Outdoors, these flagstones can be laid on a sand and cement bed. Ensure the screed bed is level, and if needed use a sub-base. Spot bedding is not recommended as its makes the flagstones unstable and susceptible to fracturing.
As our Black Tumbled sandstone flagstones are all 560mm wide they can be laid in “tram lines” or they can be laid in a completely random pattern.
To keep a traditional, random pattern there are 3 rules:
1. Do not have 4 corners meeting
2. Have no more than 3 joins running parallel
3. Do not have joins running for longer than around 3 metres. You may want to reduce this length if the overall area is small.
Joint widths are a personal decision, but a 12mm gap is standard. We recommend Jointex Easy as a fixing mortar. It’s ready mixed, easy to use, doesn’t stain the flagstones and creates a very neat professional finish. It is permanently water permeable, resistant to high pressure cleaners and helps prevents weeds. Just empty the tub onto wet flagstones and work it into the joints, making sure they are firm and compact; then wait for it to dry (see the Jointex Easy Data Sheet for full details).