Tony,
Now I'm back in the garden after a busy winter I
cannot find topic with the above title (last post dated September 5th 2003). I have a paper copy of this topic and the url is http://ext.pavingexpert.com/cgi-bin....ic=248. Would like to re-open if that is possible.
New Patios on Sloping Garden
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84-1093879891
There's an ongoing problem with the software running this message board system, in that it 'ghosts' older messages. They are still there, really, but it makes them invisible to mere mortals. That's why it only shows a couple of pages of messages in each of the fora despite reporting there are umpteen thousand posts.
The company behind the software are aware of the problem, and have given me a 'fix', but the problem keeps recurring, which is why I'm planning to upgrade to a more stable version of the program as soon as I get my poor aching head around mySQL databases.
For now, I'll see if I can resurrect your previous thread...give me a couple of hours as I'm really rushed off me feet today.
The company behind the software are aware of the problem, and have given me a 'fix', but the problem keeps recurring, which is why I'm planning to upgrade to a more stable version of the program as soon as I get my poor aching head around mySQL databases.
For now, I'll see if I can resurrect your previous thread...give me a couple of hours as I'm really rushed off me feet today.
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84-1093879891
I will need to close down the Brew Cabin to rebuild the perl files that control the missing info, so, instead of messing around everyone using the board during the day, I'll do this late this evening or around midnight, when the Brew Cabin is usually empty.
However, here's the text of your original post....
chrisevans
As my garden is north facing I have decided to lay the main patio at the end of the garden with a smaller, matching patio adjacent to the house. The garden slopes away from the house and also from right to left
It wasn't until I set the patio levels and excavated did I realise how much the garden sloped from right to left
I now have a small problem. :(
The sub-base levels of the left-hand edge (arcs) of the patios do not have anything to butt up to. I have a choice: build two small brick or concrete retainers high enough for the 100mm sub-bases? Which is best? And what footings would be best for these walls as the ground is clay. How thick should these retainers be and if concrete what ratio of sand or ballast to cement
Thanks in anticipation...
TonyMcC
Is it not possible to soil over the extended sub-base(s) once the paving is in place? This would be the simplest option, but, depending on your actual plan, I can appreciate that it's not always possible.
If you have to use retainer structures, try and keep it a simple as possible. Is there any way a flag-on-edge could be used in place of a wall? That's a much easier construction, as well as being cheaper and faster to construct
However, if a wall is your only option, the height of the wall is the critical factor - for anything less than 450mm height, a simple double-skin wall of suitable bricks (Engineering brick are the best) laid on a 450x100mm foundation of C20 (or equivalent) concrete, with at least 150mm of frost cover, ought to do the job.
chrisevans
Tony,
I have sent you a plan of the main patio via email in AutoCad .DWG format which I created in MS Visio to give you a clearer idea of the problem I have
The void area between the excavation edge and the garden boundary I have filled with crush. But the more I look at this I don't think it will be strong enough to retain the DTP1 sub-base and may be prone to some movement long term
The proposed retainer would only need to be 100mm in height to 'retain' the sub-base. Would this still require a 450mm deep :confused: C20 footing
Thanks again....
TonyMcC
I've 'coloured-in' your drawing and reproduce part of it here...
...for the benefit of other readers, the garden slopes from right to left, which is why the step down is needed at the end of the main patio.
Given that you've only 100mm or so to retain, I reckon this can be best done by using a large-size kerb unit, one that will give you 100-200mm of upstand, as shown in this cross-section....
...this form of construction acts as a retainer for the sub-base, as well as forming the riser for your steps. Where the garden level rises against the main patio as you near the house on the right hand side, this kerb can be progressively buried pr even omitted completely, if you prefer.
That seems to be the simplest solution to me. :)
chrisevans
cool: This definitely resolves the problem
I wouldn't need the step-down where the garden rises to the level of the patio but on the arc it would also be a nice decorative feature. If I assume your cross-section drawing is to scale the concrete footing for both kerb edgings would need to be 200mm deep? Also do you know if it is possible to buy curved kerb edgings (coloured?), with a radius of 300cms?
