Marshalls explains how to lay a porcelain patio.
In recent years porcelain has become a popular option for garden patios. Sometimes referred to as vitrified paving, it’s a great low maintenance choice for customers and looks particularly good in modern gardens. But if you’ve never laid a porcelain patio before, where do you start? We’ve asked an expert from Marshalls to share their advice, including tips for precision cutting.
Sub-base
When it comes to the sub-base and excavation, the methods to lay porcelain are the same as other materials. For most gardens, a sub-base of 100mm should be sufficient, but make sure you take into account the particular ground conditions and type and frequency of loads.
If excavation is needed, the depth should be based upon the thickness of the sub-base plus the sand, mortar and paving flag thickness. If you’re laying the patio up to an existing structure make sure it’s minimum of 150mm below the damp proof course to prevent problems with rising damp.
Your sub-base material, as with other paving types, should be well graded (40mm to dust) Type 1 quality material and placed in layers no more than 75mm thick, or twice the nominal maximum aggregate size.
Edge restraints should be sufficiently robust and installed prior to the installation of the sub-base. Alternatively, and a good design idea for a quality finish, you could create a border using an alternative product or material to frame the project and enhance the overall finish.
Rigidly Laid Paving
Top Tip: Vitrified paving is recommended to be installed on a full mortar bed and never on a five spot bed or alternative.
Flags should be supported on a full ‘wet’ workable mix mortar bed (1:4 cement/sharp sand), you should lay the mortar bedding to give a thickness between 15mm and 30mm. To increase adhesion to the mortar bed and prevent separation, Marshalls Paving Primer or similar flexible bonding agent compound should be applied to the back of the flag prior to installing onto the mortar bed. Gently tamp down onto the mortar bed using an appropriate rubber maul. Adjustment may be necessary to ensure that the units are fully supported and do not rock or move, and that desired levels and falls are achieved.
Cutting porcelain
We often get asked about cutting porcelain, as it’s a different skill to other materials, here are our top 5 tips.
1. Make sure you’re wearing the appropriate PPE and dust suppression when using power cutting tools
2. Always use a proprietary blade, designed for cutting porcelain
3. A table saw with water suppression gets the best results for straight cuts
4. If you only have a power saw, reduce vibration and risk of shattering by placing the product on polystyrene or a bed of sand
5. For the trickiest of cuts, measure carefully and mark out the section to be cut; a steady hand, a small angle grinder and a bit of patience will get the best results. To avoid unnecessary breakages, we recommend that you cut both ends of the flag with a blade before full run through.
Jointing a porcelain patio
Another area where the practice differs a little from other materials is jointing. Good suppliers will supply a vitrified jointing material with the product, and this should be used to full fill the joints. Joint widths should be 3-5mm wide, you could use spacers to achieve uniform joints.
Under no circumstances should dry or semi dry sand/cement mixes be brushed into the joints as this doesn’t give a rigid joint and can cause the paving to become stained.
Once you have laid the paving on the mortar bed, rake out any excess mortar between the joints to the base level of the flag with a suitable tool. This will ensure the jointing material fills all joints to the entire depth and width of the flag joint. The joints should then be filled using the supplied jointing compound following the instructions supplied. Saturate the paved area with water prior to expelling the product onto the paving then brush diagonally into the joints. Remember, different jointing compounds need to be used in different ways, so always make sure you follow the guidelines specific to the product you are using.
Top Tip: To aid jointing material into the joint, you could form slurry by adding extra water to the jointing compound which allows it to flow easily. If you want to achieve a smoother finish to the joint, let the jointing compound drain and cure for a minimum of two hours before striking off.
Cleaning down before you finish
To finish the installation, gently spray the surface of the paving with water before sweeping off any excess jointing material with a soft bristled brush.
Top Tip: If you’ve used a Marshalls porcelain product, the remaining jointing compound can be stored in the tub to re-use within 12 months. Just fill tub to the maximum with water, ensuring all jointing compound is covered.
Why is porcelain a good option for your customers?
– It’s strong and hard-wearing
– Low water absorption means it needs less cleaning due to less staining and algae
– It has excellent frost resistance
– Generally available on short lead times
– Wide range of colours and finishes, giving good options on price range.
For more advice and information including Marshalls porcelain product ranges visit www.marshalls.co.uk/builders
