Most natural stone paving products with sawn / straight cut edges may be laid with minimal joints, however it will always be necessary to have a small gap of a minimum of 5-10mm between the paving slabs to make allowances for slight size variations between the slab sizes that are typical with natural paving stone that conforms to British Standards. Always dry lay a selection of paving slabs to get a feel for how wide the joint should be.

With porcelain paving slabs, the joint width should be determined by whether the paving is 'rectified' or 'non-rectified'. The difference between these two options is described below:

Rectified - This porcelain paving is cut to size following firing in the kiln and as a result, the paving is more consistent in size and may be laid with a smaller joint than unrectified paving. As a guide, the dimensional tolerances are in the region of 2mm +/-. Sizes quoted for the paving are nominal and may differ by up to 5mm from the quoted size. For example, a 600 x 600mm paving slab, may be 595 x 595mm with a dimensional tolerance between slabs of 2mm +/-

Non rectified - This porcelain is cut to size before firing in the kiln and as a result, some slabs may expand or contract more than others. The paving is sorted into batches of similar sizes before packaging, however there may be a tolerance between individual slabs of up to 5mm +/- and jointing sizes should be gauged accordingly. As with rectified paving, sizes are nominal and may differ from around 5mm from the quoted size.

With concrete paving it is receommended that a jointing gap of at least 10mm is used and the paving pointed as usual. 

Both natural stone and concrete block paving may be butt-jointed and laid on an MOT Typ1 + sand bed, although the perimeter blocks must be laid in a mortar bed to ensure they do not move. Brush in kiln-dried sands to the joints between the butt-jointed blocks to finish.