Renewing Paving Joints: Make Your Driveway Look New Again
Scrape out old joints, clean and permanently refill – with sand or joint mortar
Disclaimer
This guide has been prepared with great care. Nevertheless, we accept no warranty for the accuracy, completeness or currency of its contents. You follow this guide at your own risk – any liability for personal injury, property damage or financial loss arising in connection with its use is excluded. The contents do not replace professional advice for your individual situation. Always observe the manufacturer instructions of your tools and materials as well as applicable local regulations (e.g. building codes, neighbour law, utility line enquiries before digging). Work on electrical, gas or water lines and on load-bearing structures must only be carried out by qualified professionals.
Scrape out old joints, clean and permanently refill – with sand or joint mortar
Paving joints play a structural role: they hold the stones in place and drain rainwater. Over the years, rain washes out the joint sand, weeds settle in, and individual stones start to rock. Renewing the joints is a rewarding DIY job – it takes more patience than expertise and visibly upgrades the whole surface. We show the two common approaches: classic joint sand for a flexible joint, and polymer joint mortar for a firm, weed-inhibiting joint.
Tools
- Joint scraper or old screwdriver
- Pressure washer (used carefully) or wire brush
- Stiff broom
- Rubber squeegee or water sprayer
- Knee pad
Materials
- Joint sand (washed quartz sand 0–2 mm) or polymer joint mortar
- Water
Step by Step
Scrape out the old joints
Scrape out weeds, moss and the old, dirty joint sand at least 2–3 cm deep. A joint scraper with a carbide blade helps with heavily encrusted joints. The cleaner the joint, the better the new material holds.
Clean the surface thoroughly
Sweep or rinse off the loosened dirt. A pressure washer is fine, but work with a flat-jet nozzle and keep your distance – a hard point jet washes out the bedding layer under the stones and damages the stone surface.
Choose your material: sand or mortar
Joint sand is cheap, flexible and right for all unbound paving – but needs topping up every few years. Polymer joint mortar cures hard, inhibits weeds and withstands pressure-washer cleaning – but requires stable joints and a permeable sub-base. For driveways with car traffic, always check the manufacturer’s approval.
Fill the joints
Joint sand: spread dry and sweep in diagonally to the joints until they are full; then water, top up, done. Polymer mortar: pre-wet the surface, slurry the mortar in wet and work it in diagonally with the squeegee, carefully sweeping off residue before it cures.
Follow-up and protection
With sand joints, top up once or twice after the first heavy rains until the joint has settled. Depending on the manufacturer, do not walk on mortar joints for 24–48 hours and protect them from rain. Re-bed any rocking or sunken stones in the grit bed before jointing.
Safety First
- Wear safety glasses when using a pressure washer – loosened sand and stone particles fly uncontrollably.
- Polymer joint mortar can irritate the skin: wear gloves and observe the manufacturer’s instructions.
- Use a knee pad for longer periods of kneeling work.
Mistakes You Should Avoid
Pointing the jet into the joints
The most common damage: the pressure washer flushes out not just the joint sand but the bedding material under the stones. The surface then subsides. Always work with a flat jet at a shallow angle.
Using play sand as joint sand
Round, unwashed sand has no grain interlock and is washed out again with the first rain. Washed, crushed quartz sand or dedicated joint sand lasts much longer.
Polymer mortar on a sealed sub-base
Polymer mortar needs water to drain downwards. On a compacted, impermeable sub-base, water backs up in the joint – frost damage is inevitable.
Common Questions
Which joint sand is the right one?
Washed quartz sand with crushed grain in 0–2 mm is the standard for joints up to approx. 5 mm; for wider joints use 0–4 mm or a crushed-sand/grit mixture. Important: no round play sand.
What does re-jointing a paved area cost?
DIY material costs are roughly €1–3/m² with joint sand and €8–15/m² with polymer mortar. Done professionally, labour of roughly €15–40/m² is added depending on the condition of the surface.
How do I permanently prevent weeds in the joints?
With sand joints you cannot prevent them completely – seeds blow in and germinate in the joint dust. You can reduce them considerably with polymer mortar, regular sweeping and thermal treatment (flame device, hot water). Note that herbicides on paved surfaces are generally prohibited in Germany.
Can I use joint mortar on a driveway used by cars?
Only products explicitly approved for car traffic, and only on an intact, load-bearing sub-base. If stones shift or rock, any rigid joint will crack – the sub-base must be fixed first.
When is a professional worth it?
If whole areas have subsided, stones rock across large sections or puddles form, the problem is not the joint but the sub-base – then only lifting and properly re-laying the affected area helps. We renovate paved surfaces of any size: from partial reconstruction with correct falls to complete re-laying including the load-bearing base course. That solves the problem for good instead of re-jointing every year.
