The simple task of cutting a hollow-core door to height can become much more difficult if you have to remove more door than the bottom plug allows. Until recently, I always used to cut a new plug. I then would remove enough of the cardboard honeycomb between the veneers to accommodate the new plug, and glue and clamp it into place. This could become a time-consuming process, especially if there were several doors to be modified.
On a recent job, I decided to try a new approach. After cutting a hollow-core door to height, I sprayed a minimally expanding window-and-door foam into the bottom of the door. I trimmed the cured foam the next day, sealed the door bottom with primer (the door was to be painted), and installed the door. I have since used this method on a couple of other jobs, and it has produced fast, consistent results.
—Michael Dexheimer, River Falls, WI
Edited by Charles Miller
From Fine Homebuilding #212
Fine Homebuilding Recommended Products
Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.
Affordable IR Camera
Reliable Crimp Connectors
Handy Heat Gun
View Comments
This sounds very fast, but I'm not convinced of the strength.
Instead of creating a new plug when I cut down a door, I push the old one through a table saw to bring it to the correct width. I then glue it back into the door and tack it with a few 18-G nails.
Cornelius99,
But don't you still have to spend the time to remove enough honeycomb to insert your plug? The point of the tip is to eliminate that step to save time.
Michael & TTTTT - What's more important - doing it fast or doing quality workmanship?
I wouldn't have either one of you do work for me.
CT_Yankee
Given the snotty attitude, no one would want to work for you.
I was merely asking for clarification, not endorsing nor condemning any technique.
TTTTT
Why would you point out the advantage of the time saved by eliminating the need to remove the honeycomb if you weren't endorsing the tip? What is the purpose of saving time if the tip is characteristic of poor workmanship as CT_Yankee says?
There are certain nuances in communication and CT_Yankee's assumption is correct given your original comment. You should be more civil and refrain from name-calling.
Full disclosure: handy with some repairs but not a professional carpenter by any means.
I repaired a masonite-faced door in my son's townhouse that had loosened glue and completely lost the bottom piece of compressed wood fibers of some kind. He felt he needed a new door; I took it off, brought it home, cut a piece of scrap wood to width (running into the door about 2") and glued and clamped it in place, along with glue and clamps for significant sections of the masonite that had loosened from the side (rails?) of the door. Inserted, glued and clamped some scraps of solid wood around the doorknob hole to strengthen it as well. Painted, it looked just fine and is back in place and strong. Truthfully, I wouldn't expect foam to hold much beyond the time a customer's check had cleared.
Spray foam just seems to be cheap to many people, but I can't see that a hollow core door is acceptable anyway. Still, they do a job. I'd use the foam technique since it has to be at least as good as cardboard. Unless you are attaching a door stop or something that needs a solid anchor the bottom will be stiff enough.
Amen to 6312.
As far as foam being mostly air, that's pretty much the definition of "hollow-core." It's a cheap door- in most cases, anything fancier than foam counts as "putting lipstick on a pig (apologies to pigs...)" Sometimes you have a hollow-core that's hard to match, but you'd like it to function for another few years and then it's worth your time to splice some real wood into it. Other times, foam probably counts as an upgrade.
In an ideal world, we'd never have to deal with hollow-cores. If wishes were horses, beggars would ride.
Jeez, this isn’t that hard to figure out: Looking at a traditional stick and rail door, we can see that the single beefiest element is the bottom rail.
Next, we ponder foam: it’s a minor amount of a liquid substance entrained with a substantial amount of AIR, the point being to lighten the weight and reduce the quantity of actual solid material (cost savings) used to effect the desired form.
If we understand that air is useless for mechanical performance in structural applications, why would one expect foam to be an adequate substitute for the solid wood that the penny-pinching manufacturer already decided was inadequate?
Then comes the question of “just how much value does one place on one’s time?”
Fix it right or buy a real door and everyone will happier in the end.
This “tip” was emailed to me today. It’s obviously recycled but not all oldies are goodies. I’m no longer in the business and no longer subscribe to FH but still get these emails and I sometimes take a look at those that seem interesting. But this one was a waste of time and of one of my 3 free monthly articles. It doesn’t take that long to rip a new door bottom from a 1x or 5/4 board. If you have a lot of doors to cut then rip all of your new door bottoms at the same time. It takes just a few seconds to remove 1” of the cardboard honeycomb with a utility knife. If I hired a carpenter to do work in my house and he did this I’d throw him out. This is a hack tip and FH shouldn’t be publishing it.