Can wainscoting or beadboard be installed in a bathroom?
All trimwork can be installed in bathrooms, as long as the moulding is properly sealed and painted, and as long as it is not being bombarded with water directly. Mouldings will swell in the presence of water. High humidity however should not affect the mouldings as long as the moisture is allowed to escape from the bathroom quickly. Removing moisture with external escaping fans, should be done as a common practice in order to reduce the incidence of mould or fungus in the room and in the walls. Run the fan on a timer up to 30 minutes after the shower or bath has been run. This will remove the majority of the moisture from the room.
What kind of surfaces can cornice mouldings be installed on?
Moulding can be installed over brick or concrete walls, but require that wooden blocks be first glued in place, adding time and complexity to the job. The most common surfaces are drywall and a stipple or popcorn ceiling. The stucco or stippled ceiling does not need to be shaved or remove prior to installation. Simply dap or apply caulking in the cracks when the moulding has been installed.
* Installing Crown Molding
This page offers illustrated, step–by–step instructions for cutting and installing crown molding. Angles and compound miter saw settings for cutting 45-45 and 38-52 crown moulding are included.
Using a Compound Miter Saw
The angles of cut required to install crown molding can be difficult for some do–it–yourselfer's. Fortunately, a compound miter saw makes cutting these complicated angles as simple as setting two guides on the saw.
To form the angles required to install crown molding, the wood must be cut in two directions at once; first it must be beveled and second it must be mitered.
A compound miter saw makes it possible to make these cuts with the molding laying flat on the saw table. These saws will most likely have a stop on the bevel and miter guides for setting the proper angles of cut for both 52° and 45° crown molding. A gauge on the back of the saw sets the bevel position of the blade and the table pivots left and right to set the miter position.
Setting the Saw to cut 45-45 crown moulding flat on the saw
Set the saw by tilting the blade and setting the bevel angle at 30° using the guide on the back. Leave the bevel setting at this position thru–out this molding installation procedure. Some compound miter saws have a double bevel feature. This means the saw blade can be tilted left and right instead of just to one side. When using a double bevel saw for the following procedure, use only the left bevel position.
Set the miter angle by moving the saw table left and right of center. The position will alternate depending on which corner piece of molding will be cut. Set the saw table at 35° right to cut the molding that will form the right inside and left outside corners, pieces C and D pictured here. Cut these pieces with the molding's ceiling edge against the saw fence.
To set the saw for the matching pieces, slide the saw table to the left and set it at 35°. With this setting the left inside and right outside corner moldings, pieces A and B, can be cut. Turn the molding so the wall edge is against the fence to make these cuts. Notice that the inside corner moldings, A and C, will always be on the left of the blade and the outside corner moldings, B and D, will always be on the right.
Cutting Inside Molding Corners
Starting at the right corner of one wall, measure to the next corner. Have a helper hold one end of a tape measure to get an accurate measurement. Use this measurement to choose a piece of molding to run the length of the wall.
Cut the right end of the molding to form piece C using the settings for a right inside–left outside corner. Place the ceiling edge of the molding against the saw fence and make the cut. Leave the molding flat on the saw to measure and mark the opposite end.
All measurements for inside corners should be made using the wall edge of the molding as the reference. Hook a tape measure over the end of the molding and mark the other end with a thin pencil mark. Set the saw to cut piece A at the opposite end of the molding by sliding the table to the left and setting it at 35°. Leave the blade bevel set at 30°. Place the wall edge of the molding against the saw fence and site along the blade to line it up and cut the wall edge just outside the mark. Install the molding using the instruction below.
Coping Corners instead of miter cut corners
It is also possible to use a coping cut to join the inside corners. Coping a molding corner requires cutting out along the profile of one of the pieces so it butts against the other piece to form a seamless 90° union. Before cutting the profile the molding must be cut with the same compound miter as above to make the union work.
Coping an inside corner on crown molding can be difficult but can be done with some patience. Coped joints have a greater tendency to crack as opposed to miter joints since the glue surface with the miter joint is much stronger due to its larger surface area of contact as opposed to a coped joint. Coped joint have very little little surface contact when glued to the adjacent moulding.
Cutting Outside Corners
All measurements for outside corners should be made using the ceiling edge of the molding as the reference. To cut a left outside corner, piece D, slide the saw table to the right and set it at 30°, leave the blade bevel set at 35°. Place the ceiling edge of the molding against the saw fence and site along the blade to line it up and cut the molding just outside the mark on the ceiling edge.
