Bent Doors
There are two types of “bend” that I know of. In the first case, when you close the door, looking at the door from the outside, there will be a gap either at the top left or the bottom left. If you put a straight edge on the latch side, the door side seems to be straight. I will refer to this type as a twisted door.
In the second case, there may be a gap at the top, the bottom, or both. Checking the edge with a straight edge, there will be a section of the door edge that is not straight. I will refer to this type as a bent door.
There is a third case of a door gap. If your door has a gap at the top, the middle and the bottom, all about the same, and the door edge is straight, you have a latch that needs adjustment. This article is not targeted at that condition.
Twisted doors
With the door closed, measure the amount of opening at the top or bottom. Get a block of wood that is about 1.5 times that thickness and tape it to the corner of the door opposite the gap.
In other words, if the gap is at the top left corner, put the block on the bottom left corner. Position the block along the vertical edge. See Figure 1, showing a ½ x ¾ block, an appropriate starting size and placement for a door with a ½” gap at the top.
Figure 1
It should be narrow enough to fit in the space where the door meets the frame, and a few inches long. Working from a ladder, place a 2x4 against the face of the door to distribute the pressure (you don’t want to change the twist into a bend), then push the part of the door where there was a gap toward the door frame until it touches. Open the door, remove the block and check to see if the twist is gone. If not, repeat with more block thickness. Continue repeating until the twist is gone.
If your gap is at the bottom, either reverse the block placement and pushing instructions, or place your RV upside down… ;-)
Bent doors
OK, so the wind blew your door and it slammed. Now it is bent and no longer makes good contact when you close it. How can you fix it? Here is what I would do.
First, you need more information about the bend. Is it a sharp bend at one point, or a gentle bowing or warping spread along a section of the door? To determine the answer, you need to identify the start and end points of the bend as well as the amount or depth of the bend.
Figure 2
In Figure 2 above, I show a (pretend) door with a large bend that extends the entire length of the “door”, I show the clamps I would use, and some straight pieces of wood that will play the part of 2x4’s.
Identifying the bend
Using a straight edge (you can use a metal yardstick, a 4-foot level, or a piece of string with a few helpers, stretching the string from one surface point to another), you start at the top of the door. Slide the straight edge down, maintaining contact at the top of the door. When you begin to see a gap midway along the straight edge, you are at the start of the bend. Mark that point. Repeat that, starting at the bottom and moving up, to locate the bottom end of the bend. Mark that point. Now, span the bend from start to end with the straight edge and measure the deflection at its maximum. Mark that point, and write down the amount of deflection. Divide that deflection by 4 and use the result as your deflection increment.
Figure 3
Figure 3 shows the bend on my pretend door. It extends almost the entire length of the door and is fairly uniform.
Planning how to straighten the bend
You need pieces of 2x4, and clamps, the more the better. Cut at least 4 pieces of 2x4, 3 1/2” long, to act as spacer blocks. Cut one uniform, knot-free 2x4 to the length of the bend. It will go on the outside of the bend to spread pressure evenly. Cut a second uniform, knot-free 2x4 8” longer than the bend, and attach a block to each end, with glue or tape. Do not use nails or screws. You might scratch the surface.
Figure 4
Why uniform and knot-free? You want the 2x4’s to apply even pressure throughout the bend. If a 2x4 has a weak spot, it won’t do that.
Straightening the bend
Using two clamps, place the 2x4 with blocks against the inside of the bend with the upper block above the start of the bend and the lower block below the end of the bend, and with the blocks facing the door so there is a cavity between the bend and the 2x4. See Figure 5.
Figure 5
Place the shorter 2x4 centered on the outside of the bend and put a clamp snugly in the center. Add other clamps evenly distributed to the remainder of the 2x4, so the loading will be uniformly distributed. Begin tightening the clamps, a bit at a time, so that smooth, even pressure is applied to the bend. Track your progress with the straight edge. Once the door seems to be straight, go a little past that point, overcorrecting the bend by the deflection increment calculated above. At this point, it should look sort of like Figure 6 below.
Figure 6
Release the clamps except for the two on the blocks, and check the door alignment. If you need further straightening, repeat, but increase the deflection increment either a little or a lot, depending on how much correction you achieved. I can’t tell you how much this should be. Use your judgment, but multiple tries, increasing a little at a time, are much better than a big overcorrection that bends the door the other way. When the door is straight, remove the clamps on the blocks. You’re done.
A few caveats -
1) A 2x4 on its side is kind of springy. Over a long span, it might bend enough to close the gap between the 2x4 and the door. If that happens, remove the setup and add a second block to each end of the 2x4. You may also want to use the 2x4 on its edge rather than on its side. It is much stiffer that way, and the protruding blocks are a good resting point for the straight edge when gauging progress. The 2x4 on the outside of the bend should always be on its flat side. You WANT that springiness to distribute the loading.
2) Do not let the span extend beyond the area of the bend. Those parts are currently straight, and you do not want to change that.
3) Don’t crank down one clamp much harder than the others. I can fix a bend. I can’t fix a crimp.
4) Try to minimize clamping adjacent to the window. You are better off with a slight bow along the window and larger corrections above and below the window than with a straight door and a cracked window. That option is gone if the entire span of the bend is within the window area. In that case, cut your deflection increment in half.
5) Once you have removed the bend in a bent door, there is a fair chance that you have created a twisted door. That’s ok. Twisted doors are easier to fix.
5) Once you have removed the bend in a bent door, there is a fair chance that you have created a twisted door. That’s ok. Twisted doors are easier to fix.
Special cases
The bend may be short and close to the latch. This is more challenging. You do not want to clamp at the latch. You want to be above or below it. You use as short a setup as you can get away with, and position the blocks, first with the upper block edge at the upper edge of the latch, and do your clamping below the latch. Check the result. Then move the setup so the lower block is at the lower edge of the latch and clamp above the latch. Check the result, then repeat as needed. Don’t be surprised if one side of the latch becomes straight while the other side still has a bend.
If the bend is very short, almost a crimp or angle rather than a curve, the basic technique is the same, but apply straightening pressure with a single clamp located at the bend point. Stop and check when it is straight without overcorrecting. Apply a deflection increment, part thereof, only if the first attempt, with no deflection increment, was unsuccessful.
A few cautions -
1) Slow, careful and gentle are the keywords on this. You want the finished product to be straight, not bent the other way. To achieve that, you need to go a little bit beyond straight, to account for the springiness in the door frame, but don’t go too far.
2) A very long bend is actually the hardest to fix, because some parts may straighten before others. When checking your progress on a long bend, don’t just check the amount of correction at the maximum deflection point. Use the straight edge to see if a portion that was bent is now straight. If so, shorten your setup so you are just dealing with a bent area. Imagine a 6-foot bend, and the middle goes straight, leaving a 2’ bend at one end and a 3’ bend at the other. Deal with them as if they are brand new short bends.
Ken F - 11/2018
A Practical Demo
A few screw clamps would have made it easier, but I don't have any of them. So, the more clamps you use, the less each clamp needs to do. Plus, multiple clamps spread out the load, avoiding creating a sharp bend at a single point.
A Practical Demo
A few screw clamps would have made it easier, but I don't have any of them. So, the more clamps you use, the less each clamp needs to do. Plus, multiple clamps spread out the load, avoiding creating a sharp bend at a single point.
