I have encountered a number of people of late that have mentioned the interest in or the actual execution of removing the aluminum capping from around their exterior trim and/or the aluminum or vinyl siding from their homes. I must say that I am so glad to hear it. As with most issues I encounter as a historic restoration contractor, the folks considering this path feel that they are crazy for considering it and are making a foolish financial decision. I am here to tell you that you are not on both accounts.
Aluminum and vinyl exterior “solutions” surfaced in the late 1950’s and early 1960’s. At the time, they seemed to be the perfect solution to the homeowner maintenance angst. These products eliminated the regular maintenance requirement of wood exteriors; they didn’t rot and never needed to be painted. Sounds glorious. There is however a major trade-off that most have (ironically) overlooked: When they fail (as everything does eventually) and let in moisture there is often no way of knowing until it is too late. Not only that, they will usually make the problem worse.
All of the “capping” scenarios at some point rely on caulk to keep moisture infiltration at bay. If you have ever bought caulk, you have seen that they are all rated based on their lifespan (on average 30 years). So at the end of its lifespan the seal and flexibility fail and water will likely begin to breach the system. Now you have a worst case scenario on your hands. It slowly lets water in but it also slowly releases it, if at all. The moisture is now contained in a dark, windless location. You now have damp wood with almost no chance of drying out and you would have no idea! If you wanted to create an incubator for mold and rot, this is the system for you.
Now let’s look at the traditional wood system that your home was originally built with. Many if not all of your exterior elements were made of wood. The actual design and construction of this system has been tested and tweaked by skilled craftsman for centuries. It is safe to say that glitches in the assembly were ironed out long ago. The only drawback was that it required fairly regular maintenance (which was also factored into the design by the way). Since wood rots and deteriorates when exposed to moisture and sunlight, your wood trim and siding were covered in paint to protect it. Just like caulk, paint has a lifespan of its own, albeit shorter (around 10-15 years). The advantage is that when it does fail you know it and you see it. The paint flakes, chips and cracks. It is funny that the very thing that people are trying to eliminate could quite possibly be one of its best qualities.
I understand the aggravation of having to paint your home every 10-15 years. But I suppose I view it as the evil I know. I much prefer having a system that lets me know how and when it is failing than one that will hide the incidence and extent of its failure. I can budget and project my maintenance obligations with a painted wood system. Not to mention I also get to enjoy the superior aesthetic of it and the ability to change my color scheme with every paint job if I so desire.
Now, are you potentially opening a can of worms if you are considering removing an existing capped exterior? Yes, you do not know what exactly is going on under there and the likelihood of there being problems is high. However, if there really is a problem under there it certainly won’t fix itself. Sticking your head in the sand isn’t really a solution. At least you can rest easy knowing that this will be the last time you will have to deal with this uncertainty regarding your exterior.