RELIABILT Slab Doors
RELIABILT slab doors are the door panel only, without frame or hinges. Used when replacing a door in an existing frame.
RELIABILT slab doors are door panels without frames, priced from $30 to $120. They are the right choice when your existing door frame is in good condition and you just need a new door. Available in all the same styles as prehung (6-panel, flat panel, shaker) and the same width options. You reuse your existing hinges, or buy new ones to match. Slab doors cost 30-50% less than the equivalent prehung door.
Slab vs Prehung
| Buy Slab | Existing frame is square, level, and in good shape. You just need a new door panel. Saves $30-80 per door. |
| Buy Prehung | New construction, frame is damaged or out of square, or you want a guaranteed fit. Easier install, no hinge mortising. |
If replacing multiple doors in an older home, check that all rough openings are standard size. Non-standard openings may require prehung doors or custom trimming.
How to Choose a RELIABILT Slab Door
Measure the old door, not the frame opening. Remove the existing door and measure its exact width, height, and thickness. Standard interior slab doors are 1-3/8" thick. Standard widths are 24", 28", 30", 32", and 36". If the old door was trimmed to fit, measure the frame opening and subtract 1/4" from width and 1/2" from height for clearance.
Match the hinge spacing to your existing frame. RELIABILT slab doors do not come with hinge mortises pre-cut. You must mortise the hinges yourself using a chisel or a router with a hinge template. Measure the hinge positions on the old door or on the frame, and transfer those measurements to the new slab. Standard spacing is 7" from the top, 11" from the bottom, and centered for the middle hinge.
Choose the same core type as the door you are replacing. If the old door was hollow core, the frame and hinges are sized for a 25-lb door. Swapping to a 60-lb solid core slab adds stress to the frame. Use three hinges instead of two if upgrading from hollow to solid core, and replace the hinge screws with longer ones.
Hollow core vs solid core for slab replacement: If you are replacing a hollow core door with solid core for better sound blocking, confirm your hinges can handle the added weight. Two standard hinges support up to 35 lbs. Solid core doors weigh 50-70 lbs and should use three hinges. Add a third hinge centered between the existing two.
For a simpler installation, consider a prehung door that includes the frame. Slab doors also work as the door panel in pocket door kits and can be mounted on barn door hardware for a sliding application.
Slab Door Installation Tips
Transfer hinge locations from the old door to the new slab. Lay the old and new doors side by side on a flat surface with the hinge edges aligned. Mark the hinge positions, knob bore height, and strike plate location on the new slab. This ensures perfect alignment with the existing frame.
Use a router with a hinge template for clean mortises. A hinge template jig ($20-30) clamps to the door edge and guides the router to cut mortises at the exact depth and shape. This is faster and more precise than hand-chiseling, especially when installing multiple slab doors.
Hang the door with only one screw per hinge first. Drive a single screw in the center hole of each hinge. Close the door and check the gap (reveal) on all three sides. Adjust as needed before driving the remaining screws. This saves time if the hinge positions need fine-tuning.
Drill the knob bore before hanging the door. It is much easier to drill the 2-1/8" face bore and 1" edge bore with the door clamped on sawhorses than after it is mounted on hinges. Use a hole saw with a pilot bit and drill from both sides of the face bore to prevent blowout on the exit side.
Test-fit the door before cutting any mortises. Hold the slab up to the frame opening and check that the height, width, and thickness match. Mark areas that need trimming. Trim the bottom first (never the top), using a straightedge and circular saw for a clean, straight cut.
Common Slab Door Problems and Fixes
Door does not fit the frame after hanging: Slab doors require precise fitting. If the door is too wide, mark the excess with a pencil and remove material with a block plane or circular saw with a straight edge guide. Remove from the hinge side to avoid re-mortising. If the door is too tall, trim from the bottom only.
Hinge mortises are misaligned: If you cut the hinge mortises in the wrong position, fill with wood filler or a wood shim glued in place, let dry, and re-cut in the correct location. For hollow core doors, use auto-body filler instead of wood filler for the thin veneer surface.
Knob bore hole is in the wrong position: Standard knob height is 36" from the bottom, centered on the door edge. If the old door had a non-standard height, match that position on the new slab so the strike plate in the frame still lines up. Use a hole saw (2-1/8" for the face bore, 1" for the edge bore) with a drill guide for clean cuts.
