Door Repair Basics
Door repair can either be a simple, inexpensive project or more complicated based on the severity of damage to the door. The most common areas for damage to a door are hinges and locks.
Do some research prior to choosing a company for your door repair. Find references, services provided and licenses as well as insurance.
Repairing Cracks
It can be alarming to see hairline cracks in your door frames. It could be an indication of structural problems or that your door is at risk of being lost to the elements. There are simple solutions to stop cracks from growing and getting worse.
The first thing you need to do is clean the crack and surrounding area thoroughly. This will help ensure that there isn't dust or dirt in the crack that could interfere with repairs later. Next, you should allow the crack to completely dry. This usually takes about 30 minutes.
There are several ways to repair cracks in your door frame. For small cracks, wood putty or filler is the best option to use. These materials are simple to work with and are fairly inexpensive. However, the best method to repair a crack in a door is to use real wood. This is because the result will be a stronger, more durable repair that is less likely to break down over time.
After you have picked the correct material, apply it to each of the cracks in the door frame. Spread the compound with a putty blade around the inside ridges. Use just a tiny amount at a time, ensuring to fill the entire surface of each of the ridges. After the filler has dried, sand the surface until it is smooth.
If you want to paint over the repaired cracks to hide the damage. However, this is not always necessary, especially when the cracks aren't too large. When fixing door cracks, the most important thing to keep in your mind is that you want the result to be completely invisible. The goal is to achieve a flawless finish, which won't be noticeable even up close.
You should be able to find a good product at your local hardware store to repair the cracks in your door's frame. If the cracks are large, you might need to use wood glue and wood splines to repair them.
Patching Hollow Core Doors
Hollow-core doors are more affordable than solid-wood doors and are common in homes. However, they can be fragile and susceptible to damage. A hole in a front door could be caused by a heavy punch or a heavy knock. It's not only unsightly however, it could also impact the efficiency of a house. It's easy to patch a hole in an hollow-core door using common tools and materials.
Gather the following materials to begin:

A utility knife
Utility knives are necessary to smooth the edges of holes and aid in the application of the patching material. Cut a small bevel with the knife around the edge of the hole. This will give the patching materials more surface area to stick to and stop them from peeling later on.
Refinishing a door
Even the most well-constructed wooden doors may be damaged as they age. The sun's UV rays and fluctuating temperatures and humidity can harm the finish of a door. Refinishing wood doors is a good idea in the event that the finish begins to peel or blister. But, before you finish your door, you'll have to remove all hardware and store it in a place that is secure.
After removing the finish, you'll have to sand down the wood in order to prepare it for staining. You can use a palm sander or an orbital sander to sand flat surfaces, but you will need to carefully scrape any moldings and details. To avoid damaging wood, it is best to sand along the grain. Apply gentle and steady pressure. After sanding, wipe off any dust with a microfiber cloth or tack cloth to ensure the surface is clean enough for the new stain coat.
It is crucial to select the right color when refinishing doors. Some people opt for gel stain as an easy fix to hide imperfections, but this kind stain will not stick well to exterior wood and will generally begin to flake within a year.
It is crucial to let your door dry for a the night following the choice of the stain. You should also sand between coats of varnish to smooth the surface and ensure that it is free of residue and oil. To get a smooth and even finish apply a natural bristle brush to apply spar urethane.
Once the varnish has dried, you can install the hardware you took off. Once the door is reinstalled then you can polish it using wax-based or polyurethane polish to protect the wood and prevent water damage from harsh weather conditions. If you regularly polish it, your door will look stunning for many years to come.
Replacing Hinges
The hinges of a door are an important component, but they could cause sagging or other issues. Replace hinges if your door is sagging or is difficult to open. Fortunately, you can accomplish this without removing the door from its frame by unscrewing the old hinges and replacing them with new ones.
Start by removing the screws from the hinges on the door jambs and hinge leaves. Use a hammer to create an opening in the wood where the hinges will be put. The mortise's depth should be approximately the same as the thickness of the leaf of the hinge. Check the hinges after forming the mortise to ensure that they fit comfortably and securely. If the hinges do not fit, re-chisel until your hole is the proper size.
Draw the screw holes of the new hinges on the jambs and doors with the pencil after you have prepared the hole. You can also use a screw guide to keep the screws straight as they are driven in. The next step is to drill pilot holes through these marks. Insert the new hinges, and secure them using an screwdriver or drill.
The screw holes on the new hinges do not need to be exactly the same as the holes in the jamb of the door, but they should be close enough. If the holes do not match precisely, it won't really matter since they'll be hidden behind the hinge plate.
Once you're done then put the door back into its place and attach it to the hinges by sliding in the hinge pins. Use upvc repairs for support while working on the door if it's fragile. Then remove the blocks, and test the door to ensure it opens and shuts correctly. If it does, you're done!