Some roofs need a repair.
Some roofs are basically asking for retirement.
This flat roof in Millbrae, CA had an older tar and gravel roofing system that had done its job for many years, but it was time for something new.
The plan was straightforward:
Remove the old tar and gravel roof, take everything down to the roof deck, repair what we found underneath, install a new asphalt torch down roofing system, and finish the project with custom aluminum gutters made right at the property.
Sounds simple when you put it in one sentence.
The actual process is a little more interesting.
First, We Had to See What Was Hiding Under the Old Roof
The first step in a complete flat roof replacement is not adding anything.
It is removing.
We stripped off the existing tar and gravel roofing material and worked our way down to the original roof sheathing.
Once that old roofing system came off, we could finally see the condition of the structure underneath.
This is the stage homeowners rarely get to see.
The roof looks rough because it is supposed to.
Old nails, roofing residue, previous connections and worn material all have to be removed before you can start building the new roof properly.
We cleaned the roof deck and removed the old flashing, roof jacks, pipes and metal components that needed replacement.
And this is exactly why we do not like simply covering an old roof and pretending everything underneath is fine.
Sometimes the roof has a surprise waiting for you.
Opening the Roof Means Finding the Real Problems
Once the old material was removed, we inspected the wood underneath.
If we find damaged or deteriorated decking, it gets repaired before the new roofing system goes down.
You can actually see this stage around the chimney, where part of the old deck required attention.
Fresh wood in the middle of an old roof may not look exciting, but this is one of the most important parts of the job.
A new roof needs a solid foundation.
There is no point installing premium roofing material over weak wood and hoping nobody notices.
The roof definitely notices.
Usually during the first serious rain.
Building the New Roof From the Bottom Up
Once the deck was cleaned, repaired and ready, we could start installing the new roofing system.
The first roofing layer creates the base for the finished membrane.
This black material you see in the photos is part of that preparation.
Instead of jumping straight to the finished surface, the roof is built in layers.
That is important on a flat or low-slope roof because the system needs to work as one continuous waterproof assembly.
The crew carefully rolled the material into place across the roof deck.
Then came the part everyone recognizes.
The torch.
Why Is It Called a Torch Down Roof?
For this project we installed a CertainTeed Flintlastic granulated modified bitumen roofing system, commonly known as a torch down roof.
The name comes from the installation process.
The modified bitumen membrane is carefully heated while it is rolled onto the prepared roof surface, creating a strong bond with the layer below.
And yes, it looks pretty dramatic while it is happening.
You can see the crew working section by section, heating and installing the membrane.
This is not simply rolling material onto the roof.
The installer has to control the heat, alignment and overlap of each section so the finished membrane becomes one continuous roofing system.
Why Torch Down Roofing Works Well on Flat Roofs
Flat roofs are different from traditional sloped roofs.
A steep roof quickly sheds rainwater.
A flat or low-slope roof has to manage water much more carefully.
That is why the roofing material, seams, flashing, drainage and roof penetrations all matter so much.
A modified bitumen torch down system provides a durable roofing membrane designed specifically for this kind of application.
The finished granulated surface also gives the roof a clean, uniform appearance.
And after seeing what the roof looked like during demolition, the transformation is pretty satisfying.
The Details Around the Chimney Matter
The middle of a roof usually gets all the attention.
But many roof leaks actually start around something that interrupts the roofing surface.
A chimney.
A vent.
A pipe.
A skylight.
A roof jack.
Anywhere the roofing membrane has to meet another material deserves extra attention.
The chimney on this Millbrae home is a perfect example.
After repairing the surrounding deck, we installed the new roofing membrane and completed the flashing around the chimney.
That metal flashing is not there for decoration.
It creates the transition between the brick chimney and the roofing system so water cannot simply run into the joint between them.
These are the details that often determine whether a roof performs well for years or starts causing trouble much sooner.
And Then the Roof Started Looking Like a Roof Again
After demolition, repairs, base material and torch down installation, we finally reached the stage everyone likes to see.
The finished roof.
Clean surface.
Finished seams.
New roof penetrations.
Completed flashing.
No gravel.
No exposed deck.
No demolition mess.
Just a new roofing system.
That is the nice thing about a good roof.
Once the work is finished, it almost looks boring.
Exactly how a roof should look.
