The Brew Cabin

Posted: **Sun May 15, 2005 9:17 pm**

My flags got delivered at the weekend and I've barrowed all 186 of them around to the back of the house. The subbase is down and well compacted so I'm ready to start laying the flags.

The flags are natural Indian Sandstone and therefore vary greatly in depth, so I will be using the individual bedding method. Having re-read all of the applicable web-pages again, I notice that on the 'Laying Riven' page, a semi-dry bedding mix of 10 sharp sand to 1 cement is quoted. However, on the 'Mortars and Concrete' page it mentions 6 small gravel, 4 sharp sand and 1 cement. Which of these is best to use for laying my Indian Sandstone? Looking at the photos on the 'Laying Riven' page, the bedding material does not seem to contain gravel, so I'm guessing a 10:1 sharp to cement is the right way to go?

I plan to use a standard class II mortar for my free edge flags, but can't decide between using edge spots or haunching up the side of the flag. It appears that haunching is a more guaranteed approach but you will see the mortar edge to some degree. Edge spots are not visible to the eye but the flags may not adhere to the mortar. The main free edge of my patio will have turf meeting it - should this sway my decision at all? Any comments on which method may be better for Indian Sandstone are much appreciated.

My final question relates to buttering and pointing. The general opinion is that a dark dyed mortar looks the best with imported sandstone and I tend to agree, so I would like to use that and have studied the 'Case Study' page in detail. When pointing will use a dyed mortar, what should I do for buttering when laying the flags? Should I use a standard class II mortar for buttering and only the dyed stuff for the 'real' pointing?... or should I use dyed mortar for everything?... or should I not bother buttering at all?

Thanks in advance for any help and advice :;): .

Posted: **Sat May 28, 2005 5:40 pm**

If I'm not too late....

The different advice given on bedding mixtures is a tad confusing, I admit, but when laying a patio with no sub-base, there's often a tendency to have slightly more than 40-50mm of bedding, so, beefing up the mix by incorpoarting small gravel rather than all sand is a good option. However, if you're fairly confident that the maximum bedding depth won't exceed 50mm, the sand/cement mix is fine.

At free edges, if the edge is going to be visible at all, then edge spots are a better choice than haunching, but, haunching is usually a 'stronger' fix. If you have any worries about the flags bonding to the edge spots (if that's what you choose) add a dash of a bonding agent, such as SBR or Ronafix, to the spot mortar.

When it comes to the buttering, if the butter isn't being squeezed up in the joint, then you can use a plain, uncoloured mortar and save the more expensive coloured mortar for topping up the joints. However, if your method of working is such that the butter mortar is squeezed up when the flags are laid, then you may have to use a coloured mortar for the buttering in order to avoid any patches of colour variation.

How's it going/gone?

Posted: **Tue May 31, 2005 10:14 am**

Thanks for the detailed reply Tony. Due to work committments and the bloody weather, I have not started laying the flags yet. I hope to start in the next couple of weeks, so your advice is not too late!

Based on your advice, I'll go for the 10:1 mix and use Edge Spots maybe adding a touch of bonding agent to be safe.

In terms of buttering, whats your honest opinion on whether its really required for when laying a light use patio? I know it will bond with the bedding layer and set together therefore creating a stronger fix, but can you get away without it? The reason I ask it that I'm doing this job myself and will already be mixing the 10:1 bedding mix and the class II mortar for Edge Spots. To add a 3rd dyed mix into the equation is making things very tricky for myself ??? . Could I get away with not buttering and following up with pointing when complete?

Posted: **Tue May 31, 2005 11:02 am**

You could, but it's always easiest to butter and point as the work proceeds.

If you were doing this over a weekend, I'd suggest buttering as you lay, and then, when you get towards the end of a shift, knock-up a pointing mix and fall back on topping up all the joints created during that shift. Even if the joints were buttered 6 hours previously, they'll still be only partially cured (even though the mortar may seem hard to the touch) and so you'll still get a good bond between butter and pointing. Obviously, if you're doing it during the evenings, it's not worth knocking-up a pointing mortar for the few flags you'd get laid each session, so it would be better to butter (so that you get regularly-spaced joints) and then do all the pointing in one go at the end of the project.

The Brew Cabin

Bedding, buttering & pointing question