What is the best / correct bedding mix for my patio

Patio flagstones (slabs), concrete flags, stone flags including yorkstone and imported flagstones.
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kjgodalming
Posts: 1
Joined: Sat Aug 30, 2003 1:38 pm
Location: Godalming, Surrey

Post: # 2623Post kjgodalming

Hello

Firstly, thanks for a brilliant site Tony, keep up the great work, you really help newbie's like me.

I have to rebuild my patio as the previous owner used spot bedding, the levels dropped and most of the sharp sand he used as a bedding layer washed out of a crumbling wall. It was also plagued by several ants nests.

The patio is not too big (18 m2) but it is raised.
The crumbling wall has been replaced by a proper retaining wall, but I ran out of funds to pay for my builder to relay the patio

I live on a very steep hill which has a very large amount of surface water run off when it rains (our road looks like a river !). Hence there is a large amount of surface water I have included a soakaway at the lowest point.

My questions are:- will your recommended 10:1 mix bedding mix be suitable for my project, given the high levels of surface water, or should I use another bedding mix.
If 10:1 mix is OK will sharp sand and cement be sufficient as recommended by my local Jewsons.

I intend to lay my flags by individual bedding as quickly as I can, working at weekends and evenings when I have time.

Would screeding be more suitable given the British weather ?

My sub base is scalps, laid to 70 mm so far, but I will be adding another 50 mm more to raise the levels.
I intended to use approx 75mm bedding, but after discovering your website is this too much, would 50 mm be more suitable ?

Many thanks

Ken






danensis
Posts: 335
Joined: Mon Aug 11, 2003 4:24 pm
Location: Derbyshire
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Post: # 2627Post danensis

I use six parts grit sand to three parts soft sand for bedding, with one part of OPC. It seems to give some resilience without things sliding all over the place.

84-1093879891

Post: # 2629Post 84-1093879891

Hi Ken,

it's good to see someone else validating my crusade to rid the world of the evil that is known as "Spot Bedding" for truly it is an abomination that must be eradicated and its proponents slung into the pit of despair!

The 10:1 bedding mix should be more than capable of dealing with you patio and the heavier-than-normal surface water regime. The purpose of the cement is to bind the aggregates, rather than make it hard-wearing or incredibly strong. As long as the cement content is adequate to hold together the aggregate particles, it will be fine, and, in my experience, 10:1 is about right. You can elect to make up the "10" from 5 parts gravel and 5 parts sharp sand, if you wish, or you can 'edge-your-bets and up the cement content to a 8:1 mix, but these are minor details that I leave to your choice.

Screeding is possible if you're using regular thickness flags or block pavers, but, if you're using the riven types, other wet-cast products or natural stone paving, individual bedding is the best method to employ. Keep the bedding to a maximum of 50mm, and no more. 35-50mm is the standard specification.

Good luck and let us know how you get on. :)

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