Repairing aluminum siding isn't a particularly difficult process; it involves more of a time commitment than special proficiency or technique. All you need are a few basic tools, along with some replacement siding to repair a section.
Finding replacement siding.
One of the most difficult parts of repairing aluminum siding is finding appropriate replacement siding; especially if it's been years since you installed your siding. If you have a place to store it, buy extra siding, or keep the leftover siding, when you install your aluminum siding. That way, you know you'll have the right siding to handle repairs in the future. If you don't have the right siding on hand, check with your local home improvement store for the right siding. Even if they don't have it, they might be able to order similar siding to meet your needs.
When to repair aluminum siding.
The question of when to repair aluminum siding depends on what sort of damage you're repairing. If the aluminum siding is damaged to the point that it could enable water to penetrate the siding, you should perform emergency repairs immediately. You want to keep water out of your walls and the important components of your home's construction.
If you're not looking at an emergency situation, the best time to repair aluminum siding is right before you paint, so it won't matter if the new siding matches your existing siding.
Cut out the damaged section.
Take a pair of tin snips to the damaged section to cut out the damaged siding. When you remove the siding, don't cut out the top section of the old siding; leave the top section intact.
Cut a piece to fit.
When you cut a replacement piece, cut it approximately six inches wider than the piece you're replacing. You can then overlap the piece by about three inches on either side of the opening for maximum protection on the install. Cut off the nailing strip on the top of your patch piece.
Attach the new piece of siding.
To attach the new piece of siding, you should apply caulk to the bottom edge and the side of the piece of siding that you're using as a patch. You should then apply roofing cement to the top part of the patch piece, where it attaches to the existing top section that you left intact when you cut the piece of siding out.
Then simply slide the siding into place; gluing the top section with roofing cement to the existing section of siding, and sliding the caulked sides over the sides of the neighboring siding. If you're using locking siding, make sure you lock the siding into place.
Paint the siding to match, if necessary.
Ideally, you'd then paint the entire siding so that all of the siding is covered with the same paint at roughly the same level of freshness. If you're not painting the entire siding, you may need to paint the siding to match when you replace a piece. Keep in mind that your replacement siding isn't going to be weathered or faded like your existing siding, so if you're not repainting your entire siding, your repaired siding will be visible.
Fiber cement siding is a popular choice for its balance between durability and cost.
Whether you're renovating or building a new home, deciding on which siding material to use is a major decision, not to mention a major expense.