Jointing

Jointing - Simple and fast with perfect tough joints every time

What joint width?

Joints are required to allow for variations in slab dimension and to protect the edge of slabs. By varying the joint width you can create different effects, but care must be taken to ensure an appropriate width is used. If a flagstone pattern uses slabs whose sizes are not modular metric then joints will vary considerably in size which can be very unattractive. All Green Garden Paving flagstone products have modular metric sizing which will allow you to lay the slabs with joint widths from as little as 7mm. Sawn edge products are more accurately sized and can be laid with quite tight joints while setts have a lot of size variation and will need to be laid with quite wide joints. Before the product is laid out we suggest you dry lay a sample area and check which joint width works best by carrying out a test joint with some dry building sand. As a rule of thumb the greater the variation in size between slabs then the greater the joint width that is required.

Tighter joints will generally give a more contemporary look, while wider joints give a more rustic appearance. If using GeoFix jointing compounds the narrower the joint the less the material cost will be.

Jointing methods

There are four common methods of jointing slabs or setts:

1. Slurry jointing. A wet mix of sand and cement is poured onto the surface that requires jointing and is brushed into the joints and across the slabs. This method is quite quick and the material content is inexpensive, but it is extremely difficult to clean the surface of the stone which is generally left with an unsightly grey cement film covering the surface. This film can take many years to wear off. The joint strength is generally weak as the mortar will have been mixed with too much water so the joints will normally deteriorate quite quickly. Green Garden Paving do not recommend this method of jointing.

2. Dry mix. A dry mix of cement and sand is mixed and applied to dry slabs. This method is quick and the material content is inexpensive. The mortar dries by fixing water from the air. However, the joint strength is very weak and will not stand up to cleaning (particularly jet washing) or moss invasion. An alternative method is to wet the joints after laying, however this only marginally improves the joint strength and is likely to lead to cement film splashes to the slabs (as does un-expected rainfall). Green Garden Paving do not recommend this method of jointing.

3. Wet pointing. A skilled person is required to wet point slabs. The method is slow and time consuming in both cost and labour, although material costs are inexpensive. The joint is strong, but will tend to mark the adjacent slab which results in an unattractive 'picture frame' effect. Time and care must be taken to avoid the picture frame effect. This type of jointing should be carried out during dry spells.

4. GeoFix jointing compound. An un-skilled person simply opens the bag, sprinkles the contents over the slabs, brushes the GeoFix in and walks away! Application should be carried out in dry weather on dry slabs. The pre-mixed GeoFix will set within 24-48 hours so the slabs should be protected from traffic during this time. The resultant joint is strong. Material costs are quite high but are more than offset by reduced labour costs and time. There must be a minimum joint depth of 25mm. GeoFix is available in buff and grey. This is the method recommended by Green Garden Paving.

Application method for GEO-Fix

1. Ensure the paving is dry and free from loose dirt, oil, grease etc.

2. Open the bag and sprinkle enough to cover an area of 4-5 sq. metres.

3. Use a soft brush to push GeoFix into the joints

Final finishing can be carried using a rounded stick to consolidate the GeoFix in the joints.

GEO-Fix Coverage Calculator for SINGLE SLAB SIZE

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GEO-Fix Coverage Calculator for MULTIPLE SIZE FLAGSTONE Patterns

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