During a remodel project, our city has determined that our garage is "occupiable space". Disregarding the fact that its where we park our car and have two gas appliances. Because of this definition, we need to add a swing door for egress or add a longer pull cord and make the electric garage door easy to open when there is no power.
For this second option, is there a limit to how much you can pre-load the garage door spring? I plan to hire this out, but still want to learn what my options are.
I have a recollection of being able to open my dad's double-wide garage door at the age of 5-ish, kindergarten, first grade times, to ride my bicycle. So yes it ought to be possible to tension the door so a 5-year-old could open it.
A garage door technician should be able to guide this project. Note: DIY on garage spring doors is very dangerous: leave it to the professionals.
Your door should be moveable by a small person if it's balanced properly. If the springs are correctly set it'll hold position when halfway open. You could bias toward too loaded so the door opens almost by itself when the door is released. Look into how that's done (safely) for your hardware. With the door closed, disconnect the opener with the trolley release and have at it. This isn't a matter of overloading the springs. They hold the weight of the door regardless, and are up to the task (until they fatigue and break, which does happen). They also weaken with age, so adjustment is likely warranted to reattain balance.
Note that you'll need to extend the pull cord from what the factory provided in order for it to meet your needs. That itself presents a danger, so provide a breakaway mechanism to prevent accidents.
I'm not one to dissuade you from working on your door. There are many things in home improvement and auto repair, for example, that are equally dangerous. Make sure you understand the hazard door springs present and act accordingly.
First, let's get an important matter out of the way: Do not mess with the garage door spring merely to increase ease of opening. It is dangerous, and stores a lot of energy. Winding springs is dangerous. Springs breaking is dangerous. Doors dropping when springs break is dangerous. There are hack laborers who will do this just to get $100 off you. But it throws off door balance completely. Properly sprung, the door will stay anywhere you put it.
If your spring is weakening ~= worn out (or incorrectly specced), you will find there is no tension that makes it "stay and not want to move" at all positions. Note that attaching things to the door will throw off the spring.
When your door is not easy to open, that isn't too loose a spring. That is other brokenness impeding the door from opening, and there's a lot to fix, and you should really fix that. I have one door where I thought I had a soft spring and advanced it; and surprise, once I fixed the door's other defects, it no longer stays where you put it and wants to creep upward.
The easiest thing is rollers, which are a T-shaped "lollipop" sort of affair, 2" roller on a 5-8" shaft. Pivot them vertically and see if they're getting floppy doppy OR if the shafts are becoming grooved from riding in the hinge a particular way. Changing a roller is pretty easy except for the bottom ones, those can hurt you if you are unwise.
Look at the door hinges. Look at both the shaft they pivot on, and also the holes that the rollers go through. If any of those are degraded, replace the hinge. Look at the screws that attach the hinge to the door and make sure they're tip top. They are typically self-tappers, and if they have gored up their hole from movement, you can fall back to "bolt and nut".
Also check the intermediate hinges in the middle of the door for anything bad.
Now look at how square the door is in the track. Happens all the time where one of the two lifting cables slips, stretches or frays, or wraps wrong onto the sheaves up top... and now one side of the door is 1/2" lower than the other side. That makes it tram, rub in the corners and move stiffly. This same problem can also happen with healthy cables but a slipped pulley on the shaft. All this is "spring work", a good time to get a pro.
Next, let's look at how the door meets the back face of the wall. You may not realize this, but the door track is not vertical! It's a couple degrees leaned back. As the door slides down, it gets slightly closer to the wall. When the door bottoms out, it should be snug against the wall, but not pressing. Any seals in there should be sensibly compressed.
How does that work? Each hinge has a different number starting with 1 at the bottom. Then 2, 3, 4, 5, etc. Each of them pushes the hinge farther away from the axis of the roller. Just compare #2 to #4 and it will be obvious. So if you (or the last guy) mixes up these hinges, that door won't be right.
So if the hinges are right, you calibrate the "spacing to the wall" by moving the track closer or farther from the wall - there is a slot adjustment on the track brackets. If this spacing is wrong, the door will be extra stiff at the very bottom but loosen up after the first foot. If there's a rubber seal, I would aim for "a piece of paper trapped between seal and door, can be pulled out with some resistance but without tearing it".
Don't just go lubricating everything, especially not the track! I do not like wet or sticky oils or greases, because in a garage they will attract and foul with dust, and now you're grinding dirt and dust into the very surfaces you're trying to lubricate, while making a hideous goo that will get on your clothes. I prefer "dry graphite paint" such as Slip-Plate, EZ-Slide, or my John Deere dealer has that too. And I use the quarts because the spray can is costly and uncontrollable. The graphite loves to settle to the bottom even while painting it, so I recommend thoroughly mixing the quart and pour off maybe an inch deep into a cup. Use any 50 cent "acid brush", start by cleaning out the groove on the paint can so it seals well, and stir the cup a lot.
DO NOT LUBRICATE THE TRACK, this is pointless, that's literally what the rollers are for! If someone has already lubricated the track, then get rags and paint thinner and gloves and thoroughly remove all grease and oil and dirt. Miserable job. The critical area is the horizontal part on the bottom, which the rollers must roll through. Of course that collects the most dust and dirt!!!
Also look at the sides of the track. If you're seeing witness marks from the ends of the rollers scraping against it, that suggests a tramming or other problem, and I would look into that problem. I wouldn't paint Slip-Plate on that as a way to avoid fixing the real problem, but I would do it to cover up witness marks from a problem already fixed, basically using it to reveal future scrubbing. Try to keep it off the top and bottom (where the rollers touch it) as it serves no purpose there except to gum things up.
The door seal is the #1 thing I'd lubricate, and Slip-Plate is the perfect stuff. I wouldn't put Slip-Plate on rubber for worry of the solvent damaging it. However I would put it on the mating surface, which will be metal. Presuming it's the door, open the door all the way and paint what would be the top of the door. Or, open the door 1 panel so the first panel is angling away, paint that panel, move the door up 1, etc. etc. Let it dry fully and then some before lowering the door.
For hinges and rollers I'd use a dry graphite lubricant as Slip-Plate won't penetrate well. For roller shafts, Slip-Plate. The cable doesn't need lubrication. The top (spring) shaft bearings should be lubricated whatever way makes sense, though don't be surprised if they are sealed bearings.
Replace / add electric garage door opener.
This will make the use of garage door more convenient for you, by the virtue of remote, and your child can just press a button inside garage to open/close the door. Install the button at height reachable to your child.
Make sure to pick opener with sensors for object collision (all modern ones should have them), and optionally, an optical sensors for obstructions.
Once done, remember to educate the child to not press the button then run out from garage, thus locking themselves out.
