What is porcelain paving?
Porcelain paving slabs are made by firing porcelain clays in extremely hot kilns. Recent developments mean that it is now possible to purchase porcelain slabs which have realistic colour and texture, mimicking many natural stone and wood materials. Tiles can have texture embossed on the surface before the photographic image is added. The better quality tiles have enough variation to create a randomised effect in the imagery.
It is important to make the distinction between porcelain and ceramic paving. Materials such as terracotta are ceramic, and are very porous, and therefore extremely frost sensitive. These materials are totally different from porcelain paving.
The finished porcelain slab is a very strong, lightweight and also virtually non-porous.
The low porosity of porcelain paving makes it very suitable for our damp climate. The slabs don’t absorb moisture and will therefore not be degraded by the frost/thaw processes that occur during our winter, which can cause natural stone to flake, and terracotta to crack.
What is the best method to lay Porcelain Paving?
Laying porcelain paving is slightly different to laying natural stone paving.
Prepare the site by digging out the site as usual, checking levels and drainage as you would for a natural stone patio.
Lay a sub base of compressed scalpings to create a firm and level foundation on which to lay the porcelain paving. We recommend 100mm depth. This will create a free-draining sub base which is always necessary if you are using our jointing compound. Buy Scalpings now>>
Prepare a mortar mix of at least 6:1 mixed sand to cement, which is to be laid as a full bed. More accuracy is required here than you might ordinarily need with a natural stone patio, as in the next step you will not have as much leeway for tamping down slabs to achieve their perfect level.
THIS IS THE DIFFEERENCE BETWEEN MOST STONE PAVING AND PORCELAIN PAVING.
Due to the non-porous nature of porcelain paving, it is necessary to create a bonding bridge, so that the slabs will adhere to the base
If you omit this step, your paving will fail quite quickly after laying.
Before starting to lay the porcelain slabs it is necessary to prime the back surface of each slab. Paint the reverse side of each slab with either a ‘slurry mix’- a wet cement mix, or a proprietary resin based primer. The slurry mix is the cheaper method, but can be messy, whereas the pre-prepared primer is easier to use, but costs a lot more.
Lay the primed porcelain pavers on the full bed of mortar of 40-50mm thick.
N.B. We often receive queries regarding this point, as some experienced landscapers will lay porcelain slabs on ‘pedestals’ (ie several 50mm high blobs of mortar- at each corner and in the centre) or work over the top of an existing patio or hard surface. Neither of these methods are wrong. However, they are not foolproof methods. To ensure a good finished result that has longevity, a solid sub-base must be created. Any movement beneath the patio will cause cracking eventually on the patio surface. Its your call! Furthermore, when working over an existing surface, it is very important to ensure that the increased height does not breach the damp proof cpourse on any adjacent buildings.
Therefore we prefer to recommend the full mortar bed method.
Pavers will require tamping into position. Although porcelain pavers are strong, they will not withstand excessive hammering, therefore careful efficient tamping down is required. In order to get a strong bond between the mortar bed and the underside of the slab it is necessary to ensure at least 70% of the paver is in contact with the mortar bed.
The strength of the completed surface relies on the bond between the mortar and the slab, therefore this stage is the most important.
As the pavers are laid, joints of 6mm should be left, using spacers to ensure an even jointing space throughout.
There are many suitable materials available to create the pointing joint
Please call us on 01844 279274 for any further advice you require. Our knowledgeable staff are always on hand for tips and advice.