What to Put Between Bricks on a Patio: Best Options

The best thing to put between bricks on a patio is polymeric jointing sand. If you're comparing options, the most common choices are polymeric jointing sand and regular jointing sand, and the right pick depends on your climate and how permeable you want the patio to be what to put between patio stones. It sweeps into the joints, hardens when you wet it, and holds together through rain, freeze-thaw cycles, and foot traffic far better than plain sand. For the layer under the bricks, you want a compacted gravel base (typically 4 to 6 inches deep) with a 1-inch screeded bedding sand layer on top. Get both of those right and you'll have a patio that stays level, drains properly, and doesn't turn into a weed garden by summer.

What the joint filler actually does

The material between your bricks isn't decorative filler. It's doing three real jobs at the same time. First, it locks the bricks together so they can't shift sideways under foot traffic or frost heave. Second, it controls weed growth by closing off the gaps where seeds germinate. Third, it manages drainage by letting water pass through or around the joints without washing the filler out. Skip this layer entirely and your bricks will creep, rock, and become a raised-bed garden within a season or two. If you skip this layer, the pavers can shift and settle, so it's a good comparison point to also review what to put between patio slabs for other joint-filler decisions.

The joint layer also protects the bedding sand underneath. If water channels through open joints and into the bedding layer, it destabilizes the whole surface. That's why joint depth matters so much: the fill needs to go all the way down to close off that pathway, not just sit on top.

The best materials for between patio bricks

You have a few real options here. Each one suits a different situation, so it's worth understanding the trade-offs before you buy a bag.

Polymeric jointing sand: the go-to choice

Polymeric sand is a polymer-modified graded sand designed to fill joints up to 2 inches wide. Brands like Techniseal, SEK Surebond PolySweep, and Quikrete HardScapes all work on the same principle: sweep the dry sand into the joints, compact the pavers, then mist the surface with water to activate the polymer binders. Once cured, the joint holds together rather than washing out the next time it rains. The polymer binders also expand and contract with temperature extremes, which is why it handles freeze-thaw cycles far better than plain sand. If you're in a climate with cold winters, this is the only material I'd seriously recommend.

Regular jointing sand: where it still makes sense

Plain sharp sand (conforming to ASTM C-144 gradation) is cheaper and easier to apply, and it's still a reasonable choice in a few scenarios: very dry climates with minimal rain, patios with intentionally wide joints meant to stay permeable, or situations where you're doing a quick temporary fix before a full reinstall. Plain sharp sand (conforming to ASTM C-144 gradation) is cheaper and easier to apply, and it's still a reasonable choice in a few scenarios: very dry climates with minimal rain, patios with intentionally wide joints meant to stay permeable, or situations where you're doing a quick temporary fix before a full reinstall regular jointing sand. The honest downside is that it migrates. Any surface runoff will gradually pull it out of the joints, and weeds will find their way in within a season or two. If you go this route, plan to top up the joints every spring.

When to consider alternatives

Stone dust and decomposed granite show up in a lot of DIY projects because they're inexpensive and easy to source. They can look good initially, but in wet climates they compact poorly, drain inconsistently, and tend to heave in frost. Save them for dry-climate informal patios or garden path bricks where movement isn't a big deal. For a proper patio with regular foot traffic, stick with polymeric sand. For a proper patio with regular foot traffic, stick with polymeric sand, and if you are trying to replace patio slabs with an easier or more forgiving option, consider other paving alternatives too like what can i use instead of patio slabs.

How to install joint filler correctly

Getting this right isn't complicated, but the order of steps matters. I've seen plenty of patios where someone skipped the compaction step or wet the sand too aggressively and ended up with a chalky haze on the brick surface or joints that crumbled after the first hard rain. Follow these steps and you'll avoid the most common mistakes.

1. Make sure the pavers are completely dry before you start. Never sweep polymeric sand over damp bricks. Moisture on the surface causes the polymer to activate prematurely, leaving a residue that's difficult to remove.
2. Sweep a dry load of polymeric sand across the surface and work it into the joints with a push broom. The goal is to fill every joint completely down to its full depth. Minimum fill depth is around 1.5 inches (4 cm) according to Techniseal's specs.
3. Run a plate compactor over the patio (or use a rubber mallet on smaller areas). This settles the sand deeper into the joints and locks the bricks more firmly in place.
4. Sweep a second round of dry sand across the surface to top up any joints that settled during compaction. Keep doing this until joints are filled to within 1/8 inch (3 mm) below the top of the paver surface or just below the chamfer. Do not fill flush to the top.
5. Use a leaf blower on low to remove all excess sand from the paver surface. Any sand left sitting on top of the bricks will bond there during activation and create a hazy film.
6. Mist the entire surface with water using a gentle spray. You want moisture penetrating to the bottom of the joints, not a hard stream that washes the sand out. SEK Surebond describes the right amount as water that 'just starts to slightly sit on top of the joint.' If it's pooling, back off.
7. Allow the joints to cure fully, typically 24 to 48 hours depending on temperature and humidity. Do not apply during temperatures below 32°F (0°C) or if rain is expected within an hour.

Edge restraints are part of this process too, not an afterthought. Plastic or steel edging secured with non-galvanized metal spikes into the base holds the perimeter bricks in place so the joint sand doesn't get undermined from the outside. Unilock recommends positioning the restraint about 1/2 inch below the top of the pavers. Without edging, the outer bricks gradually migrate outward under foot traffic and the whole surface loses its tight jointing over time.

