As a rehabber, you will need to be able inspect a property's siding and determine if it's in acceptable condition, or needs to be repaired or completely replaced.
Siding can generally last 15 to 30 years or more depending on the type of siding material, so siding is rarely replaced and typically the Original siding that was installed when the property was built.
For this reason, it is fairly easy to tell if the Siding was Original or if it was newly installed. If the Siding looks like it was original to the property be sure to thoroughly examine the siding condition and check for the warning signs discussed in this article.
Sign #1: Single Pane Windows
Single pane windows are typically found on older houses and provide very little insulation value. If you are located in an area that has harsh winters and/or hot summers, single pane windows can be very inefficient. If you property has old wood or aluminum single pane windows you should probably consider getting them replaced.
Sign #2: Aluminum Windows
Old aluminum windows generally only have a single pane, which as mentioned before offer little insulation value. If you have old aluminum windows you probably want to replace the windows with new double-paned vinyl windows.
Sign #3: Rotted/Cracked Frames
Wood window frames & vinyl window frames will rot, crack & degrade overtime. Make sure you inspect the windows that have the most sun exposure, because those windows will likely have the most damage.
If the window casing itself is rotted/cracked then you probably need to replace the windows, but if the window sill is the only issue, you may be able to get by with just a repair.
Sign #4: Condensation Between Panes
Double pane windows have a layer of gas that is trapped between the two window panes that acts as insulation. If your windows appear misty or foggy, it means that the seal protecting the window assembly has failed & has allowed moisture into the window.
The good news is that typically you don't need to replace the entire window. The vast majority of the time, you can disassemble the window and replace the window panes ($150 to $200/window) or use a method called 'defogging'.
Sign #5: Window Operation
If the windows stick or fail to open you probably need to consider replacing or at the very least repairing the window. Sticky windows could be considered a fire hazard that prevents people from safely exiting the property.