Thanks again...
TonyMcC
That drawing is "to scale" and the concrete foundation needs to be around 100mm thick, with 100mm of haunching at the back
And the good news is that, although there are radial uniots available for making curved kerb lines, for one with a radius of 3m, you can get away with the standard units, which are significantly cheaper. You might want to mortar the joints: I think they look better when they're 'pointed' but some folk choose to leave them dry. Here's a an image of a 1.5m radius formed using standard kerb units (albeit in clay, rather than concrete, but the dimensions are exactly the same).....
...note how using a dark coloured mortar has emphasised the individual kerb elements, making them look smart and attractive. :)
However, here's the text of your original post....
chrisevans
As my garden is north facing I have decided to lay the main patio at the end of the garden with a smaller, matching patio adjacent to the house. The garden slopes away from the house and also from right to left
It wasn't until I set the patio levels and excavated did I realise how much the garden sloped from right to left
I now have a small problem. :(
The sub-base levels of the left-hand edge (arcs) of the patios do not have anything to butt up to. I have a choice: build two small brick or concrete retainers high enough for the 100mm sub-bases? Which is best? And what footings would be best for these walls as the ground is clay. How thick should these retainers be and if concrete what ratio of sand or ballast to cement
Thanks in anticipation...
TonyMcC
Is it not possible to soil over the extended sub-base(s) once the paving is in place? This would be the simplest option, but, depending on your actual plan, I can appreciate that it's not always possible.
If you have to use retainer structures, try and keep it a simple as possible. Is there any way a flag-on-edge could be used in place of a wall? That's a much easier construction, as well as being cheaper and faster to construct
However, if a wall is your only option, the height of the wall is the critical factor - for anything less than 450mm height, a simple double-skin wall of suitable bricks (Engineering brick are the best) laid on a 450x100mm foundation of C20 (or equivalent) concrete, with at least 150mm of frost cover, ought to do the job.
chrisevans
Tony,
I have sent you a plan of the main patio via email in AutoCad .DWG format which I created in MS Visio to give you a clearer idea of the problem I have
The void area between the excavation edge and the garden boundary I have filled with crush. But the more I look at this I don't think it will be strong enough to retain the DTP1 sub-base and may be prone to some movement long term
The proposed retainer would only need to be 100mm in height to 'retain' the sub-base. Would this still require a 450mm deep :confused: C20 footing
Thanks again....
TonyMcC
I've 'coloured-in' your drawing and reproduce part of it here...
...for the benefit of other readers, the garden slopes from right to left, which is why the step down is needed at the end of the main patio.
Given that you've only 100mm or so to retain, I reckon this can be best done by using a large-size kerb unit, one that will give you 100-200mm of upstand, as shown in this cross-section....
...this form of construction acts as a retainer for the sub-base, as well as forming the riser for your steps. Where the garden level rises against the main patio as you near the house on the right hand side, this kerb can be progressively buried pr even omitted completely, if you prefer.
That seems to be the simplest solution to me. :)
chrisevans
cool: This definitely resolves the problem
I wouldn't need the step-down where the garden rises to the level of the patio but on the arc it would also be a nice decorative feature. If I assume your cross-section drawing is to scale the concrete footing for both kerb edgings would need to be 200mm deep? Also do you know if it is possible to buy curved kerb edgings (coloured?), with a radius of 300cms?
Thanks again...
TonyMcC
That drawing is "to scale" and the concrete foundation needs to be around 100mm thick, with 100mm of haunching at the back
And the good news is that, although there are radial uniots available for making curved kerb lines, for one with a radius of 3m, you can get away with the standard units, which are significantly cheaper. You might want to mortar the joints: I think they look better when they're 'pointed' but some folk choose to leave them dry. Here's a an image of a 1.5m radius formed using standard kerb units (albeit in clay, rather than concrete, but the dimensions are exactly the same).....
