Dry rot, wet rot, damaged or rotted wood or plywood is one the biggest concerns and threats to wood structures here in America, I have run into some scary and tough situations and this is why I decided to write this article.
A couple of weeks ago we were installing a residential roofing system for one of our clients, very nice people in a nice middle class neighborhood. I gave them an estimate a few months back and once they decided that they wanted to move forward with the job they called me to let me know they were ready to move forward with the projects of replacing their asphalt roof, membrane flat roof and guttering systems. This particular homeowner worked for the local news paper so I wanted to make sure that everything would go ok with the job so she would not write a bad article about us for everybody to see! Ha, well, everything did go ok up until half way during the tear off, we started noticing that many of the sheets of plywood on the roof-deck were just too damaged to re-use them and the reason for this was because this house had no ventilation at all. The houses in this neighborhood were about 50 years old. Back then builders weren't too concern about the ventilation of the attic thru the roof or venting the attic at all. When I first went on the roof to measure it felt ok, but once all the shingles and roof underlayment were off we could see the extent of the damage. The reason for this particular case was because having no ventilation in the attic and the excessive heat of the summer days trapped in the attic damaged this 50 year old roof deck. The bonding adhesive holding the layers of plywood together started to fail, creating a delaminating process of the plywood, completely loosing it's strength.
If we were to install shingles back on this roof deck this client would've been calling us weeks later because they would probably have missing shingles all over the roof. The only reason why most of these shingles were in place was pretty much gravity. For me it is always very diffucult to tell clients "oh by the way, your bill just went up $500 or more from the original estimate" because now we had to replace 10 sheets of plywood or more. Nobody likes those type of surprises and us as their preferred contractor hate to give those surprises as well. As usual they were ok with us fixing it and were not upset at all, in fact (just like most homeowners) were happy to take care of the problem now rather than have to worry about it in the future.
Most of the time, existing damaged plywood on roof decks will have to be replaced, there's is not treatment but only replacement. Dry rot or wet rot sometimes will be present on roof trusses or flat roof structures, many times will be present under the houses or building structures. There is many other reason why this type of situations happen, and many times this could be preventable and even treatable.
There's a few different types of dry rot, wet rot or fungal decay, all of the will cause serious structural damage to your building, dry rot and wet rot cost millions of dollars all over the US every year , they both thrive in damp, warm unventilated conditions, so it's often found in areas that will not be visible, roof attics, the underside of wooden floors, trapped between walls and many other section were wood is present. Once the damage has been significant dry rot travels quickly, always on the lookout for more timber to feed on, sometimes even masonry and plaster/sheetrock can be affected as well. In some cases within a matter of months the entire structural integrity of a building can be compromised so it's vital to always be on the lookout or have a professional inspect your home/building if you suspect dry rot.
Symptoms may vary but some of the most obvious are softness or spongy wood, splitting, shrinking and crumbly areas, dark yellow patches, it has also a distinct smell of decay. If you can poke the wood with a screwdriver and if it sinks into the wood you know it's decaying. Treatment is difficult at this point but possible in some cases. You will need to get professional help for this. Whoever you choose they will have to get rid of the infected timber, always go a few extra feet in case some fungus spreaded, eliminate the source of water leak causing the dampness, you'll need to thoroughly ventilate the area using dehumidifiers and if possible apply some heat, the new wood applied for the repair or replacement will have to have some kind of treatment (fungicide) that your professional contractor should apply to avoid more spreading of the fungus.
Wet rot is a lot more common than dry rot, this type of fungus (cellar fungus) is only attracted to very damped wood and unlike dry rot, remains confined to the wet area only. They both have the some of the same symptoms and sometimes your structure can look perfect from the outside. If you have shingles or paint covering the damaged area you can always tell by stepping on it or poke it with a screw driver and you'll discover it's affected. Both dry rot and wet rot cause much damage and if preventable you'll save (in some cases) thousands of dollars if you act before it's too late.
Good luck and thanks for reading this . If you are in the Hampton Roads area and are looking for a Roofing Contractor in the Virginia Beach Area, Norfolk, Chesapeake, Suffolk, Hampton or Newport News please don't hesitate to call us, we will be glad to help.
J Montes Inc
Roofing Systems of Hampton Roads