Home fix: Condensation on glass doors of a fireplace
Q. My fireplace is located in the basement and the chimney is located on the wall between the house and attached garage. In the summer when it is very humid outside, the glass doors on my fireplace sweat and the condensation pools on the floor in front of the fireplace hearth. We keep our home cool (67 degrees) at night in the summer. If I open the glass doors, the condensation does not occur.
I would like to put an electric fireplace insert in, but I am concerned about the condensation. The insert resembles a flat-screen TV in appearance. Any condensation could damage the insert. I have only one fireplace and it is the only thing that vents through the chimney. I have thought about inserting insulation into the top of my chimney and capping it, but I am concerned that the walls of the flue could create condensation during the humid summer days. Do you have any recommendations?
A. Condensation in the home is the process where moisture, which is present in the conditioned air, is transformed from a gas to a liquid. This process is most often noticed in the winter when moisture forms on the cold glass surfaces of windows. It’s a simple fact that cold air cannot hold or retain as much moisture as warm air, and when the two meet, the warm air starts to cool, releasing some of its moisture as condensation. Homes with high humidity levels will often have condensation forming on the interior side of windows in colder weather. When the humidity levels are too high, mold and mildew can become a problem. A normal and comfortable level of humidity inside the home would be anywhere between 30 percent and 60 percent at 65 degrees.
Humidity levels below 30 percent can result in dry skin, nosebleeds and static electric buildup, whereas higher moisture levels lead to the aforementioned mold and mildew.
A hygrometer, a device that measures humidity levels, can be purchased for under $20 and will give you an accurate reading. Only when you know you have a humidity problem can you correct it.
As you know, if you plug the top of the chimney above the fireplace, the flue-liner condensation will trickle down to the fireplace. You will need to protect the insert from moisture problems. According to one manufacturer’s recommendation, “Insulation and vapor barrier should be placed a minimum of 2 inches from the unit.”
This means you can use rigid foam insulation behind some inserts to control temperatures and airflow and a vapor barrier to protect the insert from moisture, but first read and follow all installation instructions.
Q. I purchased a home with a large wooden deck that has become an expensive maintenance nightmare over the years. The flooring is twisted with large cracks to the wood, and the railing is loose and dangerous. I plan on removing all of the old deck and replacing it to its original design. Are there any tips you can give me before I take on such an expensive project?
A. First, take a lot of photos of the original deck for future reference. Measure the deck’s width, length and height from the ground and take all the information to an architect so the new deck can be designed to meet modern code and safety requirements.
The most important thing is the attachment of the wood deck to the home’s structure. The last major defect I discovered on a new home with an exceptionally large deck was the placement of bolts, which secured the deck’s ledger board to the home’s structure. A ledger board is attached to the exterior of the home and then the floor joists are attached to the ledger board using joist hangers. Normally, a 2- by 10-inch board is used for the ledger and the bolts are set every 16 inches near the bottom and at the center of the ledger.
But on the home I inspected, the bolts were set approximately 1 inch from the top of the ledger. All the weight of this deck was now being supported by a 3/4-inch piece of lumber — which would eventually shear along the grain of the wood, causing the deck to fail. Make sure the weight of the deck is properly supported to the main structure of the home and support posts are no more than 6 feet apart.
Why is this so important? There are many people injured, some fatally, every year from deck collapses. Make sure your deck meets or exceeds all local and state code requirements.
For the support posts, I prefer to pour a footing for each post and use a metal support on top of the footing to keep the posts above grade. If a post is damaged, it can be easily replaced if it is not buried in the concrete footing. It’s important that you use the proper fasteners for the metal joist hangers and post bolts. Common house and roofing nails cannot be used on the hangers and posts, as the treated wood will eventually corrode the fasteners.
Stainless-steel or polymer-coated fasteners would be my choice to ensure the safety of the deck, but they will cost you more than the more popular hot-dip zinc-galvanized hangers and fasteners. Be careful not to mix the different products, as this might start a chemical reaction leading to corrosion and possible failure of the lesser material. I found a lot of helpful information on fasteners and suppliers at www.deckmagazine.com/article/209.html.
Another major problem I often find concerns the width of the handrail on the deck’s stairs. Installers often use a standard 2- by 4-inch or a flat 1- by 6-inch board for the handrail, but neither of these is safe. If you can’t grip the handrail on both sides, then you can’t stop your fall if you fall or trip on the steps. Information on the proper sizing of handrails can be found at en.wikipedia.org/wiki/Handrail.
Ÿ Dwight Barnett is a certified master inspector with the American Society of Home Inspectors. Write to him with home improvement questions at d.Barnett@insightbb.com.
Scripps Howard News Service