Door warps after installation: Hollow core doors can warp if one side is exposed to different humidity than the other (common on bathroom doors). Ensure both sides of the door are painted or sealed, including the top and bottom edges. An unsealed edge allows moisture to enter the core unevenly, causing the warp.
Latch does not catch in the strike plate: If the old and new doors are slightly different thicknesses, the latch may not reach the strike plate, or it may not align vertically. Adjust the strike plate position with longer screws, or use an adjustable strike plate that allows fine-tuning without re-mortising the frame.
How to Maintain Your Slab Door
Seal all six sides before installation. Apply primer and paint to the front, back, top, bottom, and both edges. Unsealed edges allow moisture absorption that leads to warping and swelling. This is especially important for bathroom and laundry room doors where humidity is higher.
Touch up paint as needed. Slab doors show scuffs and dings at knob height and kick height. Keep a small container of matching paint for quick touch-ups. Sand the damaged area lightly with 220-grit paper before painting for better adhesion.
Tighten hardware every 1-2 years. Since slab doors use your existing hinges, check that the hinge screws are secure. Also tighten the door knob set screws (usually located on the rose plate) to prevent the knob from wobbling.
Re-check the fit seasonally. Wood and wood-composite slab doors expand in summer humidity and contract in dry winter air. If the door sticks in summer, do not plane it to fit, as it will have gaps in winter. Instead, wait for the dry season and then plane only if the issue persists year-round.
Protect stored slab doors from warping. If you buy multiple slab doors for a renovation, store them flat on a level surface with support under both ends and the middle. Stand them upright only after you are ready to install. Leaning a slab door against a wall for weeks can introduce a permanent bow.
Clean and tighten the strike plate annually. The strike plate takes repeated impact from the latch bolt every time the door closes. Over time, the screw holes enlarge and the plate shifts. Tighten screws and add a dab of wood glue to any loose holes. A misaligned strike plate causes the door to not latch properly.
Seal the top and bottom edges of bathroom slab doors. Steam and humidity from showers penetrate unsealed edges and cause the door to swell at the bottom, making it stick in the frame. Apply a coat of primer and paint to all edges during installation, even if they will not be visible when the door is closed.
Slab Door Questions
Do RELIABILT slab doors come with hinge mortises pre-cut?
No. RELIABILT slab doors are sold as plain panels without hinge mortises, knob bore holes, or strike plate cutouts. You must cut all hardware locations yourself. This allows you to match the exact hinge positions on your existing frame. A router with a hinge template jig makes the mortising process faster and more precise than hand-chiseling.
Can I use a slab door with barn door hardware?
Yes. Any RELIABILT slab door can be mounted on a barn door track system. You will need a barn door hardware kit that includes the track, rollers, and floor guide. The slab must be at least 1-3/8" thick for the roller mounting brackets. Solid core slabs work better for barn door use since the added weight helps the door slide smoothly and stay in place.
How much can I trim off a hollow core slab door?
Most hollow core doors have a solid wood or MDF rail at the top and bottom edges that is 1" to 1.5" deep. You can safely trim up to 1" off the bottom and 1/2" off the top without cutting into the hollow cavity. If you need to remove more, cut into the hollow section, glue the removed rail piece back into the new bottom edge, clamp, and let dry before rehanging.
Are RELIABILT slab doors the same thickness as other brands?
Yes. RELIABILT interior slab doors are 1-3/8" thick, which is the standard interior door thickness in North America. They fit standard hinge mortises and bore holes. If you are replacing a door from a different era or manufacturer, measure the old door thickness. Pre-1960s doors may be 1-3/4" thick (exterior door thickness), which would leave a gap in the frame if replaced with a 1-3/8" slab.
Slab doors require hinge mortising if your new door is a different brand or thickness than the old one. See our installation guide for tips. Add new hardware to complete the refresh. For a completely new opening, go with a prehung door instead.
Slab doors are the most economical way to refresh all interior doors in a home renovation. At $30-120 per door versus $50-200 for prehung, the savings add up quickly across 10-15 doors. Budget an additional $20-30 per door for new hinges and knob hardware if you are not reusing the existing fittings.
For closet openings, a slab door can be hung on barn door hardware for a modern sliding look, or used as the panel in a pocket door kit for a space-saving solution. See RELIABILT reviews for feedback on slab door quality and finish consistency.