Fitting a New Ceiling

Filed Under: Do it yourself, Home repair, Remodeling    by: ITC

Gypsum board for ceilings comes in two thicknesses: 3/sin and 1/2in, the former being suitable for use where the joist spacing is no more than l8in and the latter where the joists are up to 2ft apart. The standard sheet sizes are 8 and 10 x 4ft. You may find the smaller sheets easier to handle and you can cut them in half to make them even more manageable. The edges should meet on the joist centerlines, so you will probably have to trim them slightly anyway.

The first job is to nail lengths of 2in sq or 2 x Sin wood along the walls parallel with the joists so that its lower edge is level with the undersides of the joists. Then fit more short lengths of wood to the walls between the ends of the joists to provide support for the edges of the boards.

The sheets of gypsum board must be fitted with their long edges at right-angles to the joists. Toe-nail more lengths of batten to act as bracing between the joists so that the inner edges of the sheets will fall on their center lines. A length of batten marked with the board width will help position them accurately.

Finally, mark the position of each joist on the walls as a guide for nailing the sheets in place.

To cut sheets to size, use a utility knife and steel straightedge. Cut down through one face of the board, snap back the waste against a batten and run the knife blade down the crease from the other side.

If you intend plastering the ceiling, fit the gypsum- board gray side down. For painting or papering directly over the top, leave the ivory side showing.

Holding large sheets of board against the ceiling for nailing can be difficult so nail lengths of 2 x lin batten together to foiiu T-shaped props with which a helper can support it while being nailed in place.

Nail the first board in place, working from the center outwards and spacing the nails at 6in intervals. Drive them home so that they just dimple the surface; to be filled later. Use 11/4in gypsum board nails for thinner sheets and 11/2in for thicker kinds.

Continue in this way, working across the ceiling. Keep any cut edges up against the wall, but if this is not possible make sure they meet on a joist with a slight gap in between for filling; stagger the joints.

When you have clad the entire ceiling, seal the joints between the sheets and, if you prefer, apply a thin skim coat of plaster.

Repairing an Old Ceiling

Filed Under: Do it yourself, Home repair, Remodeling    by: ITC

There are two types of ceiling construction, depending on their age. Early ceilings were made by nailing thin strips of wood (laths) to the joists so that there were narrow gaps between them. Plaster, often reinforced with animal hair, was then spread over the laths and forced through the gaps in between. The ridges so formed are called “nibs” and these hold the ceiling together.

The more modern method of constructing a ceiling is to nail sheets of gypsum board to the joists and cover them with a thin skim coat of plaster.

Cracks are the most common form of damage found in a ceiling and if they are only fine they can be filled with a filler compound. However, if they are wide and cover a large area of the ceiling the structure will be dangerously weak and should be replaced.

If a plasterboard ceiling sags it is probably because the fixing nails have loosened. Refix the affected area by renailing with 2in drywall nails spaced 6in apart.

If plaster has fallen away from the laths but they appear to be in good condition, replaster them after cutting back the original plaster to make a regular shape and reach sound plaster. Undercut the edges of the plaster and make sure there is no old plaster left between the laths. Then treat the area with an adhesive.

When plastering always work across the laths, spreading on a thin coat of bonding plaster first and keying it with a scratch comb made by knocking a row of nails into the edge of a short batten. Apply another coat of bonding plaster and key this with a devilling float, pressing it down to allow for two thin finishing coats. Polish these when hard with a wetted steel trowel.

Plastering Masonry

Filed Under: Do it yourself, Hardware, Remodeling    by: ITC

To plaster a newly built wall you will not have to do any preparation work to it at all before you fix wooden grounds or metal lath in place.

Then the masonry should be dampened by splashing on clean water with a paintbrush. This will help slow down the rate at which the wall absorbs moisture from the plaster, preventing it from drying out too quickly and possibly cracking.

It is a good idea to practice scooping plaster from the hawk and applying it to the wall before you attempt the job for real. Set the loaded trowel against the wall so that the bottom corner of the blade rests on the ground or bead and the blade is at an angle of about 30° to the wall surface. Move the blade upwards to spread a vertical strip of plaster next to the thickness guide, keeping the blade resting on the guide and gradually reducing its angle as the plaster spreads.

