Wood Dry Rot
Dry rot is a fungus that infests wood which is continuously in contact with water. Learn to recognize and repair dry rot.
Dry rot is a fungus that infests wood that is continuously in contact with water. Even though at times this fungus is visible, in most cases it is recognized when a wood surface turns brown and crumbly or white and spongy. When wood that has dry rot is probed with an ice pick or small screwdriver it will easily yield or sound hollow when tapped with a hammer. It is imperative when you find dry rot that you replace or repair it quickly so the fungus will not spread.
If you are unsure if you have dry rot in your home you can start by checking near any wet plumbing in your basement. Check any area inside or outside your home where wood is touching the soil or exposed to weather. Since the dry rot fungus usually enters at the end grain or base of a foundation post, if possible check this and the area where the window frames butt against the sill, as well as other such areas. When you reach the windward side of your house pay special attention. Wind tends to force rainwater deep into any joint or crack. If you see flaking paint or a discoloration in the paint you are seeing the first symptoms of dry rot. If you find structural damage due to dry rot you will need to call a professional.
Windowsills, doorframes, porch rails and siding are areas you might be able to fix yourself. To being you will need to cut away the affected area plus six inches on either side. Then you can splice in fresh wood. Generally it is better if you replace the whole piece to insure that all the dry rot fungus is gone. To replace a whole piece that is infected with dry rot, carefully pry the old part away trying to keep it intact, if possible, to use as a template. Thoroughly check the area beneath the wood to be sure it is not infected and then make or buy a new piece to replace the old one.
When the area that the dry rot has infected is small you can often make a repair with epoxy resin. This product is available at most hardware and boating supply stores. To use the resin you will need to drill several 1\4 inch holes deep into the affected wood. Be careful not to go completely through the wood when doing this. Mix the two parts of the resin in a plastic squeeze bottle and inject it slowly into the holes. Within the next few days the resin will seep into the pores of the wood and replace the decayed wood with plastic. As the first dose of resin soaks in, continue adding resin and then finish with an epoxy filler. If you notice any sagging floors in your home this could be caused by dry rot fungus that has caused structural damage. If the sagging is extremely bad or appears to involve the foundation or central girder you will need to call an engineer. In a case where the floor just feels bouncy you may need extra bridging. The bridges under your home are the diagonal braces between the joists. Check this and nail any loose bridging back in place. Then install solid wood blocking using lumber that is the same size as the joists. You should apply construction adhesive to each joint and stagger the pieces so you can nail into them through the joist.
A good way to prevent dry rot is to get rid of any standing water around the outside of your house. Any excessive rain water or run off that is standing around the outside of your house will leak into the basement or cause excess moisture at the base of your house. If you often see water that just doesn't seem to go away near or around your house you should talk to your local public works department about connecting the main down spout from your roof to a municipal storm sewer. When this is not possible you will need to connect to a dry well. A dry well is simple to construct using a 55 gallon oil drum or concrete blocks. Try to locate the well at least 20 feet away from your home. It will also need to be lower than the surface around the house and connected to the main down spout. To construct a dry well from a 55 gallon oil drum you should butt one of the ends with a hammer and cold chisel. Make an opening on one side near the top for an inlet and punch holes in the sides for drainage. Be sure when you position the drum that the inlet opening is facing your house.