People are always curious about this. You have 20 or 25 years of shingles, underlayment, and nails on top of your house, and then one morning a crew shows up and it is all gone by lunch. So where does it go, and what are we actually doing up there during tear-off?
Why do you tear off to the decking rather than roof over?
We do not roof over existing shingles. Some companies will offer this, and yes, it is technically allowed by code in some cases for a second layer. But I have never been a fan of it, and here is why.
When you roof over an existing layer, you cannot inspect the decking underneath. You cannot see rot, soft spots, or damage that has been sitting there for years. You cannot install ice and water shield properly. You are adding significant weight to the roof structure. On top of that, the new shingles never lay as flat or seal as well over a bumpy old layer. It shortens the life of your new roof before it even gets started.
So we tear off to the decking. Every shingle, every piece of old underlayment, every nail. The decking gets cleaned down to bare wood.
What are you looking for under the old roof?
This is one of the most important parts of the whole job, and it is something you never see from the ground. Once the old roof is off, we walk every inch of that decking looking for problems.
Rotted wood. Water that got through the old roof over the years may have damaged the plywood or OSB decking. Rotted wood is soft, dark, and sometimes you can push a finger right through it. Any section of rotted decking gets cut out and replaced with new material. You cannot install a new roof on bad wood.
Soft spots. Sometimes the wood is not fully rotted but has been weakened by moisture. We check for flex and softness by walking the deck. If it does not feel solid, it gets replaced.
Previous poor repairs. You would be amazed at what we find under old roofs. Patches of mismatched plywood, tar slathered over cracks, sections where previous roofers cut corners. All of that gets fixed properly during a replacement.
Ventilation issues. Once the deck is exposed, we can see the attic ventilation system clearly. If the ventilation is inadequate or blocked, this is the time to address it before the new roof goes on.
"You would be amazed at what we find under old roofs. This is why full tear-offs matter."
Where does the old material go?
Everything goes into the dumpster in your driveway. Old shingles are heavy. A typical residential tear-off generates somewhere between two and five tons of material, depending on the size of the roof and whether there was one or two existing layers.
The dumpster company hauls it to a landfill or a recycling facility. Asphalt shingles are recyclable in many areas and get ground up for use in road paving. It is not a perfect solution, but it is better than it used to be.
Starting completely clean
Once the tear-off is done and any bad decking is replaced, you have a clean, solid wood surface ready for the new system. Every layer from here on is fresh and installed to current standards.
This is one of the reasons I believe in full tear-offs. You are not covering up old problems and hoping they do not cause trouble. You are starting completely clean with nothing hiding underneath. After nearly 40 years of pulling off old roofs, I have learned that what is hidden underneath matters just as much as what you can see from the street.
Have questions about your roof? We offer free roof assessments across Northern Utah. We will take a look, tell you what we see, and give you an honest recommendation. No pressure, no obligation. Schedule online or call (801) 544-5125.
"The experience with Bob Harvey Roofing was great from start to finish. They were very punctual and did a super job, even going above our expectations. So difficult to get good service sometimes nowadays."Celia Rose , Google Review