If your patio starts to look like a weedy mess or your pavers shift every time it rains, chances are your joint filler isn’t doing its job. And in Central PA — where freeze-thaw cycles, heavy rains, and backyard barbecue foot-traffic all take a toll — using the wrong joint material is a shortcut to disappointment.
The Quick Version
If you want your paver patio to last, make sure your patio installer isn’t using the cheap stuff. GFTK (which comes from a German manufacturer) is hands-down the best patio paver joint filler for Central PA patios, especially for wide flagstone gaps, heavy foot traffic, and pressure-washed surfaces. It costs a little more upfront, but saves big in rework and frustration.
Why Joint Filler Matters (A Lot More Than You Think)
Joint filler is the stuff that fills the small gaps between flagstone or pavers on your patio. It keeps everything locked in place, controls weed growth, and prevents erosion every time it storms. If you’ve ever seen a patio where the jointing sand washed out and left behind a mess of loose stone and grass or weed sprouts, you know the headache.
In areas like Chambersburg and Shippensburg, where winters are cold and wet, your joint material has to hold up through freeze-thaw cycles, spring cleanups, and the occasional overenthusiastic power wash. A poorly filled joint lets weeds take over and undermines your entire patio.
Common Options And Where They Fall Short
1. Standard Sand: Cheap, and It Shows
You’ll find basic sand on a lot of patios because it’s affordable and easy. But it erodes fast, especially if your joints are wide or your patio gets cleaned regularly. It doesn’t fill joints tightly and can’t handle heavy foot traffic. Not great for long-term results.
2. Polymeric Sand: Better, But Not Bulletproof
This sand is mixed with bonding agents that harden when wet, giving more durability. It works fine in tighter joints, like those between brick pavers or concrete pavers. But throw in wide flagstone gaps or pressure washing, and polymeric sand starts to crumble. Some poly sand formulas also struggle in colder climates like ours.
3. GFTK Joint Compound: The One That’s Worth the Hype
This stuff is in a different league. The best patio contractors in Central PA are using GFTK because it lasts, holds up under pressure, and meets drainage codes. It’s permeable, meaning water flows through instead of pooling. It also resists weed growth better than anything else out there.
GFTK stands for “Gesellschaft für technische Kunststoffe”, which translates from German as “Company for Technical Plastics.
Bonus: GFTK is strong enough for pool decks and patios that get a lot of foot traffic, but flexible enough to move with temperature changes.
One catch: GFTK is not something to mess with if you’re a first-timer. It’s finicky to install and absolutely unforgiving if you skip prep work.
The Best Filler Depends on Your Patio Style
Patio Paver Joint Filler
If you’re working with interlocking concrete pavers or brick pavers, you’ll want a product that creates a tight bond and handles movement. Poly sand is okay for lighter-use patios, but if you expect pressure washing or a lot of traffic, GFTK is the safer bet.
Flagstone Patio Joint Filler
Flagstone patios have wider seams, and that means sand just won’t cut it. GFTK works especially well here, often combined with a crushed stone base or quarter inch chips to help with drainage. It’s also more durable than any standard jointing sand.
Concrete Patio Joint Filler
For patios made with poured concrete slabs, the focus is on expansion joints and filling cracks. GFTK can do both and stay intact during freeze-thaw cycles. You won’t get that from typical polymeric sand or concrete sand.
What Else You Might Consider But Probably Shouldn’t
- Concrete sand: Good for the sand layer underneath pavers, not so much for surface joints
- Mortar mix: It’s permanent, hard to fix, and prone to cracking
- Loose gravel or crushed stone: It looks rustic but doesn’t stop weeds unless you’re constantly maintaining it
What to Get Right Before You Even Add the Filler
Before you even think about pouring joint compound, base material and your prep work are critical. This is what goes BELOW your patio to keep pavers and blocks from shifting over time. As paver patio installers in the Shippensburg area, we always
- Compact your paver base with a plate compactor
- Use geotextile fabric to keep weeds and soil from pushing up
- Slope your entire patio away from the house or pool deck for drainage
- Use a straight edge and string line to keep things even
- Cut pavers cleanly using a wet saw or diamond blade
- Make sure all the pavers are level before installing filler
If you skimp on prep work, even the best joint material won’t save your new patio from falling apart.
Why GFTK Is Taking Over Central PA Patios
Installers in places like Carlisle, Greencastle, and Waynesboro are moving away from poly sand and toward GFTK. It’s already the go-to for high-end outdoor spaces where appearance and longevity both matter. Local townships like it too: the permeable rating helps with runoff regulations. Plus, GFTK fills joints of all sizes and performs well in colder climates.
And word’s spreading. While we’ve been using GFTK for years, we’re now seeing competitors promoting it all over Facebook, which means it’s working!
Should You DIY or Call in the Pros?
Short answer: If you’re using standard sand, sure — go for it. But if you’re working with GFTK or laying down a whole patio project with tight specs and lots of square footage, a professional patio company is worth every penny.
Installers bring tools you probably don’t have, like a plate compactor, a skid steer for gravel base work, and years of experience using materials like rubber mallets, string lines, and jointing sand that doesn’t crumble when it counts. You’ll get a clean finish on all the pavers and avoid weed growth later.
So, What’s the Best Joint Filler For Your Central PA Patio?
If you want your own patio to stay put, shed water, and look good without weekly maintenance, GFTK is your best bet.
Just don’t wing the install. Ask your hardscaping contractor about your joint width, paver material, sand layer, and base setup. That way, you won’t end up redoing the whole patio a year from now.
Want a patio that stays rock solid and weed-free? We help homeowners across Central PA pick the right joint filler, prep the base properly, and finish the job right, from the plastic edging to the final compaction.
Reach out today and let’s make this one stick!
P.S. We do traditional landscaping and even stamped concrete patios too!
