 5 (5 ft, 5 m, 10 ft …),you know you have a perfect 90o angle.
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