To cut a right outside corner, piece B, slide the saw table to the lefts and set it at 35°. Measure and mark the ceiling edge of the molding. Set the wall edge against the saw fence and line up the blade. Cut just to the outside of the mark on the ceiling edge. Check the molding for a good fit.
Finished Outside Corners- ’’Returns’’
To terminate the molding at the end of a wall, measure the wall and subtract an eighth inch. Cut a piece of molding with the appropriate outside corner to this length. Install the molding using the instructions below. Measure the distance from the wall to the face of the installed molding.
Cut the return with a matching outside corner using a short piece of leftover molding. Be sure the piece is long enough to cut safely with the saw and make the cut on one end. Cut the other end at 90° to fit flat against the wall.
Check the fit and then caulk the ceiling edge of the return. Brush the joint face of both pieces of molding with a thin coat of wood glue and press the end cap in place. Wipe off any excess glue and caulk with a clean, damp rag.
When working with stain grade molding, avoid using too much glue on the edges to prevent oozing. If bare wood absorbs the water–based glue it won't absorb enough stain and create white blotches in the finish.
Either nail the return in place with 23awg pins, or tape the joint together with painter's masking tape at the corner, ceiling and wall until the glue is dry.
Installing the Molding:
First of all, use two sample pieces of mouldings in the corners of the ceiling. These samples will have the corners precut into them. One left piece and one right piece, about a foot long. Match up the samples in the corners such that the mouldings create a perfect corner. Once this is achieved mark the wall at the under side of the mouldings where they hit the wall. This will be your target for where the final mouldings will with a Install the molding holding it up and shifting the placement until the edges lay flat against both the wall and the ceiling surfaces. Drive a nail thru the molding and into the wall and ceiling about 2 feet out from each corner. Leave the ends loose to allow for adjustments when joining the matching corner piece. Drive nails at about 16 inch intervals into the wall and ceiling to secure the middle of the molding. Some nails can be driven into the plaster or drywall but these should be kept to a minimum. To ensure that the molding stays in place be sure nails are driven into wood framing at regular intervals across the wall and ceiling.
Join the molding at corners adjusting the two piece together until they form a smooth union that lays flat against the walls and ceiling. Nail both pieces of molding to the walls and ceiling at the corner. Smooth out any caulk that squeezes from between the two pieces of molding before it has time to set. To glue the corner shift the molding to expose the end and use a small brush to apply a coat of wood glue to both pieces.
While holding the molding in place drive finishing nails thru the molding and into the wall and ceiling framing. Nailing the molding in place will be much easier with the use of a pneumatic nail gun. A finish nail gun with a mid–range capacity of 1½ to 2½ inches is a good choice for this and most other molding projects. If no nail gun is available, drill pilot holes and drive 2½ inch finishing nails with a hammer. Counter sink the nail heads and fill them with painter's putty before painting.
Correcting Cutting Mistakes:
If the molding piece you've cut is just a little too long, trim it by a saw blade's width or less and try the fit again, otherwise measure the wall again and measure the molding to determine where to trim it to correct the error. If the molding is too short, caulk can be used to fill small gaps. If there is a large gap in the joint, cut a new piece of molding to correct the error. Salvage the short piece by joining it with another piece using a scarf joint or use it for short runs.
A Word About Measurements:
When measuring walls at inside corners it can be hard to know exactly what point to use as the reference point. Most plaster and drywall corners are rounded and it can be difficult to get an accurate measurement. To avoid cutting the molding too short, always used the most extreme point as the reference point. The molding can always be trimmed slightly if it turns out to be a bit long when installing.
Opening of joints: A moisture driven problem!
All wood products will expand and contract with the presence of humidity and heat. Since wood is fibrous, as the relative humidity in the room rises, the fibers absorb the moisture so the moulding will expand making it wider and longer. As the humidity drops, the reverse occurs.
In the eastern part of Canada, summers are hot and humid and winters are cold and dry. You should expect the mouldings to expand and contract over this temperature and humidity swing. The expansion will manifest itself through unsightly hairline cracks at the joints. You can expect all lumber to expand and contract by 1/16’‘ over 16’ lengths.
It is recommended that during the winter, you should keep the relative humidity in your home at an ideal 45-50%. Anything less than 40%, cracks in your hardwood floor, in your furniture and in your mouldings will show up.