Laying Flag Paving

Posted on March 25, 2010 by Simply Paving There have been 17 comment(s)

Next in our Simply Do It Yourself series, we look at laying patio paving.

Site Preparation

All paving should be laid on a firm, level and well-drained base, ensuring the paving performs as it was designed to. This will ensure your patio will remain in top condition for years to come.

Bradstone Milldale Paving Weathered Cotswold.

Vegetation and top soil should be removed to an approximate depth of 200mm across the area to be paved. Mark out this area with pegs or retaining boards and adjust their height to the required finished surface levels, ensuring that you allow the recommended fall away from any buildings and walls for water drainage. Also make sure that the finished paving surface level is at least 150mm below the level of any damp proof course. After excavation, rake level to ensure an even depth and compact the whole area using a garden roller or tamper.

Preparing the foundation.

It is always preferable to start with full flags laid adjacent to a fixed point such as the house or boundary wall and to work towards an edge which may be adjustable. Alternatively, start from a corner on the longest straight edge.

If you are laying more than one size of paving, particularly if in a random pattern, or if you are laying a circle or other feature, it is recommended that you dry lay the flags first to check the fit and make sure you are happy with the pattern. It is also advised that you take the paving from a number of open packs at once, even if you are just using one size, to ensure a consistent appearance to the finished patio.

Natural Stone Paving

The area to be paved should first of all be dug out to a depth of at least 200mm. The area should then be back filled with 150mm of MoT/crusher run, compacted to 100mm.

Laying the paving.

Once the area is prepared, the laying of each flag can commence. The actual mortar bed is prepared individually for each and every flag dependent on its thickness. The bed will consist of a semi-dry mortar mix, using 4 parts sharp sand to 1 part cement. Spot bedding should never be used for natural stone paving, as the flag will not be sufficiently supported.

When laying flags that will have mortar joints, the receiving edges of the already laid flags are buttered with mortar into which the new flag is pressed, forming a well filled joint, that can be topped up when pointing. Buttering will also aid consistency of joint width. Once in place, each flag can be consolidated by tapping them down, either with a rubber mallet or by keeping a piece of softwood between a hammer or mallet and the flag. Continually check levels and falls during the laying process across the top surface profile of a number of flags at a time.

Sandstone and Limestone Taper

Lay sandstone / limestone paving onto the full bed of semi-dry mortar, with the chamfered side down, therefore leaving the side with the largest surface area facing upwards.

The hand-dressed edge detail on sandstone and limestone paving exhibits a taper or undercut running towards the back face of the flag. When laid with suitable pointing gaps the edges of the adjacent paving will provide dovetail or reverse wedge-shaped gaps which will considerably assist the keying in of the pointing mortar thereby increasing the durability of the finished joints.Leave the mortar mix to go off for at least 24 hours before pointing.

Point with a wet mortar mix of 4:1 (building sand will be more workable), ensuring the gaps between the flags are completely filled. The strength of the pointing is extremely important, as if done incorrectly, the joints will be the weakest part of the paved area. It is important to take care not to stain the paving surface with any excess mortar as this will be difficult to remove.

Checking the levels.

A plasticiser can be added to the mortar mix to improve its workability and also ensure all air pockets are eliminated. Cement dyes may also be added to the mix to change the final colouration of your pointing mortar. Simply Paving can offer a jointing compound suitable for use with natural stone flags, please contact us directly for more information.

Manufactured Paving

When laying manufactured paving, the preparation of the site should be carried out using the same methods as when laying natural stone. As manufactured paviors are produced in man-made moulds, variation in thickness is not generally an issue, and the undersides of the slabs are more consistent. Therefore, for light use patios, a screed bed of a sharp sand and cement mix (a ratio of 6:1 is more than adequate) can be used as oppose to creating a mortar bed.

If preferred, manufactured paving can also be laid on a mortar bed, but it is not always necessary.

Manufactured paving can also be pointed with a wet mortar mix, however great care must be taken to ensure it is not left on the surface of the flag as this will be almost impossible to remove when set. Many people choose to point manufactured paving with either a dry mix of sharp sand and cement brushed into the joints or a specifically designed jointing compound.


If pointing with a dry mix, a ratio of 6 parts sharp sand to 1 part cement is recommended. The dry mix should then be indirectly watered, i.e. lightly water the surface of the flags rather than the pointed joint itself. The water will then trickle into the joints and hydrate the cement, rather than splash the dry mix over the surface of the flag.

If you require any help, please give the Simply Paving office a call on 0800 032 6306 and we will try to assist you in all aspects of your landscaping project.

This post was posted in How to..., Simply Do It Yourself and was tagged with Bradstone, Building Materials, DIY, Landscaping, Milldale, Natural, Patio, Patios, Paving, Sandstone, Simply Paving, Weathered Cotswold

17 Responses to Laying Flag Paving

  • All look really skillful.

