How to lay granite setts

Inspired by a popular UK paving guide. This walk-through is based on the well-known video "HOW TO LAY COBBLES - Cobble Stone Top Tips!!", which covers the mix, the bedding technique, and the small things that make the difference between setts that stay level and ones that rock underfoot six months later.

1. Plan the area and order materials

Measure the area carefully and add ten percent for waste, cuts, and breakages. Granite setts are typically supplied in bulk bags or on pallets. For a garden path or driveway edging you will need: setts, sharp sand, cement, and kiln-dried jointing sand or a dry mortar mix for pointing.

If the area adjoins a house wall or drain, check the finished surface level leaves a gap below the damp-proof course. Typically 150mm is the minimum clearance.

2. Excavate to the right depth

For pedestrian use, dig down about 200mm from the finished surface level. That gives you roughly 100mm of compacted sub-base, 40mm of mortar bed, plus the depth of the sett itself - usually 50–100mm depending on which size you chose.

For a driveway with vehicle use, go deeper - typically 150mm of sub-base. Get the levels right at this stage. Correcting a sloping sub-base later is awkward.

3. Lay and compact the sub-base

Spread MOT Type 1 crushed stone to the excavated base and compact it in layers using a plate compactor. Hire one for the day if you are doing any reasonable area - tamping by hand does not get it properly consolidated and the surface will settle unevenly.

Check the sub-base is firm and sitting at the correct level before moving on. Any soft spots at this stage will show as sunken setts later.

4. Mix and lay the mortar bed

Mix a semi-dry mortar of roughly 4 parts sharp sand to 1 part cement - it should clump in your hand but not be wet. Spread it about 40mm deep and screed it off to a consistent level using a timber straight edge.

Do not mix more than you can lay in an hour. Semi-dry mortar firms up quickly, especially in warm weather, and setts pressed into stiff mortar do not bond properly.

5. Set the setts and check levels

Press each sett firmly into the mortar bed and tap it down with a rubber mallet. Keep a consistent joint gap - 8–12mm is typical. Use a spirit level and a straight edge to check levels constantly as you work. It is much easier to adjust a sett now than after the mortar has set.

Work from a fixed edge or string line so the pattern stays straight. If you are laying a fan or curved pattern, mark it out on the sub-base first before any mortar goes down.

6. Allow the bed to cure

Leave the laid setts undisturbed for at least 24 hours before walking on them, and 48–72 hours before pointing. Rushing this stage risks disturbing the bedding and ending up with rocking setts - which means lifting them and starting again.

Cover the area with polythene if there is rain forecast. Water washing into fresh mortar joints before they are pointed washes out the cement and weakens the whole thing.

7. Point the joints

Brush kiln-dried sand into the joints and compact it in with a brush. For a more durable finish, use a dry mortar pointing mix instead - dry mix swept in and then lightly misted with water to activate it. This gives stronger joints that do not wash out as easily.

Brush off any excess pointing material while it is still dry. Once it wets and sets on the surface of the setts it is difficult to remove cleanly.

8. Seal if needed

Granite does not need sealing, but a sett sealer will reduce moss and algae growth in shaded areas and make the surface easier to clean. Apply it once the pointing has fully cured - usually about a week after laying.

Not everyone bothers, and to be fair, unsealed granite weathers nicely over time. It is a personal preference rather than a necessity.

When to call a handyman

Call Richard for larger areas, awkward levels, kerb edging to set, or anywhere the setts need to tie into an existing patio or path. Getting the sub-base and levels right on a bigger job is the part that really benefits from experience.