Before you begin
Always dry lay your patio first. This is a simple job of laying out the paving as you want the finished patio to be. Check the size, layout and, more importantly, that you have enough pavers.
Ask your stockist to calculate howmuch all-in ballast, building and sharp sand you will need and order accordingly.
STEP 1: Marking out
Mark out the area, allowing an extra 150-300mm for working room.
STEP 2: Excavation
Excavate a total depth of 150mm, allowing for a 100mm sub-base, a 30mm mortar bed and the paving itself. To comply with building regulations and protect your property from damp, the paving must also be at least 150mm below any damp-proof course (DPC).
STEP 3: Establishing lines and levels
The paving needs a slope or fall of around 1:60, i.e. 17mm of fall for every metre width or length of the patio. Use one taught string line to guide alignment along the length of the paving, and a second along the breadth. When laying, you should use a straight edge and spirit level to repeatedly check that each new paving unit correlates to both lines, adjusting the height up or down to give the necessary fall..
STEP 4: Sub-base
A Type 1 or MOT sub-base is required to give strength and stability to your patio. If the area you are paving is unreliable or has persistent weeds, place a geo-textile over the ground first. Spread the aggregate out, forming an even layer roughly 30-40mm below the stringline. Use a plate compactor to consolidate the aggregate down to 25-30mm.
STEP 5: Bedding
Use a mechanical mixer to make a mortar of 4:1 sharp sand to Ordinary Portland Cement (OPC). Avoid building sand or white cement. The mortar should bind together without being sloppy or runny. A plasticiser can help get a more workable consistency.
STEP 6: Preparing the bed
Using a shovel or trowel, apply the mortar to the sub-base, levelling it out. Ideally, the bed will carry the flag 5-8mm above the required level. Ripple or roughen up the surface of the bed so there will be some leeway once the paving unit is placed. Spread only enough mortar for one flag at a time, ensuring the bed is larger than the flagstone.
STEP 7: Primer
A slurry primer will help the paving adhere to the bed. Use a masonry brush to coat the entire underside of the flag immediately prior to laying. Take care to avoid getting any primer on the face of the flags as it sets rock hard and can be impossible to remove if allowed to dry.
STEP 8: Placing
Once primed, the paving unit can be placed onto the bed. Bradstone porcelain pavers are quite light and can be lifted by one person. Carefully lower each one onto the bed. Beware of any drips or splashes from the primer and use spacers to guide your joint widths. If you need to cut any flags to fit, use a top quality diamond blade fitted to a bench saw with dust suppression.
STEP 9: Compaction
Use a rubber mallet to tap the flags down to the correct level. Check there are no high spots or hollows to ensure complete contact between the primer-coated base and mortar. You should also check against the string lines to make sure each flag is level and aligned. Make any adjustments now before the mortar becomes too stiff and wipe down the paving once again in case any primer or mortar has touched the face of the flags. Better to be safe than sorry!
STEP 10: Jointing and dressing
Apply the jointing using an outdoor grade jointing material suitable for use with porcelain. Then cordon off the freshly-paved area, avoiding any foot traffic for at least 24 hours.
Lastly, dress the patio…and enjoy!