This is my tribute to all of those hard working plumbers, heating and air contractors, electricians and less than knowledgeable homeowners who just don’t care about their job and how it affects the structure of the building they are working on. Without you guys, us home inspectors would have a lot less to report on.
The pictures to the left show industrious contractors that although they understood the requirements of the systems they were installing they didn’t care how it effected the rest of the home’s structure.
Here are a few guidelines on how and when floor joists should be cut
According to the 2003 IRC:
R802.7.1 Sawn lumber. Notches in solid lumber joists, rafters and beams shall not exceed one-sixth of the depth of the member, shall not be longer than one-third of the depth of the member and shall not be located in the middle one-third of the span. Notches at the ends of the member shall not exceed one-fourth the depth of the member. The tension side of members 4 inches (102 mm) or greater in nominal thickness shall not be notched except at the ends of the members. The diameter of the holes bored or cut into members shall not exceed one-third the depth of the member. Holes shall not be closer than 2 inches (51mm)to the top or bottom of the member, or to any other hole located in the member. Where the member is also notched, the hole shall not be closer than 2 inches (51 mm) to the notch.
And when the roof truss gets in the way of the satelite dish installation……. R802.10.4 
Alterations to trusses. Truss members shall not be cut, notched, drilled, spliced or otherwise altered in any
way without the approval of a registered design professional. Alterations resulting in the addition of load (e.g., HVAC
equipment, water heater) that exceeds the design load for the truss shall not be permitted without verification that the truss
is capable of supporting such additional loading.
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