Installing a Pre-hung door.

June 25, 2006 10:46 AM

Installing a pre hung door. Or rather filling the hole you put in your new house when you decided to replace the door.

This weekend while we were painting the house before we moved in I noticed that one of the back doors to the house was actually an interior door. Having my father with me eager for a project and doing a *bit* of research it seemed like a fairly easy proposition to purchase a pre hung door and install it ourselves. It is not.

The demo went fine, installed the new footer and entry way that was rotten, insured it was flat and level for the prehung door. I went with a steel door with 8 panels of double paned glass to match some other doors in the house.

So we get to the actual installig of the door, did a test fit of the door in the structure, pull it out, remove the unnecessary packaging and insure there is .5 inch of clearance all around the frame, and shim it in (doing the leveling dance and following the manufacturers instructions for the shim points. Here is where we hit problems.

Is there any special trick to get these suckers in? We had adequate clearance all around to isolate the door from the structure, but it keeps twisting, and we can't seem to get the door to open cleanly after it's been shimmed in.

I'm a bit stuck here, after 5 hours of wrestling with it yesterday with my dad and the fiancee's dad I'm about ready to call a carpenter and beg for assistance. I'm sure we're just doing something totally boneheaded and missing a critical step in the process, but nothing stands out.

posted by iamabot to Home & Garden (6 answers total)

I try to get the door squarely in place by shimming only from the bottom, perhaps by setting the whole thing on a piece of 3/8" plywood. The side shims seem to what's torquing your door out, so use those just to stabilize it, not to position it.
posted by StickyCarpet at 10:52 AM on June 25, 2006

It sounds like a problem with where your door is connecting to the hinges - if your hinge points are not perfect, the door will torque. You need to figure out at which hinge point the door is being thown off (top, bottom, or middle) and either shim (preferred) or shave behind the hinge to even out the swing. It's definitely a two person job though if you haven't done it many times (a category I'm in myself).
posted by mrmojoflying at 11:04 AM on June 25, 2006

You might want to check that the frame of the prehung door is square. I had a similar experience, and found to my chagrin that one side of the frame was 1/8 " shorter than the other - a manufacturing error.
posted by Neiltupper at 11:17 AM on June 25, 2006

Response by poster: Thanks for the suggestions, I'm headed back over there to look at it again. Please keep the suggestions rolling in, I plan on taking another look at it with a builder friend of mine but don't know when that will be.

Thanks again!
posted by iamabot at 11:26 AM on June 25, 2006

Best answer: Most exterior doors have three sets of hinges. The door should be installed with shims at each hinge. The key is that the pins for all three hinges must be in a perfect straight line from top to bottom, in both dimensions -- in/out and side to side. Otherwise the hinges will bind. What often happens is that the shims will cause a bow in the frame. If the shims are a little too loose, then when you drive a screw into the shim, it will pull tight and bow the frame.

As you attach the frame, continually look at the crack between the door and frame all the way around. It should be even and remain even as you drive in each screw tight. If not, then you have to adjust the shims.

Make sure you install a pair of shims at each point as two opposing pairs so that the combined wedges form a flat, surface. If you use just one shim, the frame will twist when you drive in the fastener. Slide a pair of opposing shims into a crack. By pulling one and pushing the other you can adjust the tightness of the shim. You may have to cut off the narrow end of one shim in order to push it far enough in. Leave the shims sticking out until the installation is finished in case you need to make adjustments. Cut them flush with a utility knife when all done.

Swing the door open and closed with just the shims and no fasteners yet to test the fit. Check the crack all the way around. Then install one fastener and test again. Proceed until all fasteners are installed. If you have binding at any point, remove the fastener and adjust the shims.
posted by JackFlash at 12:15 PM on June 25, 2006 [2 favorites]

This is a hard thing. My stepfather is an accomplished carpenter, and I have seen him fiddle with pre-hung doors for literally hours, making minute adjustments that are practically undetectable to my eyes.

Like many things carpenters do on a daily basis, it's not so much technique as it is experience and touch. Assuming you are doing the "two-shims-combine-to-form-one-flat-piece" thing (which was a real eyeopener for me), I can't think of another "trick" that I have seen him do, so you may just want to bite the bullet and call in professional help.
posted by Rock Steady at 7:14 PM on June 25, 2006