I have a 7' * 5' shed sitting on an 8' * 6' base made from 2' * 2' flagstones (i.e. 12 flags arranged 4 * 3). It looks like these flags have been laid directly on the soil but the platform looks flat and level enough.
I would like to upgrade to a 10' * 8' shed. On the face of it the job looks do-able; add one row and one column of flags (with a sand base) to create a 10' * 8' platform, with flags arranged 5 * 4. But I'm not sure how to go about this. All the DIY guides I have seen do the job from scratch starting with bare ground. I'm going to assume (tell me if I'm wrong!) I don't have to pull up the existing platform and start again, i.e. I can dig out the soil on two sides of the rectangle, level up with sand, and add the eight new flags. On this assumption, a few questions:
1. The current shed is 5' * 7' so there is a foot of unoccupied flag on each side. The new platform will be exactly the same size as the new shed. Is that OK or do I have to lay more flags to allow for a 'border'?
2. Is the sand I require what B & Q sells as 'sharp sand', and what depth of sand should I lay? Any ideas what quantity of sand I am likely to need? (I'm thinking in terms of how many of B & Q's Large Bags)
3. I will assume I need not bother with spirit levels as the new flags must align to the existing platform whether it is truly horizontal or not. Do I need to have the existing shed removed before I lay the new flags, or is the one foot perimeter of visible flagstone sufficient to get the alignment right?
I would like to upgrade to a 10' * 8' shed. On the face of it the job looks do-able; add one row and one column of flags (with a sand base) to create a 10' * 8' platform, with flags arranged 5 * 4. But I'm not sure how to go about this. All the DIY guides I have seen do the job from scratch starting with bare ground. I'm going to assume (tell me if I'm wrong!) I don't have to pull up the existing platform and start again, i.e. I can dig out the soil on two sides of the rectangle, level up with sand, and add the eight new flags. On this assumption, a few questions:
1. The current shed is 5' * 7' so there is a foot of unoccupied flag on each side. The new platform will be exactly the same size as the new shed. Is that OK or do I have to lay more flags to allow for a 'border'?
2. Is the sand I require what B & Q sells as 'sharp sand', and what depth of sand should I lay? Any ideas what quantity of sand I am likely to need? (I'm thinking in terms of how many of B & Q's Large Bags)
3. I will assume I need not bother with spirit levels as the new flags must align to the existing platform whether it is truly horizontal or not. Do I need to have the existing shed removed before I lay the new flags, or is the one foot perimeter of visible flagstone sufficient to get the alignment right?