...note how using a dark coloured mortar has emphasised the individual kerb elements, making them look smart and attractive. :)
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chrisevans
- Posts: 18
- Joined: Thu Aug 28, 2003 1:15 pm
- Location: Essex
Tony,
Picking up on your thread of last September:
Firstly please accept my sincere apologies for the inference that your excellent drawing wasn’t to scale ;)
I have some questions:
1. I would prefer to use only a single kerb construction as the edging to the patios and not use the step-down as shown in your cross section. Will this affect the rigidity of the structure?
2. When laying the kerb edgings is it best to do this in two stages? Say lay 100mm of concrete, wait for it to set then lay, profile and haunch the kerb edgings? Or all steps at the same time?
3. Assuming I mix the mortar to the correct specs will it be firm enough, particularly with the bed and haunch at the rear of the kerb edging at a depth of 200mm, to maintain its shape as in your drawing while wet without the need for shuttering?
4. I would like to use Marshall’s clay Kerbline bricks for kerb edging as per your cross section drawing, Marshall’s Chaplegate pavers for other edging where necessary and Marshall’s 56mm clay cobbles for the main surfaces. What should I expect to pay for these types of blocks? I will need approximately 15m2 of the cobbles. My local Marshalls stockists are Jewsons, Travis Perkins and a couple of independents.
5. I have decided on the Ashbourne Multi Red for the cobbles as this matches the existing house and surrounding brickwork but I’m not entirely sure yet of which colour to use for the edging – any advice would be appreciated. As I cannot find any examples locally if other readers have any suggestions it would be appreciated.
6. I intend to lay a narrow path (mowing strip?) between the two patios with 100mm wide clay pavers as edgings and clay cobbles as the main surface (4 cobbles wide). This will make the path approximately 45 – 46 cm wide. What depth of sub-base (on clay) and width of edge paver haunching would you suggest I use?
Apologies for so many questions!
Picking up on your thread of last September:
Firstly please accept my sincere apologies for the inference that your excellent drawing wasn’t to scale ;)
I have some questions:
1. I would prefer to use only a single kerb construction as the edging to the patios and not use the step-down as shown in your cross section. Will this affect the rigidity of the structure?
2. When laying the kerb edgings is it best to do this in two stages? Say lay 100mm of concrete, wait for it to set then lay, profile and haunch the kerb edgings? Or all steps at the same time?
3. Assuming I mix the mortar to the correct specs will it be firm enough, particularly with the bed and haunch at the rear of the kerb edging at a depth of 200mm, to maintain its shape as in your drawing while wet without the need for shuttering?
4. I would like to use Marshall’s clay Kerbline bricks for kerb edging as per your cross section drawing, Marshall’s Chaplegate pavers for other edging where necessary and Marshall’s 56mm clay cobbles for the main surfaces. What should I expect to pay for these types of blocks? I will need approximately 15m2 of the cobbles. My local Marshalls stockists are Jewsons, Travis Perkins and a couple of independents.
5. I have decided on the Ashbourne Multi Red for the cobbles as this matches the existing house and surrounding brickwork but I’m not entirely sure yet of which colour to use for the edging – any advice would be appreciated. As I cannot find any examples locally if other readers have any suggestions it would be appreciated.
6. I intend to lay a narrow path (mowing strip?) between the two patios with 100mm wide clay pavers as edgings and clay cobbles as the main surface (4 cobbles wide). This will make the path approximately 45 – 46 cm wide. What depth of sub-base (on clay) and width of edge paver haunching would you suggest I use?
Apologies for so many questions!
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84-1093879891
Q1 - I'm not sure just how using only a single step could compromise structural integrity. As long as the bedding and haunching are correct, there's no difference made by using only a single step.
Q2 - Lay the kerb units on fresh concrete. If you wait for the concrete to harden, how would you get the kerbs set to the required level?