Apply more strips of plaster in the same way, working upwards from the bottom and across the bay adding a good thickness of plaster to the wall.

When the bay is finished, use the long wooden rule to strike it off level with the thickness guides. Place it across the guides and draw it upwards, moving it from side to side in a sawing motion as you go. This will level off the high spots and accentuate the dips. Add more plaster and repeat the process until level.

Before it sets, key the surface for the finishing coat by passing a wooden float, with nails knocked through its face, over the plaster to leave score lines.

When the floating coat has hardened (it should take about two hours), you can apply the finishing coat. This is done in exactly the same way as plastering wallboard, applying two thin coats of Finish plaster to produce a polished, flat and hard surface.

Directions:

1. Scooping plaster from the hawk; put the trowel into the plaster and scoop forwards and upwards.

2. Practising applying paster to the wall; work upwards from waist-height, starting with the trowel at 30 degrees to the wall.

3. As you apply the plaster, tilt the trowel more parallel to the wall surface; keep the hawk close to the wall to catch droppings.

4. Applying the plaster in vertical strips; at the end of each stroke, press the lower edge of the trowel to firm the plaster onto the wall.

5. Ruling off the completed bay; use a straight-edge with a sawing motion to lower any high spots and to show up areas with too little plaster.

6. Scoring the surface to provide a key for the finishing coat; the nails should protrude in through the float.

7. Filling the gap left after taking off the ground batten; level off with the trowel, flush with the hardened plaster on each side.

8. Applying the finishing coat; work from bottom to top and cover the floating coat with a thin layer; apply a second coat. 9 Polishing the finishing coat; wet the surface sufficiently to remove ridges and marks and polish firmly with a perfectly clean, flat trowel.

Plastering Corners

Filed Under: Do it yourself, Home repair, Remodeling    by: ITC

The main problem when plastering corners, whether external or internal, is getting a good, sharp angle. You will face a similar problem at the junction between the wall and ceiling. However, the techniques for dealing with both types of corner are not difficult to master.

There are two forms of guide you can use for forming an external corner: a timber batten or purpose-made metal beading.

The wooden batten is used as a thickness guide for the floating coat then the finishing coat on each wall. Nail it on to one wall so that it projects by the right amount beyond the other and use as a ground for that wall. Then, when the plaster has set, move it round the corner and repeat the process. Any sharp ridges on the apex of the corner should be sliced off with the trowel blade and then the corner rounded off with a block plane or rasp. With wallboard you must tape the angle first.

Two depths of metal beading are available to deal with masonry or gypsum board-clad walls and they can be fixed in place with plaster or galvanized nails. On wallboard, nails must be used. The beading acts as a ground for the floating coat on masonry walls. Before this hardens, cut back the level to allow for the finish coat. Trowel off flush with beading, leaving the nose exposed to provide a knock-resistant corner.

For dealing with internal corners, you need a long wood rule. Use this to rule the floating coat outwards from the corner.

After keying the floating coat, cut out the angle by running the corner of the trowel blade up and down it, holding the blade flat against each wall in turn. This will produce a sharp angle. The finish coat should be treated in the same manner. The final job is to hold the short side of the blade against one wall so the long side is just touching the fresh plaster. Hold the blade at 30′-40° and gently run it down the corner.

For finishing corners where both walls have been plastered, use a special V=shaped angle trowel. This produces a constant right angle in the fresh plaster. Load a small amount of plaster onto the angled blade of the trowel and run it lightly down the angle.

Directions:

1. Reinforcing the external corner of a masonry wall with angle-bead; set it into blobs of plaster, 12in apart.

2. Plastering one wall; work away from the corner, using the nose of the bead as a thickness guide.

3. Plastering the adjoining wall in the same way: leave the nose just visible. Score the surface of both walls.

4. Applying the finishing coat, this time covering the nose: round off the corner by running a wet finger along the bead.

5. Securing angle-bead to the internal corner with galvanized nails; nail through the drywall into the stud.

6. Applying a coat of finishing plaster, working away from the corner; the nose should be left visible in this case.

Plastering Wallboard

Filed Under: Do it yourself, Remodeling    by: ITC

You need only apply two very thin finishing coats directly over the drywall.

