Archive
for October 22nd, 2013
Back drafts in the home and how they can kill you.
Oct 22 2013Back drafts are caused when the house is under negative pressure. A good sign the house is under negative pressure is when you open a door and it closes by itself behind you or if you open a window and a breeze blows in. Depending on the appliances you have operating in the house, back draft conditions may exist and occupants may be subject to carbon monoxide poisoning. CO is produced when you have incomplete combustion, when the fuel being burned does not have enough combustion air to completely burn the fuel. A common situation found during a home inspection is a furnace room being sealed up with dry wall without sufficient supply air. This situation is fine if the appliances in the the room is direct vented. That means the intake supply air and exhaust are piped directly to the exterior through the side walls. The appliances of concern include hot water tank or mid efficiency furnace which uses natural draft to vent the combustion exhaust, Natural draft appliances require the house to be under positive pressure to work adequately.
During a home inspection, experienced home inspectors look for the above conditions and note the potential hazard. In addition, some subtle situation the home owner may not be aware of include the dryer acting as an exhaust, a kitchen exhaust fan, a attic or whole house fan exhausting directly to the exterior, a chimney flue left open, which all can contribute to the house being under negative pressure preventing natural draft appliances from working properly.
Another subtle condition are the leaks in the ducts from the boot of the furnace to the jumper in the furnace room. All the leaks add up to the equivalent of having return vent near the blower motor. First, the return air should come from either the first floor or second floor but not in the basement as a rule of thumb. There is typically enough leaks in the duct works around the furnace to decrease the efficiency of the system about approximately 15%. The blower motor is strong enough to create a negative pressure environment in the furnace room and thus create back drafts in the natural draft vents. With a return vent close by or at the blower motor, a negative pressure environment is also created.
Can I build storage cabinets and shelves in my garage?
Oct 22 2013This my seem like a simple question. It is your house and shelves and cabinets are easy to build. What is the big deal? Why even ask such a question?
From the home inspector’s point of view, it depends. Generally, as home inspectors, we view shelves and cabinets secured to the walls of car garages as unsafe and not rated for load. Often we see home owners store items that may overload the shelves and thus create a hazardous condition.
Some home owners are correct to be concerned and should check with an expert before taking on such a simple project. The issue to be concerned with is structural safety and the load that shelves can take. The current home owner may be aware of these safety issues but as a home buyer moving into the home, they may not know what load the shelve and cabinets were rated for. A worst case scenario is that new owners move in and decide to store some tires on the shelves. The shelves may sage or fail and worst, compromise the framing of the garage and the house. The new home owners call up the home inspector and complains that they were not warned of this and threatens to take legal action.
So from a home inspector’s point of view, when asked about a simple project as putting up storage space in the garage can be a legal mess. And if the home owner insist on building such structures to the garage, I recommend they check with a structural engineer first to get proper drawing plans, building materials, and the proper skilled carpenter to build it.