What is the advantages of setting the soldier 1st?
I've always layed the boarder along with the field then gone back and set the boarder in concrete. I can see one would avoid concrete invasion @ the field boarder joint. Not good when the field edges don't vibe down with the rest of the field. I avoid this by only using enough concrete for a 3/4 footing.
Thanks
Soldier boarder
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84-1093879891
This question is on my list of subjects that need faqqing, as many contractors in the UK and RoI have asked more or less the same thing, and it’s getting to the point where I could do with a cut’n’paste answer.
There are advantages and disadvantages for both the “edge course first� and “edge course last� school of thought, and I’ll summarise these below, but, for me, the “edge course first� argument takes some beating.
When working in a bounded area, where edge courses need to be laid tight against a fixed structure, such as house/garage walls etc., the edge courses are best laid first because they will then act as a guide when it comes to fitting full blocks into the body (what you overseas types call the ‘field’) of the pavement.
When constructing a pavement of pre-determined dimensions, laying and haunching the edge courses first helps define the outline and eliminate the need to keep line pins, profile boards, string lines and all the other setting-out accoutrements in place for the duration of the job .
Laying the edges courses first, and having them firmly retained by the bedding/haunching allows them to be used as level guides when screeding the bed for the body blocks, rather than having to go to all the hassle of setting-up and screed rails and titivating when they’re removed.
By having the edge courses laid and haunched prior to laying the body blocks, the haunching (assuming a concrete haunch is used, which is not always the case in North America) will have had a reasonable chance to cure sufficiently to keep the edge blocks in place during the final consolidation.
On t’other hand, laying the edge courses to suit the body blocks has one main advantage: On a loosely defined, or undefined pavement (ie, one where the actual dimensions are left to the discretion of the contractor), the edge courses can be positioned to minimise cutting of the body blocks.
The problem I have with the ‘edge courses last’ approach is that many of the less scrupulous contractors lay the edge blocks on the screeded bed, and then just slap a trowelful of mortar or concrete to the outside edge as haunching. This is bad practice, and does not comply with the requirements of BS7533/3. The haunching is generally enough to keep the pavement in place for a couple of months or until the cheque has cleared, but this practice is the underlying cause of many, if not most, of the problems with spread pavements.
I appreciate your comments regarding differential settlement, but this can be, and is, minimised by good site practice. When the edge courses are laid on a cement bound bed (as I advocate), the body-side of the blocks should be scraped clear of surplus concrete, so that, when the body blocks adjacent to the edge course are laid, they are laid on the unbound bedding material that underlies the rest of the pavement. An experienced contractor will understand that, while the edge courses are ‘fixed’, and cannot be consolidated downwards any further, the body blocks will be hammered down by the plate compactor and so allowance will be made to ensure that, once consolidation is complete, the edge blocks and the body blocks are flush.
I’d be happy to hear other opinions, so that the eventual faq is as balanced and informative as possible. I know that some contractors do as you describe, laying the body blocks first and then scotching-out the bedding at the edges to accommodate a cement-bound bed and haunch, and I’ve no problem with that methodology, but it does seem like a lot of extra work.
There are advantages and disadvantages for both the “edge course first� and “edge course last� school of thought, and I’ll summarise these below, but, for me, the “edge course first� argument takes some beating.
When working in a bounded area, where edge courses need to be laid tight against a fixed structure, such as house/garage walls etc., the edge courses are best laid first because they will then act as a guide when it comes to fitting full blocks into the body (what you overseas types call the ‘field’) of the pavement.
When constructing a pavement of pre-determined dimensions, laying and haunching the edge courses first helps define the outline and eliminate the need to keep line pins, profile boards, string lines and all the other setting-out accoutrements in place for the duration of the job .
Laying the edges courses first, and having them firmly retained by the bedding/haunching allows them to be used as level guides when screeding the bed for the body blocks, rather than having to go to all the hassle of setting-up and screed rails and titivating when they’re removed.
By having the edge courses laid and haunched prior to laying the body blocks, the haunching (assuming a concrete haunch is used, which is not always the case in North America) will have had a reasonable chance to cure sufficiently to keep the edge blocks in place during the final consolidation.
On t’other hand, laying the edge courses to suit the body blocks has one main advantage: On a loosely defined, or undefined pavement (ie, one where the actual dimensions are left to the discretion of the contractor), the edge courses can be positioned to minimise cutting of the body blocks.
The problem I have with the ‘edge courses last’ approach is that many of the less scrupulous contractors lay the edge blocks on the screeded bed, and then just slap a trowelful of mortar or concrete to the outside edge as haunching. This is bad practice, and does not comply with the requirements of BS7533/3. The haunching is generally enough to keep the pavement in place for a couple of months or until the cheque has cleared, but this practice is the underlying cause of many, if not most, of the problems with spread pavements.
I appreciate your comments regarding differential settlement, but this can be, and is, minimised by good site practice. When the edge courses are laid on a cement bound bed (as I advocate), the body-side of the blocks should be scraped clear of surplus concrete, so that, when the body blocks adjacent to the edge course are laid, they are laid on the unbound bedding material that underlies the rest of the pavement. An experienced contractor will understand that, while the edge courses are ‘fixed’, and cannot be consolidated downwards any further, the body blocks will be hammered down by the plate compactor and so allowance will be made to ensure that, once consolidation is complete, the edge blocks and the body blocks are flush.
I’d be happy to hear other opinions, so that the eventual faq is as balanced and informative as possible. I know that some contractors do as you describe, laying the body blocks first and then scotching-out the bedding at the edges to accommodate a cement-bound bed and haunch, and I’ve no problem with that methodology, but it does seem like a lot of extra work.
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socalscott
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