The plaster needed for the job is sold ready mixed or in a powder form requiring only the addition of water. It is mixed in the same way as other plasters and has a creamy texture.

Because you are only applying a finishing coat to the drywall board there is no need for thickness guides, except at any external corners.

It is a good idea to practice scooping the plaster from the hawk on to the trowel first, using a spare piece of drywall to try your hand at spreading the plaster and making it stick to the board_ The technique is to hold the hawk in your left hand (or right if you are left handed) so the top is level and set the trowel blade on edge, so it is at right angles to the top of the hawk. Use the trowel to push some plaster towards the edge of the hawk, scooping it off at the same time as tilting the hawk towards you. The whole is done in one smooth movement.

The first job is to seal the joints between the individual panels of gypsum board, reinforcing them with perforated paper tape or nylon tape to prevent the plaster cracking. The standard paper tape is available in 2in wide rolls of 50-500 feet.

Cut strips of tape to run the length of each joint, including any horizontal ones, before you begin plastering. They must be exactly the right length and should not overlap or be folded, otherwise the plaster will not grip the wall properly.

To seal the joint, spread a thin layer of plaster, about 4in wide, along it from bottom to-top. Hold the trowel so that the blade is at an angle of about 30° to the wall, reducing it as you move up the joint and the plaster on the trowel thins.

While the plaster is still wet, press the tape into it. The easiest way to do this is by draping one end over the blade of the trowel and pressing this into the plaster at the ceiling. Then gently slide the trowel down the plaster, positioning the tape with your other hand. Once the tape is in place, run the trowel carefully up the plaster to make sure it is bedded properly. Treat all the other joints between the panels in the same way.

When the taped joints have dried — which should take about 11/2 hours — fill in the areas between them with more plaster. Work upwards from the floor, spreading the plaster in thin vertical strips and being careful not to build up ridges at the joint positions. Stop just short of the ceiling and work downwards from there to get a clean, sharp angle.

Unless you are working on a very small area, by the time you have finished putting on the first coat, the area you started on will be ready for the second coat. This should be about 1/sin thick and applied with long, sweeping strokes to eliminate ridges. Start at the bottom corner of the wall and work upwards and along to make one continuous coating.

Allow the plaster to set slightly and then go back over it with a clean trowel to smooth off the surface. Finally, when it has hardened fully, “polish” the surface by splashing clean water on to it with a paintbrush (about 4in wide) then sweep the trowel back and forth lightly. This will give a smooth, matt finish ready for decoration.

Setting Out For Plaster

Filed Under: Do it yourself, Home repair, Remodeling    by: ITC

One problem the beginner faces when tackling a plastering job is that of producing a floating coat that is uniform in thickness and level over the entire wall. The answer is to divide the wall into sections and use the dividers as depth guides.

Space the dividers as close together or as far apart as you like, but a suitable distance is about 3ft.

There are various methods for dividing the wall into bays, and a traditional way is to trowel narrow strips of plaster from floor to ceiling. Known as “screeds”, these strips of plaster are allowed to harden, then more plaster is spread on the wall between them and brought up to their level, using a long straightedge placed across the screeds to check.

The problem with the screening method is being able to get the plaster strips to the right thickness in the first place. Small blocks of wood, known as “dots”, can be fixed to the wall at the top and bottom of the screed position and used as thickness guides by setting a straightedge between them.

An easier way is to use wooden “grounds”. These are lengths of planed, %in thick by about 2in wide softwood, which are fixed to the wall with masonry nails. Since you plaster only one bay at a time, you need only two grounds per wall and, therefore, you can move them along as you work.

After setting out the first bay, you can apply a floating coat between the two wooden grounds, striking it off level with a long wooden straightedge called a “rule”. Then, having let the plaster harden off for a while, you should carefully pull one ground from the wall and nail it back on further along the wall to make a second bay.

Continue applying the floating coat in this way until you have completed the job.

When fitting wooden grounds it is essential that they are set vertically, otherwise the plaster surface will be out of true. Use a long mason’s level to check that they are upright and, if necessary, slip small wooden shims as packing pieces behind the grounds to bring them into line.

