I've searched the forum and read the relevent sections of the website but I'm still not sure of the answer to my question.
I've layed a grit sand bed and compacted and screeded it ready to lay Marshalls Heritage. I then re-read your flag laying section more thorougly and realised screed bedding is not suitable for those type of flags. (Doh!) I've now started raking each flag bed with a hand rake and bedding onto that. I've literally layed just a few flags atm (never done this before so the learning curve is steep!). Having read a couple of the posts wrt 'mortar or not' I'm worried that my bed of just grit sand will not be suitable. Should I have made it a 10:1 mix ? Your advise pages seemed to say the cement was optional so I opted not to use it because I was screeding and knew I could not lay the whole patio before the mix went off (I now know I should not have screeded !).
Should I continue raking and laying onto the grit sand or should I start all over again
I'm not an expert but based on my experiences with Q&A on this forum, flags can be laid successfully onto a pure grit sand bed. However, it is usual to use a 10:1 cement mix to harden the bedding layer slightly. I think this is only mandatory if you are using thin flags or in wetter areas where the bed might move due to water movement.
How you proceed may depend on how far you've got. If you've only laid a small amount of flags, you could start again with a 10:1 mix for peace of mind. I believe you can re-use the grit sand as long as it has not become too wet or contaminated with weeds etc.
Good Luck!
"I have a plan so cunning you could stick a tail on it and call it a weasel." - Edmund Blackadder III.
I've only layed a few flags so I may start again with a 10:1 mix. I'm just fed up at the time I spent screeding the level with all the correct slopes etc.
Many good flaggers would choose to lay onto a bed of clean sand (ie: no cement), but they are well-practised at forming accurate beds and acheiving full consolidation of the flags. For DIYers and occasional flaggers, the 10:1 mix is a touch more forgiving as the cement content will tighten up the bedding and make good any incomplete consolidation. It's also useful if you have a patio that's plagued by ants or other mining invertebrates.
Screeding is not always totally wasted with a quality flags such as Heritage. Although there is some variation in flag thickness, it's not as pronounced as can be the case with some budget wet-cast products, or with some of the stone flags. So, if you have screeded a bed in advance, it may be that each flag will require minimal adjustment of the bed to accommodate its idiosyncracies, and it can be a good way of estimating overall falls and profiles.
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