Asked on Jan 10, 2012

Replacing a solid wood exterior front door with a fiberglass door.

by Barbara
Our front door is currently solid wood and I would like to replace it with a fiberglass door with decorative glass. I have found a door that is just the slab and not prehung. Is this installation possible as I've learned that fiberglass doors are 35 7/8" wide as opposed to our current wood door that is exactle 36"?
Thanks for your help,
  11 answers
  • 3po3 3po3 on Jan 10, 2012
    That should be doable, but I would shop this out to a pro. Hanging interior doors is pretty straightforward, but exterior doors can leak so much energy if they are not installed properly. You could make up the cost of a pro in about a month in energy savings, I bet. Not to mention that an improperly installed door may be insecure (as in liable to be broken in, not lacking self-confidence - ha) and not properly functional.
  • Barbara Barbara on Jan 10, 2012
    Thanks Steve, I totally agree.
  • Barbara Barbara on Jan 10, 2012
    Thanks for the answers, but I'm still hoping for more ideas.
  • You can hang these doors, but it takes a craftsman to do the job correctly. Typical exterior doors utilize gaskets and seals to prevent air leakage into the home. This can be threshold gaskets and side and top gaskets as well. All require attention to details when fitting the door slab to a older frame. Can the new door utilize the old door saddle and door seal gasket? That would be the first concern that I had. Some doors have seals that are fastened to the bottom of the door, some use threshold gaskets. Some even both. Be sure you check to see what you have and what will work with the door that your picking out. As some may not work with the door you are considering. You may need to remove the existing threshold to install a gasket system that works with the new door your considering. Your chosen door is only 1/8 of an inch smaller then the one you have. This leaves only a 1/16 space from door to frame. Nothing to worry about My bet is that if you measure your door frame and door it changes in size that much in many locations. Check to see if the new door style accepts the location of the door knob system. Some frames locate the door knobs higher or lower then others because of designs and door qualities. The lower cost doors may not align properly with the location of of the existing door frame lock set. Meaning additional carpentry work. Not sure what type of fiberglass door it is that you have, but cutting them for hinges also can be difficult. Ideally special jigs are used to align the door with the existing door hing locations. Do it wrong and you cannot fix this as you can with a wood door. I would shop around and pick out a complete door and frame that matches. Pre-hung and done. Fitting an exterior door cost can be as much or even more then a complete door with frame ready to go in this case.
  • Barbara Barbara on Jan 11, 2012
    So basically this application can work, but would be much easier just going with prehung. Right? Your information is very helpful and I thank you for taking the time to post.
  • Exactly right. The door would work, but if whoever puts it in does it wrong, you end up with a nice door that you cannot use. So unless you have someone who really understands how to hang a door and does this for a living. Purchase a pre hung unit. It will come with warranty and all.
  • Mike N Mike N on Jan 11, 2012
    This is splitting hairs, but you might also want to consider hinge preps. Typically, the fiberglass "slab-only" purchase comes from a manufacturer such as Thermatru, Jeld-Wen, etc., and often they pre-mortise their exterior slabs for their typical jambs - as if they were to be pre-hung in their own units. Often the hinge locations do not match what is existing in your home. There are ways to modify this (meaning your jambs, filling old hinge locations in full or just partially), but ideally you'd purchase a new door slab asking for NO hinge preps. Some manufacturers will do this, others won't. For those that will expect potentially longer lead times. Apparently door producer's assembly lines are programmed to handle things one way, and when an order is received that actually requires a break from the norm, special attention is required. I tend agree with Woodbridge above. The door as a complete unit will be far more energy efficient and will likely qualify for a tax credit. Installed in an existing jamb does not. Also, when hung in an existing jamb, you can kiss any warranty the door would otherwise come with good-bye! And from a cost perspective, the difference is negligible when you consider how much futzing around you must do to make the compression weather-stripping seal tightly, not to mention adjusting the threshold properly. In the end you'll get a superior finished product with a pre-hung unit.
  • Jane B Jane B on Jan 12, 2012
    I agree with Woodbridge and Steve -- get a pro. Mike is right in that the hinge locations don't match -- this happened to me. I need to replace three exterior doors and will be doing so with pre-hungs and a professional.
  • Buy the 35 7/8" slab and put a thick cardboard shim behind the hinges on the frame side. Hire someone who knows what they are doing it will be much cheaper than home owner practicing on a door doing hinge and lock holes, one oop's can cost you another new door slab.
  • The Money Pit The Money Pit on Jan 15, 2012
    Hanging a door that is just a slab is possible, of course, but really for a pro. This is not a DIY project unless you have substantial carpentry experience.
  • Dick Dick on Jul 09, 2017

    the guy asks a question and all he gets are pay someone else

    or do it this way

    no answers about how to hang a slab door

    answer the question dont give you opinions