An alternative to using wood grounds is the metal screed bead which you can buy from your builder’s supply house. It does the same job as the ground but is designed to be left in place on the wall; it disappears under the finishing coat of plaster.

The center of the bead is formed into a raised, inverted U-shape, the depth of which is equal to the depth of the floating coat, and on each side there is expanded metal mesh. You can cut it by snipping through the mesh with metal snips then sawing through the bead with a hacksaw.

Beading is fixed to the wall with “dabs” — blobs of plaster troweled on to the wall. Push the beading into the dabs then check with a level.

Allow the plaster to harden off and then use the beads as thickness guides for the floating coat.

Home Repair Tips – Wall Repairs

Filed Under: Do it yourself, Home repair, Remodeling    by: ITC

Older walls and sometimes even new ones will need some repair before finishing. The most common wall repairs include:

• Dents

• Small holes

• Large holes

• Nail pops

• Split tape

You can repair dents by sanding around them, trowling joint compound (spackle) into the dent, and finally smoothing out the area. This is essentially plastering. Once it is dry, you can sand, seal, paint, or wallpaper the patch to match the rest of the wall.

Small holes are repaired like dents. A wad of newspaper behind the hole will prevent the joint compound from falling between the walls.

For large holes, you will have to patch a piece of drywall into place. Remove all loose material from around the hole with a utility knife. Then cut a piece of drywall to fill the hole. If the patch doesn’t rest on solid wood, set a screw in the patch to use as a handle. After the joint compound hardens, remove the screw and plaster the whole patch with joint cement. Then sand the patch to match the rest of the wall.

When the house framing expands or shrinks, nails pop and become visible under the paint or wallpaper. If the nails are tight, just drive them back below the surface with a claw hammer. Plaster the dent with joint compound. If the nails are loose, pull them if it won’t damage the wall, or drive them so deep they won’t come out again. Then drive new nails nearby. Cover the nails with joint cement. Use only drywall nails. Regular nails will rust when covered with joint cement.

Split tape is caused by the house settling. The tape will bulge like a bubble or blister or actually crack. Cut and pull off the loose tape. Remove all the loose tape or it will split again. Then sand the area and spread a thin coat of joint compound over it. With a wide putty knife work the tape into this compound. Plaster over the tape with compound. When it is dry, sand it.

Bathroom and kitchen walls are sometimes covered with ceramic tile. When a tile is cracked, it should be replaced. Start by removing the tile and old grout. You may have to break the tile with a hammer and chisel.

Repair large holes by cutting a piece of drywall to fit the hole. Cement the patch and hold it in place with a handle made from a screw. When it has dried, remove the screw and plaster, sand and finish the whole area.

Sometimes it is necessary to back a hole with newspaper when filling a hole with spackle or patching plaster. A piece of wire screen or plasterboard works well also.

Most wall repair is essentially plastering. On drywall, use drywall cement or spackle to fill the hole. Wood walls are repaired with wood putty.

Nail pops that are tight can simply be driven back in with a hammer and a nail set. Loose nails should be pulled or driven in. Drive a new nail nearby.

Although the tile is usually set in a special cement, it is much easier to glue the replacement tile with white epoxy cement. The wall must be dry. Use a putty knife or cover your finger with a piece of plastic or cellophane and work the epoxy around the tile to match the old grout. Hold the tile in place until the epoxy begins to set.

Clean all cement off the tiles before it hardens.

Wallpaper is difficult to repair. To replace a greasy or torn spot, carefully tear a piece of matching wallpaper from the front of the patch so the backing will be torn away from the edges. Remove the old piece. Match the pattern and paste down the new patch. The seams will always be slightly visible, but the ragged edges will make them less obvious.

Sometimes wallpaper bulges loose in a bubble. Cut a small slit in the bubble and force paste behind it, in order to work the bubble down. The cut is less visible if it is made along a straight line in the wallpaper pattern.

Remove all tape that is loose. Spread joint compound over the area and work new tape down with a putty knife. Then plaster over.

An uneven piece of wallpaper is less noticeable than one that is cut straight. Tearing the backing off the edges will make it even less obvious.

Gluing tiles with white epoxy cement is easier than using grout. The cement must be spread by hand to look like grout. Protect your finger with a piece of plastic.