What goes under the bricks: your base build-up

The joint filler only works if the bricks are sitting on a stable, properly drained base. If you want stable support, use the right base layers and consider what to lay under patio slabs before you start installing the joints. A common cause of joint failure isn't the joint material at all: it's a base that shifts, compresses unevenly, or holds water. The good news is that a correct base isn't complicated. It's just a few layers done in the right order.

The standard base build-up

1. Excavate the area to a depth that accommodates your base layers plus the brick thickness, typically 8 to 12 inches total below finished grade.
2. Compact the native subgrade soil. If it's soft, wet, or clay-heavy, this is where you consider laying a geotextile separation fabric. The fabric keeps the compacted gravel base from mixing with fine-grained soil below, which is especially important in wet climates where frost can push moisture upward.
3. Spread and compact a gravel base layer (crushed stone, not round pea gravel). For a residential foot-traffic patio, 4 inches is a common minimum; go 6 inches in freeze-thaw climates or on soft subgrades. Compact in 2-inch lifts if you're building up a deep layer.
4. Slope the base at least 2% away from any structure (house, wall, retaining feature) so water drains outward rather than pooling under the bricks.
5. Spread a 1-inch (25 mm) layer of clean coarse bedding sand over the compacted base and screed it level. ICPI guidance specifies this layer should not exceed 1.5 inches (40 mm); thicker bedding sand compresses unevenly under load.
6. Lay bricks on top of the screeded bedding sand without disturbing it. Use kneeling boards if you need to work across the surface.

One thing worth noting: the bedding sand layer and the jointing sand layer are two different materials with two different jobs. Bedding sand supports the bricks from below; jointing sand locks them laterally. Don't confuse them or try to consolidate them into one step.

If you're also thinking through what to lay under other patio surfaces, the same base logic applies across most types, whether you're working with stone, porcelain, or concrete slabs. The specific materials and depths shift a little depending on the surface, but stable compacted base plus adequate drainage is the constant.

Troubleshooting: weeds, washout, settling, and pooling

Even well-installed patios run into problems over time, usually from one of four causes. Here's how to diagnose and fix each one.

Weeds growing through the joints

Weeds in brick joints almost always mean the joints weren't filled to full depth, or the original filler was plain sand and has since migrated out. The fix is to clear the existing joint material (a flat screwdriver or oscillating tool works), clean out any debris, let everything dry thoroughly, and reinstall polymeric sand from scratch. Techniseal specifically notes that for restoration projects you need to empty the joints first before refilling, and that minimum fill depth applies just as strictly to repairs as to new installs. A pre-emergent weed treatment over the patio before you refill can help knock back whatever's already germinating.

Joint sand washing out after rain

Washout is usually one of three things: the polymeric sand was wet-activated with too strong a stream and the polymer didn't have time to bond before getting displaced; it rained within an hour of activation; or the bricks themselves were damp during application. All three prevent the polymer from curing properly. The solution is the same as for weeds: remove remaining material, wait for dry conditions, and reinstall correctly. If your drainage slope is also pushing water across the surface in volume, check that your 2% crossfall is actually directing runoff away from the patio rather than across it.

Uneven settling or rocking bricks

Isolated rocking bricks usually point to a bedding sand problem, not a joint filler problem. Common causes are bedding sand that was too thick (over 1.5 inches), base gravel that wasn't compacted in lifts, or a soft spot in the subgrade underneath. To fix it, pull the affected bricks, remove and rescreen the bedding sand to a level 1-inch depth, and relay. If the issue is widespread rather than isolated, the base itself may need to be rebuilt.

Water pooling on or near the patio

Pooling water usually means either the crossfall is wrong (less than 2%) or the base isn't draining effectively. Check whether the perimeter has adequate drainage and whether there's anywhere for the water to go. For patios built against a house wall, weep holes in the edging or perimeter border (at least 1-inch diameter, spaced roughly every 10 feet) covered with geotextile can help relieve pressure and let water escape without washing bedding sand out. If you're dealing with a chronic drainage problem, sometimes the right answer is converting to a permeable design with open-graded base and appropriate jointing stone rather than fighting it with a conventional build.

Keeping it in shape: your maintenance schedule

A well-installed polymeric sand patio doesn't need constant attention, but a little annual maintenance goes a long way toward preventing the big repairs.

Sealing is optional but genuinely useful if you have colored or textured bricks you want to keep looking sharp. It doesn't replace good jointing: the joint needs to be solid before you seal over it. Sealing a degraded joint just traps moisture and makes the repair harder later.

Your action plan right now

If you're starting fresh: build your base with 4 to 6 inches of compacted gravel, a 1-inch screeded bedding sand layer, proper edge restraints, and polymeric jointing sand filled to within 1/8 inch of the paver surface. When planning a patio fire pit, use the same kind of stable, well-drained base and jointing approach so the pavers or slabs stay level and don’t shift over time what to put under fire pit on patio. Activate it correctly on a dry day above 32°F and give it 48 hours before heavy use.

If you're repairing an existing patio: assess whether the problem is in the joints (weeds, washout) or the base (settling, rocking). Joint problems are a dry-day weekend fix with a bag of polymeric sand. Base problems need the bricks pulled and the base rebuilt properly. Don't just fill over a bad base hoping it holds.

Either way, &lt;a data-article-id=&quot;3CB02D73-25D2-4EC5-AA6F-F39A44838EE7&quot;&gt;&lt;a data-article-id=&quot;642C29A1-7ED9-41C3-BF56-3335AE18A8CE&quot;&gt;polymeric sand</a></a> is the right material for most homeowners in most climates. It costs more than a bag of regular sand, but it lasts years longer and saves you the frustration of redoing the same joints every spring. Buy a quality brand, follow the installation steps exactly, and you're done.