following

Bondo or wood filler, sand, paint

You have your answer; MDF is ok at ceiling level. It could probably hold up in rooms that aren't heavily used, but why go through all the installation and painting costs for a product that doesn't hold up to active family life or pets.

You can buy wood doors that are well made and look good and that don't cost a fortune if you stay with softwood choices. You can paint these with a semi-gloss marine grade paint that won't chip, crack or fade. A regular semi-gloss paint will chip, so use a marine-grade.

I did my prior house in a softwood door and used semi-gloss marine grade paint. The doors always looked good with heavy dog traffic.

My current house has stained and poly sealed hardwood doors that act the same as the painted softwood doors. Hard as a rock, resists scratching, pawing, cracking, holes.,,,,stands up to punishment.

Look at doors with the core being MDF, then laminated with wood. I just installed a door like that between my garage and the interior. I did also build the frame, so took into account the possible swelling/shrinking and built in a wee bit more clearance. Finished it with non poly varnish(no stain) and used compressible weatherstripping. Been two years now and zero problems.

... and always seal all 6 sides of the door

Composite doors have minimized door failures vs wood since their introduction.

Why cant MDF be repaired? The biggest issue with MDF as with many products is the installer's lack of knowledge.

MDF moldings work fine. All seams need to be glued and this is what almost every installers doesn't do. MDF actually makes a stronger edge to edge bond then wood does making seamless seams.

The biggest mistake installers make is use joint compound to fill nail holes or damages. MDF swells when wet. So when you apply a swipe of the above it swells the nail hole. Sherwin Willaims makes a yellow putty specifically for this. The yellow makes sure you don't miss sanding.

If they insist on using joint compound use X-35 primer sold at Home Depot. You seal the holes and then apply tour fill on top.

Another issue with all pre primed molding is the primer. It needs to be sanded and sealed before its painted or it will just drag and be like painting mud. Again the RX-35 can be applied and it will give a great seal coat for additional primers. You can also use Kills but for some odd reason that RX 35 just works great on MDF which it shouldn't as it is water based.

The problem with MDF and even wood lower cost or box store molding is the intricate details are dull and not sharp. Then add the primers and they get lost. This also makes any repairs difficult as its almost impossible to fix. How do you fix a line you can barely make out?

There is nothing wrong with MDF core doors and they are probably more stable anyway unless you can afford high quality doors.

MDF and pine which almost all moldings are made of dent the same neither is a hard surface so it should be a non issue in regards to the decision.

People refuse to educate themselves and then blame their shortcomings on the products. MDF has its shortcomings but if your comparing a box store MDF molding to a box store finger jointed pine molding its a coin flip and I would actually get the MDF. You arent coping either as they just fall apart. They are made for get it close and use caulk finished product.

We have had MDF solid core doors for 16 years and they are still perfect. Door casings, not so much. Anytime you bump them, like with the vacuum cleaner, they chip. The crown is fine and actually we've had no problems with the baseboards or window casings either.

MDF is actually harder (and therefore dent-resistant) than many people seem to think. It runs about 1200 on the Janka wood hardness scale - only a little softer than sugar maple (1400) or white or red oak (1300) but harder than walnut, red maple, birch, pretty much any softwood (spruce, pine, fir, etc.) and vastly harder than poplar (540) which is coincidentally the most common paint-grade wood used for trim and millwork.

It's only the exposed edges of MDF panels which can sometimes be vulnerable to abuse (e.g., the edge of a door); but the same applies to any edge exposed to traffic in a home, whatever the material.

so many times I forget people buy stuff at the "big box" stores ...

Trim MDF is defeinitely a different density material than doors.

MDF if you are painting. Not one thing wrong with it.

MDF is usually medium to light brown in color and has no grain nor does it have any definition. Pressed board and chip board(both being a different color and both having easily seen particles because the materials are made by treating particles/wood chips with adhesive and curing under pressure and heat) are not MDF and should not be confused as such. I have seen OSB referred to as MDF, which it is not.

The major problem with MDF is the holding power of screws is much diminished because of the nature of the material. That is why, at least on entry doors, a MDF core door has a wood insert at least on each side.

The door I used has an insert a full 2&1/2" thick on each side. The door is 34" by 80" and probably weighs in excess of 80 pounds. I used 2&1/2" screws on the hinge side for the door and 3" screws on the frame side(which went into the studs as well).

MDF may be harder, but the edges chip more easily than wood when impacted.

There are also LDF(low density fiberboard) and HDF(high density fiberboard) products.

HDF is also called hardboard and is usually made in thinner sheets of 1/8" or 1/4" thicknesses. The darker brown boards with holes(often called pegboard) use for hanging things on is HDF. HDF is also used in cabinets, RV's, and even aircraft, among many other uses.

LDF is usually referred to as chipboard or particleboard.There are also medium and high density variations of particle board.

OSB is not included in this designation as the pieces are larger and oriented by design to provide more strength.

I have painted MDF baseboards and doors, and not one is dented. I also have 2 grown German Shepherds who are rough on everything.

Clt3...you said your door casings and baseboard dent but not your MDF doors...I’m replacing all of mine....what are your door casings made of? MDF or solid wood?

I still don’t understand What the difference is between an MDF door and a solid core door?

An MDF door can be either hollow core or solid core. A wood door is always solid core.