Q3 - The amount of water you use in mixing the mortar detrmines its 'slump', which is a measure of wetness/sloppiness. As long as you don't overdo the water, then there is absolutely no need for shuttering or formwork.
Q4 - I can't tell you what to pay. Prices vary from merchant to merchant, and we in the trade tend to get keener prices than casual diyers. Also, the quantities bought will influence pricing. You should get 2 or 3 prices from different merchants in your area and see who offers the best price and service.
Q5 - on previous projects, and in my own garden, I've used a dark, chocolatey brown clay paver (used to be Rushmere Brown from Marshalls) as a contrasting edge course, but you might prefer a blue.
Q6 - lay the lot as a rigid pavement, by laying the pavers and the cobbles on 75-100mm of semi-dry concrete, rather than having a separate sub-base and bedding layer.
Q2 - Lay the kerb units on fresh concrete. If you wait for the concrete to harden, how would you get the kerbs set to the required level?
Q3 - The amount of water you use in mixing the mortar detrmines its 'slump', which is a measure of wetness/sloppiness. As long as you don't overdo the water, then there is absolutely no need for shuttering or formwork.
Q4 - I can't tell you what to pay. Prices vary from merchant to merchant, and we in the trade tend to get keener prices than casual diyers. Also, the quantities bought will influence pricing. You should get 2 or 3 prices from different merchants in your area and see who offers the best price and service.
Q5 - on previous projects, and in my own garden, I've used a dark, chocolatey brown clay paver (used to be Rushmere Brown from Marshalls) as a contrasting edge course, but you might prefer a blue.
Q6 - lay the lot as a rigid pavement, by laying the pavers and the cobbles on 75-100mm of semi-dry concrete, rather than having a separate sub-base and bedding layer.
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chrisevans
- Posts: 18
- Joined: Thu Aug 28, 2003 1:15 pm
- Location: Essex
Bear in mind you are dealing with a complete novice here (albeit ambitious)! ;)
I checked at my local Jewsons and the cobbles work out at approximately £30 per metre (10p per cobble) + VAT which was a nice surprise as I seem to remember one of the threads on this forum last year mentioning 16p per cobble!
Definitely agree with the Rushmere Brown (saw that at Jewsons also) - the red is bit too bright for my tastes.
Your answer to question 6 - do mean literally lay the pavers and cobbles on the semi-dry concrete or push them into the mix (if so how far into the mix)? ...and use kiln dried sand for the joints as well?
Thanks...
I checked at my local Jewsons and the cobbles work out at approximately £30 per metre (10p per cobble) + VAT which was a nice surprise as I seem to remember one of the threads on this forum last year mentioning 16p per cobble!
Definitely agree with the Rushmere Brown (saw that at Jewsons also) - the red is bit too bright for my tastes.
Your answer to question 6 - do mean literally lay the pavers and cobbles on the semi-dry concrete or push them into the mix (if so how far into the mix)? ...and use kiln dried sand for the joints as well?
Thanks...
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84-1093879891
Yes - just lay the blocks/cobbles directly onto a semi-dry mix, tapping them down to level with a rubber hammer. The edges will need to be haunched, but only lightly - if you use just 25mm of so of the semi-dry mix to retain the edge blocks, that should be ample for this sort of project.
Don't fret about pushing the blocks/cobbles into the bedding, that's not quite how it works. Some of the bedding will squeeze up into the joints, but it's minimal and of no real consequence. The key idea is to provide a firm bed for the paving, and then rely on sand jointing to lock everything together.
Don't fret about pushing the blocks/cobbles into the bedding, that's not quite how it works. Some of the bedding will squeeze up into the joints, but it's minimal and of no real consequence. The key idea is to provide a firm bed for the paving, and then rely on sand jointing to lock everything together.
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chrisevans
- Posts: 18
- Joined: Thu Aug 28, 2003 1:15 pm
- Location: Essex