Roof Decking Information
How long has it been since you have taken time to check out the plywood or OSB decking on your roof?
Often damage to the roof decking on a home can go unnoticed because it is not visible. Damage could be caused by shingles being blown off allowing water to be absorbed into the wood decking.
There may be rotting, swelling, or cracking. You may have even had your shingles replaced a few times on your home but never questioned whether or not the plywood or OSB decking needed to be replaced. However the decking on your roof is very important to the structure of your home.
Plywood and OSB Decking
What is the difference in plywood and OSB. Plywood is several thin layers of wood glued and pressed together to form a single 4’X8’ sheet of wood. OSB (oriented strand board ) is similar to particle board. It is an engineered wood formed by adding adhesives and then compressing layers of wood strands in orientations ( formed and cut into 4’X8’ sheets ).
Plywood boasts of being stronger and smoother for decking roofs. When it comes to a wet test, plywood can get wet and the plys will come unglued and cause problems. Whereas, OSB is more cost effective compared to plywood, but when OSB gets wet the stands tend to swell and it weakens the board. They both have pros and cons for the homeowner.
Replacing Your Decking
To keep your home in tip top condition your roof decking should be changed each third or fourth time you have new shingles installed, or when you notice damage or rotting on or in the plywood or OSB. In certain parts of the country severe thunder storms with large hail occur regularly each year. Which means many homes may have hail or wind damage bad enough that the shingles have to be replaced regularly as well.
One of our customers had to replace his shingles four times in less than ten years. The amount of damage inflicted by the roofing nails after new shingles were installed several times left the decking inferior and substandard. Needless to say his roof decking no longer had the integrity left for another re-roof.
Be Careful on Inspections
Taking a walk on your roof can be a good way to tell if decking needs to be replaced. Always use caution and don’t take chances. Because of how steep the pitch is on some roofs they are just too dangerous to try and walk on. In this case an experienced roofer should be called to do an inspection for you. But if it is safe, you can walk back and forth on the decking to see if it has a hard solid surface.
If on the other hand, if the decking feels either mushy or you can hear it cracking ( likely due to being old dry and brittle ) then it probably needs to be replaced. Or at least the compromised sheets need replacing.
Your home is probably the most expensive investment you’ll ever make. Make sure that investment is solid from top to bottom.