Screw-Set vs. Foam-Adhesive Tile: The Florida Difference Most Homeowners Miss

If you're shopping contractors for a tile roof in Florida, here's a nuance most homeowners never hear about — and it can be the difference between a roof that lasts and one that leaks. It comes down to how the tile is actually held down to your roof.

The screw-set shortcut

A lot of roofers in Florida default to a screw-set system when installing tile. It's the cheaper way to go because it's fast and screws are cheap. The problem is what happens once the roof is on.

On most roofs, water will inevitably get under the tiles and run down the underlayment. When that water hits a screw, and it happens enough times over the years, it will eventually leak right where the screw punches through the underlayment and into the decking.

Where the water finds the screws

Now, if you've got an all-hip roof, water has a harder time getting under the tile in the first place, so you've got a bit more margin. But most tile roofs in Florida use off-ridge vents, and that is always a spot where water finds its way under the tile — usually a substantial amount of it. Over time, that's what causes the leak.

The alternative: foam adhesive

Foam adhesive-set systems use products like Tile Bond. The tile is glued down to the deck and at the laps — tile to tile — so there are no unnecessary penetrations through your brand-new underlayment.

That adhesive at the laps does something else important: it greatly improves wind uplift resistance, because the tiles are bonded directly to each other at the exact spot where wind could otherwise get in and under the tile during a storm.

And if water does get under the tile with a foam-adhesive system, it simply runs out under the tile to the eave and off the roof — no screw to punch through, no damage done.

To be fair to screw-set roofers

It's not always a corner being cut. Above a 6/12 pitch, you typically can't install tile with adhesive — it's too steep and can create its own issues. So on steeper roofs, extra steps have to be taken to keep water from getting under the tile, and screws, or even battens, may be required.

That's where specialized flashing comes in. Wall tray and captive valleys can be used to keep water from getting under the tile in the first place, or to hold it in the valley metal so it stays away from the screws. Done right, a steep screw-set roof can absolutely be done well.

The catch is that these are exactly the steps some roofers will quietly skip to come in at a lower price and win the job.

What this means when you're shopping contractors

Most homeowners don't know any of this, so they just see the cheaper price and figure a roof's a roof's a roof. But not all roofs are the same, just as not every car is the same. You get what you pay for.

Here's how to use it. These extra steps — adhesive set, the right flashing — are often offered as upgrades at an additional cost, and they tend to be high-profit items for roofing companies. It may not cost them much extra, but they charge a premium for it. That makes them a good negotiating tool. You may be able to get a contractor to throw in adhesive set or upgraded flashing at no extra cost if you sign up, since the margin is there for them to give.

So before you sign anything, ask how your tile is being held down, and ask what's being done at the vents and valleys to keep water away from any penetrations. The answer tells you a lot about whether you're getting a roof built to last — or just the cheapest version of one.