MDF slopes on entrance and interior doors

Recommendation points

• Door installation rules
• Opening preparation before installation
• Marking and trimming extensions
• How to install and on what glue
• How to properly trim and install platbands

In this article, you will learn about the most popular way to trim the slopes of interior doors without flaws in practicality and durability. We offer a detailed scheme for the installation of slopes from door MDF extensions. You will also learn the rules for the appropriate preparation of the opening and installation of doors.

Over time, every professional builder adopts more and more technical solutions that are perfect in all respects. The dispute about the most acceptable option for finishing door slopes and portals can be considered closed, the best way has already been found and is being practiced more and more often.

Surprisingly, the installation of MDF slopes does not require professional participation; it is simple enough for home craftsmen to perform using a set of the simplest tools: a jigsaw, a syringe gun and an assembly knife. Among other things, you will need: a tape measure, a square and a pencil, as well as a brush. For correct and durable finishing of slopes, appropriate preparation of openings and adherence to the rules for installing door frames will be required.

Door installation rules

The door frame is assembled on unhardened self-tapping screws; the upper segment is always located on top of the side posts, and not between them. After assembling the box, it is necessary to cut off excess rim from the edges of the crossbeam so that the installation groove is continuous on all three sides..

The only safe option for fixing interior doors is the technique of direct mounting with frame anchors 8×120 mm in the amount of three pieces for the hinged side and two pieces for the opposite side of the frame. When attached to “dry” partitions, the anchors are replaced with screw pins.

After fixing, the box must be adjusted for bends, then the technological seam is filled with polyurethane foam from the side opposite to the slope. After filling the seam, the door must be kept closed for about 40 minutes, by laying spacer plates along the porch. After the foam has cured, the adjusting wedges must be removed and the cavities formed are foamed..

Opening preparation before installation

Openings in brick or concrete partitions, even before installing the doors, must be plastered along two guide boards nailed to opposite walls. At this stage, the desired slope angle and the installation dimensions of the opening are set. Each edge of the opening should have a uniform bevel from 3.5 to 15 °. The opening itself should be 100 mm wider and 60 mm higher than the door block leaf.

After installing the door, the installation groove is cleaned from the mounting foam, and a piece of door fitting is tried on. If the thickness of the gap is more than 3 mm during the installation of the board into the installation groove, it is advisable to apply a leveling layer of tile adhesive to the plaster. At the same time, the installation groove should be periodically cleaned, after drying, the surface must be saturated twice with an adhesive primer.

Marking and trimming extensions

Finishing the slopes of interior doors with MDF docks does not apply to dusty work, so it is better to do it after finishing finishing work in the rooms, so that you can immediately install the platbands.

The standard extension widths are 90, 120, 170 and 380 mm. If the width of the slope is greater than the available standard sizes, two or three parallel boards go to it. In the case of telescopic extensions that have a tongue-and-groove profile, a wide slope will have to be recruited from an even larger number of strips, however, no cracks at the joints of the door block are guaranteed to appear. And yet, telescopic extensions are better to build up door blocks in “dry” partitions with narrow slopes.

First, the upper crossbar is marked and cut out. To do this, on the floor directly under the door, you need to spread the required number of boards in parallel with the back side up. Measure the width of the top edge of the opening at opposite points. Mark it on the back of the boards with the condition that the longitudinal cut line of ordinary extensions faces the door frame, and telescopic ones – to the platbands. Measure the length of the upper slope in the wide and narrow parts, and set the exact difference on each side. Transfer the markings to the blanks with an indent from the corners of 5 mm and number the boards in the order of installation.

Vertical extensions are measured and installed after fixing the top bar. The difference in height is established along the square attached to the end of the door frame, the resulting dimensions are transferred to the marking. It is advisable to make the side slope boards 1–2 mm longer, so that it is possible to accurately fit the part with an emery bar.

How to install and on what glue

Slopes from MDF extensions are allowed to be fixed on liquid nails or polyurethane foam. When using foam, you do not need to build up plaster for a tighter fit, but this requires a professional approach. The choice in favor of glue should be made when the gap between the MDF panel and the plaster is up to 5 mm thick, foam is used to fill thicker joints.

Boards on the slopes are glued in rows, starting from the door frame. First, the trimmed parts are tried on and the level of inclination is visually noted. Then glue or polyurethane foam is applied to the back of the board, 15–20 mm from the cut edge, pieces of cork or other elastic material are inserted into the adhesive, approximately equal in thickness to the glue seam after drying. These mortgages act as fulcrum points: so that the board fits as tightly as possible in the groove of the box, it is enough to slightly press down its edge.

The upper slope is finished first, the boards are temporarily fixed with remontine. It is enough to simply deduce the common plane with a square, but for this you need to set the correct direction for the first board. After setting, the crossbars are marked and cut into parts for vertical edges. They are also tried on first “dry”, adjusting the size and cut for a tight fit. After gluing, each plank is wedged from the floor and pressed up, the allowable gap between the slope and the floor covering is 2-3 mm.

How to properly trim and install platbands

After installing the add-ons and glue hardening, it is necessary to close the ends of the slopes and the foam seam with platbands. The way of their fastening for different shapes of the box profile and add-ons may differ.

Telescopic platbands are installed with a comb into the groove of the box or add-on, the fastening can be reinforced with concentrated PVA glue or liquid nails. It is possible to install such platbands only after the glue or foam has completely hardened on the extensions, otherwise their separation is possible.

Smooth platbands are attached to the extensions with small furniture studs with anodized finish and no caps. Their installation is possible already after 1–2 hours after the installation of extensions.

The trims should only be cut using a miter box or a cutting saw. As for the notch angle, the platbands with a semicircular shape of the front surface are cut at 45 °, and the rectangular ones are cut strictly perpendicularly. In this case, the contour of the casing is formed according to a scheme opposite to the assembly of door frames: two vertical posts and a crossbar between them. Thus, the places of the cuts will not be visible, since they are facing up.