Installation and Application
 | Storage: MDF mouldings should be stored horizontally off the floor and in a dry location. |
| Cutting: A triple-chip carbide finishing blade produces a beautiful chip free finish. Crosscut carbide blades also produce acceptable results. Rip or steel blades are not recommended. |
| Nailing: Best results are obtained using 18 gauge pneumatic T-nails. Air pressure should be 90-110 psi, depending on the manufacturer. If a rim or lip of raised material is created around the nail hole (volcano effect), remove the driver from the nail gun and remove any burrs on the tip using a fine metal file. The rim is caused by burrs on the nail gun driver pulling material out of the nail hole as the driver retracts. Pre-drilling and counter sinking is recommended when using screws or hand nails. |
| Gluing: PVA adhesive (children’s’ white glue) should be used to secure joints or when laminating MDF. Yellow carpenters’ glue is not recommended. |
| Filling: White Lightning (by Bondo) or similar lightweight sandable auto body filler is recommended for filling straight joints or casing corners. Inside corners should be caulked using any good quality, paintable latex caulking. Silicone caulking is not recommended. |
| Sanding: 80 Grit garnet paper is recommended for most sanding applications. Dynamic course/medium double-sided sanding sponges are very good for sanding profiled surfaces. |
| Top Coat: A good quality alkyd or latex finish is recommended for most architectural applications. High or semi-gloss finishes provided a more durable finish and are easy to clean. |
1) Mouldings must be unloaded and stored in a dry area and off of the ground. Do not cover with plastic or anything that will prevent air circulation.
2) MOULDINGS MUST BE ACCLIMATIZED, just as you would for any other wood moulding. 72 hours prior to installation, mouldings should be unbundled and allowed to acclimate to the environment in the room in which they will be installed, with a controlled humidity level. The humidity at time of acclimation should be similar to the humidity expected upon occupancy of project.
3) Every project and finisher is different. If this is your first time using MDF mouldings, please take a few minutes to practice nailing until you have mastered a technique that will allow you to install with the best possible results. MDF can have a tendency to “volcano” at the nail head, but making small adjustments in air pressure, position of nailer, and/or type of nail used can eliminate this. A common tendency is to use too much air pressure, which forces the nail deep into the moulding, forcing material out around the nail head. MDF does not normally warp, so it is not necessary to drive the nail in deeply.
4) Joints should be cut just as with any other wood moulding, but installation is slightly different. Since MDF does not normally twist and warp, it is not necessary or recommended to nail into the edge of a mitre joint to hold the mouldings flush together. The joint should be glued, and the mouldings faces nailed.
5) Shrinkage is always a potential issue on a major project with any moulding. In order to help minimize this factor, we have primed the mouldings on all 4 sides. This will assist in preventing excess moisture absorption but what we cannot control however are conditions of the jobsite. We suggest taking all necessary precautions to prevent the possible absorption of moisture while on site. We also recommend GLUEING ALL JOINTS in an effort to further seal the product.
6) All mouldings should be inspected, filled and sanded prior to top coating. Different finishers in different regions will top coat MDF mouldings with a variety of products using a variety of methods. The ABI Mouldings prime coat is a water-based product and should not react with any product that is used properly.
****Heat and Air Conditioning, which is not in use at time of installation, can seriously affect the amount of expansion and contraction mouldings will have. Please take this into account at time of installation.
Your Tools
A good job always begins with the
proper tools. The tools described below are those that would be most likely used
by the professional carpenter for the installation of architectural mouldings.
The tool
belt
Although not a necessity, the use
of a tool belt will save a substantial amount of time. The tool belt will allow
most tools, nails, screws and other accessories to be readily available,
reducing time taken to search for tools or trips back to the nail box.
The tape
measure
The tape measure should be the
standard spring steel type with a one inch blade. The blade should be clearly
marked in either metric or imperial measurements, as your project requires. You
should avoid tape measures that have metric on one side and imperial on the
other since these are often difficult to read.
The hammer
A finishing hammer should be of
medium-size, have a smooth face, be well balanced, and fit nicely in your hand.
Handles can be made of wood, metal, or fibreglass and the weight of the head
should be 16 to 20 ounces.
The razor
knife
There are many beautiful and highly
designed razor knives though a simple, inexpensive variety would do just fine.
Useful for trimming and as a general cutting tool.
The square
A good quality square will always
ensure your mitres fit snugly and your cuts are exact.
The rasp
A rasp is an essential tool in a
finishing carpenters arsenal. Simple adjustments and alterations can be quickly
made with this versatile tool.
The nail gun
An 18 gauge pneumatic nail gun
should be employed with 1 3/4 brad nails. Nail guns come in a variety of sizes
and qualities. This is one tool where quality counts.
The purpose of the baseboard is to finish the region where the wall meets the floor. It is best to select a baseboard that is proportional to the dimensions of the house. A well chosen baseboard is the base upon which the architectural finishing of the house is determined. A contemporary style of architecture would suggest clean, geometric lines. A more traditional house will require sweeping profiles with more lines. Using standard moulding profiles, a rule of thumb states a 2-¼ inch casing would use a baseboard of either 3 ¼ or 4 ¼ inches. A house with 3-¼ inch casing would use a baseboard of 4 - 5 inches. The size of the baseboard will balance the weight of the rest of the mouldings.