    Posted on February 23, 2011 at 3:54 pm

  • I intend laying a pattern of terracotta tiles/slabs (using 300 x 300mm squares and diamond shapes) for light use around a summerhouse.
    Presumably, the method is as described above?

    Posted on March 18, 2011 at 12:22 pm

  • Good afternoon,

    The above method is perfectly fine for use when constructing light use paths and patios. If you do require any further assistance, please do not hesitate to call the office on 0800 032 6306.

    Best regards

    Simply Paving

    Posted on March 18, 2011 at 12:54 pm

  • My house is late victorian.
    I intend laying a sloping garden path with bradstone sandstone---
    ----the path to be one metre wide .
    What design and size paving would you recommend?

    colin woods

    Posted on October 23, 2011 at 12:15 pm

  • Hi Colin,

    It really is all down to personal preference and which paving you feel would look best with the property and any possible colour schemes you have in mind. Your best bet may be to check out our natural stone departments to see what you like the look of.

    Natural Stone

    Premium Natural Stone

    Although you mention Bradstone sandstone, it may also be worth you looking at slate and limestone. If you would like any assistance, please do not hesitate to call the Simply Paving office on 0800 032 6306.

    Best regards

    Simply Paving

    Posted on November 8, 2011 at 9:23 am

  • Andy says:

    I'm planning to use a 6:1 sand to cement mix, should this be a dry mix? if so, what's the best method - use a mixer. Apologies if this is a really basic question, first timer at patio laying...

    Posted on April 14, 2012 at 7:50 pm

  • richard says:

    Hi, it depends on the product you're laying. Is it a natural or manufactured product?

    Best regards

    Simply Paving

    Posted on April 18, 2012 at 2:17 pm

  • can sand stone be used on a driveway?

    Posted on May 4, 2012 at 6:38 pm

  • Hi,

    Unfortunately the sandstone that we supply is only 22mm - this is perfect for use on patios and pathways, however, it is too thin for driveways.

    Best regards

    Simply Paving

    Posted on May 11, 2012 at 11:13 am

  • Hi there,

    I ordered some Panache paving slabs from you. My tradesman is wondering whether the slabs will need some sort of sealant on them afterwards? Is this necessary or not?


    Posted on July 19, 2012 at 2:18 pm

  • Hi,

    The StoneFlair by Bradstone Panache Paving is pre-treated with Bradstone Surface Protection which makes everyday contaminants such as oil, grease, moss, bird droppings, wine and soft drinks much easier to clean from patios and driveways. The protection will last from 4-6 years.

    Best regards

    Simply Paving

    Posted on July 20, 2012 at 8:28 am

  • Lucy says:

    How thick should the mortar bed be for laying natural slate paving?

    Posted on June 18, 2013 at 2:47 pm

  • Hi,

    You want to be laying slate on a full mortar bed of around 35-50mm - enough to allow the flags to be fully supported whilst also taking into account the varying thickness of the product (18-23mm). The actual mortar bed should be prepared individually for each and every flag dependent on its thickness.

    Being a dense material Slate paving does not readily take up water and it is therefore advisable to use a SBR admix to the bedding mortar to create the necessary key or adhesion. This can be bought at a local builders merchants near to yourself.

    Best regards

    Posted on June 19, 2013 at 8:51 am

  • Lucy says:

    Thank you
    Could you also tell me if the natural slate paving needs to be sealed after laying?

    Posted on June 20, 2013 at 11:40 am

  • Hi,

    The slate paving doesn't have to be sealed, however, it can be if you wish to.

    We supply a product called Signo Flexiguard which is a water based product that will protect any of our porous products against ingrained soiling from dirt, staining from oil and water based contaminants and even moss and algae growth. Once this product is applied you won't be able to tell it's there.

    There are numerous other products on the market, some that may give different finishes such as "wet look", however, it may be best speaking to the suppliers / manufacturers of these products to ensure they are fit for use with slate.

    Best regards

    Posted on June 20, 2013 at 11:53 am

  • Hi,
    I'm looking at laying Bradsone Abbey paving over an existing concrete base patio.
    Can I use the 5 spot method or do I need to lay a mortar or dry mix bed?

    Posted on July 29, 2013 at 5:31 pm

  • Good morning,

    Paving slabs, whether they are natural or manufactured, should never be laid using spot bedding.

    All paving should be fully supported when laid without any voids underneath the slabs (as per the method in the above post).

    If laying on top of an existing concrete base, you will also need to ensure that there is a sufficient fall or adequate drainage to allow water to flow away.

    Best regards

    Simply Paving

    Posted on July 30, 2013 at 8:36 am