Baseboards should be purchased in the longest possible lengths. If you live in an apartment building, be sure that you can fit the moulding in the elevator or make alternate plans for delivery. Most projects use baseboards in 14’ – 16’ lengths. The idea is to minimize the number of joints when the baseboard is installed. Straight joints are the source of many imperfections on completed projects, even joints that seem perfectly finished upon completion often must be redone a year or two later as a new home settles, shifts, and dries. Measuring the total wall space where it is to be applied and adding 10 percent for waste gives you the best estimate for baseboard.
The most efficient way to apply baseboard is to go through each room on an entire floor and carefully measure every piece that will be required, noting their length and how each end is cut. In most cases, there are only four types of cuts required for this type of moulding. When the baseboard lands straight into a surface, such as into a casing, it is cut straight off at ninety degrees. Forty-five degree inside mitred corners are the most common since this type is required at every inside corner. Outside corners require an opposite forty-five degree mitre. Walls are occasionally designed with forty-five degree corners such as for bay windows. This requires the use of 22.5-degree cuts.
Once the measuring is completed, the cutting can proceed using a power-mitre saw. Work on a table with blocks on both sides of the saw to keep the work-piece level. Care must be taken to keep the pieces in order so that time will not be wasted looking for the misplaced ones. Once all of the pieces are cut they should be laid out along the walls to which they are to be fastened. Each piece should be fastened to the wall using a nail gun using an appropriate sized nail for the thickness of the baseboard. The nail should be a least 3/4 to 1 inch longer than the thickness of the base. As one piece is installed the next should be fit. Work along in the same direction until the job is complete. This process often requires trimming every fourth or fifth piece to get an exact fit.
Nail holes, outside corners, and straight joints should be filled with a fast setting joint compound. The lightweight automotive filler works very well. Usually, two or three coats are required with sanding between coats. The rule is: if you can feel it you will see it. Eighty-grit sand paper should be used followed with finer grit. Flexible sanding sponges, available at your local paint store, are useful for sanding profiles.
Once all of the sanding is completed, a fine bead of a paintable, latex caulking should be applied along the tops of the baseboards and at each inside corner
A casing is the moulding that is used to trim windows, doorways and archways. It's design and weight must be balanced with the architecture and other mouldings. A home with high ceilings and large rooms would suggest a 3-¼ inch casing. 8 foot doors might require a casing of 4-¼ inches or larger.
Casing can be used to trim completely around each side of the doorway or they can be used in conjunction with other architectural elements such as headers, rosettes, and plinth blocks. You must consider how ornate you would like your project to appear as well as your budget. It should be kept in mind that the proper use of architectural mouldings can dramatically improve the internal appearance of a home. A more contemporary design would generally employ casing that wraps completely around the doorway. These corners are cut at 45 degrees. A higher-end traditional home may lend itself to the use of a decorative series of moulding, called headers, which dress the top of the door. In such an application casings are used only to trim along sides of the door, from the floor to the header. In some cases, an additional block is applied at the bottom of the door. In this application the casing stands on top of the plinth block. Rosettes are square decorative blocks that are used on the top corners of the casings and instead of the header. Rosettes can vary from extremely complex floral designs to plain flat smooth blocks. The most common type of rosette is a simple series of circles inscribed into the face of the block.
Casings are one of the mouldings that also serve a structural purpose. It aids in securing the doorframe to the wall. Without this support the door would quickly wiggle free and fall out of alignment.
As you begin to install your casing you can either pre-cut all of the pieces prior to installation or you can work your way along from door-to-door. When working with casing it is better to fit each piece individually since there can be more variables with casing than with other mouldings. Casing is used to hide a large number of minor defects in framing and drywall. Walls may not be a uniform thickness, they bulge in the middle and require the casing to be inscribed into the drywall, or they may not be perfectly plumb causing the doorframe to stick out from the plane of the wall. These variations are easy to deal with and considered normal. These defects and many others can be significantly moderated with the expert use of casing.
It is important to the cut the long lengths that will be required first and then to move to progressively shorter pieces in such a manner that the material is used to its best economy. This is true for all mouldings.
After cutting, the pieces, they should be placed against the wall near their desired locations and then nailed in place in one operation. The nail should be ¾ to 1 inch longer than the thickness of the casing. The nailing should begin within about an inch of the ends of the casing. Window casing can also be done together with door casings. Many carpenters apply an additional small nail through the top corner of the casing. This step is okay for a thick casing if it can be achieved without cracking the material.
Adhesive should also be used in the corners of the casing. When applying MDF casing, white glue provides superior holding ability. Once the casing is installed the joints should be filled and sanded with a lightweight auto body filler or lightweight, easily sandable gypsum filler. Two or three coats are usually sufficient. Since the joints of the casing are close to eye level, it is important to take considerable care in finishing these joints.